JP2006285086A - Sound absorbing heat insulating material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sound absorbing heat insulating material which has superior sound absorptivity even in a low-frequency range although the heat insulating material is lightweight and thin. <P>SOLUTION: The sound absorbing heat insulating material is characterized in that at least one peak of vertical incidence method sound absorptivity is present between 315 and 6500 Hz and ≥60%, the thickness is 3 to 20 mm and basis weight per thickness of 1 cm is ≤400g/m<SP>2</SP>. For example, the peak of sound absorptivity is set by composing the the sound absorbing heat insulator of a layer formed by sticking a porous film layer B of resin of 90 to 160°C in fusion point on long-fiber non-woven fabric A of 10 to 70g/m<SP>2</SP>in basis weight consisting principally of fiber of 3 to 25 microns in fiber size and a plurality of fibers that short-fiber non-woven fabric C of 7 to 50 microns in fiber size, 50 to 80g/m<SP>2</SP>in basis weight, and 3 to 20 mm in thickness penetrates. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a sound-absorbing material having excellent sound-absorbing properties and heat-insulating properties despite being lightweight and thin. More 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 and heat insulating material having excellent sound absorbing characteristics and heat insulating characteristics when used for interior materials such as ceilings and floors of vehicles such as automobiles and door trims.

Conventionally, short fiber nonwoven fabric has been widely used as a sound absorbing material for automobiles and construction applications. In order to obtain high sound absorption performance, the fiber diameter is reduced to increase the air passage resistance or the basis weight. Such a method is adopted. As a result, when high sound absorption performance is required, a relatively thin fiber having a fiber diameter of about 15 microns is used, and a thick and heavy short fiber nonwoven fabric having a basis weight of 500 to 5000 g / cm ² is generally used. .
Nonwoven fabrics containing ultrafine fibers with a fiber diameter of 10 microns or less have excellent sound absorption properties, filter properties, shielding properties, etc. and have been used in many applications, but they are weak in strength and form stability is poor. In order to improve this problem, it is used by laminating and combining with another nonwoven fabric. In this case, as a method of laminating and integrating the nonwoven fabric, resin or heat that becomes a binder by spraying or transferring, etc. A fused fiber or the like is used (see, for example, Patent Document 1). However, these methods require heat treatment for the purpose of drying or melting and bonding the resin, and are not 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.

On the other hand, the method of laminating and integrating ultrafine fiber nonwoven fabric and long fiber nonwoven fabric is known as S / M / S, which is known as S / M / S. How to do is known. However, these nonwoven fabrics have a problem in that they lack volume and have a hard texture, which limits their application.
In addition, a nonwoven fabric called a coform, which is a composite of blown nonwoven fibers of about 20 to 30 microns blown into the melt blown nonwoven fabric, has been commercialized and is said to exhibit excellent sound absorption performance (see, for example, Patent Document 2). ).
In addition, sound absorbing materials incorporated into automobile interior materials and electrical products are often three-dimensionally molded. However, if the diaphragm is deep during molding, deformation at the throttling area is large and the sound absorbing material cannot follow the deformation. There was a problem of running out.
In addition, when ultrafine fibers are used to improve the sound absorption performance, there is a problem that the specific surface area increases, so that it is easy to burn. In particular, when ultra-fine fibers are made by the melt blow method, polypropylene is generally used, and there is a problem that it is easier to burn from the viewpoint of the material, and it is practically used for safety reasons in applications where it contacts a heating element such as a motor. It was difficult.

On the other hand, with the recent progress in miniaturization and weight reduction mainly for automobile applications, it has become difficult to take the conventional method of sound insulation using high-weighted sound-absorbing material, so lightweight and high sound-absorbing performance in the low frequency range. There is a need for nonwoven fabrics. However, when the thickness of the conventional nonwoven fabric is increased to increase the sound absorption coefficient in the low frequency range, there is a problem that the sound absorption performance is deteriorated in the high frequency range. It has also been confirmed that the sound absorption performance in the low frequency range of 500 to 1000 Hz is improved when a film-like sheet is bonded to the surface of the porous sound absorption material, but the sound absorption performance in the high frequency range of 2000 Hz or higher. Cause the problem of low.
Japanese Patent Laid-Open No. 10-203268 JP-A-5-247822

  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. It is another object of the present invention to provide a sound-absorbing heat insulating material with good thermal efficiency for an air conditioner.

The present invention takes the following means in order to solve this problem.
In the first invention, at least one peak of the normal incidence method sound absorption coefficient exists between 315 to 5000 Hz, the peak sound absorption coefficient is 60% or more, the thickness is 3 to 20 mm, and the thickness per 10 mm thickness. A sound-absorbing heat insulating material having a basis weight of 400 g / m ² or less.

The second invention has a thickness of 7 made of a resin having a melting point of 90 ° C. or more and 160 ° C. or less to a long fiber nonwoven fabric A having a basis weight of 10 to 70 g / m ² mainly composed of fibers having a fiber diameter of 3 to 25 microns. 35 microns and the porous film layer B comprising been the bonded layers, the fiber diameter of 7 to 50 microns, more fiber weight per unit area of 50 to 800 g / m ^2, thickness through the short fiber nonwoven fabric C of 3~20mm It is a sound-absorbing heat insulating material characterized by being combined and integrated.

A third invention is the sound-absorbing heat insulating material according to the second invention, characterized in that the Frazier air permeability is between 0.03 and 50 cm ³ / cm ² · sec.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, the nonwoven fabric A and the film layer B are combined by an extrusion laminating method, and are combined and integrated by a short fiber nonwoven fabric C layer and a needle punching method. It is a sound-absorbing heat insulating material.

Fifth invention, by compounding by the needle pan method in the fourth invention, characterized in that the height of 0.3mm or more loops are present at least 5 to 100 / cm ² on one side of the film layer B It is a sound-absorbing heat insulating material.

  According to a sixth invention, in the second invention, the film layer B is made of high-density polyethylene, low-density polyethylene, or a copolymer containing any of these, and the thickness is between 10 and 50 microns. This is a sound-absorbing material.

  Furthermore, the sound absorbing heat insulating material according to any one of the second to sixth inventions, wherein aluminum is deposited on the surface of the sound absorbing heat insulating material.

  The sound-absorbing material of the present invention is a sound-absorbing material that is thin and has high sound-absorbing performance and good form stability even when the basis weight is small. In addition, it exhibits excellent workability. In particular, it can be used as a lightweight and excellent sound-absorbing heat insulating material for improving fuel efficiency and comfort in automobile applications. In addition, it is suitably used as a sound absorbing material in a wide range of industrial applications such as a sound absorbing material for home appliances and a sound absorbing material for buildings.

The present invention is described in detail below.
The sound-absorbing heat insulating material used in the present invention has at least one or more of frequencies between 315 and 6500 Hz when a graph having the horizontal axis of 1/3 tarb frequency and the vertical axis of sound absorption coefficient is created. The rate is preferably 60% or more. Different sound absorption characteristics are required depending on the form of the sound-absorbing heat insulating material, but in automobile applications, the peak of the normal incidence method sound absorption coefficient is more preferably between 1000 and 4000 Hz, and particularly preferably between 1600 and 3150 Hz. is there. The peak position of the characteristic frequency varies depending on the structure, thickness, air permeability, and the like of the sound-absorbing heat insulating material. The peak sound absorption coefficient is preferably at least 70%, particularly preferably 90% or more. Furthermore, it is particularly preferable that the sound absorption rates at 1000 Hz, 2000 Hz, and 4000 Hz are 20, 50, and 60% or more, respectively, from the viewpoint that there is less hindrance to conversation in an automobile.

  In general, the greater the thickness and weight of the sound-absorbing material, the higher the sound-absorbing performance can be set.However, since the sound-absorbing material is installed in a limited space in the car, there is a limitation on the thickness. Since a lighter sound-absorbing material is required, the structure must be optimized. The present inventors have found that the sound absorption efficiency in the required frequency range is maximized by controlling the peak position of the sound absorption rate by controlling the structure and thickness of the nonwoven fabric.

  In the sound-absorbing heat insulating material of the present invention, it is preferable that at least the nonwoven fabric and the porous film layer are combined and integrated. In order to control air permeability and the like, it is also a desirable form to combine a nonwoven fabric layer containing ultrafine fibers. Further, it is also preferable to make a composite with a woven fabric or a woven fabric depending on the usage pattern. Furthermore, a surface layer nonwoven fabric having a design or color with a color or pattern may be attached to the outside of the composite nonwoven fabric, and can be suitably used as a soundproofing material for vehicle interior materials or building materials.

In the present invention, a long-fiber nonwoven fabric A having a basis weight of 20 to 200 g / m ² mainly composed of fibers having a fiber diameter of 3 to 25 microns, and a film layer B made of a resin having a melting point of 90 to 160 ° C. And a fiber layer having a fiber diameter of 7 to 50 microns, a basis weight of 50 to 800 g / m ² , and a short fiber nonwoven fabric C having a thickness of 3 to ²⁰ mm are combined and integrated by a plurality of fibers. preferable.

The long fiber non-woven fabric A is used for the reinforcing layer of the film layer and air permeability control, but the more the thinner fibers are contained, the better the sound absorption performance. Although the whole nonwoven fabric may be comprised only with the ultrafine fiber, when the content rate is too small, it is difficult to obtain the effect due to the ultrafine fiber characteristics. In addition, the reinforcing effect is reduced. The fiber diameter is preferably 25 microns or less, particularly preferably between 3 and 18 microns, and most preferably between 5 and 16 microns. The fiber production method is not particularly defined, and may be long fibers or short fibers, but nonwoven fabrics obtained by a melt blow method or a spun bond method that allow random arrangement of fibers and low production costs are particularly preferable. Since the melt-blown nonwoven fabric has low strength, it is also preferable to use a nonwoven fabric joined to a reinforcing nonwoven fabric such as a spunbond nonwoven fabric, or to laminate three or more nonwoven fabrics simultaneously in the lamination step. At this time, it is particularly preferable that the spunbonded nonwoven fabric excellent in wear resistance is placed on the surface layer side during use. Embossed laminated nonwoven fabrics of meltblown nonwoven fabric and spunbonded nonwoven fabric are called and commercially available under names such as S / M / S and S / M (S is a spunbond nonwoven fabric, M is a meltblown nonwoven fabric, and is also preferred) To express).
The sound-absorbing heat insulating material is often cut and used by punching, and the long-fiber non-woven fabric is more preferable than the short-fiber non-woven fabric from the viewpoint of preventing fiber scraps from falling off.

Further, the long fiber nonwoven fabric A preferably has a basis weight of 20 to 200 g / m ² . If the basis weight is less than 20 g / m ^2, it is difficult to obtain a desired reinforcing effect and air permeability control effect. When the basis weight is larger than 200 g / m ² , it is difficult to obtain a lightweight sound-absorbing material that is an object of the present invention. Further, when the needle punch method, which is a suitable composite method of the long nonwoven fabric A layer, the film layer B, and the short fiber nonwoven fabric C layer, is applied, needle breakage is likely to be a big problem. Preferably, a 20 to 50 g / m ^2. When compounding by the needle punch method, if the basis weight is smaller than 20 g / m ² , the fiber entanglement is weak, and peeling is likely to occur, which is not preferable.

  The film layer B is preferably made of a resin having a melting point of 90 ° C. or higher and 160 ° C. or lower. A lower melting point of the resin is preferable because the sound absorption performance is higher, but if the melting point is too low, not only the applicable applications are limited, but also heat is generated due to friction when the needle penetrates when compounding by the needle pan method. Then, the resin is attracted to the barb portion, which is not preferable because the fibers are caught more than necessary to induce needle breakage. In the process of needle punching, when the stroke of the needle punching machine is high, the needle surface temperature rises remarkably due to frictional heat generated by penetration of the needle into the nonwoven fabric or film layer. Therefore, when the piercing density is high, it is preferable to use a resin having a high melting point. When the melting point is higher than 160 ° C., the resin becomes hard and the sound-absorbing heat insulating material is likely to generate problems when it is blown or deformed. As a resin having a melting point of 90 ° C. or higher and 160 ° C. or lower, a high-density polyethylene and a low-density polyethylene homopolymer are generally used. However, as a resin that imparts moderate softness and does not generate abnormal noise during film deformation, A copolymer containing either polyethylene or polyoctene is also particularly preferable. In addition, it is particularly preferable to add 0.01 to 10% of fine particles such as titanium oxide and carbon to these resins because needle breakage hardly occurs during needle punching.

Further, the thickness of the film is preferably between 7 and 50 microns, particularly preferably 10 to 30 microns. Films thinner than 15 microns often have problems with mechanical strength properties, and abnormal noise tends to occur when the thickness is 30 microns or more. Also, when compounding by the need punch method, care should be taken because a film of 30 microns or more tends to induce needle breakage. When the needle punch method is used, it is possible to make holes in the film, and as a result, the air permeability can be controlled. The air permeability also seems to be related to the peak frequency of sound absorption performance, but the relationship is not clear, but if the film layer thickness is larger than 30 microns, it is difficult to set the desired peak frequency, which is not preferable. The lamination of the nonwoven fabric layer A and the film layer B is not particularly defined as an adhesive or a thermal laminating method, but the adhesive strength and processing can be performed by extruding and laminating the resin forming the film layer B onto the nonwoven fabric layer A. This is particularly preferable from the viewpoint of cost.
When importance is attached to heat insulation, it is also preferable to use a film on which aluminum is deposited.

In the sound-absorbing heat insulating material of the present invention, 5-100 loops / cm ² are preferably present on at least one side of the film layer B by a needle punch method or the like. If the film layer is on the surface of the sound-absorbing heat insulating material, a rubbing sound may be generated when another object is touched. It is possible to solve this problem by introducing fiber loops on the surface. If the number of fiber loops is less than 5 / cm ² , the improvement effect is small and not preferable. If it is more than 100 pieces / cm ^2, the mechanical strength of the film layer is lowered, which is not preferable.

Further, the material constituting the short fiber nonwoven fabric C is not particularly defined, but the main component is preferably polyester or polyolefin from the viewpoint of VOC problems and recyclability. In order to improve the shape stability, it is also one of preferable modes to contain about 10 to 80% of heat-fusible fiber or three-dimensional crimped fiber. It is preferable that the fiber diameter is 7 to 50 microns, the basis weight is 50 to 800 g / m ² , and the thickness is 3 to ²⁰ mm. Within the scope of the inventors' studies, the fiber diameter is preferably between 7 and 50 microns, particularly preferably between 7 and 20 microns. A fiber diameter smaller than 7 microns does not cause a major problem directly, but is not preferable in view of productivity such as spinning performance from a card machine. Also, if the fiber diameter is much smaller than 7 microns, the lamination effect according to the present invention will be 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 microns, the contribution to the sound absorbing performance is reduced, which is not preferable. The length of the short fibers to be configured is preferably 38 mm or more and 150 mm or less, and particularly preferably between 50 mm and 150 mm. Within the scope of the study by the present inventors, the longer the fiber length, the better the sound absorption coefficient. However, if the fiber length is too long, the spinning property from the card deteriorates, which is not preferable. 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. If there are too many thick fibers, problems such as the feeling of the nonwoven fabric becoming too hard are likely to occur, which is not preferable. It is also preferable to use heat-fusible fibers having different melting points from the viewpoint of improving dimensional stability and preventing fiber scraps from falling off during punching. It is particularly preferable that the thermal bonding fiber having a low melting point component is reduced by 10 to 50%.

The weight-based packing density of the short fiber nonwoven fabric is preferably between 0.005 and 0.3 g / cm ³ from the viewpoint of bulkiness. When the packing density is too small, the form stability is deteriorated, which is not preferable. If the packing density is greater than 0.3 g / cm ³ , the sound absorption is likely to deteriorate, making it difficult to satisfy the object of the present invention. From the viewpoint of environmental problems, it is also possible to use reclaimed hair that is a recycled nonwoven fabric. The material may be a natural fiber or a rigid fiber, but 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.

The sound absorbing heat insulating material of the present invention preferably has a fragile air permeability of 0.03 to 50 cm ³ / cm ² · sec, preferably 1 to ³⁰ cm ³ / cm ² · sec, particularly preferably. 5 to ³⁰ cm ³ / cm ² · sec. If the Frazier air permeability of the sound-absorbing heat insulating material of the present invention is smaller than 0.03 cm ³ / cm ² · sec, sound reflection occurs on the surface of the sound-absorbing heat insulating material, which is not preferable. When the Frazier air permeability is too high, it becomes difficult to set so that at least one peak of the normal incidence method sound absorption coefficient exists between 315 to 5000 Hz.

Basis weight of the thermal-acoustic insulation material of the present invention is preferably a short fiber nonwoven 80~800g / m ^2. When the basis weight is less than 80 g / m ² , the sound absorbing effect is small, which is not preferable from the viewpoint of the bulkiness of the nonwoven fabric. On the other hand, if the basis weight is greater than 800 g / m ² , the thickness becomes too large, taking up space and increasing the weight. Moreover, it is preferable that the thickness of this nonwoven fabric exists between 5-20 mm. If the thickness is less than 3 mm, the sound absorption performance and the heat insulation performance are deteriorated. The higher the thickness is, the higher the sound absorption coefficient at a low frequency can be. However, when the thickness exceeds 20 mm, it is bulky, which is not preferable. Preferably, the thickness is 3 to 20 mm from the viewpoint of handling and cost performance.

  The method of composite integration of the nonwoven fabric is not particularly limited, and an adhesive, adhesive powder, or the like can be used, but it is preferable to integrate by a needle punch method or a hydroentanglement method. The needle punch method is generally practiced as a nonwoven fabric processing method, and details are described in detail in “Basics and Applications of Nonwoven Fabrics” edited by the Textile Society of Japan. Although it is considered known to use this needle punching method to combine nonwoven fabrics, it is extremely fine to combine ultrathin nonwoven fabric with uniform eyes and bulky short fibers with relatively thick fibers using a needle punch machine. As far as the inventor knows, the product cannot be found in the market because it is thought that it is difficult to obtain ultrafine fiber characteristics due to a hole in the fiber nonwoven fabric, resulting in a decrease in sound absorption performance and filter performance. When performing needle punching, it is preferable to use a needle (needle) thinner than 38th, particularly preferably 40-42. 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 are prone to fluff because the fibers get caught or cut by other objects, but the short fiber loops prevent the non-woven fabric containing ultrafine fibers from fuzzing or become a cushion layer. It has been found that relaxing the external force applied to the ultrafine fiber nonwoven fabric layer helps to prevent destruction.

Also, when laminating with another non-woven fabric or film having an elongation higher than 30%, the loop and the third material to be laminated are bonded to each other, so that when an external force such as bending or pulling is applied, the fine fiber It has also been found that it is possible to prevent the nonwoven fabric containing the material from being destroyed. In order to form an appropriate loop size, the needle depth of the needle punch is preferably 15 mm or less. Above that, the nonwoven fabric is often torn due to the impact when the needle and the short fiber penetrate the ultrafine fiber nonwoven fabric, and the needle hole after penetrating becomes too large. The needle depth is preferably 5 mm or more, although it depends on the position of the needle barb, in order to increase the entanglement of the nonwoven fabric and prevent peeling. The puncture density is preferably 5 to 100 locations / cm ² . If the puncture density is less than 30 locations / cm ^2, the problem of peeling of the nonwoven fabric tends to occur. If the puncture density is greater than 100 locations / cm ^{2, the} total area of the openings due to the puncture is too large, or the nonwoven fabric containing ultrafine fibers is torn or broken. It is easy to occur and is not preferable. The laminated body of the nonwoven fabric A and the film layer B combined with the short fiber nonwoven fabric layer C may be composited with either side facing the short fiber nonwoven fabric layer C side. When they are mixed, it is more preferable to bring the molten component of the heat-bonding fiber into contact with the one having better adhesion.

  In order to improve heat insulation, when using the film layer which vapor-deposited aluminum on the surface, it is preferable that the aluminum vapor deposition surface has faced the direction opposite to the short fiber nonwoven fabric layer C.

  The breaking elongation of the laminated sound absorbing material is preferably 30% or more, preferably 50% or more, particularly preferably 100% or more. A non-woven fabric having a breaking elongation of 30% or less is not preferable because it cannot follow the deformation at the time of molding, and the sound absorption rate is remarkably reduced due to breakage in the ultrafine fiber layer or the like. Further, if 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. In the component of the sound-absorbing material of the present invention, since the elongation of the nonwoven fabric having the crimped portion is small, it is preferable to set the elongation of the nonwoven fabric alone to 30% or more. It is particularly preferable that the long-fiber nonwoven fabric A is composed of composite fibers because the moldability is often improved.

  It is also one of preferred embodiments that the surface of the sound-absorbing heat insulating material of the present invention is combined with a fabric having a design property by coloring or printing a pattern. Thereby, it becomes possible to harmonize visually and the surroundings visually as a sound absorbing material used for a sound absorbing material of a building structure or an automobile interior material.

  Nonwoven fabric A and short fiber nonwoven fabric B are preferably flame retardant. It is preferable to apply a phosphorus-based flame retardant containing no halogen or to copolymerize flame retardant components. Even if other components tend to burn somewhat, if the non-woven fabric A layer as the surface layer has high flame retardancy, the overall flame retardance of the composite can be improved.

  Examples will be described below. In addition, the value measured by the following method was employ | adopted for evaluation.

(Average fiber diameter) Scanning electron micrographs were taken at an appropriate magnification, 20 fiber side surfaces were measured, and the average value was measured. When the ultrafine fiber nonwoven fabric was melt blown, the fiber diameter variation was large, and 100 fibers were measured and the average value was adopted.

(Weight and packing density) A value obtained by cutting a nonwoven fabric into 20 cm square and measuring its weight was converted to 1 m ² to obtain a basis weight. 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 .

(Breaking elongation) The nonwoven fabric was cut into a rectangle having a length of 20 cm and a width of 5 cm. The elongation at break was determined when low-speed extension 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.

(Sound Absorption Rate) The normal incidence method sound absorption rate was determined according to JIS A-1405.

(Fragile permeability) Measured according to 6.27.1 (Method A) of JIS L-1096.

(Insulation) Measurement was performed according to ASTM D-1518. The thickness is particularly preferably 60% or more at 10 mm and 70% or more at 20 mm.

Example 1
A low-density polyethylene resin (melting point: about 110 ° C.) is extruded onto a polyester spunbonded non-woven fabric (Eure 6301A manufactured by Toyobo Co., Ltd.) having an average fiber diameter of 14 microns and a basis weight of 30 g / m ² to form a 20 micron film layer. Formed. Thermal bond made of polyethylene terephthalate containing 30% by weight of heat-bonded fibers with an average fiber diameter of 14 microns, fiber length of 51 mm, and crimped 12 fibers / inch (4.7 fibers / cm) and a basis weight of 200 g / m ² After stacking the short fiber non-woven fabric, using a 40th needle and performing a composite processing by the needle punch method at a puncture density of 50 / cm ² and a needle depth of 10 mm, the temperature is 30 degrees higher than the fusion fiber temperature. The sound-absorbing heat insulating material having a thickness of 10 mm was obtained by integration by thermal bonding. The number of loops having a height of 0.3 mm or more present on the film layer side was 50 pieces / cm ² , and the fragile air permeability was 5 cm ³ / cm ² · sec. The sound absorption rate is shown in FIG. The peak frequency was 3150 Hz, the sound absorption rate was 96%, and the sound absorption rates at 1000 Hz, 2000 Hz, and 4000 Hz were 36, 93, and 81%, respectively. The heat retention rate was also good at 74%.

(Example 2)
In Example 1, when a polyethylene film was extruded and laminated on a spunbond nonwoven fabric, a 50 micron film (melting point of about 263 ° C.) made of polyethylene terephthalate deposited with aluminum was deposited so that the vapor deposition surface was opposite to the spunbond nonwoven fabric. Pasted together. Then, a sound-absorbing heat insulating material was created under the same conditions except that it was combined by the needle punch method. The number of loops with a height of 0.3 mm or more present on the film layer side was 50 / cm ² , and the fragile air permeability was 6 cm ³ / cm ² · sec. The peak frequency was 3150 Hz, the sound absorption rate was 91%, and the sound absorption rates at 1000 Hz, 2000 Hz, and 4000 Hz were 39, 90, and 77%, respectively. The heat retention rate was also good at 83%.

(Comparative Example 1)
A sound-absorbing heat insulating material was prepared in the same manner as in Example 1 except that a low-density polyethylene film having a melting point of about 110 ° C. having a thickness of 30 microns was extruded and laminated. When the piercing density exceeded 95 locations / cm ² , needle breakage occurred frequently in the processing step, and when it reached 100 locations / cm ² or more, production was impossible.

(Comparative Example 2)
In the melt blown nonwoven fabric manufacturing process, a heat insulating sound-absorbing material having a weight per unit area of 10 g and a weight of 200 g / m ² was prepared by a coform method so that 58% polyester short fibers were 15% by weight separation. There was no peak frequency between 315 and 5000 Hz. The sound absorption rates at 1000 Hz, 2000 Hz, and 4000 Hz were 20, 57, and 94%, respectively. The heat retention rate was as low as 52%.

  The sound-absorbing heat insulating material of the present invention can provide a sound-absorbing material that has high sound-absorbing performance even in a low frequency range, is thin and lightweight, and has good shape stability, and can be widely used especially in the automobile industry. It is great to contribute to the industry.

It is a graph showing a sound absorption characteristic.

Claims (7)

At least one peak of the normal incidence method sound absorption coefficient exists between 315 to 6500 Hz, the peak sound absorption coefficient is 60% or more, the thickness is 3 to 20 mm, and the basis weight per 10 mm thickness is 400 g / m ^2. A sound-absorbing heat insulating material characterized by the following. A long-fiber nonwoven fabric A mainly composed of fibers having a fiber diameter of 3 to 25 microns and having a basis weight of 10 to 70 g / m ² and made of a resin having a melting point of 90 to 160 ° C. and having a thickness of 7 to 35 microns The film layer B is laminated and integrated with a plurality of fibers through which a short fiber nonwoven fabric C having a fiber diameter of 7 to 50 microns, a basis weight of 50 to 800 g / m ² and a thickness of 3 to 20 mm passes. A sound-absorbing heat insulating material. The sound-absorbing heat insulating material according to claim ² , wherein the Frazier air permeability is between 0.03 and 50 cm ³ / cm ² · sec. The sound-absorbing heat insulating material according to any one of claims 1 to 3, wherein the nonwoven fabric A and the film layer B are combined by an extrusion laminating method, and are combined and integrated by a short fiber nonwoven fabric C layer and a needle punching method. 5. The sound-absorbing heat insulating material according to claim 4, wherein loops having a height of 0.3 mm or more are present on at least one side of the film layer B at 5 to 100 pieces / cm ² by compositing by a needle pan method. The sound absorbing material according to claim 2, wherein the film layer B is made of polyethylene or a copolymer thereof and has a thickness of 10 to 50 microns. The sound absorbing heat insulating material according to any one of claims 2 to 6, wherein aluminum is vapor-deposited on the surface of the sound absorbing heat insulating material.

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