JP2004232162A - Felt sound absorbing material having multiple density construction - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sound absorbing material formable to a desired three-dimensional form by thermal forming, integrating the whole components by omitting the surface skin and advantageously usable as a dashboard insulator, floor insulator and roof insulator of automobile, electrical train and aircraft. <P>SOLUTION: The felt sound absorbing material having a multiple density construction is composed of an upper mat densified by the needle punching of the front side and the back side and leaving the intermediate part as a wrapped state and a lower mat having relatively large thickness and having an intermediate density. Both mats are integrated together by hot-pressing at a prescribed temperature. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a felt sound-absorbing material that is entirely integrated without a skin, and particularly relates to a felt sound-absorbing material having a multi-density configuration suitable for dashboard insulators, floor insulators, and roof insulators in automobiles, trains, aircrafts, and the like.
[0002]
[Prior art]
Automobiles and trains generate noise while traveling, which has a serious adverse effect on the environment inside the vehicle, and also causes noise pollution to residents along roads and roads. In particular, noise sources such as an automobile engine or a train motor are not sufficiently sound-insulated and sound-proof if they are entirely surrounded by a sound-insulating material such as a damping steel plate or a sound-insulating plate. For this reason, in some automobiles and trains, polyurethane foam resin is attached to the back surface of a dashboard or the like in order to enhance the sound insulation and soundproofing effect of the sound absorbing material.
A foamed resin such as polyurethane has excellent performance as a cushioning material, and can be reinforced with glass fiber or the like when a structure is required to have a high strength. Heat resistance is a problem, and the strength is remarkably reduced in a high-temperature atmosphere, and the sound absorption and sound insulation are insufficient. For this reason, the sound absorbing material made of polyurethane resin is not suitable for dashboard insulators, floor insulators, and roof insulators of automobiles and the like, and if chemical treatment for improving heat resistance is added, the production cost becomes extremely high.
[0004]
[Problems to be solved by the invention]
As a sound absorbing material for automobiles, a polyester fiber felt material having relatively high sound absorbing property and heat resistance is often used for dashboard insulators and the like. For example, as in JP-A-2000-202933, a skin such as PVC, EVA, or bitumen is adhered to the surface of a felt material made of polyester fiber. This type of sound absorbing material is less likely to lose its strength in a high-temperature atmosphere than a polyurethane resin, and has excellent mechanical properties and heat resistance in a severe use environment such as a dashboard insulator.
[0005] A fiber mat material having a skin becomes heavier due to the presence of the skin, and the mass use thereof adversely affects the overall weight of the dashboard itself, which is contrary to the ultimate purpose of reducing the weight and speed of an automobile. This skin complicates the manufacturing process of the sound-absorbing material, and requires peeling and removal when recycling the automobile parts for environmental protection, which increases the recycling cost. Further, even if a skin having a sound insulating effect is present, the fiber mat material still has insufficient sound absorbing properties, and there is an urgent need to further improve sound absorbing and sound insulating properties.
SUMMARY OF THE INVENTION The present invention has been proposed to solve the above-mentioned problems relating to a conventional sound absorbing material having a skin, and has been proposed for use in automobiles, trains, aircrafts, etc., which have further improved sound absorbing performance and weight reduction. It is an object of the present invention to provide a felt sound absorbing material having a configuration. Another object of the present invention is to provide a felt sound-absorbing material which has improved sound absorbing properties especially in a low-frequency range and which is simple in manufacturing process and easy to recycle. Another object of the present invention is to provide a dashboard insulator, a floor insulator, and a roof insulator having excellent moldability and improved sound absorbing performance.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the felt sound-absorbing material according to the present invention can be formed into a desired three-dimensional shape by heat molding, the front side and the back side are densified by needle punching, and the middle part remains wrapped. It consists of an upper mat and a lower mat that is relatively thick and of medium density. In this felt sound absorbing material, both mats are integrated by heating and pressing at a predetermined temperature.
In the felt sound absorbing material of the present invention, the upper mat has a thickness of 1.0 to 3.0 mm and a density of 0.050 to 0.400 g / cm. ³ A front side portion and a back side portion having a thickness of 3.0 to 10 mm and a density of 0.010 to 0.100 g / cm ³ And an intermediate portion that is In comparison, the front side and the back side are determined to have a high density and the middle part has a low density. The lower mat has a thickness of 10 to 35 mm and a density of 0.014 to 0.150 g / cm. ³ And relatively medium density.
In the felt sound-absorbing material of the present invention, if an intermediate mat is arranged between the upper mat and the lower mat, the upper mat and the intermediate mat are combined so that the low-density layer is substantially two high-density layers. What is necessary is just to comprise so that it may be located between. In this felt-absorbing material, the upper, middle and lower mats are integrated by heating and pressing.
On the other hand, the felt sound absorbing material of the present invention has a low melting point of 50 to 90% by weight of at least two kinds of ordinary fibers having different deniers in the denier range of 0.1 to 10 denier and 0.5 to 15 denier. And an upper mat laminated with a wrap obtained by blending 10 to 50% by weight of heat-fusible fibers with at least two kinds of ordinary fibers having different fineness in a fineness range of 0.1 to 10 denier. And a lower mat on which a wrap obtained by mixing 10 to 40% by weight of low melting heat-fusible fibers having a fineness of 0.5 to 10 denier is laminated. In this felt sound absorbing material, the entire upper and lower mats are integrated by heating and pressing at a predetermined temperature. Preferably, the upper mat has a thickness of 5 to 15 mm, the lower mat has a thickness of 10 to 35 mm, an overall thickness of 15 to 40 mm, and the upper and lower mats include hollow spiral shaped fibers.
In the dashboard insulator of the present invention, the whole thickness of the felt sound absorbing material is 15 to 40 mm, and is formed by press molding and then adhered to the back side of the dashboard. In the floor insulator of the present invention, the entire thickness of the felt sound-absorbing material is 15 to 40 mm, and it is press-formed after being bonded to the lower side of the floor carpet material. In the roof insulator of the present invention, the heat-fusible fibers contained in the upper and lower mats of the felt sound-absorbing material have a melting point of 100 ° C. or more or are of a crystallized type, and have an overall thickness of 15 to 40 mm. Press forming after bonding.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
As shown in FIG. 1, the felt sound absorbing material 1 according to the present invention densifies the front side portion 6 and the back side portion 7 of the upper mat 2 and the middle portion 8 remains wrapped, while the lower mat 10 Is relatively medium density. In the sound absorbing material 1, the front side portion 6 and the back side portion 7 of the upper mat 2 have a density of 0.050 to 0.400 g / cm. ³ The intermediate part 8 has a density of 0.010 to 0.100 g / cm. ³ The lower mat 10 has a density of 0.014 to 0.150 g / cm. ³ It is preferable that the ratio is within the above range, and the sound absorbing material 1, the sound insulating property, and the soundproofing property of the sound absorbing material 1 can be further enhanced. The middle portion 8 of the upper mat 2 remains wrapped and generally corresponds to a low density layer. In the sound absorbing material 1 of the present invention, since the level of the fiber density in a part or the whole thereof is a relative evaluation, the density of the low density layer or the middle density layer of the sound absorbing material 1 is higher than that of another sound absorbing material. May be higher.
The felt sound absorbing material 1 has a total thickness of 15 to 65 mm, and preferably has a thickness of 15 to 40 mm in order to further reduce the weight. In the felt sound absorbing material 1, the upper mat 2 has a thickness of 5 to 15 mm and the lower mat 10 has a thickness of 10 to 35 mm, and the front side 6 and the back side 7 of the upper mat have a thickness of 1.0 to 3.0 mm. It is preferable to set the thickness of the intermediate portion 8 to 3.0 to 10 mm in order to enhance the sound absorbing performance of the sound absorbing material 1. If desired, an intermediate mat 36 may be interposed between the upper mat 2 and the lower mat 10, as illustrated in FIGS.
The intermediate mat 36 (FIG. 7) is arranged between the upper mat 2 and the lower mat 10 to further enhance the sound absorbing performance of the sound absorbing material, and has, for example, the same or similar fiber structure as the upper mat 2. The thickness may be 5 to 15 mm as in the case of the upper mat 2. Like the upper mat, the intermediate mat 36 may have the high-density layer 38 (FIG. 7) formed on the front side and the back side, or may be formed only on one of the front side and the back side. Intermediate mat 36, together with upper mat 2, is configured such that low density layer 40 (FIG. 7) is located substantially between the two high density layers.
In the felt sound absorbing material 1, the fineness and type of the constituent fibers of the upper mat 2 and the lower mat 10 usually differ. The upper mat 2 has at least two kinds of normal fibers having different deniers in a denier range of 0.1 to 10 deniers, 50 to 90% by weight, and heat-fusible fibers having a denier of 0.5 to 15 deniers, 10 to 50% by weight. It is preferable to laminate wraps obtained by blending the two. Further, the lower mat 10 has at least two types of normal fibers having a fineness of 60 to 90% by weight in the fineness range of 0.1 to 10 denier, and heat-fusible fibers 10 to 40 denier having a fineness of 0.5 to 10 denier. It is preferable to laminate wraps obtained by blending the wrap with a weight%. In the mats 2 and 10, when the content of the ordinary fibers, which are synthetic or natural fibers, exceeds the above-mentioned content range, the whole may be too hard or may not be able to maintain the shape, which may hinder the subsequent steps.
Although the above-mentioned ordinary fibers usually use fibers of 3 to 6 deniers, the sound absorption can be increased by mixing finer denier fibers. Examples of the ordinary fiber include synthetic fibers such as polyester, polypropylene, acrylic, nylon, and aromatic polyamide; natural fibers such as wool and cotton; chemical fibers such as rayon and acetate; and fibers mixed with each other. It is preferable to use polyester fibers that can be easily adjusted. As these constituent fibers, anti-hair (recovered and regenerated cotton) may be partially used.
The above-mentioned heat-fusible fiber usually has a melting point of about 20 ° C. or less with respect to the fiber, and usually has a melting point of 90 to 170 ° C., such as polyethylene, polypropylene, low-melting polyester, and low-melting fiber. The melting point is polyamide or a mixed fiber thereof. The heat fusible fiber may be a copolymer of low melting point polypropylene or polyester and ethylene or butene, and may be a two-layer type such as core-sheath or side-by-side or a multi-layer type composite fiber such as multi-parallel or multi-core. You may. It is preferable to use a relatively inexpensive low-melting polyester fiber as the heat-fusible fiber. If this sound absorbing material is used as the roof insulator 32 (FIG. 6), a fiber having a higher melting point or a crystallization type fiber may be selected in consideration of the dripping of the member when the temperature inside the vehicle rises.
The above-mentioned ordinary fibers and heat-fusible fibers are generally white or colorless and transparent. If the white fibers are seen through the gap of the dash panel when the sound absorbing material 1 is applied to the dashboard insulator 20 (FIG. 5), for example, when the handle is tilted up, some or all of these fibers should be changed to black-based fibers. Just fine. Black polyester fibers can be used for both the normal fibers and the heat-fusible fibers.
In the sound-absorbing material 1 composed of the mats 2 and 10, in order to improve the sound-absorbing performance, the normal fiber and the heat-fusible fiber include five or more types of fibers having different finenesses, and a fine fiber is appropriately added. Preferably, the felt sound absorbing material 1 contains nine or more fibers having different finenesses throughout, and the fineness of each fiber is widely dispersed in the range of 0.1 to 6 denier.
The upper mat 2 and the lower mat 10 preferably contain hollow spiral fibers (for example, trade name: S-Up, manufactured by Toyobo Co., Ltd.) to prevent sag. Further, when the lower mat 10 contains 5 to 15% by weight of a latent crimpable fiber, for example, a latent crimpable polyester fiber (trade name: Natura, manufactured by Toyobo), the lower mat 10 can be further bulked by heating. It is preferred.
The upper mat 2 and the lower mat 10 are made by mixing ordinary fibers and heat-fusible fibers, and the mixed cotton is uniformly formed by a known lap forming method, and then spread and laminated. Other wraps can also be used. Since the felt sound absorbing material 1 is heat-pressed at a predetermined temperature, the whole is integrated, and the felt sound absorbing material has no boundary such as a base fabric layer or an adhesive layer.
In order to manufacture the felt sound absorbing material 1, as shown in FIG. 2A, predetermined amounts of ordinary fibers and heat fusible fibers are mixed with a carding machine 3, respectively, and the obtained wraps are laminated. To form the upper mat 2. The upper mat 2 is partially densified by needle-punching the front side 6 and the back side 7 with shallow and high density, respectively, by ordinary locking needle machines 4 and 5, and the middle 8 is wrapped, that is, low density. Remains in the form of floc. With respect to the upper mat 2, the front side portion 6, the back side portion 7, and the intermediate portion 8 may be separately formed, and the whole may be overlapped and integrated at the time of heat compression.
On the other hand, as the lower mat 10, predetermined amounts of ordinary fibers and heat-fusible fibers are mixed with a carding machine (not shown), and the obtained wrap 12 is distributed to the back-facing upper mat 2 for a predetermined amount. Laminate (see FIG. 3). As shown in FIG. 2 (2), the stacked bulky mats 14 are run on a belt conveyor, fed into a heat treatment furnace 15 and heated, and after leaving the furnace, are heat-pressed with a roller pair 16 or the like to be integrated. . The polymerized mats 2 and 10 may be sent to a known hot press (not shown) and heated and pressed. Therefore, this heat compression bonding can be either a batch process or a continuous process. The upper mat 2 and the lower mat 10 are easily heat-bonded with an appropriate amount of heat-fusible fibers interposed therebetween.
According to the present invention, the dashboard insulator 20 (FIG. 5), the floor insulator 26 (FIG. 6), the roof insulator 32 (FIG. 6), and the like can be manufactured from the plate-shaped felt sound absorbing material 1. When the felt sound-absorbing material 1 is heat-formed, it is usually necessary to heat the felt sound-absorbing material 1 at a temperature of about 160 to 280 ° C. for a short time, immediately perform three-dimensional forming by a cold press, and then appropriately trim.
The felt sound absorbing material 1 has excellent mechanical properties and heat resistance in a severe use environment, and has a basis weight of 750 to 2600 g / m. ² Therefore, it is lighter than the thickness. Since the felt sound absorbing material 1 contains 10 to 50% of the heat-fusible fiber, it can be formed into a desired shape by pressing immediately after heating, and is used as an automobile 33 (FIG. 6) having a complicated three-dimensional shape and a component for a train. It is suitable. In the sound absorbing material 1, dust such as glass powder is not generated at the time of the drilling operation and the cutting operation of the bolt hole 21 (FIG. 5), and it is not necessary to consider the deterioration of the working environment.
[0026]
【Example】
Next, the present invention will be described based on examples, but the present invention is not limited to the examples.
Embodiment 1
In order to manufacture the upper mat 2 of the felt sound absorbing material 1 shown in FIG. 1, a carding machine 3 (FIG. 2) uses a 30-denier white polyester fiber 30%, a 3-denier white polyester fiber 20%, and a 6-denier hollow. 20% of spiral crimped polyester fiber (trade name: S-up) and 30% of 4-denier white low melting point polyester fiber (trade name: Melty, manufactured by Unitika) are charged.
The mat material mixed and layered by the carding machine 3 is actually in a state of facing down, and the back side is 270 lines / cm by the rocking needle machine 4. ² Needle punching shallowly and densely with a needle density of 270 needles / cm. ² Needle punching shallow and high density with needle density of As a result, in the upper mat 2, the front side portion 6 and the back side portion 7 have a high density, and the middle portion 8 has a low-density cotton-like fiber structure.
On the other hand, as a mat material for the lower mat 10, 30% of 3 denier white polyester fiber, 30% of 0.75 denier white polyester fiber, and 2 denier of white low melting polyester fiber (trade name: Melty) Another car using 20%, 6 denier hollow spiral crimp polyester fiber (trade name: ESUP) 10% and 2.5 denier white latently crimpable polyester fiber (trade name: Natura) 10% The wrap 12 is obtained by mixing with each other in a wrapping machine (not shown). As shown in FIG. 3, the wrap 12 is distributed on the back-facing upper mat 2 and laminated in a predetermined amount to produce a bulky mat material.
Next, as shown in FIG. 2 (2), the bulky mat material 14 is heated at 180 ° C. for 1 minute in a hot air drying furnace 15 and the whole is pressed by a known forming roller pair 16 and then cooled in a cool air cooling chamber. Send to 18. The back side of the upper mat 2 and the laminated wrap are thermally bonded by the roller pair 16 with an appropriate amount of heat-fusible fiber interposed therebetween, and the laminated wrap becomes the lower mat 10 (FIG. 1). The obtained sound absorbing material 1 has an apparent total weight of 1600 g / m. ² And an apparent thickness of 25 mm.
For the upper mat 2 having a thickness of about 8 mm in the sound absorbing material 1, the front side 6 has a thickness of 1.5 mm and a basis weight of 200 g / m2. ² , The middle part 8 has a thickness of 5 mm and a basis weight of 200 g / m ² , The back side 7 is 1.5 mm thick and has a basis weight of 200 g / m2. ² It is. The lower mat 10 has a thickness of about 17 mm and a basis weight of 1000 g / m. ² It is. As a result, the front side 6 and the back side 7 of the upper mat 2 have a density of 0.133 g / cm. ³ And the middle portion 8 has a density of 0.040 g / cm ³ Is a low density layer. The lower mat 10 has a density of 0.059 g / cm. ³ Is a relative medium density layer.
The weight of the sound absorbing material 1 is reduced from about 25% to a maximum of 45% as compared with the current dashboard insulator, which is advantageous when mounted on a vehicle such as an automobile 33 (FIG. 6) or a train. Further, in the sound absorbing material 1, the upper mat 2 corresponds to a pseudo skin, and the entire skin can be integrated due to the elimination of the skin, whereby the processing time can be shortened, and the recycling of automobile parts becomes easy.
Test Example 1
In order to confirm the sound absorbing performance of the sound absorbing material 1 manufactured in Example 1, the sound absorbing properties when the light was incident from the upper mat 2 side and when the light was incident from the lower mat 10 side were measured by the vertical incidence method. Were also measured, and the respective results are shown in the graph of FIG. The single-layer sound-absorbing material has the same fiber structure as the upper mat 2 of Example 1, and has an apparent weight of 1600 g / m2 by heat compression. ² And an apparent thickness of 25 mm, a density of 0.06 g / cm ³ Corresponds to a relative medium density layer.
From this test result, the sound absorbing material 1 obtained in Example 1 has excellent sound absorbing performance at almost all frequencies as compared with the single-layer sound absorbing material, and exhibits a unique high sound absorbing performance particularly in a low frequency range. The reason for this is that, as exemplified on the right side of FIG. 1, the sound (noise) S incident from the upper mat 2 side is repeatedly reflected between the high-density layers of the upper mat 2 to be contained, and the residence time is lengthened to increase the wavelength. Some of the sound S 'that has been attenuated and transmitted through the mat also depends on the multi-density configuration, which is further absorbed by the lower mat 10, the medium density layer. The sound absorbing material 1 can further improve the sound absorbing coefficient in a low sound range by adding various kinds of fine denier ordinary fibers to the upper mat 2 and the lower mat 10.
Embodiment 2
The plate-shaped felt sound absorbing material 1 manufactured in Example 1 was heated at 160 to 260 ° C. for 9 to 60 seconds, immediately formed by a cold press, and then trimmed by a trim press to obtain, for example, a dashboard insulator 20 (FIG. 5). ) Can be manufactured. The molded insulator 20 is adhered after applying an acrylic adhesive to the back side of the vehicle body panel of a dashboard (not shown). The obtained insulator 20 is 23 to 45% lighter than the current product, and the sound absorbing performance is improved, so that the sound insulating effect inside the automobile is further enhanced. In the insulator 20, dust such as glass powder is not generated at the time of drilling the mounting bolt holes 21, and it is not necessary to consider the deterioration of the working environment.
Embodiment 3
As shown in the lower part of FIG. 6, the plate-shaped felt sound absorbing material 1 manufactured in Example 1 is bonded to the lower surface of the floor carpet material 24 via an adhesive sheet 22 or an adhesive, and is bonded at 180 to 280 ° C. for 30 to 120. Heat for 2 seconds, immediately press-mold with a cold press, and then trim the shape with a trim press. The molded floor insulator 26 is adhered after applying an acrylic adhesive to the front side of the automobile floor. The obtained floor insulator 26 is considerably lighter than the current product, and the sound absorbing performance is improved, so that the sound insulating effect inside the automobile is further enhanced.
Embodiment 4
As shown in the upper part of FIG. 6, the plate-shaped felt sound absorbing material 1 manufactured in Example 1 is bonded to the lower surface of the ceiling skin 30 via an adhesive sheet 28 or an adhesive, and is heated at 180 to 280 ° C. for 30 to 120 seconds. It is heated and immediately press-formed by a cold press, and then trimmed by a trim press. The molded roof insulator 32 is adhered after applying an acrylic adhesive to the back side of the dashboard body panel. The obtained floor insulator 32 is considerably lighter than the current product, and the sound absorbing performance is improved, so that the sound insulating effect inside the automobile is further enhanced.
Embodiment 5
In the felt sound absorbing material 34 shown in FIG. 7, an intermediate mat 36 is interposed between the upper mat 2 and the lower mat 10 in the first embodiment. The intermediate mat 36 has the same fiber configuration and the same thickness as the upper mat 2. The lower mat 10 is arranged by distributing the same lower mat wrap as in the first embodiment on the polymerized upper mat 2 and intermediate mat 36. As shown in FIG. 2 (2), the obtained bulky mat material is heated in a hot air drying furnace at 180 ° C. for 1 minute, and the whole is pressed by a known pair of forming rollers, and then sent to a cool air cooling chamber. The upper mat 2, the intermediate mat 36, and the lower mat 10 can be thermally bonded by a pair of rollers by interposing an appropriate amount of heat-fusible fibers.
The obtained sound absorbing material 34 had an apparent total weight of 2200 g / m 2. ² And an apparent thickness of 33 mm. The upper mat 2 and the intermediate mat 36 have a thickness of about 8 mm, and the front and back sides of both have a thickness of 1.5 mm and a basis weight of 200 g / m2. ² , The middle part is 5mm thick and the basis weight is 200g / m ² It is. The lower mat 10 has a thickness of about 17 mm and a basis weight of 1000 g / m. ² It is.
In the sound-absorbing material 34, the front side and the back side of both mats together with the upper mat 2 and the intermediate mat 36 correspond to the high-density layer 38. A low density layer 40 is located between each two high density layers 38, and there are two low density layers.
Embodiment 6
An intermediate mat 44 is interposed in the felt sound absorbing material 42 shown in FIG. The intermediate mat 44 has the same fiber structure as the upper mat 2, but is determined to have a thickness of about 5 mm in the end, and only the front side thereof is needle-punched to have a thickness of 1.5 mm and a basis weight of 200 g / m2. ² Only the front side portion 46 is formed. Then, the lower mat 10 was arranged on the polymerized upper mat 2 and the intermediate mat 44, and then heated in the same manner as in Example 5 to give an apparent total weight of 1940 g / m2. ² Further, a felt sound absorbing material 42 having an apparent thickness of 30 mm is obtained.
In the sound absorbing material 42, the front side and the back side of the upper mat 2 and the front side 46 of the intermediate mat 44 together with the upper mat 2 and the intermediate mat 44 correspond to the high-density layer 48. A low density layer 50 is located between the two high density layers 48.
Embodiment 7
As shown in FIG. 9, an intermediate mat 52 is interposed in the same manner as in the fifth embodiment. 9, only the front side 56 of the upper mat 55 and the back side 58 of the intermediate mat 52 are needle-punched to form the high-density front side 56 and the back side 58. After arranging the lower mat 10 on the polymerized upper mat 55 and intermediate mat 52, heat treatment was performed in the same manner as in Example 5 to give an apparent total weight of 1800 g / m2. ² Further, a felt sound absorbing material 54 having an apparent thickness of 30 mm is obtained.
In the sound absorbing material 54, the front side 56 of the upper mat 55 and the back side 58 of the intermediate mat 52 together with the upper mat 55 and the intermediate mat 52 correspond to the high-density layer 62. A low density layer 64 is located between the two high density layers 62,62.
Embodiment 8
As shown in FIG. 10, an upper mat 55 and an intermediate mat similar to those of the seventh embodiment are used. However, in the intermediate mat 64, only the front side 66 is densified. After arranging the lower mat 10 on the polymerized upper mat 55 and the intermediate mat 64, it was heat-treated in the same manner as in Example 5 to give an apparent total weight of 1800 g / m. ² Further, a felt sound absorbing material 68 having an apparent thickness of 30 mm is obtained.
In the sound absorbing material 68, the front side 56 of the upper mat 55 and the front side 66 of the intermediate mat 64 together with the upper mat 55 and the intermediate mat 64 correspond to the high-density layer 70. The low density layer 72 is located between the two high density layers 70, 70.
[0047]
【The invention's effect】
The felt sound absorbing material according to the present invention has excellent sound absorbing performance at almost all frequencies from a low frequency range to a high frequency range as compared with a conventional sound absorbing material, and exhibits a unique high sound absorbing performance particularly in a low frequency range. The felt sound-absorbing material of the present invention has a multi-density configuration including various types of raw material fibers, and in the upper mat, a low-density layer is sandwiched by a high-density layer to enhance sound absorption performance by repeating sound containment and reflection. I have.
The felt sound-absorbing material of the present invention achieves weight reduction and simplification of the manufacturing process by eliminating the skin such as PVC, thereby shortening the manufacturing time and reducing the manufacturing cost, and improving the sound absorbing material. The weight reduction contributes sufficiently to the ultimate goal of high speed and light weight in automobiles, trains and aircraft. The felt sound-absorbing material of the present invention has no intervening skin, and if the whole is unified with polyester fiber or the like, it becomes unnecessary to partially remove or remove when recycling automobile parts for environmental protection. Processing can reduce recycling costs.
The felt sound-absorbing material of the present invention can be formed into a desired three-dimensional shape by a cold press or the like after heating, and can be formed and laid as a dashboard insulator into a complicated shape at a narrow installation place such as inside an automobile. The felt sound absorbing material of the present invention is excellent in formability, so that it can be applied as a floor insulator and a roof insulator in addition to a dashboard insulator, or as a separate sound insulation / sound insulation application. With the felt sound absorbing material of the present invention, various noises generated from many noise sources such as an engine room can be efficiently absorbed and insulated, so that the driver can enjoy quiet and comfortable touring and reduce noise pollution.
[Brief description of the drawings]
FIG. 1 is a schematic sectional view of a felt sound absorbing material according to the present invention.
FIG. 2 is a schematic explanatory view showing a manufacturing process of a felt sound absorbing material, in which (1) is an upper mat formation, and (2) is a processing order of a bulky mat material.
FIG. 3 is a schematic side view showing a manufacturing process of a lower mat.
FIG. 4 is a graph showing the sound absorption coefficient of the felt sound absorbing material of the present invention.
FIG. 5 is a schematic cross-sectional view illustrating a dashboard insulator.
FIG. 6 is a schematic cross-sectional view illustrating a floor insulator and a roof insulator.
FIG. 7 is a schematic sectional view showing a modification of the present invention.
FIG. 8 is a schematic sectional view showing a second modification of the present invention.
FIG. 9 is a schematic sectional view showing a third modification of the present invention.
FIG. 10 is a schematic sectional view showing a fourth modification of the present invention.
[Explanation of symbols]
1 felt sound absorbing material
2 Upper mat
6 Front side
7 Back side
8 Middle part
10 Lower mat
12 laps
20 Dashboard insulator
26 Floor insulator
32 Roof insulator
36 Intermediate mat

Claims (8)

A felt sound-absorbing material that can be formed into a desired three-dimensional shape by heat molding, wherein the front side and the back side are densified by needle punching and the middle part remains wrapped. A multi-density felt sound-absorbing material consisting of a lower mat having a high density, and both mats are integrated by heating and pressing at a predetermined temperature. 2. A felt sound absorbing material that can be formed into a desired three-dimensional shape by heat molding, and has a thickness of 1.0 to 3.0 mm and a density of 0.050 to 0.400 g / cm ³ , a front side portion and a back side portion, and a thickness of 3. an upper mat having a middle portion is the density 0.010~0.100g / cm ³ at 0 to 10 mm, composed of a lower mat is the density 0.014~0.150g / cm ³ with a thickness of 10～35Mm, The lower mat is a multi-density felt sound-absorbing material that has a lower density than the front and back sides of the upper mat, and integrates both mats by heating and pressing at a predetermined temperature. A felt sound-absorbing material that can be formed into a desired three-dimensional shape by heat molding, wherein an intermediate mat is arranged between an upper mat and a lower mat, and the upper mat and the intermediate mat are combined to form substantially two low-density layers. Felt sound-absorbing material constructed so as to be located between the high-density layers, and integrated by heating and pressing the upper, middle and lower mats. A felt sound-absorbing material that can be formed into a desired three-dimensional shape by heat molding, wherein 50 to 90% by weight of at least two kinds of ordinary fibers having different fineness in a fineness range of 0.1 to 10 denier and 0.5 to 15 denier. An upper mat laminated with a wrap obtained by mixing 10 to 50% by weight of a low-melting heat-fusible fiber, and at least two types of ordinary fibers 60 to 60 having different fineness in a fineness range of 0.1 to 10 denier. A lower mat laminated with a wrap obtained by blending 90% by weight and 10 to 40% by weight of a low-melting heat-fusible fiber having a fineness of 0.5 to 10 deniers. Felt sound-absorbing material integrated by heating and pressure bonding. The upper mat according to any one of claims 1 to 4, wherein the upper mat has a thickness of 5 to 15 mm, the lower mat has a thickness of 10 to 35 mm, the total thickness is 15 to 40 mm, and the upper and lower mats include hollow spiral shaped fibers. Felt sound absorbing material. A felt sound-absorbing material that can be heat-molded into a desired three-dimensional shape. The upper and lower mats are made denser by needle punching on the front side and the back side, and the middle part is kept at a low density. A dashboard insulator comprising a certain lower mat, having an overall thickness of 15 to 40 mm, and being pressed and then bonded to the backside of the dashboard. A felt sound-absorbing material that can be heat-molded into a desired three-dimensional shape. The upper and lower mats are made denser by needle punching on the front side and the back side, and the middle part is kept at a low density. A floor insulator made of a certain lower mat, having an overall thickness of 15 to 40 mm, and being press-formed after being bonded to the lower side of the floor carpet material. A felt sound-absorbing material that can be heat-molded into a desired three-dimensional shape. The upper and lower mats are made denser by needle punching on the front side and the back side, and the middle part is kept at a low density. The heat fusible fiber contained in the upper and lower mats has a melting point of 100 ° C. or more or is of a crystallization type, has a total thickness of 15 to 40 mm, and is pressed after being adhered to the ceiling skin. Roof insulator to be molded.

Images