Press felt for papermaking

A technology for pressing felts and wool layers, which is applied in papermaking, papermaking machines, textiles and papermaking, etc. It can solve the problems of volume expansion and rewetting, and achieve smoothness maintenance, depilation resistance and abrasion resistance, and paper product quality improvement. Effect

Inactive Publication Date: 2009-01-28
ICHIKAWA ELECTRIC CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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

Method used

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  • Press felt for papermaking
  • Press felt for papermaking

Examples

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Effect test

preparation example Construction

[0042] When hot pressing is performed in the production process of the press felt, the sheath component melts, thereby causing fiber shrinkage of the core-sheath composite fibers 41, and accompanying this, the base side batt layer 22 and the wet paper contact side batt layer 21 become dense, so the felt Surface smoothness is improved.

[0043] After the base side batt layer 22 and the wet paper contact side batt layer 21 become dense, when the press felt 10 is out of the nip pressure, the moisture in the press side batt layer 23 is difficult to move because the dense layer forms a barrier, thus effectively inhibiting rewetting phenomenon.

[0044] In the present invention, the batt layer 21 on the wet paper contact side does not contain the core-sheath composite fiber 41 but is composed of normal nylon fibers 42 , and only the core-sheath composite fiber 41 is contained in the structure of the base side batt layer 22 . Therefore, smoothness, depilation and abrasion resistance...

Embodiment

[0063] The first embodiment of the press felt for papermaking of the present invention will be specifically described by the following examples. However, the present invention is not limited to these Examples.

[0064] Preparation of core-sheath composite fibers;

[0065] Prepare refined nylon 6 (caprolactam: melting point 220°C) and copolymerized nylon 6 / 12 (caprolactam / laurolactam: melting point 140°C), put them into separate extruders with devolatilization ports, and then Remove the volatile matter in the middle, and the melted core material nylon 6 and the sheath material copolymerized nylon 6 / 12 are quantified with a quantitative gear pump in a melted state, and supplied to each core-sheath composite spinning nozzle. After passing through the core-sheath composite spinning nozzle, the core-sheath composite fiber spun into silk is cooled in the air cylinder, oiled at the same time, wound at a natural stretch ratio, and then cut to a fixed length after stretching and crimp...

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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 ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): D21F7/08
CPCD21F7/083D21F7/00D21F7/08
Inventor 鬼久保明川岛伸小田浩之
Owner ICHIKAWA ELECTRIC CO LTD
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