JP2009209542A - Composite fiber board and box-shaped structure using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a building material which enables the damping of daily life noises in a low-frequency band, hardly capable of being realized by a conventional technology. <P>SOLUTION: A composite fiber board 10 has a three-layered structure which is composed of a pair of outer layers 12 with high surface density and an intermediate layer 14 with a low surface density; the intermediate layer 14 is composed of discontinuous wood fibers and plastic fibers, which are intertwined with one another; and the outer layers are composed of a thermoplastic resin. A large number of holes 16 passing through the composite fiber board 10 are provided, and a cut surface of the discontinuous wood fiber constituting the intermediate layer 14 is exposed on the inner peripheral surface of the hole 16. The composite fiber board 10 and an unperforated fiber board are used; and a box-shaped structure sealed by thermally welding joint surfaces to each other is obtained, and internally filled with a fibrous low-density filler, so as to be utilized for a soundproof floor, a partition wall, etc. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a composite fiber board and a box-type structure using the same, and more particularly to a sound absorbing and insulating structure that can be used as a building material for an apartment house or a wooden house.

  There are many sound absorbing and perforated panels in which a large number of holes are formed in housing materials such as veneer plywood and plasterboard, and sound absorbing and insulating structures and the like that are integrated with the panels. However, conventional perforated panels or sound-absorbing sound insulation structures cannot obtain sound insulation or attenuation effects in the low frequency region when used as apartment housing wall materials or flooring materials.

  For example, Patent Document 1 (Utility Model Registration No. 3001759) proposes enhancing the sound absorption effect by using a large number of perforated plates for the partition plate in order to absorb noise generated in the construction site.

  In Patent Document 2 (Japanese Patent Application Laid-Open No. 7-217091), the damping effect is enhanced by providing a cylindrical cavity continuous to the opening in a trumpet shape on the back surface provided with a number of perforated plates. Has been proposed. However, there are drawbacks such as requiring more attenuation distance than necessary.

Among the complaints regarding the improvement of the housing environment, noise problems account for about 86%. To build a comfortable living environment, it is desirable to provide housing construction materials that are lightweight, inexpensive, and have a highly functional damping effect. It is.
Utility Model Registration No. 3001759 Japanese Patent Laid-Open No. 7-217017

  Most troubles with housing noise occur at midnight. It has been confirmed that sound is transmitted by vibration and that the vibration energy changes depending on the mass, Young's modulus, temperature, etc. of the substance. For example, in the living environment, the sound during the day is not much of a concern, but it is often the case that the sound from the same source can be heard at midnight. In warm daytime, as the temperature increases, the activity of air particles in the air becomes active, and the air-borne sound promotes active vibration, so that vibration energy is efficiently converted into heat energy. As a result, the sound attenuation effect can be enhanced. On the other hand, as the outside air temperature becomes lower at night, the activity of air particles stagnate and the air-borne sound becomes easier to pass. For this reason, phenomena such as being able to hear far away sounds well at midnight.

  2. Description of the Related Art Conventionally, as a method for enhancing the sound attenuation effect in a building material, the sound absorption / sound insulation effect is enhanced by adjusting the density / distance of the building material. For example, there are many soundproof panels in which density is changed by bonding veneer plywood and lead plate with large specific gravity, and hollow structures using distance attenuation law by sandwiching glass wool between veneer plywood and veneer plywood, etc. . At present, the most commonly used soundproofing measure is a method of increasing the sound transmission attenuation effect by increasing the thickness of the concrete slab. As a loan standard for apartment houses, etc. in the Housing Finance Corporation, it is stipulated that the concrete slab thickness for upper and lower floors is 20 cm or more and has sound insulation performance (L-45 or more).

  By utilizing a conventional technique, it is easy to secure a higher sound insulation effect by securing a certain amount of distance attenuation interval with high density. However, the construction cost related to the building structure is greatly different between concrete with a large specific gravity (specific gravity 2.3) and wood with a low specific gravity (specific gravity 0.57). With excessive competition in the residential environment, it is desired to provide inexpensive and high-performance housing. If a lightweight soundproofing material that has a specific gravity comparable to that of wood and has a sound insulation effect higher than that of a concrete slab is realized, it is possible to greatly reduce the construction cost related to the building structure body.

  Furthermore, based on many experiments such as noise problems, it has been confirmed that the daily noise at night is felt as the most annoying sound in the low frequency range below 250 Hz. As a result, it was newly confirmed that footsteps that fall below the 250 Hz range penetrated through concrete slabs with a high specific gravity and caused daily noise under conditions where the outside air temperature dropped.

  The present invention is intended to provide a building material useful for attenuating daily noise in an apartment house or a wooden house. More specifically, an object of the present invention is to provide a lightweight and inexpensive soundproof material that exhibits a damping effect even in a low frequency region below the 250 Hz band, thereby reducing the overall construction cost. Is.

  The composite fiberboard of the present invention comprises an intermediate layer and a pair of outer layers sandwiching the intermediate layer, the intermediate layer is composed of wood pieces and plastic fibers entangled with each other, the outer layer is formed of a thermoplastic resin, and the intermediate layer A plurality of through-holes are provided by drilling in a state where the outer layer and the layer are overlapped. A wooden piece of road pipe or temporary road pipe is exposed on the inner peripheral surface of the through hole, absorbing vibration energy and enhancing the sound absorption effect. Further, the outer layer is made of a thermoplastic resin having a large specific gravity, and the wood layer is mixed with wood pieces to reduce the density. Thus, this composite fiber board has a three-layer structure, and the outer layer and the intermediate layer have different specific gravities. This provides sound insulation and sound absorption.

  The box-type structure of the present invention is a box-type structure in which a plurality of composite fiber boards are used and the joint surfaces are sealed by heat welding to each other, and the composite fiber board sandwiches the intermediate layer and the intermediate layer. The outer layer is composed of wood short fibers and plastic fibers intertwined with each other, the outer layer is composed of a thermoplastic resin, and the composite fiber board constituting the surface is formed by superimposing the intermediate layer and the outer layer. In this state, a number of through holes are provided by drilling. A box-type sound absorbing and insulating structure in which the composite fiberboards are heat-sealed and sealed can be obtained.

  The box-type structure may be filled with a low-density fibrous material. As such a fibrous material, for example, one or any combination of glass wool, rock wool, and wood fiber can be employed.

  By providing a flange for attachment to the box-type structure, it is possible to attach it directly to a vibration-damping rubber mat or a column.

  According to the present invention, it is possible to solve the problem of providing a lightweight and inexpensive soundproofing material that exhibits a damping effect even in a low-frequency region below the 250 Hz band.

In the living environment, sound hits various objects and is sucked or bounced. The state in which sound is transmitted through the air is called air-propagating sound, and the sound transmitted through an object is called individual-propagating sound, both of which are transmitted by vibration energy. In order to solve the problem of daily noise, the present invention has improved the absorption effect of vibration energy caused by collision of objects and pursued the absorption and sound insulation effect.

  It has been confirmed that the absorption efficiency of vibration energy varies greatly depending on environmental changes such as the mass, Young's modulus, and temperature of the object. Wood has a large number of fiber pipes (road pipes, temporary road pipes), so that it can appropriately absorb the air-borne sound, but the sound insulation is not high. Since wood releases the vibration energy once absorbed to the outside along the fiber tube, it is considered that a certain amount of sound absorption cannot be obtained from the wood. In contrast, thermoplastic plastics that are easily plastically deformed are excellent in viscoelasticity and have a low Young's modulus, and therefore have a high vibration energy absorption effect.

  Sound insulation varies greatly depending on the surface hardness and surface roughness of the material. If a sound insulating wall is constructed of glass, iron plate, etc., it has been confirmed that the indoor space leads to the occurrence of an echo phenomenon.

  Therefore, in order to construct a comfortable living environment, it is necessary to prepare various conditions such as surface hardness, surface roughness, mass, and Young's modulus. From the viewpoint of soundproofing measures, it is considered that the provision of moderate vibration energy absorption efficiency is the most necessary condition for creating a comfortable living environment.

  In order to satisfy the above various conditions, a composite fiber board 10 as shown in FIG. 1 is employed. The composite fiberboard 10 has a three-layer structure including a pair of outer layers 12 and an intermediate layer 14 sandwiched between the outer layers 12. The intermediate layer 14 is composed of wood fibers and plastic fibers that are intertwined with each other. After the wood fibers and the plastic fibers are uniformly stirred and mixed, they are pressed and hardened by heat and pressure to obtain a predetermined mass, Young's modulus, surface hardness, and surface. This is a web-like fiberboard having roughness, physical strength, and the like. The outer layer 12 is made of a thermoplastic resin. That is, in order to enhance the sound insulation effect, the surface of the intermediate layer 14 is covered with the outer layer 12 made of a thermoplastic plastic, and a surface layer having a predetermined surface hardness, surface roughness and the like is constructed. The composite fiberboard 10 can exhibit high sound insulation by having a uniform surface hardness and surface roughness.

  A number of through holes 16 are provided by drilling in a state where the outer layer 12 and the intermediate layer 14 are overlapped. Thereby, the composite fiber board 10 can be made into a sound absorption and insulation board having a high sound absorption effect. In other words, the composite fiber board 10 whose surface is covered with thermoplastic and numerous perforations are formed is configured as a sound absorbing and insulating board having both sound insulating characteristics and sound absorbing characteristics.

  The composite fiber board 10 is usually configured as a thin plate of about 4 mm to 30 mm. A plurality of composite fiber boards 10 made of such thin plates are prepared. As a specific example, as shown in FIGS. 2 and 3, there are a front panel 22, a back panel 24, and a side panel 26 interposed between the front panel 22 and the back panel 24. The surface panel 22 is provided with a large number of through holes 16 to form a perforated plate, that is, the above-described composite fiber plate 10 is used. The back panel 24 and the side panel 26 are made of holes-free plates without providing through holes. The box-type structure 20 is obtained using these. Then, the composite fiberboards are heat-welded at the joint surfaces so that sound leakage does not occur, thereby obtaining a sound absorption / insulation box type structure composed of composite fiberboards whose surfaces are covered with thermoplastic.

2A shows an example in which the box-type structure 20 is used for a soundproof floor, FIG. 2B is an enlarged view of the box-type structure 20 portion in FIG. 2A, and FIG. ) Is an enlarged view of the through-hole 16 portion of FIG.
3A shows an example in which the box-shaped structure 20 is used as a partition wall, FIG. 3B is an enlarged view of the box-shaped structure 20 portion in FIG. 3A, and FIG. ) Is an enlarged view of the through-hole 16 portion of FIG.

  In the box-type structure 20, the front panel 22 includes a large number of sound absorbing holes 16, and the back panel 24 and the side panel 26 are sealed box-type structures formed by plates without holes. Only the front panel 22 has a large number of sound absorbing holes. It is released by the hole 16. A filler 28 in which a certain amount of a material having a small specific gravity, such as glass wool, non-woven fabric, or foamed polystyrene, is mixed in a certain amount in one type or two or more in any combination is filled in the box-shaped structure 20, and the bonded surfaces of the composite fiberboards Can be made into a box-shaped structure 20 having both a high sound absorption effect and airtightness.

  The filler 28 sealed inside the box-shaped structure 20 is a low-density felt-like material that uniformly stirs different materials in accordance with the required low frequency band region, etc., based on the density, material, blending ratio, etc. It is desirable to insert it into the box-type structure after being pressed. In this case, a higher sound absorption effect can be expected by mixing 10% or more of the wood fiber.

By applying a number of perforations to the surface panel 22 (composite fiber board 10) of the box-shaped structure 20, the fiber tubes (road tubes, temporary road tubes) of wood fibers are exposed on the inner peripheral surface of each hole 16. . Thereby, high sound absorption efficiency can be expected. As is well known, since wood has fine fiber tubes, it has a very high effect of absorbing vibration energy such as air-borne sound. In the process of drilling, the wood fiber constituting the composite fiber board 10 is cut, and the cut surface is exposed to the inner peripheral surface 18 (FIG. 1) of the hole 16. Since the inner peripheral surface 18 of the hole 16 is orthogonal to the incident sound source, the vibration energy absorbing surface can be secured by exposing the cut surface of the fine fiber tube to the hole.

If the hole 16 having a diameter of 6 mm is provided in the composite fiber board 10 having a plate pressure of 12 mm, the area of the hole 16 is only 28.26 cm ² , but the surface area of the inner peripheral surface 18 of the hole 16 is 226.08 cm ^2. It becomes. The sound source collides as incident sound in a form orthogonal to the surface of the composite fiber board 10. The cut surfaces of many wood fiber fiber tubes are exposed on the inner peripheral surface 18 of the hole 16 having a surface area about 8 times the area of the hole 16, so that orthogonal vibration energy is efficiently absorbed.

  Conventionally, there existed a perforated sound absorbing plate in which a large number of perforations were made in veneer plywood or the like. However, the conventional perforated sound-absorbing plate is limited to a thin peeled bark laminated with an adhesive or the like, and a continuous wood fiber tube is present without being divided in the middle. The continuous wood fiber tube has a result of releasing incident vibration energy as it is to the outside of the plate, and has not achieved a sufficient sound absorbing effect as an indoor environment. In the experiment, about 25% of the absorbed sound source was released again into the room.

In this invention, it is comprised as a short fiber or a piece of wood by performing a defibration process etc. to wood. All pieces of wood or wood fibers exposed on the inner peripheral surface of the hole formed by the perforating process of the surface layer are short fibers. Therefore, the cut surface of the wood fiber tube is exposed on the inner peripheral surface 18 of the hole 16 and efficiently absorbs and propagates the incident vibration energy, but is consumed as thermal energy with the end of the short fiber. In contrast to the continuous wood fiber tube, the wood fiber tube of short fibers does not necessarily leak sound to the outside because the propagation destination of vibration energy always ends.

The sound source collides with the surface layer of the composite fiber board as an incident wave. By providing this surface layer surface, which is a coating layer made of thermoplastic, the composite fiberboard has a certain hardness. The sound source that has collided with the surface layer of the composite fiberboard is partly reflected as a reflected wave and partly absorbed by the wood fiber tube exposed on the inner peripheral surface of the hole in the surface layer. The wood fiber tube exposed on the inner peripheral surface of the hole can efficiently absorb vibration energy with a sudden change in hole diameter, and can convert much vibration energy into heat energy.

  The wood fiber is finely pulverized or defibrated in advance, and cut to about 5 mm to 100 mm. In the wood fiber cut short, fiber pipes, such as a road pipe and a temporary road pipe, are also cut short, and are not continuous but cut into pieces like a veneer plywood. Although the vibration energy absorbed inside the fiber tube is transmitted through the fiber tube, the end of the fiber tube is immediately cut off, so it is urged to be converted into heat energy until it is transmitted to the thermoplastic. High damping effect can be expected.

Many holes provided in the surface layer of the composite fiber board exhibit a high sound absorption effect. Thermoplastic fibers with constant viscoelasticity and Young's modulus facilitate conversion to thermal energy when vibrational energy is transmitted. While the Young's modulus of wood is 30-50 N / mm ² , the thermoplastic has a Young's modulus of about 2 N / mm ² and has viscoelasticity. In this way, thermoplastic plastics are rich in viscoelasticity and have a small Young's modulus compared to wood. A material with a low Young's modulus is easily plastically deformed and has high energy absorption efficiency.

Since the wood fiber and the thermoplastic fiber are intertwined and integrated with each other, vibration energy transmitted between adjacent fibers can easily be converted into heat energy. Since each fiber is cut short, the vibration energy transmitted through the short cut fiber is interrupted each time. The fiber cut shortly transmits the vibration energy to the adjacent fibers while repeatedly interrupting the transmission of the vibration energy in this way. Vibration energy is consumed as thermal energy each time. Furthermore, since the surface layer of the composite fiber board is made of a melted or welded plastic, vibration energy once absorbed is not released to the outside.

There are many sound absorbing holes on the surface of the composite fiberboard. The sound source collides with the surface of the composite fiber board and is absorbed by the wood fiber tube exposed on the inner peripheral surfaces of many holes. The sound source that has passed without being absorbed by the wood fiber tube collides with a felt-like fiber mixture present inside the composite fiber structure. The vibration energy that collides with the fiber mixture generates frictional energy and is attenuated and consumed. The composite fiber structure is kept in a sealed state by thermally welding the bonding surfaces of the fiber plates so that sound leakage does not occur. Therefore, the sound source incident from a large number of holes enters the sealed composite fiber structure, and then repeatedly diffuses and rubs and attenuates vibration energy each time it collides with the felt-like fiber mixture. Results.

Thus, the composite fiber structure can be expected to have a light weight and high sound absorption and insulation effect. The sound absorbing and insulating structure using a composite material can be expected to have a light absorbing and insulating effect that is not as light as conventional products. A comparison experiment was conducted with concrete slabs used as flooring for apartments and apartment buildings. The results are shown in FIG. If a 92 m ² building floor is constructed, the sound-absorbing and sound-insulating structure using composite fibers exhibits a 36 dB attenuation effect against midnight noise (125 Hz) that cannot be attenuated with a concrete slab structure. Achieved 7,820 kg reduction of the building body. The construction cost reduction effect due to the weight reduction has a great effect on the cost reduction of the construction cost as well as the improvement of vibration resistance.

It is sectional drawing which shows the Example of a composite fiber board. (A) is an elevational sectional view of a soundproof floor showing an embodiment of a box structure, (B) is a partially enlarged view of FIG. 2 (A), and (C) is a partially enlarged view of FIG. 2 (B). . (A) is the plane sectional view of the partition wall which shows another example of a box type structure, (B) is the elements on larger scale of Drawing 3 (A), and (C) is the elements on larger scale of Drawing 3 (B). is there. It is a table | surface which shows a contrast test result with a concrete slab.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Composite fiber board 12 Intermediate | middle layer 14 Outer layer 16 Through-hole 18 Inner peripheral surface 20 Box-type structure 22 Front surface panel 24 Back surface panel 26 Side surface panel 28 Filler

Claims (5)

  It consists of an intermediate layer and a pair of outer layers sandwiching the intermediate layer, the intermediate layer is composed of wood short fibers and plastic fibers entangled with each other, the outer layer is made of a thermoplastic resin, and the intermediate layer and the outer layer are overlapped A composite fiber board in which a number of through holes are provided by drilling in a state of being cut.   A box-type structure in which a plurality of composite fiber boards are used and the bonding surfaces are heat-sealed to each other and hermetically sealed, the composite fiber board includes an intermediate layer and a pair of outer layers sandwiching the intermediate layer, Composed of short wood fibers and plastic fibers that are intertwined with each other, the outer layer is made of a thermoplastic resin, and the composite fiber board constituting the surface is subjected to a punching process in a state where the intermediate layer and the outer layer are overlapped. A box-shaped structure provided with through holes.   The box-type structure according to claim 2, wherein a low-density fibrous material is filled therein.   The box-type structure according to claim 3, wherein the fibrous substance is made of one or any combination of glass wool, rock wool, and wood fiber.   The box-type structure according to claim 2, 3 or 4, further comprising a mounting flange.

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