JP6936597B2 - Vehicle parts - Google Patents

Description

The present invention relates to sound absorbing materials and vehicle parts.

An automobile has a power source such as an engine and a motor, and when these are operated, various sounds are generated, and such sounds are also transmitted to the inside of the automobile. Further, not only the sound generated by the vehicle itself but also the sound generated from the outside such as road noise and wind noise generated when the vehicle is running is transmitted to the inside of the vehicle. These sounds may overlap, resulting in a sound with a frequency that makes a person uncomfortable, that is, a sound with a frequency of 800 to 2000 Hz.
Therefore, soundproofing measures are taken by sound insulation / absorption in the engine, the engine room, the interior of the vehicle, the vehicle body, the periphery of the exhaust pipe, and the like.

As such a soundproofing measure, Patent Document 1 describes a sound absorbing material for a sound deadening device, which is made of crystalline alumina fibers having an α-alumina crystallization rate of 5% or less and a mullite crystallization rate of 80% or less. It is disclosed that it is used for.

Japanese Unexamined Patent Publication No. 2006-22817

When the sound absorbing material is applied to an automobile, it is required to maintain the sound absorbing property even at a high temperature.
In particular, a sound in the frequency range of 800 to 2000 Hz becomes an unpleasant sound for humans, and therefore, it is required to improve the sound absorbing performance of the sound absorbing material in this frequency range.

Since the sound absorbing material in Patent Document 1 uses a crystalline alumina fiber material, the fiber can be used even at a high temperature of 400 ° C. or higher around the engine as compared with the case where a resin fiber is used as the material. The sound absorption performance is maintained without changing the characteristics.
However, the sound absorbing material in Patent Document 1 has a sound absorbing coefficient of less than 0.5 in a low frequency region of 2000 Hz or less when the examples are reproduced, and the sound absorbing performance cannot be said to be sufficient.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a sound absorbing material having a sound absorbing performance having an average sound absorbing coefficient of 0.6 or more in a frequency region of 800 to 2000 Hz. That is.

That is, the sound absorbing material of the present invention is a sound absorbing material composed of a fiber layer and an inorganic material layer, and the fiber layer and the inorganic material layer are in contact with each other, and the fiber content in the fiber layer is 50% by weight. The inorganic material layer is composed of fibers and inorganic particles, and the content of the fibers in the inorganic material layer is 50% by weight or less.

The sound absorbing material of the present invention comprises a fiber layer and an inorganic material layer.
In the sound absorbing material of the present invention, the inorganic material layer is a surface that receives sound. Since the inorganic material layer is composed of fibers and inorganic particles, when the sound absorbing material receives a sound, the sound is converted into energy that vibrates the inorganic particles and the fibers. Further, a fiber layer is provided in contact with the inorganic material layer on the opposite side of the inorganic material layer when viewed from the sound source. Since the fiber layer is in contact with the inorganic material layer, it is considered that the vibration of the inorganic material layer is transmitted to the fiber layer. Therefore, it is considered that the sound absorbing performance is improved as compared with the case of using only the fiber layer and the case of using only the inorganic material layer, and the sound absorbing performance in the frequency range of 800 to 2000 Hz can also be improved.
Further, since it is provided with an inorganic material layer containing inorganic particles, it is also excellent in shape retention against a temperature change of 300 ° C. or higher.
The contact between the fiber layer and the inorganic material layer means that the vibration applied to the inorganic material layer can be transmitted to the fiber layer, and the fiber layer and the inorganic material layer are in direct contact with each other. Not only the case but also the case where the fiber layer and the inorganic material layer are adhered by an adhesive layer or the like is included.

In the sound absorbing material of the present invention, it is desirable that the density of the fiber layer is smaller than the density of the inorganic material layer.
When the density of the fiber layer is smaller than the density of the inorganic material layer, it is possible to sufficiently absorb the vibration of the inorganic material layer.

In the sound absorbing material of the present invention, it is desirable that ^{the density of the inorganic material layer is 3 to 6 g / cm 3.}
Further, the density of the inorganic material layer is preferably 3 times or more, more preferably 3 to 30 times the density of the fiber layer.

In the sound absorbing material of the present invention, the thickness of the fiber layer is preferably 3 mm or more.
If the thickness of the fiber layer is less than 3 mm, it is too thin to absorb sound, and it becomes difficult to secure sufficient sound absorption performance.
Further, the thickness of the fiber layer in the sound absorbing material of the present invention is more preferably 3 to 50 mm. If the thickness of the fiber layer exceeds 50 mm, there is no problem with the functional performance and sound absorption as a sound absorbing material. The thickness becomes a bottleneck, and it may not be possible to arrange the sound absorbing material for vehicle applications.

When the fiber layer and the inorganic material layer, in which the fiber layer and the inorganic material layer are individually prepared, are bonded to each other, the thickness of the fiber layer and the inorganic material layer is determined with the bonded portion as a boundary.
Further, when the fibers constituting the fiber layer and the fibers constituting the inorganic material layer are the same and the boundary between the fiber layer and the inorganic material layer is not clear, for example, a mixture of fibers and inorganic particles on the surface of the fiber layer ( Or, in the case of a sound absorbing material in which an inorganic material layer is formed on the fiber layer by applying (a dispersion liquid in which these are dispersed in a solvent), the ratio of the fibers constituting each layer is determined by element analysis, and the fiber content is obtained. The portion having a value of 50% or more is a fiber layer, and the portion having a value of less than 50% is an inorganic material layer.
When the fiber layer and / or the inorganic material layer has an element common to the fiber and other components, the fiber content cannot be determined by simple elemental analysis. Therefore, first, a scanning electron microscope (SEM) is used. -The composition of each component constituting the fiber layer or inorganic material layer is qualitatively determined including trace components by elemental mapping such as energy dispersive X-ray spectroscopy (EDX) and fluorescent X-ray analysis (XRF). , The fiber content can be determined by performing a precise quantitative analysis such as inductively coupled plasma (ICP) emission analysis.

In the sound absorbing material of the present invention, it is desirable that the fiber layer is formed by laminating two or more fiber layers.
By using two or more fiber layers, the thickness of the sound absorbing material can be easily adjusted.

In the sound absorbing material of the present invention, it is desirable that the fiber layer is composed of inorganic fibers.
Inorganic fibers have high heat resistance, and sound absorption performance can be easily obtained even in a high temperature usage environment.

In the sound absorbing material of the present invention, the thickness of the inorganic material layer is preferably 0.1 mm or more.
If the thickness of the inorganic material layer is less than 0.1 mm, it becomes difficult to obtain the vibration effect due to the presence of the inorganic material layer, and it becomes difficult to maintain the sound absorbing performance against a temperature change of 300 ° C. or higher.
The thickness of the inorganic material layer in the sound absorbing material of the present invention is more preferably 0.1 to 50 mm. If the thickness of the inorganic material layer exceeds 50 mm, there is no problem with the functional performance and sound absorption as a sound absorbing material, but when the sound absorbing material is used for vehicle applications such as engines, engine rooms, vehicle interiors, vehicle bodies, and exhaust pipes. , The thickness becomes a bottleneck, and it may not be possible to arrange the sound absorbing material for vehicle applications.

In the sound absorbing material of the present invention, the fibers constituting the fiber layer are selected from at least one inorganic fiber selected from the group consisting of alumina fibers, alumina-silica fibers, silica fibers, biosoluble fibers, glass wool and rock wool. It is desirable to be.
These inorganic fibers have high heat resistance and do not easily change their shape due to temperature changes. Therefore, it is suitable as an inorganic fiber constituting a fiber layer.

In the sound absorbing material of the present invention, the fiber constituting the inorganic material layer is at least one inorganic fiber selected from the group consisting of alumina fiber, alumina-silica fiber, silica fiber, biosoluble fiber, glass wool and rock wool. It is desirable to consist of.
These inorganic fibers have high heat resistance and do not easily change their shape due to temperature changes. Therefore, it is suitable as an inorganic fiber constituting an inorganic material layer.

In the sound absorbing material of the present invention, it is desirable that the inorganic particles are at least one material selected from the group consisting of silica-based materials, alumina-based materials, carbon-based materials, and titania-based materials.
Combining these materials with the fibers constituting the inorganic material layer can increase the sound absorption coefficient in the frequency range of 800 to 2000 Hz.

In the sound absorbing material of the present invention, it is desirable that the inorganic particles are at least one material selected from the group consisting of silica particles, silica sol, silica gel, alumina particles, carbon particles and titania particles.
When these materials are combined with the fibers constituting the inorganic material layer, the sound absorption coefficient in the frequency range of 800 to 2000 Hz can be further increased.

The sound absorbing material of the present invention preferably has an average sound absorbing coefficient of 0.6 or more in the frequency range of 800 to 2000 Hz.
Sounds in the frequency range of 800 to 2000 Hz are unpleasant to humans. When the average sound absorption coefficient in this frequency region is 0.6 or more, it is possible to absorb sounds that are unpleasant for humans, so it can be said that the sound absorption performance as a sound absorbing material is obtained.
In the present invention, the "sound absorption coefficient" means the sound absorption coefficient measured according to JIS A 1405-2: 2007 "Measurement of sound absorption coefficient and impedance by acoustic tube-Part 2: Transfer function method". ..

In the sound absorbing material of the present invention, it is desirable that the sound absorbing material is used for at least one part including an engine, an engine room, a vehicle interior, a vehicle body, and an exhaust pipe.
Since the sound absorbing material of the present invention has a sound absorbing performance in which the average sound absorbing coefficient in the frequency range of 800 to 2000 Hz is 0.6 or more, it can be suitably used for the above-mentioned applications.

The vehicle component of the present invention is formed by arranging the sound absorbing material of the present invention so that the inorganic material layer is in contact with the surface of a member constituting an engine, an engine room component, a vehicle interior, a vehicle body, or an exhaust pipe. It is characterized by.
Since the sound absorbing material of the present invention has an average sound absorbing coefficient of 0.6 or more in the frequency range of 800 to 2000 Hz, the sound absorbing material is used as a member for an engine, engine room parts, vehicle interior, vehicle body, or exhaust pipe. The vehicle component of the present invention, which is arranged so that the inorganic material layer is in contact with the surface, can prevent the transmission of sound to a person in the vehicle.

FIG. 1 is a cross-sectional view schematically showing an example of the sound absorbing material of the present invention. FIG. 2A is a schematic view showing an example of a fiber layer constituting the sound absorbing material of the present invention, and FIG. 2B is a schematic diagram showing an example of an inorganic material layer constituting the sound absorbing material of the present invention. Is. FIG. 3 is an explanatory diagram schematically showing a measuring device for a vertically incident sound absorption coefficient with respect to a sound absorbing material. FIG. 4 is a chart of the sound absorption coefficient in the sound absorption coefficient measurement using the sound absorbing material according to the first embodiment. FIG. 5 is a chart of the sound absorption coefficient in the sound absorption coefficient measurement using the sound absorbing material according to Comparative Example 1. FIG. 6 is a chart of the sound absorption coefficient in the sound absorption coefficient measurement using the sound absorbing material according to Comparative Example 2. FIG. 7 is a chart of the sound absorption coefficient in the sound absorption coefficient measurement using the sound absorbing materials according to Example 1, Comparative Example 1 and Comparative Example 2.

(Detailed description of the invention)
Hereinafter, the sound absorbing material of the present invention will be described in detail.

The sound absorbing material of the present invention is a sound absorbing material composed of a fiber layer and an inorganic material layer, and the fiber layer and the inorganic material layer are in contact with each other, and the fiber content in the fiber layer exceeds 50% by weight. The inorganic material layer is composed of fibers and inorganic particles, and the content of the fibers in the inorganic material layer is 50% by weight or less.

The configuration of the sound absorbing material of the present invention will be described with reference to FIG.
FIG. 1 is a cross-sectional view schematically showing an example of the sound absorbing material of the present invention.
As shown in FIG. 1, the sound absorbing material 1 is composed of a fiber layer 10 and an inorganic material layer 20 laminated on the fiber layer 10.

The fiber layer and the inorganic material layer constituting the sound absorbing material of the present invention will be described with reference to FIGS. 2 (a) and 2 (b).
FIG. 2A is a schematic view showing an example of a fiber layer constituting the sound absorbing material of the present invention, and FIG. 2B is a schematic diagram showing an example of an inorganic material layer constituting the sound absorbing material of the present invention. Is.
As shown in FIG. 2A, the fiber layer 10 is composed of fibers 11. As shown in FIG. 2B, the inorganic material layer 20 is composed of fibers 21 and inorganic particles 22. The fiber 11 is a fiber constituting the fiber layer 10, and the fiber 21 is a fiber constituting the inorganic material layer 20.
It is desirable that the sound absorbing material of the present invention is used by arranging an inorganic material layer on the sound source side.

The thickness of the fiber layer constituting the sound absorbing material of the present invention is preferably 3 mm or more, and more preferably 3 to 50 mm.
If the thickness of the fiber layer is less than 3 mm, it is too thin to absorb sound, and it becomes difficult to secure sufficient sound absorption performance.
If the thickness of the fiber layer exceeds 50 mm, there is no problem in terms of functional performance and sound absorption as a sound absorbing material, but the sound absorbing material is used for vehicle applications such as engines, engine rooms, vehicle interiors, vehicle bodies, and exhaust pipes. At that time, the thickness becomes a bottleneck, and it may not be possible to arrange the sound absorbing material for vehicle use.

In the sound absorbing material of the present invention, the fiber layer may be formed by laminating two or more fiber layers.
By using two or more fiber layers, the thickness of the sound absorbing material can be easily adjusted. The two or more fiber layers may be adhered by an adhesive such as an inorganic adhesive or an organic adhesive.

Further, the types of materials such as fibers constituting each fiber layer in the two or more fiber layers may be the same type or different types.
The thickness of each fiber layer in the two or more fiber layers may be the same or different. The bulk density of each fiber layer in the two or more fiber layers may be the same bulk density or different bulk densities.

In the sound absorbing material of the present invention, it is desirable that the fiber layer is composed of inorganic fibers.
That is, it is desirable that the fibers constituting the fiber layer are inorganic fibers.
Inorganic fibers have high heat resistance and do not easily change shape due to temperature changes. Therefore, by using an inorganic fiber for the fiber layer, sound is absorbed even in the voids formed by the fiber, so that sound absorption performance can be easily obtained.

In the sound absorbing material of the present invention, the fibers constituting the fiber layer are at least one inorganic fiber selected from the group consisting of alumina fibers, alumina-silica fibers, silica fibers, biosoluble fibers, glass wool and rock wool. Is desirable.
These inorganic fibers have high heat resistance and do not easily change their shape. Therefore, it is suitable as an inorganic fiber constituting a fiber layer.
It is more desirable that the inorganic fibers constituting the fiber layer are alumina-silica fibers.

When alumina-silica fiber is used as the inorganic fiber, the composition ratio of alumina to silica is preferably alumina (Al ₂ O ₃ ): silica (SiO ₂ ) = 60: 40 to 80:20 in terms of weight ratio. , Alumina (Al ₂ O ₃ ): Silica (SiO ₂ ) = 70:30 to 74:26.

The average fiber length of the fibers constituting the fiber layer is preferably 0.1 to 150 mm, more preferably 1 to 20 mm, and even more preferably 2 to 15 mm.
If the average fiber length of the fibers constituting the fiber layer is less than 0.1 mm, the fibers are too short, so that the fibers are less likely to be entangled with each other in the fiber layer, and it is difficult to obtain the strength of the fiber layer, and the shape of the fiber layer is maintained. The property deteriorates, and it cannot serve as a sound absorbing material.
If the average fiber length of the fibers constituting the fiber layer exceeds 150 mm, the fibers are too long and it becomes difficult to prepare the fiber layer. Further, since the denseness of the fiber layer is lowered and the shear strength is also lowered, defects such as cracks are likely to occur as the sound absorbing material, and the function as the sound absorbing material cannot be fulfilled.

Further, the fiber layer constituting the sound absorbing material can be obtained by various methods, but can be produced by a needling method or a manufacturing method.

The fiber layer obtained by the needling method exhibits an entangled structure. In order to obtain this structure, the fibers need to have a certain average fiber length. Therefore, the average fiber length of the fibers used in the needling method is preferably 1 to 150 mm, more preferably 10 to 80 mm.
If the average fiber length of the fibers is less than 1 mm, the fiber lengths of the fibers are too short, so that the fibers are not sufficiently entangled with each other, the strength of the fiber layer is difficult to obtain, and the shape retention of the fiber layer is lowered. Therefore, it cannot serve as a sound absorbing material. Further, when the sound absorbing material is wound around the exhaust gas treated body, the wrapping property is lowered and the sound absorbing material is easily cracked.
If the average fiber length of the fibers exceeds 150 mm, the fiber lengths of the fibers are too long, and the fibers may be excessively entangled with the needles during needling, making it difficult to control the shape of the sound absorbing material. The needle marks formed in the fiber layer obtained by the needling method are in a state where the fibers are continuously entangled along the thickness direction of the fiber layer, and are not through holes formed in the fiber layer.

The average fiber length of the fibers constituting the fiber layer obtained by the fabrication method is preferably 0.1 to 20 mm.
If the average fiber length of the fiber is less than 0.1 mm, the fiber length of the fiber is too short, and the shape retention as a fiber layer is lowered. Further, when the fiber aggregate of the fiber layer is formed, suitable entanglement does not occur between the fibers, and it becomes difficult to obtain a sufficient surface pressure.
When the average fiber length of the fiber exceeds 20 mm, it is necessary to further increase the fiber length of the fiber used as a raw material at the time of papermaking. However, since the fiber length of the fiber is too long, the entanglement of the fibers in the slurry solution in which the fibers are dispersed in water in the papermaking process becomes too strong, and the fibers are unevenly accumulated when the fiber aggregate of the fiber layer is formed. Since it is easy to carry out and the shear strength is also lowered, defects such as cracks are likely to occur as a sound absorbing material.

To measure the fiber length, tweezers are used in both the needling method and the fabrication method to extract the fiber from the fiber layer so that the fiber does not break, and the fiber length is measured using an optical microscope.
In the present specification, the average fiber length means the average length obtained by extracting 300 fibers from the fiber layer and measuring the fiber length. If the fibers cannot be removed from the fiber layer without breaking, the fiber layer should be degreased, the degreased fiber layer should be put into water, and the fibers should be collected so as not to break while loosening the entanglement between the fibers. ..

The average fiber diameter of the fibers constituting the fiber layer is preferably 1 to 20 μm, more preferably 2 to 15 μm, and even more preferably 3 to 10 μm.
When the average fiber diameter of the fiber is less than 1 μm, the fiber strength is weak and the fiber is easily cut by an impact or the like. Therefore, it becomes difficult to obtain the strength of the fiber layer, and it cannot serve as a sound absorbing material.
When the average fiber diameter of the fiber exceeds 20 μm, the fiber diameter is too large, the Young's modulus of the fiber itself becomes high, and the flexibility of the fiber layer tends to be low. Therefore, it cannot serve as a sound absorbing material.

The fiber layer of the present invention may contain fibers such as glass fibers and biosoluble fibers in addition to the above-mentioned inorganic fibers.

In the sound absorbing material of the present invention, the thickness of the inorganic material layer is preferably 0.1 mm or more.
If the thickness of the inorganic material layer is less than 0.1 mm, it becomes difficult to obtain the vibration effect due to the presence of the inorganic material layer, and it becomes difficult to maintain the sound absorbing performance.
The thickness of the inorganic material layer in the sound absorbing material of the present invention is more preferably 0.1 to 50 mm. If the thickness of the inorganic material layer exceeds 50 mm, there is no problem with the functional performance and sound absorption as a sound absorbing material, but when the sound absorbing material is used for vehicle applications such as engines, engine rooms, vehicle interiors, vehicle bodies, and exhaust pipes. , The thickness becomes a bottleneck, and it may not be possible to arrange the sound absorbing material for vehicle applications.

In the sound absorbing material of the present invention, the fibers constituting the inorganic material layer are selected from at least one inorganic fiber selected from the group consisting of alumina fibers, alumina-silica fibers, silica fibers, biosoluble fibers, glass wool and rock wool. It is desirable to be.
These inorganic fibers have high heat resistance and do not easily change their shape due to temperature changes. Therefore, it is suitable as an inorganic fiber constituting an inorganic material layer.

The average fiber diameter of the fibers constituting the inorganic material layer is preferably 1 to 20 μm, more preferably 2 to 15 μm, and even more preferably 3 to 10 μm.
When the average fiber diameter of the fibers constituting the inorganic material layer is less than 1 μm, the fiber strength is weak and the fibers are easily cut by impact or the like. Therefore, it becomes difficult to obtain the strength of the inorganic material layer, and it cannot serve as a sound absorbing material. On the other hand, when the average fiber diameter of the fibers constituting the inorganic material layer exceeds 20 μm, the fiber diameter is too large, the Young's modulus of the fiber itself becomes high, and the flexibility of the inorganic material layer tends to be low. Therefore, when it is arranged as a sound absorbing material, it is easily damaged and cannot serve as a sound absorbing material.

The average fiber length of the fibers constituting the inorganic material layer is preferably 0.1 to 20 mm.
If the average fiber length of the fibers constituting the inorganic material layer is less than 0.1 mm, the fibers are too short, so that the fibers are less likely to be entangled with each other in the inorganic material layer, and it is difficult to obtain the strength of the inorganic material layer. The shape retention of the layer is lowered, and the layer cannot serve as a sound absorbing material.
When the average fiber length of the fibers constituting the inorganic material layer exceeds 20 mm, it is necessary to further increase the fiber length of the fibers used as a raw material at the time of papermaking. However, since the fiber length of the fiber is too long, the entanglement of the fibers in the slurry solution in which the fibers are dispersed in water in the papermaking process becomes too strong, and the fibers are unevenly accumulated when the fiber aggregate of the fiber layer is formed. It becomes easy to do, the shear strength also decreases, and defects such as cracks easily occur as a sound absorbing material. Further, since the denseness of the inorganic material layer is lowered and the shear strength is also lowered, defects such as cracks are likely to occur as the sound absorbing material, and the sound absorbing material cannot serve as a sound absorbing material.

In the sound absorbing material of the present invention, the inorganic particles constituting the inorganic material layer are preferably at least one material selected from the group consisting of silica-based materials, alumina-based materials, carbon-based materials, and titania-based materials. Further, the inorganic material layer may be composed of these single materials or may be composed of a plurality of materials.
Combining these materials with the fibers constituting the inorganic material layer can increase the sound absorption coefficient in the frequency range of 800 to 2000 Hz.

Examples of the silica-based material include silica particles, silica sol, and silica gel.
Examples of the alumina-based material include alumina particles.
Examples of the carbon-based material include carbon particles and the like.
Examples of the titania-based material include titania particles.

The shape of the inorganic particles is not particularly limited, and examples thereof include a spherical shape, an elliptical spherical shape, a needle shape, a plate shape, and a polyhedron having a tetrahedron or more.

The average particle size of the inorganic particles is preferably 0.5 to 20 μm.
The particle size of the inorganic particles whose particle shape is not spherical is defined as the diameter equivalent to the projected area circle (also referred to as Haywood diameter).

The weight ratio of the fibers constituting the inorganic material layer to the inorganic particles is preferably 1:99 to 50:50, more preferably 5:95 to 50:50, and is 10:90 to 40:60. It is even more desirable to have.

As the combination of the fibers constituting the inorganic material layer and the inorganic particles, alumina-silica fibers are used as the fibers constituting the inorganic material layer, and the inorganic particles are a silica-based material, a titania-based material, or a mixture of the silica-based material and the titania-based material. The combination using is desirable.

The sound absorbing material of the present invention preferably has an average sound absorbing coefficient of 0.6 or more in the frequency range of 800 to 2000 Hz.
Sounds in the frequency range of 800 to 2000 Hz are unpleasant to humans. When the average sound absorption coefficient in this frequency region is 0.6 or more, it is possible to absorb sounds that are unpleasant for humans, so it can be said that the sound absorption performance as a sound absorbing material is obtained.

The shape of the sound absorbing material of the present invention is not particularly limited as long as it fits in the place where the sound absorbing material is arranged.

The use of the sound absorbing material of the present invention is not particularly limited, but it is desirable that it is used for vehicle applications, and specifically, it may be used for any of an engine, an engine room, a vehicle interior, a vehicle body, and an exhaust pipe. desirable.
The sound absorbing material of the present invention can obtain sound absorbing performance in a low frequency region of 800 to 2000 Hz. Therefore, it can be suitably used for vehicle applications.

Further, when the sound absorbing material is used for the engine, the engine room, the vehicle interior, the vehicle body, and the exhaust pipe, it may be arranged on a curved surface. In such a case, it is necessary to bend the sound absorbing material. In this case, stress is generated in the sound absorbing material, and cracks and cracks are likely to occur in the inorganic material layer. Therefore, a sound absorbing material having a shape that matches the shape of the curved surface may be prepared in advance and arranged on the curved surface. Further, by preparing a large number of small sound absorbing materials and arranging the large number of the sound absorbing materials on a curved surface, the stress generated in each sound absorbing material can be relaxed and the inorganic material layer can be prevented from cracking or cracking. good.

The vehicle parts of the present invention will be described.
The vehicle component of the present invention is formed by arranging the sound absorbing material of the present invention so that the inorganic material layer is in contact with the surface of a member constituting an engine, an engine room component, a vehicle interior, a vehicle body, or an exhaust pipe. It is characterized by.
Since the sound absorbing material of the present invention has an average sound absorbing coefficient of 0.6 or more in the frequency range of 800 to 2000 Hz, the sound absorbing material is used as a member for an engine, engine room parts, vehicle interior, vehicle body, or exhaust pipe. The vehicle component of the present invention, which is arranged so that the inorganic material layer is in contact with the surface, can prevent the transmission of sound to a person in the vehicle.

Next, an example of the method for producing the sound absorbing material of the present invention will be described.
The method for producing a sound absorbing material of the present invention described below includes (1) a fiber layer manufacturing step, (2) an inorganic material layer forming step, and (3) a laminating step.

(1) Fiber layer manufacturing process In this step, a fiber layer is prepared. The method of preparing the fiber layer is not particularly limited. The method of preparing the fiber layer by the fabrication method, which is an example thereof, will be described below. The fabrication method described below includes a mixture preparation step, a dehydration step, and a heating and pressurizing step.

(Mixed solution preparation step)
A mixture is prepared by mixing the fiber, the inorganic binder, and water and stirring with a stirrer. At this time, an organic binder may be mixed if necessary. Since the desirable types of fibers used in this step have already been described, the description thereof will be omitted here.

(Dehydration step)
The mixed solution obtained in the mixed solution preparation step is poured into a molding machine having a mesh for filtration formed on the bottom surface. Then, the water in the mixed solution is dehydrated through the mesh to prepare a raw material sheet.

(Heating and pressurizing step)
The raw material sheet is heated and pressed to prepare a fiber layer. Further, at the time of heating and pressurizing, the raw material sheet may be subjected to a heat treatment in which hot air is aerated to dry the raw material sheet, or may be in a wet state without the heat treatment.
The fiber layer can be prepared through the above steps.

(2) Inorganic material layer forming step In this step, an inorganic material layer is formed. The method for forming the inorganic material layer is not particularly limited, but a method of dispersing a mixture of fibers and inorganic particles in a solvent and pouring the mixture into a molding machine using a mesh or the like on the bottom surface to remove the solvent (absorption). ), And a method (impregnation) of applying a solvent in which inorganic particles are dispersed to a layered material made of fibers to remove the solvent.
The method of forming the inorganic material layer by papermaking will be described below.

(Raw material preparation step)
In this step, an inorganic material layer slurry for forming an inorganic material layer by desolvation is prepared. Since the types of fibers and inorganic particles used as raw materials have already been described, the description thereof will be omitted here.

(Inorganic material layer slurry preparation step)
In this step, first, water as a solvent is mixed with fibers and inorganic particles to prepare an inorganic material layer slurry. At this time, an organic binder, an inorganic binder, or the like may be added as needed. As the organic binder, an acrylic resin such as polyacrylamide can be used. As the inorganic binder, silica gel, silica sol, silica gel or the like can be used.

(Papering step)
In this step, the inorganic material layer slurry prepared in the inorganic material layer slurry preparation step is poured onto a mesh having a predetermined shape, and the fibers and inorganic particles constituting the inorganic material layer slurry are separated from the solvent to generate a small amount of solvent. A mixture layer consisting of the contained fibers and inorganic particles is obtained.

(Drying step)
In this step, an inorganic material layer is obtained by removing the solvent that could not be completely removed in the fabrication step from the mixture layer. The drying conditions are not particularly limited, but are preferably 70 to 100 ° C. and 5 to 15 minutes.

(3) Laminating step In this step, the fiber layer and the inorganic material layer are laminated.
The method of laminating the fiber layer and the inorganic material layer is not particularly limited, but a method of adhering with an adhesive such as an inorganic adhesive or an organic adhesive or forming an inorganic material layer on the fiber layer [for example, (2) above ) A fiber layer is used instead of the mesh in the step of forming the inorganic material layer].

Through the above steps, the sound absorbing material of the present invention can be produced.

(Example)
Examples of the present invention will be described in more detail below, but the present invention is not limited to these examples.

(Example 1)
(1) Preparation of fiber layer A fiber layer was prepared by a needling method.
The composition ratio of the inorganic fibers after firing is alumina (with respect to the basic aluminum chloride aqueous solution prepared so that the Al content is 70 g / L and Al: Cl = 1: 1.8 (atomic ratio). A _{silica sol was blended so that Al 2} O ₃ ): silica (SiO ₂ ) = 72: 28 (weight ratio), and an appropriate amount of an organic polymer (polyvinyl alcohol) was further added to prepare a mixed solution.
The obtained mixture was concentrated to prepare a mixture for spinning, and this mixture for spinning was spun by a blowing method to prepare an inorganic fiber precursor.
The spun inorganic fiber precursors were laminated and subjected to needling treatment to prepare two sheet-like substances.
Each of the obtained sheet-like materials is continuously fired at a maximum temperature of 1250 ° C., and is an inorganic fiber (fiber) containing alumina and silica in a length of 50 mm, a width of 50 mm, and a thickness of 7 mm at a ratio of 72:28 (weight ratio). One fiber layer composed of fibers constituting the layer) was obtained.
The bulk density of the obtained fiber layer was 0.15 g / cm ³ , and the basis weight was 1050 g / m ² .
Since the obtained fiber layer was composed only of the above-mentioned inorganic fibers, the fiber content in the fiber layer was 100% by weight.
(2) Preparation of Inorganic Material Layer An inorganic material layer was prepared by a manufacturing method.
Ceramic fiber (Product name: Ibiwool-E bulk Manufacturer: IBIDEN Co., Ltd.) 22 parts by weight, silica particles that are inorganic particles (Product name: CARPLEX # 30 Manufacturer: DSL. Japan Co., Ltd.) 45 parts by weight and titania particles ( Product name: Lucille Flower S Manufacturer: Kinsei Matek Co., Ltd. 22 parts by weight, silica sol which is an inorganic binder (Product name: Snowtex Manufacturer: Nissan Chemical Industry Co., Ltd.) 8 parts by weight and powdered sulfuric acid band (Manufacturer: Oji) A raw material solution was prepared by mixing 1 part by weight of Paper Manufacturing Co., Ltd. and 2 parts by weight of cationic polyacrylamide (product name: RD7142 manufacturer: Starlight PMC Co., Ltd.), which is an organic binder, with 200 parts by weight of water.
The prepared raw material liquid is poured into a molding machine having a mesh of 40 mm × 40 mm formed on the bottom surface so that the basis weight is 400 g / cm ^2, and the water in the raw material liquid is dehydrated through the mesh to form a raw material sheet. Made. The raw material sheet was compressed and dried to obtain an inorganic material layer having a thickness of 7 mm. The density of the inorganic material layer was 4 g / cm ³ .
When the fiber content in the obtained inorganic material layer was measured by elemental analysis (using SEM-EDX and ICP in combination), the content was 22% by weight.
The sound absorbing material according to Example 1 was obtained by laminating the inorganic material layer obtained in (2) on the fiber layer obtained in (1).

(Comparative Example 1)
Comparative Example 1 in the same procedure as in Example 1 except that (1) the fiber layer to be produced in the production of the fiber layer was formed into 7 mm thick × 2 sheets and laminated, and (2) the inorganic material layer was not produced. The sound absorbing material according to the above was prepared.

(Comparative Example 2)
Sound absorption according to Comparative Example 2 in the same procedure as in Example 1 except that (1) the fiber layer was not produced and (2) the thickness of the inorganic material layer produced in the production of the inorganic material layer was changed to 14 mm. The material was prepared.

(Measurement of sound absorption coefficient)
The sound absorption coefficient was determined by a vertical incident sound absorption coefficient test. The measurement was performed according to JIS A 1405-2: 2007 "Measurement of sound absorption coefficient and impedance by acoustic tube-Part 2: Transfer function method".
When measuring the sound absorption coefficient, the sound absorbing materials according to Example 1 and Comparative Examples 1 and 2 are cut into a circle having a diameter of Φ29 mm to prepare a measurement sample, and a vertically incident sound absorption coefficient measuring device (Nitto Boseki Acoustics). After arranging it in the acoustic tube of Engineering model number: WinZac MTX), the measurement was performed in the frequency range of 500 to 6400 Hz.

FIG. 3 is an explanatory diagram schematically showing a measuring device for a vertically incident sound absorption coefficient with respect to a sound absorbing material.
In this measuring device 80, a sample 82 is arranged at the tip of the acoustic tube 81, noise is generated from the speaker 84 by a signal from the noise generator 83, and a sound field is generated inside the acoustic tube 81. Then, the sound pressure signals of the two 1/4 inch microphones 85 and 86 are FFT (Fast Fourier Transform) analyzed by the FFT analyzer 87, and the vertically incident sound absorption coefficient is calculated.
Table 1 shows which side of each sound absorbing material is arranged toward the speaker (sound source) side.
The charts for measuring the sound absorption coefficient of the sound absorbing materials according to Example 1 and Comparative Examples 1 and 2, respectively, are shown in FIGS. 4 and 5 to 6, respectively. Further, FIG. 7 shows a collection of charts for measuring the sound absorption coefficient of Example 1, Comparative Example 1 and Comparative Example 2. In FIGS. 4 to 7, the vertical axis represents the vertical incident sound absorption coefficient, and the horizontal axis represents the frequency.
Further, the average sound absorption coefficient of each angular frequency of 800, 1000, 1250, and 2000 Hz divided into 1/3 octave bands is calculated, and is shown in Table 1 together with the maximum sound absorption coefficient.

As shown in Table 1, the sound absorbing material according to Example 1 had an average sound absorbing coefficient of 0.6 or more in the frequency band of 800 to 2000 Hz. Since a sound having a frequency of 800 to 2000 Hz becomes an unpleasant sound for a person, the sound absorbing material according to Example 1 having a high sound absorbing coefficient in this frequency region is an excellent sound absorbing material. On the other hand, the sound absorbing materials according to Comparative Examples 1 and 2 had an average sound absorbing coefficient of less than 0.6 in the frequency band of 800 to 2000 Hz.

Further, as shown in Table 1 and FIG. 7, the sound absorbing material according to Example 1 in which the inorganic material layer is laminated on the fiber layer includes the sound absorbing material according to Comparative Example 1 consisting only of the fiber layer and the inorganic material layer. It was found that the sound absorbing material exhibited excellent sound absorbing performance in the frequency band of 800 to 2000 Hz as compared with the sound absorbing material according to Comparative Example 2 consisting of only fibers.

1 Sound absorbing material 10 Fiber layer 11 Fiber 20 Inorganic material layer 21 Fiber 22 Inorganic particles 80 Measuring device 81 Acoustic tube 82 Sample 83 Noise generator 84 Speaker 85, 86 Microphone 87 FFT analyzer

Claims (9)

Ri Do from the fiber layer and an inorganic material layer,
The fiber layer and the inorganic material layer are in contact with each other.
The fiber content in the fiber layer exceeds 50% by weight.
The inorganic material layer is composed of fibers and inorganic particles.
The fibers constituting the fiber layer consist of at least one inorganic fiber selected from the group consisting of alumina fibers, alumina-silica fibers, silica fibers, biosoluble fibers, glass wool and rock wool.
The content of the fibers in the inorganic material layer state, and are 50 wt% or less,
The density of the inorganic material layer is ³ to 6 g / cm 3.
A sound absorbing material having an average sound absorbing coefficient of 0.6 or more in the frequency range of 800 to 2000 Hz is arranged so that the inorganic material layer is in contact with the surface of the engine, engine room parts, or members constituting the exhaust pipe. Vehicle parts featuring . The vehicle component according to claim 1, wherein the density of the fiber layer is smaller than the density of the inorganic material layer. The vehicle component according to claim 1 or 2 , wherein the fiber layer has a thickness of 3 mm or more. The vehicle component according to any one of claims 1 to 3 , wherein the fiber layer is formed by laminating two or more fiber layers. The vehicle component according to any one of claims 1 to 4 , wherein the fiber layer is made of an inorganic fiber. The vehicle component according to any one of claims 1 to 5 , wherein the thickness of the inorganic material layer is 0.1 mm or more. Claims 1 to 6 wherein the fiber constituting the inorganic material layer is composed of at least one inorganic fiber selected from the group consisting of alumina fiber, alumina-silica fiber, silica fiber, biosoluble fiber, glass wool and rock wool. Vehicle parts described in any of. The vehicle component according to any one of claims 1 to 7 , wherein the inorganic particles are at least one material selected from the group consisting of silica-based materials, alumina-based materials, carbon-based materials, and titania-based materials. The vehicle component according to claim 8 , wherein the inorganic particles are at least one material selected from the group consisting of silica particles, silica sol, silica gel, alumina particles, carbon particles and titania particles.

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