JP3972296B2 - Sound absorbing material and vehicle interior material - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sound-absorbing material that is excellent in sound-absorbing properties and vibration-damping properties despite being lightweight and thin. Specifically, the present invention relates to a sound absorbing material having excellent sound absorbing characteristics at 500 Hz to 4000 Hz. Furthermore, the present invention relates to a sound-absorbing material having good formability that does not break even if the deformation at the throttle portion during molding in a wide temperature range is large.
[0002]
[Prior art]
Short fiber nonwoven fabrics are widely used as sound absorbing materials for automobiles and construction applications. In order to increase the sound absorption performance, methods such as reducing the fiber diameter to increase the air passage resistance and increasing the basis weight have been adopted. As a result, when high sound absorption performance is required, a relatively thin fiber having a fiber diameter of about 15 μm is used, and a thick and heavy short fiber nonwoven fabric having a basis weight of 500 to 5000 g / cm ² is used.
Non-woven fabrics containing ultrafine fibers have excellent properties such as sound absorbing properties, filter properties, and shielding properties and have been used in many applications, but there are problems such as low strength and poor shape stability. For improvement, it has been used by laminating with another non-woven fabric. At this time, as a method for laminating and integrating the nonwoven fabrics, a resin or a heat-sealing fiber that becomes a binder by spraying or transfer has been used. However, these methods require heat treatment for the purpose of drying or melting and bonding the resin, and are not very preferable from the viewpoint of environmental pollution caused by exhaust gas and energy saving. In addition, there is a problem that the binder resin forms a film at the interface between the nonwoven fabrics, resulting in a decrease in sound absorption.
[0003]
On the other hand, the method of laminating and integrating the ultrafine fiber nonwoven fabric and the long fiber nonwoven fabric is to laminate the meltblown nonwoven fabric (M), which is an ultrafine fiber, between the spunbond nonwoven fabric (S), commonly known as S / M / S. There is a known method of joining by hot embossing. However, these nonwoven fabrics have a problem in that they lack volume and have a hard texture, which limits their application.
A non-woven fabric called a coform, which is a composite of melt-blown non-woven fabric blown with short fibers of about 20-30 μm, has been commercialized and is said to exhibit excellent sound absorption performance.
[0004]
The nonwoven fabric using extra fine fibers has a problem that the sound absorbing performance is not so good in a low frequency region around 500 Hz, although the sound absorbing performance in a high frequency region of 800 Hz or more is excellent. Further, in order to solve this problem, it is possible to use a method of increasing the thickness to about 20 to 50 mm. However, in that case, there is a problem that the sound absorption performance in the high frequency range is lowered.
[0005]
In recent years, with the progress of miniaturization and weight reduction mainly for automobile applications, it has become difficult to take the conventional method of sound insulation using a high-weight sound-absorbing material, so lightweight nonwoven fabric with high sound-absorbing performance in the low frequency range Is required. However, when the thickness of the conventional nonwoven fabric is increased to increase the sound absorption rate in the low frequency range, there is a problem that the sound absorption performance is deteriorated in the high frequency range. In addition, it has been confirmed that when a film-like sheet is bonded to the surface of a porous sound absorbing material, the sound absorbing performance in a low frequency range of 500 to 1000 Hz is remarkably improved, but the sound absorption in a high frequency range of 2000 Hz or higher is confirmed. There was a problem that the performance was not good. In addition, automobile interior materials are often three-dimensionally molded for sound absorbing materials incorporated into electrical products, etc. However, if the diaphragm at the time of molding is deep, deformation at the diaphragm will be large and deformation of the sound absorbing material cannot be followed. There was a problem of running out.
[0006]
[Problems to be solved by the invention]
An object of the present invention is to provide a low-frequency sound-absorbing material that has high sound-absorbing performance even in a low frequency range and is thin and lightweight and has good shape stability. In particular, in automobiles, lightweight and excellent sound absorbing materials are required for improving fuel efficiency and comfort, and the purpose is to meet the demand. The present invention relates to a sound-absorbing material having good formability that does not break even if the deformation at the throttle portion during molding is large. Moreover, it aims at providing a flame-retardant sound-absorbing material as needed.
[0007]
[Means for Solving the Problems]
The present invention takes the following means in order to solve this problem.
The first invention is a short fiber nonwoven fabric in which a nonwoven fabric is bonded to a resin layer having a glass transition temperature of 50 ° C. or less, a fiber diameter of 7 to 50 μm, a basis weight of 50 to 2000 g / m ² , and a thickness of 4 to 50 mm. Is a sound-absorbing material characterized by being laminated and integrated.
[0008]
According to a second invention, in the first invention, the Frazier air permeability of the layer in which the resin layer having a glass transition temperature of 50 ° C. or lower and the nonwoven fabric is bonded is 0.05 to 50 cm ³ / cm ² · sec. Is a sound-absorbing material.
[0009]
The third invention is the first or second invention, wherein the nonwoven fabric bonded to the resin layer is a hydroentangled nonwoven fabric, a nonwoven fabric composed of core-sheath type composite fibers, a nonwoven fabric composed of polytrimethylene terephthalate fibers, and A sound-absorbing material characterized in that the sound-absorbing material is any one of nonwoven fabrics composed of block-copolymerized polyester fibers having a hard segment and a soft segment.
[0010]
According to a fourth aspect of the present invention, there is provided a vehicle interior material characterized in that a member formed by molding the sound absorbing material according to any one of the first to third aspects is used at least in part.
[0011]
According to a fifth aspect of the present invention, there is provided an interior material for a vehicle, wherein the molded member according to the fourth aspect is a member used for any one of a ceiling material, a dashboard lower portion, and a carpet portion.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
The present invention is described in detail below.
The sound absorbing material in the present invention requires at least a layer in which a resin layer having a glass transition temperature of 50 ° C. or less and a nonwoven fabric are bonded together. In addition, the glass transition temperature in this invention is a temperature calculated | required by the peak temperature of internal transmission loss (tan-delta).
[0013]
The resin used for the resin layer has a glass transition temperature of 50 ° C. or lower, preferably 40 ° C. or lower. The resin having a glass transition temperature of 50 ° C. or lower is not particularly limited, and examples thereof include polyester elastomers, polyolefin elastomers, polyolefins such as polyethylene, and the like. The inventors have found that the sound absorption characteristics are excellent when the glass transition temperature of the resin layer is 50 ° C. or lower. When the glass transition temperature is higher than 50 ° C., the bending rigidity is high and the deformation is difficult. The tendency to generate abnormal noise is increased. Although it is not clear about the performance expression mechanism of the sound-absorbing material of the present invention, it is presumed that the air between the resin layer and the back wall surface resonates. Moreover, since the internal transmission loss tends to increase when the glass transition temperature is close to room temperature, there is a possibility that the sound absorption performance can be further improved.
[0014]
When the thickness of the resin layer is approximately 30 to 50 μm, sound reflection on the surface of the sound absorbing material is increased and the sound absorbing performance in a high frequency range of about 2000 Hz or more tends to be lowered. As a countermeasure, it is preferable to make a hole by making a hole by a needle punch method or the like. Within the scope of the study by the present inventor, it was recognized that the higher the air permeability was set, the better the sound absorption performance as the resin having a higher glass transition temperature was used.
[0015]
The method for laminating the resin layer and the nonwoven fabric is not particularly limited, but after the resin film has been created in advance, it may be pasted with an adhesive or the like, but the extrusion lamination method for laminating the resin layer and the nonwoven fabric simultaneously with film formation, etc. The method may be used.
[0016]
The nonwoven fabric to which the resin layer is bonded is preferably 20% or more in elongation. If the elongation is less than 20%, moldability such as deformation following property during deep drawing tends to be deteriorated. Moreover, it is preferable that the fabric weight of this nonwoven fabric is 10-200 g / m < ² >. When the basis weight is smaller than 10 g / m ² , the strength is reduced. On the other hand, when the basis weight exceeds 200 g / m ² , there is a problem that wrinkles occur when the composite with the short fiber nonwoven fabric is formed or the bonding force is weak. There is a case. Further, even if the basis weight is too large, the intended improvement effect such as sound absorption is not changed so much, which is not preferable from the viewpoint of cost reduction and weight reduction.
[0017]
The fiber constituting the nonwoven fabric to which the resin layer is bonded may be either a long fiber or a short fiber, but in the case of a long fiber, a soft material such as an elastomer fiber having a high stretch recovery property is capable of following deformation during deep drawing. From the viewpoint of the above. Moreover, it is preferable from the point of recycling that it is a raw material similar to the short fiber nonwoven fabric laminated | stacked. On the other hand, there is no problem even with a nonwoven fabric in which fibers made of a plurality of materials are mixed.
[0018]
When laminating the nonwoven fabric and the resin layer by the needle punch method, there may be a case where there is a hole in the needle mark due to the needle, and air is channeled through the hole so that the sound absorption rate decreases. If the fiber material or the resin layer is an elastomer, it is deformed and returns to its original shape, so that the size of the hole is reduced and the sound absorption rate is hardly lowered. In the range of investigation by the inventors, when the piercing density is about 100 to 200 places / cm ² , even when the non-elastomer nonwoven fabric or the resin layer is used, the sound absorption performance is remarkably lowered, but in the case of the elastomer, the performance is almost lowered. There is no. Therefore, when an elastomer is used, it is possible to increase the puncture density and increase the peel strength of the laminate, and it is possible to increase the form stability.
[0019]
When a nonwoven fabric having an elongation of 20% or more is used, there is no problem that the deformation is well tracked when deep drawing is performed as an automotive interior material such as a ceiling material, a dash member, and a carpet. Particularly preferred. The nonwoven fabric preferably has appropriate strength characteristics, but may be a nonwoven fabric with few fiber ends produced by a spunbond method, a melt blow method, a flash spinning method, or the like, a point bond method, an area bond method, a thermal bond method, etc. It may be a short fiber nonwoven fabric produced by
[0020]
The resin layer is composed of hydroentangled nonwoven fabric, nonwoven fabric comprising core-sheath composite fibers, nonwoven fabric comprising polytrimethylene terephthalate, nonwoven fabric comprising block copolymerized polyester fibers having hard segments and soft segments. Any of the above is particularly preferable because the following property at the time of molding is very good.
[0021]
As the fiber diameter of the non-woven fabric is thinner, the sound absorbing performance becomes higher, but the strength tends to decrease. When emphasizing sound absorbing performance, the fiber diameter is preferably 1 to 10 μm, and when emphasizing strength, about 12 to 40 μm is preferable.
[0022]
Moreover, it is also one of the preferable forms that the said nonwoven fabric uses the ultrafine fiber obtained using a split fiber or a sea-island type fiber. The split fibers may be those that have been split in advance, or may be split simultaneously during the laminating process using a needle punch or hydroentanglement method.
[0023]
Furthermore, the nonwoven fabric has a basis weight is 20 to 200 g / m ^2. When the basis weight is smaller than 20 g / m ^{2, the} sound absorption effect of the ultrafine fiber cannot be expected so much. On the other hand, if the basis weight exceeds 200 g / m ² , there may be a problem that wrinkles may occur when the composite with the short fiber nonwoven fabric is formed or the bonding force is weak. Moreover, even if the basis weight is too large, the intended improvement effect such as sound absorption is not changed so much, which is not preferable from the viewpoint of cost reduction and weight reduction.
[0024]
The fiber material constituting the nonwoven fabric is not particularly limited, but is a core-sheath type composite fiber having high elongation, a fiber mainly composed of polytrimethylene terephthalate, or a block copolymer polyester having a hard segment and a soft segment. The fiber is more preferable from the viewpoint of deformation followability at the time of deep drawing of the nonwoven fabric. Furthermore, it is particularly preferable that the material is similar to the short fiber nonwoven fabric laminated on the ultrafine fiber because it is easy to recycle. On the other hand, there is no problem even if fibers made of a plurality of materials are mixed. In the case of ultrafine fibers by the melt blow method, it is preferable to use an elastomer because the fibers are long fibers and have almost no cut surface.
[0025]
When an ultra-fine fiber nonwoven fabric is laminated with other nonwoven fabrics by the needle punch method, there is a possibility that holes that are the passage of many needles will be formed by the needle, but in that case, air will channel through the holes. A problem arises that the sound absorption rate is lowered due to blowing, but an elastomer is preferable because it deforms and returns to its original shape, so that the hole size is reduced and the sound absorption rate is hardly lowered. Therefore, in the case of an elastomer, it is possible to increase the peel strength of the laminate by increasing the piercing density, and it is possible to increase the form stability.
[0026]
The short fiber nonwoven fabric laminated on the nonwoven fabric on which the resin layer is bonded has a fiber diameter of 7 to 50 μm, preferably 7 to 20 μm. A fiber diameter smaller than 7 μm does not cause a major problem directly, but is not so preferable in terms of productivity such as spinning from a card machine. On the other hand, when the fiber diameter is significantly smaller than 7 μm, the lamination effect in the present invention is reduced. In addition, other problems may occur, such as the non-woven fabric being easily fluffed. On the other hand, if the fiber diameter is larger than 50 μm, the contribution to the sound absorbing performance tends to be small.
[0027]
Basis weight of the short fiber nonwoven fabric, a short fiber nonwoven fabric of 50 to 2000 g / m ^2. Weight per unit area small lamination effect as 50 g / m ² less than, it is not preferred in view of bulkiness and texture of the nonwoven fabric. On the other hand, when the basis weight is larger than 2000 g / m ² , the thickness becomes too large or the weight becomes heavy. Moreover, the thickness of this short fiber nonwoven fabric is 4-50 mm. If the thickness is thinner than 4 mm, the sound absorption performance tends to be lowered. The larger the thickness, the higher the sound absorption coefficient at a low frequency. However, when the thickness exceeds 50 mm, it is not preferable because it is bulky. When thickness is 5-20 mm, it is preferable from a viewpoint of handling or cost performance.
[0028]
The fiber length of the short fiber nonwoven fabric is preferably 38 to 150 mm, more preferably 50 to 150 mm. Within the scope of the study by the present inventors, the longer the fiber length, the better the sound absorption coefficient. However, when the fiber length was too long, the problem that the spinning property from a card | curd worsened was recognized. The short fiber may be a single component, but may be a mixture of two or more types or a multicomponent composite fiber. If the weight fraction is about 30% or less in order to adjust the stiffness of the nonwoven fabric, the characteristics do not change much even if thicker fibers are mixed. When there are too many thick fibers, it becomes easy to produce problems, such as a nonwoven fabric texture becoming too hard. It is also preferable to use heat-fusible fibers having different melting points from the viewpoint of improving dimensional stability.
[0029]
The weight-based packing density of the short fiber nonwoven fabric is preferably 0.005 to 0.3 g / cm ³ from the viewpoint of bulkiness. If the packing density is too small, the form stability tends to be poor. When the packing density is higher than 0.3 g / cm ³ , the sound absorption tends to be deteriorated.
[0030]
The raw material of the short fiber nonwoven fabric may be a natural fiber or a synthetic fiber. However, when using a hydrophilic fiber, care must be taken not to apply water. This is because if the pores of the nonwoven fabric are clogged with water, the sound absorption performance may be lowered. In addition, from the viewpoint of environmental problems, it is also possible to use a bristles that is a recycled nonwoven fabric.
[0031]
The method for laminating and integrating the nonwoven fabric and the short fiber nonwoven fabric is not particularly limited, and an adhesive, an adhesive powder, or the like can be used, but it is preferable to integrate by a needle punch method. As the needle punch method, basically, a method described in detail in “Basics and Applications of Nonwoven Fabrics” edited by the Nonwoven Fabric Research Society of the Japan Textile Machinery Society can be adopted.
Generally, when laminating non-woven fabrics, there is a problem that there are holes that are passing traces of a large number of needles due to needles, but in the present invention, surprisingly, even with the needle punch method, If the non-woven fabrics are combined with each other, there will be a problem that the sound absorption performance and filter performance will deteriorate due to the influence of relatively thick and bulky short fibers that will cause holes in the uniform ultra-fine fiber non-woven fabric. It can be prevented.
[0032]
When needle punching is performed in the present invention, it is preferable to use a needle (needle) thinner than 38, particularly preferably 40 to 42. It is preferable that the needle enters from the short-fiber non-woven fabric side and causes a short-fiber loop to be formed on the outside of the non-woven fabric containing the ultrafine fibers. Non-woven fabrics containing ultrafine fibers have the disadvantage that the fibers tend to fluff when they are caught by other objects or cut with needles, but the loops of short fibers prevent surface fluffing of non-woven fabrics containing ultrafine fibers or cushions Since it plays the role of a layer and can relieve the external force applied to the ultrafine fiber nonwoven fabric layer, it helps to prevent destruction of the laminate. In addition, when laminating with another nonwoven fabric or film having an elongation higher than 30%, when the short fiber loop and the third material of the lamination partner are bonded, an external force such as bending or pulling is applied. It becomes possible to prevent the nonwoven fabric containing the ultrafine fibers from being broken.
[0033]
In order to make the short fiber loop have an appropriate loop size, the needle depth of the needle punch is preferably 15 mm or less. Above that, the ultrafine fiber nonwoven fabric may be broken by impact when the needle and the short fiber penetrate the ultrafine fiber nonwoven fabric, or the needle hole after penetrating may become too large. The needle depth is preferably 5 mm or more, although it depends on the position of the needle barb, in order to prevent the peeling by increasing the entanglement of the nonwoven fabric. The puncture density is preferably 30 to ²⁰⁰ / cm ² . Togeana density 30 yarns / cm ² less than the peeling problems liable nonwoven, 250 lines / cm ² larger than or too large opening total area by Togeana, the tear and destruction of the nonwoven fabric containing ultra-fine fibers It is easy to occur and is not so preferable.
[0034]
The breaking elongation of the entire laminated sound absorbing material is preferably 20% or more, more preferably 50% or more, and particularly preferably 100% or more. Nonwoven fabrics having a breaking elongation of less than 20% cannot follow the deformation at the time of molding, and the sound absorption coefficient tends to be remarkably reduced due to breakage in the ultrafine fiber layer or the like. Further, if the elongation at break is high and there is deformability even in the processing step, it becomes easy to avoid problems such as cutting due to poor stress control. Processing at a molding temperature from room temperature to around 200 ° C. can be considered, but there is almost no problem as long as the requirements of the present invention are satisfied.
[0035]
The air permeability of the entire laminated sound absorbing material is preferably 0.05 to 50 cm ³ / cm ² · sec in terms of Frazier air permeability. If the air permeability is too low, it tends to cause a problem that the sound absorbing property in the high frequency range is lowered. If the air permeability is too high, it is difficult to improve the sound absorbing performance in the low frequency region which is intended by the present invention. Tend to be.
[0036]
It is preferable to use a flame retardant type resin for all the nonwoven fabrics and resin layer materials used in the present invention. It is also preferable to apply a phosphorus-based flame retardant containing no halogen or to copolymerize flame retardant components. Even if other components are flammable, it is relatively easy to achieve normal flame retardant standards by providing a flame retardant layer on the surface layer.
[0037]
【Example】
The present invention will be described below with reference to examples. Evaluation and measurement were carried out by the following methods.
(Glass-transition temperature):
The peak temperature of internal transmission loss (tan δ) was determined using RHEOVIBRON MODEL RHEO-1021 and DDV-01FP manufactured by Orientec Corporation.
(Average fiber diameter):
In the scanning electron micrograph, 20 or more fiber side surfaces were measured and measured from the average value. When the ultrafine fiber nonwoven fabric was melt blown, the fiber diameter variation was large, so 100 or more were measured and the average value was adopted.
[0038]
(Weight and packing density):
A value obtained by measuring the weight was basis weight in terms of per 1 m ² by cutting the nonwoven fabric to 20cm square. The packing density was obtained by calculating the unit of g / cm ³ by obtaining a value obtained by dividing the basis weight of the nonwoven fabric by the thickness under a load of 20 g / cm ² .
[0039]
(Peeling):
The operation of bending the composite nonwoven fabric by 90 degrees by hand was repeated 20 times, and whether or not peeling occurred was visually evaluated.
[0040]
(Elongation at break):
The nonwoven fabric was cut into a rectangle 20 cm long and 5 cm wide. The elongation at break was determined when a low-speed elongation tensile measurement was performed at a room temperature of 25 ° C. with a test length of 10 cm and a crosshead of 10 cm / min.
[0041]
(Sound absorption rate):
In accordance with JIS A-1405, the normal incidence method sound absorption coefficient was determined. Values of 500 Hz, 2000 Hz and 4000 Hz were used as representative values.
[0042]
(Fragile air permeability):
It was measured according to JIS L-1096 6.27.1 (Method A).
[0043]
Example 1
A block copolymer polyester elastomer having a hard segment and a soft segment (Perprene P40B manufactured by Toyobo Co., Ltd., glass transition temperature of about -70 ° C.) is extruded and laminated so that the thickness is 25 μm, and the average fiber diameter is 14 μm. It was bonded to a 15 g / m ² polyester spunbond nonwoven fabric (Ecule 6151A manufactured by Toyobo Co., Ltd.). In addition, 30% by weight of heat-sealing fibers (melting point: about 130 ° C.) having an average fiber diameter of 14 μm, a fiber length of 51 mm, a basis weight of 300 g / m ² consisting of short fibers of 12 crimps / 2.54 cm, and a thickness of 20 mm are included. The thermal bond short fiber nonwoven fabric made of polyethylene terephthalate is layered, and needle punching is performed with a needle count of 50 / cm ² and a needle depth of 10 mm using a 40th needle to adjust the thickness to 15 mm. Then, they were integrated by thermal bonding at a temperature 30 ° C. higher than the melting point of the heat-fusible fiber. The laminated sound absorbing material had a fragile air permeability of 0.16 cm ³ / cm ² · sec. Even if the sound absorbing material was bent about 20 times, no problem of peeling occurred. The sound absorption coefficient was 28% at 500 Hz, and 89% and 83% at 2000 Hz and 4000 Hz, respectively.
[0044]
Example 2
In Example 1, the polyester spunbond nonwoven fabric bonded to the elastomer resin layer is a block copolymer polyester elastomer (perprene P40B manufactured by Toyobo Co., Ltd.) in which the core component having an average fiber diameter of 12 μm is composed of a hard segment and a soft segment. The core component was changed to a spunbonded nonwoven fabric having a basis weight of 20 g / m ^{2 made} of a composite fiber of polytrimethylene terephthalate. Further, a melt-blown nonwoven fabric of perprene P40B (average fiber diameter 2.5 μm, basis weight 50 g / m ² ) was sandwiched between the short-fiber nonwoven fabrics and laminated in the same manner as in Example 1. The laminated sound absorbing material had a fragile air permeability of 0.10 cm ³ / cm ² · sec. Even if the produced nonwoven fabric was bent about 20 times, the problem of peeling did not occur. The sound absorption coefficient was high and good at 60% at 500 Hz, 100% and 100% at 2000 Hz and 4000 Hz, respectively. Even if the surface was rubbed with a finger, it was not fuzzy at all, and the form stability was excellent. The breaking elongation of the nonwoven fabric was 57%. Even when the molding temperature was 140 ° C. and the maximum molding drawing depth was about 80%, molding was possible without any problem.
[0045]
Comparative Example 1
A short fiber nonwoven fabric made of polyethylene terephthalate with a basis weight of 500 g / m ² consisting of short fibers with an average fiber diameter of 14 μm, fiber length of 51 mm, and 12 crimps / 2.54 cm is used from both the front and back sides using a 40th needle. Needle punching was performed at a puncture density of 30 / cm ² and a needle depth of 10 mm to obtain a nonwoven fabric having a thickness of 10 mm. Although the nonwoven fabric had a higher basis weight than that of Example 1, when the sound absorption coefficient was measured, it was 12% at 500 Hz, 22% at 2000 Hz and 4000 Hz, and 61%, respectively, which was a problem.
[0046]
Comparative Example 2
The polyethylene terephthalate polyester heat-bonding nonwoven fabric thickness made of resin films of 25μm of basis weight 20 g / m ² of (glass transition temperature of about 70 ° C.), an average fiber diameter of 14 [mu] m, basis weight 15 g / m ² of polyester scan made spunbond It bonded together with the nonwoven fabric (Ecule 6151A by Toyobo Co., Ltd.). In addition, 30% by weight of heat-sealing fibers (melting point: about 130 ° C.) having an average fiber diameter of 14 μm, a fiber length of 51 mm, a basis weight of 300 g / m ² consisting of short fibers of 12 crimps / 2.54 cm, and a thickness of 20 mm are included. The thermal bond short fiber nonwoven fabric made of polyethylene terephthalate is layered, and needle punching is performed with a needle count of 50 / cm ² and a needle depth of 10 mm using a 40th needle to adjust the thickness to 15 mm. Then, they were integrated by thermal bonding at a temperature 30 ° C. higher than the melting point of the heat-fusible fiber. The laminated sound absorbing material had a fragile air permeability of 0.16 cm ³ / cm ² · sec. Even if the sound absorbing material was bent about 20 times, no problem of peeling occurred. The sound absorption coefficient was 48% at 500 Hz, 89% and 21% at 2000 Hz and 4000 Hz, respectively.
[0047]
【The invention's effect】
The sound-absorbing material of the present invention has a high sound-absorbing performance even in a low frequency range, and is a thin and lightweight sound-absorbing material with good form stability. Moreover, good moldability is shown by selecting the material. In particular, it can be used as a lightweight and excellent formable sound absorbing material in order to improve fuel efficiency and comfort in automobile applications. In addition, it can be suitably used as a sound absorbing material in a wide range of industrial applications.

Claims (5)

A layer in which a nonwoven fabric having a basis weight of 10 to 200 g / m ² is bonded to a resin layer having a glass transition temperature of 50 ° C. or less, a fiber diameter of 7 to 50 μm, a basis weight of 50 to 2000 g / m ² , and a thickness of 4 to 50 mm A sound-absorbing material characterized by being laminated and integrated with a nonwoven fabric. The sound absorbing material according to claim 1 , wherein the Frazier air permeability is 0.05 to 50 cm ³ / cm ² · sec . 3. The block according to claim 1 or 2, wherein the nonwoven fabric bonded to the resin layer is a hydroentangled nonwoven fabric, a nonwoven fabric composed of core-sheath composite fibers, a nonwoven fabric composed of polytrimethylene terephthalate fibers, and a hard segment and a soft segment. A sound-absorbing material, wherein the sound-absorbing material is any one of nonwoven fabrics composed of copolymer polyester fibers. A vehicle interior material, wherein a member obtained by molding the sound absorbing material according to any one of claims 1 to 3 is used at least in part. 5. The vehicle interior material according to claim 4, wherein the molded member is a member used for any of a ceiling material, a dashboard lower portion, and a carpet portion.