JP3284729B2 - Automotive sound insulating material and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sound insulating material for automobiles and a method for manufacturing the same, and more particularly to a sound insulating material for automobiles having excellent sound absorbing performance and sound insulating performance, and a method for manufacturing the same.

[0002]

2. Description of the Related Art Among sound insulation materials for automobiles, shape, weight,
Dash insulators and floor insulators for automobiles, which have severe restrictions on space and the like, play a central role. FIG. 1 shows an example of a conventional dash insulator and a floor insulator used for an automobile.
As shown in FIG. 1, the dash insulator 2 is located on a vehicle interior surface of a dash panel 1 that partitions an engine room 6 and a vehicle room 7, and prevents transmission of noise from the engine room 6 to the vehicle room 7. It has the role of. Also,
The floor insulator 5, as shown in FIG. 1, is located on the interior surface of the floor panel 12 that divides the vehicle floor 7 from under the floor, and prevents transmission of noise from under the floor.

As shown in FIG. 2, the dash insulator 2 includes a relatively high-density sound insulating material layer 3 composed of a vinyl chloride sheet or a rubber sheet mixed with a filler, and a felt, a polyurethane foam, a nonwoven fabric, or the like. It is generally used as a laminated structure with a sound absorbing material layer 4 composed of a representative porous substrate. The sound absorbing material layer 4 absorbs noise from the engine room 6 and, together with the double sound insulating effect of the dash panel 1 and the high-density sound insulating material layer 3, exhibits good sound insulating performance in combination with the sound absorbing effect. It is configured to be.

Recently, the dash panel 1 and the sound absorbing material layer 4
It has been found that the sound insulation performance changes greatly due to the adhesion with the dash insulator, and the use of a molded sound absorbing material as the sound absorbing material layer 4 has led to the use of a dash insulator of a type that can accurately fit the surface shape. I have.

For example, a fiber-based sound-absorbing material is prepared by adding a binder resin to a chemical fiber or a natural fiber, heat-forming, and pressing. As a binder used in this case, a thermoplastic resin is, for example, a heat-fusible resin such as a polyethylene resin, a polypropylene resin, or a polyester resin, and a thermosetting resin is mainly a phenol resin.

However, since these binder resins have about 30% by weight with respect to the total amount of the fiber-based sound-absorbing material, the sound-absorbing effect is reduced as the weight of the fiber is reduced, and this is effective for the weight. It was difficult to obtain a sound absorbing effect. On the other hand, floor insulators for automobiles are required to have good sound insulation performance in addition to the decorative effect in the car. Generally, as shown in FIG. 3, the floor insulator includes a carpet skin 8, a backing material 9, and a sound insulating material layer 1.
0, the melt sheet 11 and the floor panel 12 are laminated in this order. In conventional floor insulators, felt or urethane foam is used as a sound insulating material layer.

However, when felt is used for the sound insulating material layer, the adhesion between the felt panel and the floor panel (mel sheet) is deteriorated due to poor moldability such as mold followability. Sound insulation performance cannot be obtained. Also, to lay the carpet skin and insulator separately,
A bonding process is required, resulting in high costs. In addition, since irregularities due to the shape of the ribs of the body panel, the wire harness, and the like cannot be sufficiently absorbed, irregularities are generated on the carpet skin, and the appearance deteriorates.

On the other hand, when urethane foam is used as the sound insulating material layer, although the adhesion to the floor panel (mel sheet) is improved, a bonding step between the carpet skin and the urethane foam is required, resulting in high costs. . Also, a method has been developed in which a carpet skin and a urethane foaming raw material are simultaneously charged into a foaming mold and integrally molded, but a resin injection step and a foam fixing step are required, so that the process requires time and exhaust. A large-scale facility including the facility is required, and there is a disadvantage that productivity is poor.

Furthermore, since urethane foam is used as a raw material, exhaust equipment is required to prevent deterioration of the working environment. Also, urethane foam is difficult to recycle, and is not preferable even in view of recent environmental problems. Also,
Since urethane foam is harder than felt, sound insulation performance is inferior. To solve these drawbacks, it is possible to increase the weight of the backing material or add a mass back to ensure sound insulation performance. Is not preferred.

[0010]

As described above, in the conventional dash insulator, the use amount of the internal fiber aggregate (felt or the like) is increased for the purpose of improving the sound insulation performance due to insufficient adhesion to the body panel. Means were used. However, when this means is used as a sound insulating material for automobiles, there is a drawback that the weight increases and the material cost increases. In addition, from the viewpoint of moldability, there is a part where the density is extremely increased due to the shape of the dash insulator, so if there is a part that is further increased in density and hardly formed, the sound insulation performance is reduced. Had the disadvantage of doing so.

[0011] Since the surface rigidity of the dash insulator itself is already maintained even in a general portion, the product subjected to hot press molding has a disadvantage that the surface is particularly hard. That is, as shown in FIG. 2, when the sound absorbing material layer 4 is hard, the vibration from the dash panel 1 is easily transmitted to the sound insulating material layer 3 via the sound absorbing material layer 4, and the vibration of the sound insulating material layer 3 becomes noise. , Which hinders quietness in the cabin. The same is true for floor insulators, and even if hard felt or urethane foam is used as the material, it cannot be said that the sound insulation performance is high.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a sound insulating material for automobiles capable of maintaining high sound insulating performance as compared with the case where a conventional felt or the like is used and reducing the weight and processing cost of a vehicle, and manufacturing the same. It is to provide a method.

[0013]

Means and Action for Solving the Problems The present inventors have
As a result of intensive studies to solve the above-described problems, when a fiber aggregate composed mainly of ultra-fine fibers having a predetermined average fineness is used as a sound insulating material, a high sound insulating performance is maintained and a vehicle is maintained. The present inventors have found that it is possible to reduce the weight and the processing cost of the present invention, and have reached the present invention.

The object of the present invention is to provide a synthetic fiber having an average fineness in the range of 0.0001 to 1d as a main component.
95% by weight and having a softening point of at least 20
50% by weight or less of synthetic fibers in the range of 1.5 to 18d in average fineness differing by at least
d. a synthetic fiber in the range of d, wherein the fiber aggregate has an average areal density of 0.1 to 1.5 kg.
/ M ² and a thickness in the range of 1 to 40 mm. Hereinafter, the present invention will be described in more detail.

The sound insulation performance, which is the basic performance of the dash insulator and the floor insulator, can be estimated by measuring the sound absorption rate and the vibration transmission rate. Therefore, in order to improve the sound insulation performance, it is necessary to increase these two performances. First, the sound insulation performance is better if the sound absorption coefficient is higher. The sound absorption coefficient is caused by various factors such as areal density and fineness, and increasing the areal density is a very effective means for improving the sound absorption coefficient. However, when the density is increased, the weight is increased and the cost is also increased. Further, as the density increases, the vibration transmissibility in a high frequency range increases, and there is a disadvantage that the sound insulation performance is reduced.

Second, the smaller the vibration transmissibility, the higher the sound insulation performance. Here, the vibration transmissibility greatly depends on the spring constant of the object, and it is necessary to reduce the spring constant in order to improve the sound insulation performance. Therefore, in order to improve the sound insulation performance, a high sound absorption coefficient and a low spring constant are ideal, but both performances are generally contradictory and it is difficult to improve both.

Here, since the number of fibers relative to the areal density of the ultrafine fibers is extremely increased, the sound absorption coefficient is improved due to the change of sound energy into friction between fibers and air. Can be. However, since the fiber itself loses its rigidity due to ultrafineness, there is a drawback that a material formed into a fiber aggregate by applying a load becomes plate-like, a spring constant increases, and a vibration transmission rate deteriorates. . Therefore, based on the concept of forming a frame in order to give a shape to the fiber assembly, fibers having different softening points were slightly mixed. That is, by dispersing the ultra-fine fibers of uniform or intentionally changed density around the fibers forming the frame, the sound absorbing performance and the reduction of the spring constant could be satisfied at the same time.

In the present invention, in order to obtain the above effect, the average fineness of the ultrafine fibers is 0.0001 as a main component.
Use synthetic fibers in the range of ~ 1d. In order to improve the sound insulation performance, the smaller the fineness, the better. In the present invention, since the object is to obtain a high-performance sound insulating structure, the average fineness of the fiber that is a fiber type for the purpose of sound insulating performance of a fiber assembly composed of several types of fibers is not less than 1d. Not be. On the other hand, in the current general technology, the average fineness of the fiber having the smallest fineness is about 0.0001d, and thus the use of this fiber is particularly effective for improving the sound insulation performance. This ultrafine fiber is 10 to 9 with respect to the whole fiber.
It is blended in the range of 5% by weight. 10 ultra-fine fibers
If the amount is less than 95% by weight, the desired sound insulation performance cannot be obtained.
It becomes below, and molding becomes impossible.

Further, a product can be produced by hot press molding while maintaining the shape as a fiber aggregate by blending another fiber having a softening point different by at least 20 ° C. or more. If the softening point is lower than 20 ° C., the entire fiber is softened due to difficulty in controlling the temperature, the fiber aggregate cannot be maintained, and the entire fiber is softened, resulting in a plate shape. The average fineness of the other fibers blended with the ultrafine fibers is in the range of 1.5 to 18d.
If the average fineness is less than 1.5 d, it is difficult to produce fibers with sound absorbing performance and the cost is high. In addition, to maintain the shape, the thicker fibers are better, and the performance of eliminating sagging Cannot be formed so as to have the following. Conversely, if it exceeds 18d, the relative number of fibers decreases, and on the contrary, the moldability decreases. The blending amount of this fiber is 50% by weight or less based on the total fiber weight. If the compounding amount exceeds 50% by weight, the sound-insulating performance is deteriorated because the fiber aggregate is formed into a plate shape after processing.
Also, depending on the part used as a part, it may not be necessary to mix this kind of fiber, so that the mixing may be 0% by weight.

In the present invention, in addition to the above two types of fibers, synthetic fibers having an average fineness in the range of 1 to 30 d can be blended as required. By using the fiber aggregate composed of the two types of fibers described above, the sound absorption performance and the frame performance can be sufficiently maintained. However, when other fibers are blended within the specified range, the performance is reduced. There is no offset. When the average fineness of the other fibers is less than 1d, they are no different from the above-mentioned ultrafine fibers, and only the amount of the ultrafine fibers increases. Conversely, if it exceeds 30d, the total number of fibers will be extremely reduced, which will have a considerable effect on the sound absorption performance, and the dispersion of the ultrafine fibers will not be uniform.

The areal density of the fiber assembly composed of the above fibers is in the range of 0.1 to 1.5 kg / m ² . If the areal density is less than 0.1 kg / m ² , it is greatly restricted in terms of space when used as a sound insulating material for automobiles.
The sound absorption performance and the sound insulation performance are hindered by the presence of an object used for a part that needs to be thin and high in density or an object used for a part that needs to be thick and low in density. Conversely, 1.5Kg
/ M ² directly affects weight and cost.

The thickness of the fiber assembly is 1 to 40 m.
m. If the thickness of the fiber aggregate is less than 1 mm, good sound insulation performance cannot be obtained, and if it exceeds 40 mm, it is impossible to secure a space in the vehicle interior in a layout.

Such a fiber aggregate can be formed by dispersing synthetic fibers according to the intended use in three modes of a random form, an orthogonal form and a spherical form. In order to add uniform mechanical performance to the entire surface without directionality in addition to the sound absorbing and insulating performance, it is preferable to disperse fibers in a random form to form a fiber aggregate. On the other hand, when mechanical performance is given in a certain direction, it is preferable to disperse in an orthogonal form. Further, when a material having a partially different hardness, that is, a material having a different spring constant is required, or for a material having a complicated shape, a large number of cotton-ball-shaped fiber aggregates can be collected into a nonwoven fabric. . Since the spherical fibrous body having a high degree of freedom can be evenly dispersed and arranged according to the shape of the molded part at the time of molding, the density can be kept constant even at a tightly drawn portion. As a result, the dash insulator and the floor insulator can prevent the sound insulation performance from being lowered due to the increase in the density of the tight portion of the aperture. In addition, since the spherical fiber itself already has a certain level of elasticity, the sag when it is made into a fiber aggregate is small, and it is easy to put ultra-fine fibers into the sphere, so the sound absorption coefficient and the spring constant are reduced. Is very effective.

The fiber aggregate dispersed in this spherical form is
It is preferable to use as a structure constituted in a state of being entangled three-dimensionally in a range of a diameter of 1 to 40 mm. When the diameter of the spherical fiber body is less than 1 mm, the weight of the fiber body becomes extremely small and the cohesiveness deteriorates, so that the molding time becomes longer than necessary and the economic efficiency deteriorates,
The mechanical properties are also extremely reduced. Conversely, when the diameter exceeds 40 mm, not only is it impossible to use as a sound insulating material for automobiles due to space restrictions, but also the fibrous body cannot be dispersed smoothly from the viewpoint of moldability, and It is difficult to arrange an arbitrary amount in the area.

The single fiber constituting the fiber assembly is 1
It may be a short fiber of less than 0 cm, a long fiber of 10 cm or more, or a fiber aggregate composed of only one fiber. In particular, a fiber aggregate composed of long fibers can improve mechanical properties such as surface tension and tensile strength. In addition, a fiber aggregate composed of only short fibers can improve moldability such as followability of a mold when molded as a part.

The above three types of fiber aggregates are not particularly limited, but are preferably integrally formed using a needle punch method or the like in order to give a sense of unity as a whole. Also, in order to use it as an actual part,
In addition to the fiber assembly that is to be the core of the sound absorption and insulation, various parts for improving the sound insulation performance can be added to the upper surface and the lower surface thereof. For example, a floor insulator is a mass back and the like, and a dash insulator is a rubber skin and the like. In particular, as a result of repeated studies for improving the sound insulation performance, it was found that it is effective to add various components to both surfaces of the fiber assembly. The layer added to the fiber aggregate preferably has at least twice the surface density of the fiber aggregate. If the areal density is less than twice, not only the sound absorbing and absorbing performance is not sufficiently obtained, but also the cost and weight are increased. The laminate thus obtained preferably has a range of 1 to 40 mm. The laminate is 1
mm, the original sound insulation performance cannot be obtained,
When the distance exceeds m, a large space is required for use on a vehicle, so that interference occurs with other components.

As the synthetic fiber which is a main component of the fiber aggregate, a synthetic fiber produced by a melt blown method is preferably used. According to this method, the polymer solution is ejected from the extremely fine pores, so that inexpensive and very thin fibers can be produced. By using the synthetic fibers obtained by this method, ultrafine fibers having an average fineness of about 0.1 d can be produced, and a fiber aggregate having a high sound absorption coefficient can be obtained.

Since the sound absorption coefficient is closely related to the total number of fibers and the total area, it is preferable to mix fibers as thin as possible in the fiber assembly. Such fine fibers have an average fineness of 0.000 in consideration of technical and cost aspects.
It is preferable to contain 5% by weight or more in the range of 1 to 0.1d. To improve the sound insulation performance, the smaller the average fineness is, the better. However, the fiber with the smallest fineness obtained by the current general technology is about 0.0001d. Conversely 0.1
If it exceeds d, a high-performance sound insulating structure cannot be obtained. When the content of the fiber is less than 5% by weight,
The sound insulation performance obtained by blending ultra-fine fibers is reduced.

The fibers forming the frame have an average fineness of 1.5
It is preferably in the range of 6 to 6d. Average fineness is 1.5
When it is less than d, the shape of the fiber aggregate cannot be maintained, and the moldability is reduced. Conversely, if it exceeds 6d, the sound insulation performance will decrease. The blending amount of the fiber is preferably in the range of 5 to 40% by weight. If the amount is less than 5% by weight, the moldability will be reduced, and if it exceeds 40% by weight, the material will be hardened and the cost will increase.

The synthetic fibers constituting the fiber assembly include:
It can be appropriately selected from known synthetic fibers and used, but from the viewpoint of cost and ease of melt spinning, particularly polyethylene terephthalate (hereinafter abbreviated as PET).
And polypropylene fibers (hereinafter abbreviated as PP) are preferably used. Above all, PP has a specific gravity of 0.91 and is only 65% of 1.4 of PET, so that it has about 1.25 times the surface area at the same areal density. Generally, the sound absorption coefficient tends to depend on the surface area, and the use of PP can contribute to the improvement of the sound absorption coefficient. Further, in consideration of ease of recycling, thermoplastic polymers such as nylon, polyacrylonitrile, polyacetate, polyerylene terephthalate, polyethylene, polypropylene, linear polyester, and polyamide can also be suitably used.

Next, the manufacturing method of the present invention will be described. The automotive sound insulating material of the present invention is manufactured by simultaneously and integrally forming a structure in which a fiber assembly layer and another layer are laminated, by heating the structure at 70 to 260 ° C. for several minutes and press-forming. You. As a result, fibers having a low melting point, which are partially precipitated on the surface, can be adhered to the entire laminate, and the number of steps can be reduced by enabling simultaneous integral molding. Although there is no particular limitation on the lamination method, it is preferable to perform integral molding using a needle punching method or the like in order to perform favorable molding such that the entire unit is separated. Here, the heating temperature is 70 ° C.
If the heating time is longer, the molding cannot be performed even if the heating time is prolonged. On the other hand, if the heating temperature exceeds 260 ° C., the fiber aggregate is melted, and the molding cannot be performed similarly. The heating method is not particularly limited, but it is preferable to use a hot-air circulation oven in order to shorten the heating time.

As described above, by forming the dash insulator and the floor insulator using the sound insulating structure for automobiles according to the present invention, the sound absorbing performance due to the ultrafine fibers and the fiber forming the frame can be improved. It is possible to obtain an excellent sound insulating material for automobiles, which maintains the resulting good formability and the ability to prevent an increase in the spring constant.

[0033]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto.

Example 1 70% by weight of synthetic fiber A mainly composed of PET having an average fineness of 1d, and PE having an average fineness of 2d having a softening point lower than that of A by 20 ° C.
A surface density of 1.0 Kg / m ² and a width of 300 × 3 in which 30% by weight of synthetic fiber B containing T as a main component are dispersed in a random form.
A fiber assembly having a thickness of 00 mm and a thickness of 30 mm was heated at 165 ° C. and press-molded at 50 kgf / cm ² to produce a sound insulating material for automobiles.

Example 2 A sound insulating material for an automobile was prepared in exactly the same manner as in Example 1 except that the material was dispersed in the orthogonal shape instead of the random shape used in Example 1.

Example 3 The sound insulation for an automobile was carried out in exactly the same manner as in Example 1 except that instead of being dispersed in the random form used in Example 1, it was dispersed in the form of a spherical fiber having a diameter of 20 mm which was entangled three-dimensionally. Materials were created.

Example 4 80% by weight of a synthetic fiber A composed mainly of PP having an average fineness of 0.1 d prepared by a meltblown method and PET having an average fineness of 1.5 d having a softening point lower than that of A by 20 ° C. Surface density 0.4 kg / m ² , 300 × 300 mm and thickness 10 in which synthetic fiber B and 20% by weight are dispersed in random form
mm fiber assembly is heated at 165 ° C. and 50 kgf / c
Press molding was carried out at m ² to produce a sound insulating material for automobiles.

Example 5 The areal density and thickness were 0.8 kg / m ² and 30 m, respectively.
Except for using m, a sound insulating material for automobiles was prepared in exactly the same manner as in Example 4.

Example 6 A sound insulating material for automobiles was prepared in exactly the same manner as in Example 5, except that an area density of 1.0 kg / m ² was used.

Example 7 A sound insulating material for automobiles was prepared in exactly the same manner as in Example 5, except that an area density of 1.2 kg / m ² was used.

Example 8 A sound insulating material for automobiles was prepared in exactly the same manner as in Example 1 except that the average fineness of the synthetic fiber A was 0.0005 d.

Example 9 A sound insulating material for automobiles was prepared in exactly the same manner as in Example 1 except that the average fineness of the synthetic fiber B was changed to 15d.

Example 10 60% by weight of synthetic fiber A mainly composed of PET having an average fineness of 1d, and PE having an average fineness of 2d lower than A by 20 ° C.
30% by weight of synthetic fiber B containing T as a main component and an average fineness of 6
area density 1.0 kg / m ² , 30 in which 10% by weight of synthetic fiber C containing PET as a main component is dispersed in a random form.
A fiber assembly having a size of 0 x 300 mm and a thickness of 30 mm is heated at 165 ° C
And press molded at 50 kgf / cm ² to produce a sound insulating material for automobiles.

REFERENCE EXAMPLE 1 Except for using a fiber aggregate having a width of 1000 × 2000 mm, the same method as that of Example 6 was adopted except that the fiber assembly was laminated so as to be located on the surface layer of a rubber skin having an area density of 4.0 kg / m ^2. To produce a sound insulating material for automobiles having an average thickness of 35 mm.

Reference Example 2 The width and thickness were 1000 × 1000 mm and 4 m, respectively.
m, and a laminated structure was formed in exactly the same manner as in Example 4 except that the laminated structure was formed so as to be positioned on the back surface layer of a skin material mainly composed of PET, and the average thickness was 5 m.
m sound insulation material for automobiles.

Reference Example 3 The width and thickness were set to 1000 × 1000 mm and 25, respectively.
mm, and the laminated structure was formed in exactly the same manner as in Example 7 except that the laminated structure was placed so as to be located between a skin material mainly composed of PET and a melt sheet composed of asphalt. It was molded to produce an automotive sound insulating material having an average thickness of 30 mm.

Comparative Example 1 A sound insulating material for automobiles was prepared in exactly the same manner as in Example 1, except that 5% by weight of the synthetic fiber A, 40% by weight of the synthetic fiber B and 55% by weight of the other fiber C were used.

Comparative Example 2 A sound insulating material for automobiles was prepared in exactly the same manner as in Example 1 except that 15% by weight of the synthetic fiber A, 55% by weight of the synthetic fiber B and 30% by weight of the other fiber C were used.

Comparative Example 3 A sound insulating material for automobiles was prepared in exactly the same manner as in Comparative Example 1, except that synthetic fiber B having a softening point lower by 10 ° C. than synthetic fiber A was used.

Comparative Example 4 A fiber having a particularly small average fineness was prepared by the melt blown method to prepare a fiber aggregate.
A fibrous body having an average fineness of d or less could not be obtained.

Comparative Example 5 A sound insulating material for automobiles was prepared in exactly the same manner as in Example 1, except that the average fineness of the synthetic fiber A was changed to 2d.

Comparative Example 6 Example 1 was repeated except that the blending amount of the synthetic fiber A was 97% by weight.
An attempt was made to produce a sound insulating material for automobiles in exactly the same manner as described above, however, the fibrous body could not be formed and molded, and no sound insulating material for automobiles could be obtained.

Comparative Example 7 Except that the average fineness of the synthetic fiber B was 1d, an attempt was made to produce a sound insulating material for automobiles in exactly the same manner as in Example 1, except that a fiber B having a softening point differing by 20 ° C. or more was obtained. It was difficult to produce a sound insulating material for automobiles. Also, we considered using a double-structured fiber made of a polymer having a different softening point by the surface area of the fiber B. However, there is generally no technology for stably producing a fiber having an average fineness of 1d with this structure. Similarly, a sound insulating material for automobiles could not be produced.

Comparative Example 8 An attempt was made to produce a sound insulating material for automobiles in exactly the same manner as in Example 1 except that the average fineness of the synthetic fiber B was changed to 20 d.
It was difficult to mix fiber A and fiber B uniformly. Although molding was attempted, molding could not be performed due to the extremely reduced number of fibers B.

Comparative Example 9 The areal density of the fiber assembly was changed from 1.0 kg / m ² to 0.08 K.
Except that g / m ² was changed, a sound insulating material for automobiles was prepared in exactly the same manner as in Example 1.

Comparative Example 10 The areal density of the fiber assembly was changed from 1.0 kg / m ² to 1.8 kg.
/ M ² , except that the sound insulating material for automobiles was prepared in exactly the same manner as in Example 1.

COMPARATIVE EXAMPLE 11 Except that the thickness of the fiber assembly was changed from 30 mm to 0.8 mm, a sound insulating material for automobiles was prepared in exactly the same manner as in Example 1.

Comparative Example 12 Except that the thickness of the fiber assembly was changed from 30 mm to 45 mm, a sound insulating material for an automobile was prepared in exactly the same manner as in Example 1, and the performance could be secured. However, the material was too thick to interfere with other parts, so that it could not be accommodated in the limited space inside the vehicle.

Reference Example 4 A fiber assembly was press-molded in exactly the same manner as in Example 1 except that the molding temperature was 60 ° C., but the fibers did not soften and could not be integrally molded, so that a sound insulating material for automobiles was produced. Could not create.

Reference Example 5 A fiber assembly was press-molded in exactly the same manner as in Example 1 except that the molding temperature was changed to 270 ° C., but the entire fiber assembly was completely softened, and the sound insulating material for automobiles was manufactured. Could not create.

Conventional Example 1 30 composed of natural fibers opened and synthetic fibers opened
0 × 300mm, thickness 30mm and area density 1.0Kg /
m ² of molded felt was heated at 200 ° C. and 50 kgf /
Press molding was carried out at m ² to produce a sound insulating material for automobiles.

[0062] except for using molding felt 1.2 Kg / m ² is in place of a conventional example 2 surface density 1.0 Kg / m ^2, was prepared automotive sound insulation material in exactly the same manner as the first conventional example.

[0063] except for using molding felt 1.2 Kg / m ² is in place of a conventional example 3 surface density 1.0 Kg / m ^2, was prepared automotive sound insulation material in exactly the same manner as the first conventional example.

[0064] except for using molding felt 2.1 kg / m ² is in place of a conventional example 4 surface density 1.0 Kg / m ^2, was prepared automotive sound insulation material in exactly the same manner as the first conventional example.

Test Example 1 With respect to the samples obtained by the methods of the above Examples, Comparative Examples and Conventional Examples, the normal incidence sound absorption coefficient of the building material was measured based on the in-pipe method according to JIS1405. The sample size is 100Φ and the measurement area is 0.1 to 1.
6 kHz.

Test Example 2 With respect to the samples obtained by the above Examples, Comparative Examples and Conventional Examples, the transmission loss between reverberation chambers was measured by a measuring method in accordance with JIS A1416. From this measured value, the average sound insulation level difference (dB) with respect to Conventional Example 2 was calculated in the range of 0.2 to 10 KHz.

Table 1 shows the results.

[Table 1]

From the results shown in Table 1, the various sound insulating material structures prepared in the examples have excellent sound absorbing performance as compared with the conventional example.
High sound insulation performance was confirmed. On the other hand, in the comparative example and the conventional example, there was a case where a sound insulating material structure having unsatisfactory performance was obtained or a sound insulating material could not be formed.

[0069]

The sound insulating material for automobiles of the present invention has the effect of increasing the sound absorption coefficient by blending predetermined ultra-fine fibers, and retains a higher sound insulating performance than the conventional felt. Further, according to the manufacturing method of the present invention, it is possible to easily obtain a sound insulating material for an automobile, which is economical due to reduction in weight and processing cost.

[Brief description of the drawings]

FIG. 1 is a diagram showing a conventional dash insulator and a floor insulator.

FIG. 2 is a sectional view showing the dash insulator of FIG. 1;

FIG. 3 is a sectional view showing the floor insulator of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Dash panel 2 Dash insulator 3 High-density sound insulation material layer 4 Sound absorption material layer 5 Floor insulator 6 Engine room 7 Car room 8 Carpet skin 9 Backing material 10 Sound insulation material layer 11 Mel sheet 12 Floor panel

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G10K 11/16 E04B 1/86 B60R 13/08 B32B 5/26

Claims (7)

(57) [Claims] An average fineness as a main component of 0.0001 to 1.
10 to 95% by weight of synthetic fibers in the range of 1d, and 50% by weight or less of synthetic fibers in the range of 1.5 to 18d in average fineness having a softening point different from that of the synthetic fibers by at least 20 ° C. A fiber aggregate in which synthetic fibers having a fineness of 1 to 30 d are blended, wherein the fiber aggregate has an average areal density of 0.1 to 1.5 kg / m ² and a thickness of 1
A sound insulating material for automobiles, which is in a range of up to 40 mm. 2. A structure comprising a fiber aggregate in which synthetic fibers are dispersed in a random form, an orthogonal form, or a three-dimensionally entangled spherical form in a range of 1 to 40 mm in diameter. Item 4. The sound insulating material for vehicles according to Item 1. 3. A laminate having a fiber assembly located on a surface layer, an inner surface layer, or a back layer of a sound insulating structure, and having at least another layer having a surface density twice as high as that of the fiber assembly. 3. The sound insulating material for automobiles according to claim 1, wherein said laminate has a range of 1 to 40 mm. 4. The sound insulating material for an automobile according to claim 1, wherein the fiber aggregate is composed mainly of synthetic fibers produced by a melt blown method. 5. The fiber aggregate has an average fineness of 0.0001 to
5% by weight or more of synthetic fibers in the range of 0.1 d and an average fineness of which softening point differs from the synthetic fibers by at least 20 ° C.
5. The sound insulating material for automobiles according to claim 1, wherein the main component is 5 to 40% by weight of synthetic fibers in the range of 5 to 6 denier. 6. The synthetic fiber constituting the fiber assembly, wherein the main component of the synthetic fiber is polypropylene and / or polyethylene terephthalate.
The sound insulating material for automobiles according to the above. 7. Simultaneously and integrally forming a structure obtained by laminating the fiber assembly layer according to claim 1 and another layer by heating at 70 to 260 ° C. for several minutes and press forming. The method for producing a sound insulating material for an automobile according to any one of claims 1 to 6, wherein