Patent Publication Number: US-2006019569-A1

Title: Sound absorbing composite material

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to a sound-absorbing composite material, and more particularly to a sound-absorbing composite material that provides a better sound-absorbing effect.  
      2. Description of the Related Art  
      A sound-absorbing material is used to absorb the acoustic wave and to weaken the intensity or strength of the acoustic wave until the acoustic wave vanishes. The acoustic wave usually has a higher frequency, an intermediate frequency or a lower frequency, wherein the acoustic wave having a higher or an intermediate frequency easily causes an uncomfortable sensation to the people. However, the conventional sound-absorbing material has a better sound-absorbing effect to the acoustic wave having a higher frequency and also has a poor sound-absorbing effect to the acoustic wave having an intermediate frequency, or alternatively, has a better sound-absorbing effect to the acoustic wave having an intermediate frequency and also has a poor sound-absorbing effect to the acoustic wave having a higher frequency, thereby decreasing the sound-absorbing effect of the conventional sound-absorbing material.  
     SUMMARY OF THE INVENTION  
      In accordance with the present invention, there is provided a sound-absorbing composite material, comprising a super thin fiber layer, and a non-woven fiber layer laminating the super thin fiber layer.  
      The primary objective of the present invention is to provide a sound-absorbing composite material that provides a better sound-absorbing effect.  
      Another objective of the present invention is to provide a sound-absorbing composite material, wherein the super thin fiber layer co-operates with the non-woven fiber layer to provide a better sound-absorbing effect, thereby enhancing the sound-absorbing effect of the sound-absorbing composite material.  
      A further objective of the present invention is to provide a sound-absorbing composite material, wherein the super thin fiber layer is rested on and attached to the non-woven fiber layer which provides support to the super thin fiber layer to enhance the strength of the super thin fiber layer, so that the super thin fiber layer is not easily worn out when in use, thereby enhancing the lifetime of the sound-absorbing composite material.  
      A further objective of the present invention is to provide a sound-absorbing composite material, wherein the sound-absorbing composite material also has a heat insulation effect.  
      A further objective of the present invention is to provide a sound-absorbing composite material, wherein the sound-absorbing composite material also has a shock-absorbing effect.  
      A further objective of the present invention is to provide a sound-absorbing composite material, wherein the sound-absorbing composite material also has a refractory effect.  
      Further benefits and advantages of the present invention will become apparent after a careful reading of the detailed description with appropriate reference to the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a plan cross-sectional view of a sound-absorbing composite material in accordance with the preferred embodiment of the present invention;  
       FIG. 2  is a schematic operational view of the sound-absorbing composite material as shown in  FIG. 1  in use;  
       FIG. 3  is a plan cross-sectional view of a sound-absorbing composite material in accordance with another preferred embodiment of the present invention;  
       FIG. 4  is a plan cross-sectional view of a sound-absorbing composite material in accordance with another preferred embodiment of the present invention;  
       FIG. 5  is a plan cross-sectional view of a sound-absorbing composite material in accordance with another preferred embodiment of the present invention;  
       FIG. 6  is a plan cross-sectional view of a sound-absorbing composite material in accordance with another preferred embodiment of the present invention; and  
       FIG. 7  is a plan cross-sectional view of a sound-absorbing composite material in accordance with another preferred embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      Referring to the drawings and initially to  FIG. 1 , a sound-absorbing composite material  1  in accordance with the preferred embodiment of the present invention comprises a super thin fiber layer  10 , and a non-woven fiber layer  20  laminating the super thin fiber layer  10 .  
      The super thin fiber layer  10  is a super thin fiber laminating layer formed by a sputtering process or a filament extrusion process. The super thin fiber layer  10  has a dimension substantially equal to or smaller than 0.7 Denier. The non-woven fiber layer  20  is a non-woven fiber laminating layer formed by a non-woven manufacturing process. The non-woven fiber layer  20  has a dimension substantially equal to or greater than 0.8 Denier. The super thin fiber layer  10  is combined with the non-woven fiber layer  20  by a bonding agent, an adhesive or by a heat melting connection process.  
      The super thin fiber layer  10  has a relatively smaller thickness so that the laminating thickness of the super thin fiber layer  10  is relatively smaller. In addition, the voids formed by the staggered winding fiber filaments of the super thin fiber layer  10  are relatively smaller, so that when the acoustic wave reaches the super thin fiber layer  10 , the acoustic wave wholly enters the super thin fiber layer  10  without reflection. Thus, the super thin fiber layer  10  receives the acoustic wave wholly.  
      When the acoustic wave having a relatively greater frequency (smaller wavelength) enters the voids of the super thin fiber layer  10 , the width of each of the voids of the super thin fiber layer  10  is closer to the wavelength of the acoustic wave to produce interruption action which breaks continuity of the acoustic wave and converts the dynamic energy of the acoustic wave into a frictional heat energy to reduce the intensity of the acoustic wave rapidly until the acoustic wave vanishes. Thus, most of the acoustic wave having a relatively greater frequency is directly absorbed by the super thin fiber layer  10 . In addition, the sound-absorbing composite material has a better sound-absorbing effect when the thickness of the super thin fiber layer  10  is increased.  
      The non-woven fiber layer  20  has a relatively greater thickness so that the non-woven fiber layer  20  has greater laminating thickness, strength and void. Thus, the voids formed by the non-woven fiber layer  20  are available to receive the acoustic wave having a relatively intermediate frequency (intermediate wavelength). In fact, when the acoustic wave having a relatively intermediate frequency enters the super thin fiber layer  10 , the intensity of the acoustic wave is weakened. Thus, after the acoustic wave having a relatively intermediate frequency enters the non-woven fiber layer  20 , the width of each of the voids of the non-woven fiber layer  20  is closer to the wavelength of the acoustic wave, so that vibration of the acoustic wave and the fibers of the non-woven fiber layer  20  produce impact friction to convert the dynamic energy of the acoustic wave into a frictional heat energy to reduce the intensity of the acoustic wave rapidly until the acoustic wave vanishes. In addition, the sound-absorbing composite material has a better sound-absorbing effect when the thickness of the non-woven fiber layer  20  is increased.  
      Accordingly, the super thin fiber layer  10  co-operates with the non-woven fiber layer  20  to provide a better sound-absorbing effect, thereby enhancing the sound-absorbing effect of the sound-absorbing composite material. In addition, the super thin fiber layer  10  is rested on and attached to the non-woven fiber layer  20  which provides support to the super thin fiber layer  10  to enhance the strength of the super thin fiber layer  10 , so that the super thin fiber layer  10  is not easily worn out when in use, thereby enhancing the lifetime of the sound-absorbing composite material.  
      Referring to  FIG. 2 , when the sound-absorbing composite material is mounted on a sheet metal “M”, the super thin fiber layer  10  has a surface bonded onto an inner face of the sheet metal “M”, so that the sound-absorbing composite material provides a better sound-absorbing effect to the sheet metal “M”. Preferably, the sound-absorbing composite material further comprises a refractory agent located between the super thin fiber layer  10  and the non-woven fiber layer  20  to provide a refractory effect.  
      Referring to  FIG. 3 , the sound-absorbing composite material further comprises a secondary non-woven fiber layer  20 A mounted on an outer surface of the super thin fiber layer  10  so that the super thin fiber layer  10  is sandwiched between the non-woven fiber layer  20  and the secondary non-woven fiber layer  20 A. Thus, the sound-absorbing composite material has the same sound-absorbing effect with greater strength and enhanced lifetime.  
      Referring to  FIG. 4 , the sound-absorbing composite material further comprises a secondary super thin fiber layer  10 A mounted on an outer surface of the non-woven fiber layer  20  so that the non-woven fiber layer  20  is sandwiched between the super thin fiber layer  10  and the secondary super thin fiber layer  10 A. Thus, the sound-absorbing composite material has a better sound-absorbing effect.  
      Referring to  FIG. 5 , the sound-absorbing composite material further comprises a foamable layer  30  mounted on an outer surface of the non-woven fiber layer  20  so that the non-woven fiber layer  20  is sandwiched between the super thin fiber layer  10  and the foamable layer  30 . Thus, the sound-absorbing composite material has a better sound-absorbing effect.  
      Referring to  FIG. 6 , the sound-absorbing composite material further comprises an aluminum foil layer  40  mounted on an outer surface of the non-woven fiber layer  20  so that the non-woven fiber layer  20  is sandwiched between the super thin fiber layer  10  and the aluminum foil layer  40 . Thus, the sound-absorbing composite material also has a heat insulation effect.  
      Referring to  FIG. 7 , the sound-absorbing composite material further comprises a shock-absorbing cushion  50  mounted on an outer surface of the super thin fiber layer  10 , a bonding gel  60  mounted on an outer surface of the shock-absorbing cushion  50 , and a releasing paper  70  mounted on an outer surface of the bonding gel  60 . In practice, after the releasing paper  70  is removed from the bonding gel  60 , the shock-absorbing cushion  50  is bonded by the bonding gel  60  onto an inner face of an object, such as a sheet metal, thereby attaching the sound-absorbing composite material to the sheet metal. Thus, the sound-absorbing composite material also has a shock-absorbing effect.  
      Although the invention has been explained in relation to its preferred embodiment(s) as mentioned above, it is to be understood that many other possible modifications and variations can be made without departing from the scope of the present invention. It is, therefore, contemplated that the appended claim or claims will cover such modifications and variations that fall within the true scope of the invention.