Composite Fiber Web Having Superior Heat Resistance and Sound Absorption and Method of Manufacturing Same

Abstract

A composite fiber web having superior heat resistance and sound absorption and including a center layer containing a carbon fiber and a heat-resistant layer, and to a method of manufacturing the same. The method of the present invention can exhibit a fast manufacturing speed through a melt-blowing process that will generate economic benefits. The composite fiber web includes a composite layer and individual layers with various fiber diameters resulting in a superior sound absorption rate. The PET fiber included in the heat-resistant layer of the composite layer is an environmentally friendly material with superior heat resistance due to the inclusion of ultrafine fiber. Also, the composite fiber web has superior strength, conductivity, and electromagnetic shielding and deodorization effects, which allows it to be widely utilized for sound absorption materials and in all application fields thereof.

What is claimed is: 
     
         1 . A composite fiber web, comprising:
 a center layer containing a carbon fiber; and   a heat-resistant layer formed on at least one surface of the center layer.   
     
     
         2 . The composite fiber web of  claim 1 , further comprising an outer layer formed on the heat-resistant layer and including a nonwoven fabric. 
     
     
         3 . The composite fiber web of  claim 2 , wherein the composite fiber web comprises:
 20 to 35 wt % of the center layer;   51 to 69 wt % of the heat-resistant layer; and   11 to 14 wt % of the outer layer.   
     
     
         4 . The composite fiber web of  claim 1 , wherein the heat-resistant layer comprises:
 43 to 78 wt % of a polyethylene terephthalate (PET) fiber; and   20 to 55 wt % of a staple fiber.   
     
     
         5 . The composite fiber web of  claim 4 , wherein the heat-resistant layer further comprises 2 to 5 wt % of an antioxidant. 
     
     
         6 . The composite fiber web of  claim 4 , wherein the PET fiber has a fiber diameter of 2 to 12 μm, an intrinsic viscosity (IV) of 0.43 to 0.5, and a melt flow rate (MFR) of 150 to 1500 g/10 min. 
     
     
         7 . The composite fiber web of  claim 4 , wherein the staple fiber is at least one of a hollow staple fiber, a modified cross-section hollow fiber, a modified cross-section fiber, or a cross-section fiber, and has a thickness of 2.0 to 6.0 denier and a length of 18 to 68 mm. 
     
     
         8 . The composite fiber web of  claim 1 , having a weight of 580 to 690 g/m 2 , a thickness of 20 to 30 mm, an average fiber diameter of 2 to 15 μm, a heat-resistant temperature of 225 to 235° C., a specific surface area of 900 to 2,500 m 2 /g, and an average noise reduction coefficient (NRC) of 0.92 to 0.94. 
     
     
         9 . A method of manufacturing a composite fiber web, the method comprising:
 manufacturing a center layer containing a carbon fiber;   manufacturing a heat-resistant layer;   forming a composite layer by stacking the heat-resistant layer on at least one surface of the center layer; and   stacking an outer layer on at least one surface of the composite layer.   
     
     
         10 . The method of  claim 9 , wherein the manufacturing step of the center layer comprises:
 extruding an isotropic pitch resin;   spinning the extruded pitch resin to afford a pitch-based carbon fiber;   infusibilizing the carbon fiber;   carbonizing the infusibilized carbon fiber; and   treating the carbonized carbon fiber with water vapor.   
     
     
         11 . The method of  claim 10 , wherein the spinning step of the extruded pitch resin is performed at a spinning nozzle temperature 50 to 70° C. higher than a softening temperature of the pitch and at a hot-air temperature 30 to 50° C. higher than the softening temperature of the pitch. 
     
     
         12 . The method of  claim 10 , wherein the infusibilizing step of the carbon fiber is performed at a temperature 20 to 30° C. higher than a softening temperature of the pitch and at a belt speed of 0.3 to 1 m/min in an oxygen gas atmosphere. 
     
     
         13 . The method of  claim 10 , wherein the carbonizing step of the infusibilized carbon fiber is performed at 900 to 1100° C. for 30 sec to 5 min in an inert gas atmosphere. 
     
     
         14 . The method of  claim 9 , wherein the manufacturing step of the heat-resistant layer comprises:
 crystallizing a polyethylene terephthalate (PET) resin;   drying the crystallized PET resin:   extruding the dried PET resin;   spinning the extruded PET resin to afford a PET fiber; and   mixing the PET fiber with a staple fiber.   
     
     
         15 . The method of  claim 14 , wherein the crystallizing step of the PET resin is performed at a temperature of 110 to 130° C. for 3 to 6 hr to thereby crystallize a surface of the PET resin. 
     
     
         16 . The method of  claim 14 , wherein the drying step of the crystallized PET resin is performed at a temperature of 150 to 170° C. for 3 to 4 hr. 
     
     
         17 . The method of  claim 14 , wherein the spinning step of the extruded PET resin is performed at a spinning temperature of 200 to 300° C. and a spinning speed of 30 to 120 m/s. 
     
     
         18 . The method of  claim 14 , further comprising heating the PET fiber obtained after spinning the extruded PET resin, wherein the spun PET fiber is heated at a heat treatment temperature of 80 to 120° C. and a belt speed of 0.3 to 1 m/min. 
     
     
         19 . The method of  claim 9 , comprising, on a continuously moving conveyor belt:
 manufacturing the heat-resistant layer, obtained by mixing a PET fiber resulting from crystallizing, drying, extruding and spinning a PET resin with a staple fiber, into a first web and a third web;   manufacturing the center layer, obtained by subjecting a pitch-based carbon fiber resulting from spinning an extruded pitch resin to infusibilization, carbonization and water-vapor treatment, into a second web; and   stacking the first web to the third web, which are continuously manufactured, in an order of first web/second web/third web.