Press Felt for Papermaking

Abstract

A press felt 10 comprises a base body 30, a wet paper web side batt layer 20, and a press side batt layer 23. The wet paper web side batt layer 20 has a wet paper web contact side batt layer 21 and a base body side batt layer 22, the wet paper web contact side batt layer 21 being made of a core-in-sheath fiber 41 which has a core member made of high-molecular-weight nylon with an absolute viscosity of 80 mPa·s or more and a sheath member made of nylon with a lower melting point than the core member, and the base body side batt layer 22 being made of a nylon fiber 42 which does not include the core-in-sheath fiber 41. Rewetting of the wet paper web can be prevented, because water within the press side batt layer 23 is blocked from moving to the wet paper web side due to increased density of the wet paper web contact side batt layer 21 resulted from melting of the sheath member of the core-in-sheath fiber 41. Moreover, since the base body side batt layer 22 is made of nylon without the core-in-sheath fiber, the press felt is provided with a balanced combination of smoothness, resistance to dehairing, abrasion and compression fatigue, and dewatering capability.

1 . A press felt for papermaking comprising a base body and a batt layer having a wet paper web side layer and a press side layer, characterized in that said wet paper web side layer is composed of a wet paper web contact side batt layer and a base body side batt layer, said wet paper web contact side batt layer having a core-in-sheath fiber comprising a core member made of high-molecular-weight nylon with an absolute viscosity of 80 mPa·s or more and a sheath member made of nylon with a lower melting point than the core member; and said base body side batt layer being made of nylon without said core-in-sheath fiber. 
   
   
       2 . A press felt as claimed in  claim 1 , in which a content rate of said core-in-sheath fiber in said wet paper web contact side batt layer ranges from 25% to 75%. 
   
   
       3 - 4 . (canceled) 
   
   
       5 . A press felt as claimed in  claim 1 , in which said wet paper web contact side batt layer has a plurality of layers in which the content rate of said core-in-sheath fiber increases incrementally from the press side toward the paper side thereof. 
   
   
       6 . A press felt as claimed in  claim 1 , in which said base body is a woven fabric made of a warp yarn and a weft yarn which are monofilament single yarns. 
   
   
       7 . A press felt as claimed in  claim 2 , in which said wet paper web contact side batt layer has a plurality of layers in which the content rate of said core-in-sheath fiber increases incrementally from the press side toward the paper side thereof. 
   
   
       8 . A press felt as claimed in  claim 2 , in which said base body is a woven fabric made of a warp yarn and a weft yarn which are monofilament single yarns. 
   
   
       9 . A press felt as claimed in  claim 5 , in which said base body is a woven fabric made of a warp yarn and a weft yarn which are monofilament single yarns. 
   
   
       10 . A press felt as claimed in  claim 7 , in which said base body is a woven fabric made of a warp yarn and a weft yarn which are monofilament single yarns.