JP2008089629A - Composite sound-absorbing material of inorganic fiber and organic fiber, and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an sound-absorbing material having sound absorption effect by forming a complex having a composite three-layer structure, by weaving organic fiber between inorganic fiber and inorganic fiber and driving needles from both sides of the organic fiber and organic fiber, and to provide a manufacturing method therefor. <P>SOLUTION: In the composite sound-absorbing material of inorganic fiber and organic fiber which has composite three-layer structure has a second layer sandwiched in between first and third layers, the first layer and the third layer comprise PET organic fiber layers, and the second layer is formed of an aluminum fiber layer. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a sound-absorbing material having a sound-absorbing effect, and more particularly, a composite material having a composite three-layer structure in which an inorganic fiber layer is sandwiched between organic fiber layers on both sides, and has a high-frequency range of 1000 to 4000 Hz. The present invention relates to a sound absorbing material having a high sound absorbing effect in the frequency band of.

Today, in the field of passenger cars, a cover is attached to the engine section. In this case, in a 1500 to 4000 cc class passenger car, a single layer organic fiber polyethylene terephthalate fiber sound absorbing material (hereinafter referred to as PET fiber body) is used for the engine cover as a material for absorbing engine sound.

In the field of architecture, various sound absorbing materials are used as interior materials for indoor and outdoor structures. In particular, sound absorbing materials are used for ceilings of music halls and theaters because of the need to improve the sound absorbing effect. Some of these outdoor soundproofing, sound absorbing, sound absorbing walls, indoor soundproofing, sound absorbing, sound absorbing walls, soundproofing, sound absorbing, sound absorbing ceiling materials, etc. are made of metallic porous materials, mainly bent flat or two-dimensionally. There is a deck plate type. Further, as the three-dimensional processed plate, there are those obtained by compression-molding a flame-retardant nonwoven fabric or a flame-retardant nonwoven fiber.

In addition, many inventions have been proposed as examples of soundproofing, sound absorbing and sound absorbing materials. For example, a sound-absorbing heat insulating material that is lightweight and thin but has excellent sound-absorbing properties in a low-frequency region, and is a nonwoven fabric having a basis weight of 10 to 70 g / m ² mainly composed of fibers with a fiber diameter of 1 to 25 μm A porous film layer made of a resin having a melting point of 120 ° C. or more and a short fiber nonwoven fabric having a fiber diameter of 7 to 50 μm, a basis weight of 50 to 200 g / m ² , and a thickness of 4 to 30 mm penetrate. A proposal has been made that allows the peak of the sound absorption coefficient to be set by combining and integrating with a plurality of fibers (see Patent Document 1).

JP 2006-47628 A

As described above, as represented by Patent Document 1, when summarized, the conventional sound-absorbing material has the following problems.

That is, the problem with the conventional sound absorbing material is that the sound absorbing performance of the engine cover made of organic fibers is insufficient for the application of a large engine of 2500 to 4000 cc in the case of an automobile, Development is required. For this purpose, it has been ideal to use inorganic fibers having a large specific gravity. However, it has been very difficult to combine organic fibers and inorganic fibers with conventional lamination techniques.

Therefore, the sound absorbing material of the present invention was made in order to solve the problems of such a conventional sound absorbing material. Aluminum fibers were selected as inorganic fibers, and after various trials and errors, organic fibers were used. This aluminum fiber is knitted from both sides of the thickness. An object of the present invention is to provide a sound-absorbing material having a sound-absorbing effect that is formed into a composite with a composite three-layer structure by driving needles from both sides of the organic fiber in this state.

Therefore, the present inventors paid attention to a method for producing a nonwoven fabric by a needle punch method. Therefore, when an idea was developed to create an inorganic fiber layer between the organic fibers on both sides and needle punching to entangle the adjacent fibers together, a sound absorbing material with a high sound absorption rate was obtained. Obtained knowledge. The sound absorbing material of the present invention and the manufacturing method knowledge of the sound absorbing material are embodied, and the invention of claim 1 has a composite three-layer structure in which the second layer is knitted between the first layer and the third layer. A sound absorbing material, wherein the first layer and the third layer are organic fiber layers, and the second layer is a sound absorbing material having a composite three-layer structure composed of inorganic fiber layers.

According to a second aspect of the invention, in addition to the above feature of the first aspect of the invention, the second inorganic fiber layer is a sound absorbing material made of aluminum fibers.

The invention of claim 3 is a sound absorbing material characterized in that, in addition to the above feature of the invention of claim 1, the basis weight is 1500 to 2500 g / m ² .

The invention of claim 4 is a method of manufacturing a sound absorbing material having a composite three-layer structure in which a second layer is knitted between the first layer and the third layer, and the outside of the first layer and the third layer. A method for producing a sound-absorbing material, in which a plurality of needle-like bodies are driven toward the second layer, whereby the fibers of the adjacent layers are entangled with each other.

According to a fifth aspect of the present invention, in addition to the above feature of the fourth aspect of the invention, the lengths of the plurality of needle-like bodies are different from each other, and the driving of the plurality of needle-like bodies is different. A method for producing a sound-absorbing material, characterized in that the pitch is 5 to 50 / cm ² .

Here, the “entanglement” in the present specification means that overlapping fibers are bonded while being intertwined. Specifically, in the process of repeatedly driving and pulling back a plurality of needles from the outside of the organic fiber layers on both sides toward the inner inorganic fiber layers sandwiched by the organic fiber layers on both sides in the thickness direction, It means that the inner inorganic fiber layer and the outer organic fiber layer are intertwined with each other because the fiber layer is caught by the barb of the needle-like body and returns.

It consists of a composite material with a three-layer structure in which an inorganic fiber layer is knitted between two organic fiber layers, and has a special effect as a sound absorbing material used in a luxury passenger car. A passenger car equipped with a large engine is unsatisfactory in the sound absorption coefficient of the PET fiber body, and the demand is not satisfied particularly in a frequency band in a high sound range. When the composite of the PET aluminum fiber of the present invention is used, it has been found that a sound absorbing effect is obtained particularly in a high frequency range of 1000 to 4000 Hz, and engine noise is efficiently absorbed.

Embodiments of the present invention will be specifically described below based on the embodiments of the present invention illustrated in the accompanying drawings.

First, Embodiment 1 of the present invention will be described with reference to FIGS. FIG. 1 is a manufacturing process flow chart according to an embodiment of the present invention. FIG. 2 is a conceptual diagram of the main manufacturing process. FIG. 3 is a perspective view of the completed sound absorbing material. FIG. 4 is a graph comparing the difference in sound absorption characteristics depending on the type of the sound absorbing material.

As shown in the manufacturing process of FIG. 1, a composite sound absorbing material is completed as a product in a product process 500 through a raw material process 100, a raw material adjustment process 200, a molding / finishing process 300, and then an assembly inspection process 400, and then an automobile manufacturer. Delivered to a building material manufacturer or a housing construction company. The products are distributed to an engine cover material 501 for automobiles, a sound absorbing material 502 for building materials, an air supply filter material 503, and the like. In the first raw material process 100, organic fibers 1 and 3 including natural fibers such as cotton and wool, and synthetic fibers such as PET, nylon, PP, PE, and acrylic, and inorganic fibers 2 made of aluminum or aluminum alloy are prepared. Next, in the raw material adjustment step 200, the blended mixed cotton 202 is processed through the processing of the repellent hair 201. Here, the organic fibers 1 and 3 and the inorganic fiber 2 are formed in a nonwoven fabric formed as a fiber accumulation layer called a fleece. Next, the process proceeds to the forming / finishing process 300, and the needle-like body 4 is moved from the outside of the organic fibers 1 and 3 on both sides in the thickness direction to the inorganic fibers 2 sandwiched in the knitting / enveloping process 301 by driving. Type in. Next, the process proceeds to a step of molding and cutting 303 for shortening the strip-shaped composite three-layer structure to the product size through the heat treatment 302. In this step of forming and cutting 303, dimensions are taken depending on the use of the sound absorbing material. The details of the process of braiding and enveloping 301 by driving and the process of heat treatment 302 will be described later. In the next assembly inspection step 400, a specification inspection 402 is performed for each type of product through a molding process 401. In this molding process 401, for example, a hollow process is performed in accordance with the shape of the engine cover material depending on the use of the sound absorbing material.

Next, specifications of the used organic fibers 1 and 3 and the inorganic fibers 2 made of aluminum or aluminum alloy will be described. The organic fiber 1 of the first layer and the organic fiber 3 of the third layer use PET fibers and have a length of 64 mm, but can be used in a range of 30 to 80 mm. The fiber thickness was 6 to 18 denier, and was divided into 3 groups for each wire diameter, and then into 3 groups each blended in a weight range of 15 to 45%, and these were mixed. Aluminum fibers are used as the second layer, and aluminum fibers having a specific gravity larger than that of organic fibers are 100 μm. This range can be used up to 80-1000μ. By appropriately selecting the wire diameter of the aluminum fiber or the thickness of the aluminum fiber layer, the basis weight of the sound absorbing material having a composite three-layer structure could be adjusted to a range of 1500 to 2500 g / m ² .

Although the first layer and the third layer have been described with the same material PET fiber, the first layer and the third layer may be made of different materials as long as they are organic fibers. Therefore, if the first layer is a PET fiber, the third layer may be another natural material such as cotton or hair, or a synthetic fiber such as nylon, PP, PE, or acrylic. The reverse is also possible.

Further, the main manufacturing process will be described with reference to the conceptual diagram of the manufacturing process shown in FIG. The figure shows a forming / finishing process 300 after the raw material adjusting process 200. In the raw material adjustment process 200, the mixed organic cotton fibers 1 and 3 are formed, and the inorganic fibers 2 are sandwiched between them. In this way, preparation is completed as a strip B1 having a composite three-layer structure. Further, in this step, a tool in which a plurality of needle-like bodies 4 are implanted into the needle board 5 from both outside of the upper and lower organic fibers 1 and 3 is set at a fixed position so as to be sandwiched from above and below the belt-like body B1. Next, the forming / finishing process 300 is started, and first, the process proceeds to the process of knitting / enveloping 301 by driving. Then, while moving the belt-like body in the traveling direction H, the operation of driving and returning the needle-like body 4 toward the inorganic fiber body 2 sandwiched from the outside of the upper and lower organic machine fibers 1 and 3 is repeated. . Next, the belt-like body B <b> 2 is moved in the direction of arrow H, and a heat treatment 302 is performed while passing through the tunnel-type heat treatment furnace 6. The heating conditions at this time are 170 ° C. in an air atmosphere. In this way, a composite three-layer composite body (hereinafter referred to as PET aluminum fiber body) in which aluminum fibers are knitted from both sides of the thickness with PET fibers is manufactured.

Details of the process of knitting / enveloping 301 by driving and the process of heat treatment 302 will be described. The tip of the needle-shaped body 4 made of steel subjected to quenching treatment has a protrusion called a barb. The wire diameter of the needle-like body 4 is No. 36, but the usable range is No. 25 to No. 40. The length of the needle-like body 4 is selected from those having a length of 3 to 4 inches, and a combination of these lengths is implanted in the needle board 5. The pitch of the needle-like body 4 was knitted / entangled 301 by driving under the condition of 8 pieces / cm ² , but can be freely selected within the range of 5-50 pieces / cm ² . The tip of the needle-like body 4 has projections called multi-stage barbs in the longitudinal direction of the needle, and the shape of the needle-like body 4 has two triangular needles each having a triangular cross section and opposite directions on three sides. Alternatively, each barb may have three oppositely pointed barbs on three sides of each triangle. While moving the belt-like body B2 in the traveling direction H, the operation of driving the needle-like body 4 toward the inorganic fiber body 2 sandwiched from the outside of the upper and lower organic machine fibers 1 and 3 and the operation of returning it are repeated. Through the above steps, as shown in FIG. 3, a sound absorbing material A having a composite three-layer structure in which an inorganic fiber layer 2 is knitted between A1 and A3 composed of organic fiber layers on both sides is completed as a composite material. Specifically, a composite having a composite three-layer structure (hereinafter referred to as PET aluminum fiber body) in which aluminum fibers are knitted in a sandwich shape from both sides of the thickness with PET fibers is manufactured.

Next, the operation of the sound absorbing material of the present invention will be described.

The entangling action in the process of knitting and enveloping 301 by driving will be described. The first action of the needle-like body 4 is to form a three-layer structure in which the upper and lower fibers are entangled and the adjacent fibers are entangled integrally. In other words, the needle-shaped body 4 is engraved at the tip of the needle-shaped body 4 and is sharpened in the opposite direction to the needle tip. Therefore, it is entangled with the upper organic fiber 1. The degree of entanglement between filaments changes by changing the number and shape of the barbs and the needle depth of reciprocation. In this way, the needle-like body 4 reciprocates up and down, thereby forming a composite material having a composite three-layer structure in which the filaments of the organic fiber 1 and the inorganic fiber 2 are intertwined. The same applies to the organic fiber 3 side. As described above, the length of the needle-like body 4 is selected from those having a length of 3 to 4 inches, and a combination of these lengths is implanted in the needle board 5. Here, the needle depth will be described. The acicular body 4 penetrates the organic fiber 1 from above, the next inorganic fiber 2 also penetrates, and further penetrates the organic fiber 3 and passes about 17 mm. This is the case where the longest needle-like body 4 is stabbed. In the case of the shortest needle-like body 4, the organic fiber 1 is penetrated, the next inorganic fiber 2 is penetrated, and the middle of the next organic fiber 3 is stopped. Thereafter, the needle-like body 4 returns. In the case where the needle-like body 4 is pierced from the organic fiber 3 side, the knitting / entanglement 301 step by driving is completed at the same needle depth. That is, the long, medium, and short needle-like bodies 4 implanted in the needle board 5 may penetrate the organic fiber 1, the next inorganic fiber 2, and the next organic fiber 3, or the organic fiber 1, The behavior of passing through the next inorganic fiber 2 and stopping in the middle of the next organic fiber 3 is repeated. The second function of the needle-like body 4 is to make a needle hole in the composite three-layer structure. If the pitch of the needle-like body 4 is selected and the number of needle holes is adjusted, a desired sound absorption rate can be obtained. . When the pitch number of the needle-like body 4 is increased, the number of penetrating needle holes is increased, so that sound is not absorbed and absorbed as the sound absorbing material, and the sound absorption rate is lowered. Therefore, the optimum number of pitches is selected according to the use of the sound absorbing material. The sound absorption rate can be adjusted according to the use of the sound absorbing material. The number of pitches can be changed within a range of 5 to 50 / cm ² . When the number of pitches exceeds 50 / cm ² , the entanglement effect between the fibers increases and the binding force of the composite three-layer structure increases, but the needle holes of the three-layer composite increase and sound is lost and absorbed. This is not preferable because the sound absorption rate decreases. On the other hand, when the number of pitches is less than 5 / cm ² , the entanglement effect between the fibers decreases and the binding force of the composite three-layer structure decreases, but the sound absorption rate improves. The number of needles may be selected in accordance with the use of the sound absorbing material in the range of 5 to 50 / cm ² .

Next, the operation of the heat treatment 302 will be described. Although the sample was heated at 170 ° C., the temperature of 120 to 180 ° C. melted the PET fibers of the first layer and the third layer to increase the degree of bonding with the aluminum fibers, and the fibers did not peel off.

The sound absorption characteristics of the composite three-layer structure manufactured as described above will be described. The measuring method of sound absorption characteristics is according to JISA1405. The results are shown in Table 1 in which differences in sound absorption characteristics depending on the type of sound absorbing material are compared. As a sample used for measuring the sound absorption characteristics, a PET fiber body having a single layer structure is selected as a conventional material for comparison. The sample of the present example is a PET aluminum fiber body having a composite three-layer structure. The specifications of the samples used for measurement are as follows. The PET fiber body has a thickness of 20 mm and a basis weight of 800 g / m ^2. One PET aluminum fiber body has a thickness of 20 mm and a basis weight of 2050 g / m ² . Furthermore, a measurement sample of two sizes is produced from these two types of fiber bodies. The A tube shown in the table is a large tube having a diameter of 99 mm, and the B tube is a small tube having a diameter of 29 mm. In this way, two-size measurement samples are prepared from two types of fiber bodies, and the sound absorption coefficient is measured for each frequency. The average orchid is the arithmetic average value of the measured values by tube A and tube B.

A graph of Table 1 is shown in FIG. The acoustic absorptance of the two types of fiber bodies was plotted as the arithmetic average value of the measured values by the A tube and the B tube. The horizontal axis indicates the frequency band in Hz, and the vertical axis indicates the sound absorption coefficient (%). As shown in the figure, in the frequency band in the high frequency range of 1000 to 4000 Hz, the conventional PET fiber body has a sound absorption rate of 20 to 65%, whereas the PET aluminum fiber composite of the present invention has 27 to 93%. Sound absorption coefficient is excellent.

A passenger car equipped with a large engine is unsatisfactory in the sound absorption coefficient of a conventional single-layer PET fiber body, and the requirement is not satisfied particularly in a high frequency range of 1000 to 4000 Hz. When the PET aluminum fiber body having the composite three-layer structure of this embodiment is used, the engine noise is absorbed particularly in a high frequency range of 1000 to 4000 Hz, so that the ride comfort is good.

Since the specific gravity of the aluminum fiber of the second layer is larger than that of the organic fiber, the basis weight can be increased in the range of 1500 to 2500 g / m ² by changing the wire diameter to 80 to 1000 μm. Therefore, the sound absorption rate can be increased by this. In addition, since aluminum fiber has high thermal conductivity, when it is used as a sound absorbing material for an automobile engine cover, the heat of the engine is not stored but is easily dissipated. Up to now, passenger cars equipped with a large engine of 2500 to 4000 cc have been required to have a material with higher sound-absorbing performance. To do.

The use of the present invention may be used for floors and side walls of automobile interiors in addition to engine sound absorbing materials for automobile applications. Moreover, you may use for the use to the sound absorption material stuck on the inside of a building, the outer wall of a house, a roof, and other air supply filters. Also, it is related to sound absorbing plates used for indoor ceilings or indoor exterior walls, especially indoors such as soundproofing, sound absorbing, sound absorbing walls attached to outdoor structures, public halls, music halls, theaters, gymnasiums, indoor swimming pools, etc. The present invention relates to a sound-absorbing material that is optimal as a sound-proofing, sound-absorbing, sound-absorbing wall, and ceiling member in a building. Since the sound absorbing material of the present invention is porous, application development to an air supply filter material is also conceivable.

It is a manufacturing process systematic diagram concerning the Example of this invention. It is a conceptual diagram of a main manufacturing process same as the above. It is a perspective view of the completed sound-absorbing material. It is a graph which compared the difference of the sound absorption characteristic by the kind of sound-absorbing material same as the above. It shows a prior art example and is a perspective view of a sound absorbing material.

Explanation of symbols

A Sound absorbing material
A1 Organic fiber layer A2 Inorganic fiber layer A3 Organic fiber layer B1, B2 Strip H H Direction V Driving direction 1, 3 Organic fiber 2 Inorganic fiber 4 Needle body 5 Needle 6 Heat treatment furnace 100 Raw material process 200 Raw material adjustment process 201 Anti Hair 202 blended cotton
300 Forming and Finishing Process 301 Knitting / Entangling by Driving 302 Heat Treatment 303 Molding Cutting 400 Assembly Inspection Process 401 Molding Process 402 Inspection 500 Product Process 501 Engine Cover Material 502 Sound Absorbing Material 503 Air Supply Filter Material

Claims (5)

A sound absorbing material having a composite three-layer structure in which a second layer is sandwiched between a first layer and a third layer,
The first layer and the third layer are composed of organic fiber layers,
The second layer is a sound absorbing material having a composite three-layer structure composed of inorganic fiber layers. The sound absorbing material according to claim 1, wherein the inorganic fiber layer of the second layer is made of aluminum fibers. Sound absorbing material according to claim 1, wherein the basis weight is characterized by a 1500~2500g / m ^2. A method for producing a sound absorbing material having a composite three-layer structure in which a second layer is sandwiched between a first layer and a third layer,
A method for producing a sound-absorbing material, wherein a plurality of needle-like bodies are driven from the outside of the first layer and the third layer toward the second layer, whereby the fibers of the adjacent layers are entangled with each other . The lengths of the plurality of needles are large, medium, and small different,
And The method according to claim 4 sound absorbing material, wherein the to implantation pitch of the plurality of needle members to 5-50 present / cm ^2.

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