Press felt for papermaking

Abstract

A press felt (10) for papermaking which is composed of a substrate (30), a wet paper side vat layer (20), and a press side vat layer (23), wherein the wet paper side vat layer (20) is composed of a wet paper contact side vat layer (21) and a substrate side vat layer (22); the substrate side vat layer (22) containing a core-sheath composite fiber (41) constituted of a core made of a high-molecular nylon having an absolute viscosity of 80mPas or above and a sheath made of a nylon having a melting point lower than that of the core-constituting nylon; and the wet paper contact side vat layer (21) being made of a nylon fiber (42) free from the composite fiber (41). Since the substrate side vat layer (22) is enhanced in denseness through the melting of the sheath of the fiber (41), the water in the press side vat layer (23) little moves to the wet paper side, whereby the remoisturization of paper is inhibited. Further, the felt is improved in fiber breakaway resistance, wear resistance, and compression fatigue resistance by virtue of the high-viscosity core of the fiber (41).

Description

technical field [0001] The present invention relates to a papermaking press felt (hereinafter simply referred to as "press felt") used in a papermaking machine. Background technique [0002] Conventionally, in the papermaking process, a press device has been used to dehydrate wet paper. In the press unit, the wet paper forming the ply is dewatered in the press nip through the press felt. In addition, the pressing device usually consists of a plurality of pressing nips. [0003] Figure 5 It is a schematic diagram of the pressing nip in the pressing device. [0004] The press nip includes a pair of press rolls P', P' and a pair of press felts 11', 11' clamping the wet paper W'. , 11' and wet paper W' apply pressure, and the moisture in wet paper W' is squeezed out and absorbed by press felts 11', 11'. [0005] However, since the pressure applied to the wet paper W' and the press felts 11', 11' is suddenly released from the center of the press section (nip section) to the ...

AI Technical Summary

Problems solved by technology

[0005] However, since the pressure applied to the wet paper W' and the press felts 11', 11' is suddenly released from the center of the press section (nip section) to the exit, the volume of the press felts 11', 11' Rapid expansion

As a result, a negative pressure is generated in the press felts 11', 11', and furthermore, since the wet paper W' is composed of fine fibers and accompanied by capillary phenomenon, the moisture absorbed by the press felts 11', 11' will reappear. The phenomenon of moving to the side of the wet paper, that is, the rewetting phenomenon

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