Bulky sheet and process of producing the same

Abstract

A bulky sheet 1 has a network sheet 11 and a nonwoven fabric-like fiber aggregate 10 having fibers arranged on at least one side of the network sheet 11. The fibers of the fiber aggregate 10 is in entanglement among themselves and with the network sheet 11 to be unitary with the network sheet 11. The network sheet 11 is three-dimensionally shaped to form a number of protrusions and depressions, and the fiber aggregate 10 is united with the network sheet 11 along the contour of the three-dimensionally shaped network sheet 11 such that the bulky sheet, as a whole, has a three-dimensional profile with a number of protrusions and depressions.

1 . A bulky sheet comprising a network sheet and a nonwoven fabric-like fiber aggregate having fibers arranged on at least one side of the network sheet, the fibers of the fiber aggregate being in entanglement among themselves and with the network sheet to be unitary with the network sheet, 
 the network sheet being three-dimensionally shaped to form a number of protrusions and depressions, and    the fiber aggregate being unitary with the network sheet along the contour of the protrusions and the depressions of the network sheet such that the bulky sheet, as a whole, has a three-dimensional profile with a number of protrusions and depressions.    
   
   
       2 . The bulky sheet according to  claim 1 , wherein the three-dimensional shaping of the network sheet is by plastic deformation.  
   
   
       3 . The bulky sheet according to  claim 2 , wherein the plastic deformation of the network sheet is carried out by heat embossing using a pair of matched engraved rolls both having a number of protrusions and depressions or a combination of an engraved roll having a number of protrusions and depressions and a smooth roll comprising an elastic material.  
   
   
       4 . The bulky sheet according to  claim 1 , wherein the network sheet comprises a first thermoplastic resin, and the fiber aggregate comprises a second thermoplastic resin, the first thermoplastic resin having a lower melting point than the second thermoplastic resin.  
   
   
       5 . The bulky sheet according to  claim 1 , which is for use as a cleaning sheet.  
   
   
       6 . A process of producing the bulky sheet according to  claim 1 , comprising the steps of: 
 superposing a fiber web on at least one side of a network sheet,    hydro-entangling fibers of the fiber web among themselves and with the network sheet to convert the fiber web into a nonwoven fabric-like fiber aggregate and to unite the fiber aggregate with the network sheet, and    heat embossing the resulting unitary sheet by inserting the sheet between a pair of matched engraved rolls both having a number of protrusions and depressions or between an engraved roll having a number of protrusions and depressions and a smooth roll comprising an elastic material to shape the unitary sheet to the contour of the engraved roll.    
   
   
       7 . The process according to  claim 6 , wherein the network sheet comprises a first thermoplastic resin, and the fiber aggregate comprises a second thermoplastic resin, the first thermoplastic resin having a lower melting point than the second thermoplastic resin, and the step of heat embossing is carried out at a temperature lower than the melting point of the first thermoplastic resin.  
   
   
       8 . The process according to  claim 6 , wherein the step of heat embossing is followed by the step of cooling the resulting sheet.  
   
   
       9 . The process according to  claim 8 , wherein the step of cooling is carried out by blowing cool air to the sheet or wrapping the sheet around a cooling roll.