EP0734471A1 - Papermachine clothing - Google Patents

Papermachine clothing

Info

Publication number
EP0734471A1
EP0734471A1 EP95902897A EP95902897A EP0734471A1 EP 0734471 A1 EP0734471 A1 EP 0734471A1 EP 95902897 A EP95902897 A EP 95902897A EP 95902897 A EP95902897 A EP 95902897A EP 0734471 A1 EP0734471 A1 EP 0734471A1
Authority
EP
European Patent Office
Prior art keywords
papermachine clothing
polymer
thixotrope
base cloth
making
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP95902897A
Other languages
German (de)
French (fr)
Inventor
Craig Valentine
Ian Christison Sayers
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Voith Fabrics Heidenheim GmbH and Co KG
Original Assignee
Scapa Group Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Scapa Group Ltd filed Critical Scapa Group Ltd
Publication of EP0734471A1 publication Critical patent/EP0734471A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
    • D21F3/00—Press section of machines for making continuous webs of paper
    • D21F3/02—Wet presses
    • D21F3/0209—Wet presses with extended press nip
    • D21F3/0218—Shoe presses
    • D21F3/0227—Belts or sleeves therefor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
    • B29D29/00—Producing belts or bands
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
    • B29L2031/00—Other particular articles
    • B29L2031/733—Fourdrinier belts

Definitions

  • the present invention relates to papermachine clothing and particularly but not exclusively to shoe press belts.
  • One form of papermachine clothing comprises a woven or non woven base cloth to which a coating of polymer is applied.
  • an endless base cloth is fed around a series of rollers and around a part of a horizontally mounted rotatable drum. As the belt passes around the drum heat-softened polymer is applied into the nip between the belt and the drum.
  • the present invention has been made from a consideration of this problem.
  • a method of making papermachine clothing comprising the step of feeding a base cloth over a rotating body and applying a polymer coating to the base cloth as the base cloth is fed over the rotating body, wherein the polymer coating is impregnated with a thixotrope.
  • the thixotrope acts to increase the viscosity of the "fluid" polymer once applied to the base cloth.
  • the toughness, modulus and abrasion resistance of the papermachine clothing is significantly improved by incorporation of the thixotrope into the polymer coating.
  • papeptiachine clothing comprising a base cloth having a coating of polymer thereon, wherein the polymer is impregnated with a thixotrope.
  • Aramid fibres such as KEVLAR (RTM) (para-phenylene terephthalamide) are preferred.
  • the fibres are preferably-chopped into lengths in the range from 0.8mm to 4.00mm and preferably have a diameter in the order of 12u ⁇ .
  • KEVLAR (RTM) is particularly preferred in that the random orientation and physical entanglement of the fibres and fibrils thereof align in the direction of applied shear thus increasing the viscosity of the polymer.
  • fused silica may be used as a thixotrope.
  • the polymer is preferably thermoset. Polyurethane is preferred.
  • a series of infra-red heaters 14 are provided adjacent the drum 11 on the side of the base cloth 13 which is remote from the drum 11.
  • a polyurethane coating may be applied to the base cloth 13 by utilising a feed nozzle to project the heat softened polymer into the nip 15 between the base cloth 13 and the top of the drum 11.
  • the polyurethane coating is impregnated with chopped aramid fibres in order to prevent sagging of the polymer on the drum and to improve the abrasion resistance of the belt.
  • the fibres are added in substantially equal amounts to the thermoset precursor material.
  • the aramid containing precursors e.g. polyol and isocyanate
  • the amount of aramid fibre added is preferably less than 3% by weight.

Abstract

A method of making a shoe press belt comprises the step of feeding a base cloth (13) over a rotating drum (11) and applying a polymer coating to the base cloth (13), as the base cloth (13) is fed over the rotating drum (11). The polymer coating is impregnated with a fused silica or aramid thixotrope.

Description

PAPERMACHINE CLOTHING
The present invention relates to papermachine clothing and particularly but not exclusively to shoe press belts.
One form of papermachine clothing comprises a woven or non woven base cloth to which a coating of polymer is applied. In one method of manufacture an endless base cloth is fed around a series of rollers and around a part of a horizontally mounted rotatable drum. As the belt passes around the drum heat-softened polymer is applied into the nip between the belt and the drum.
In this process there is a tendency for the heat softened polymer to slump as it approaches the base of the drum. This is undesirable in that the polymeric layer applied to the belt is of non uniform thickness.
The present invention has been made from a consideration of this problem.
According to a first aspect of the present invention there is provided a method of making papermachine clothing comprising the step of feeding a base cloth over a rotating body and applying a polymer coating to the base cloth as the base cloth is fed over the rotating body, wherein the polymer coating is impregnated with a thixotrope. The thixotrope acts to increase the viscosity of the "fluid" polymer once applied to the base cloth. Surprisingly the toughness, modulus and abrasion resistance of the papermachine clothing is significantly improved by incorporation of the thixotrope into the polymer coating.
According to a second aspect of the present invention there is provided papeptiachine clothing comprising a base cloth having a coating of polymer thereon, wherein the polymer is impregnated with a thixotrope.
Aramid fibres such as KEVLAR (RTM) (para-phenylene terephthalamide) are preferred. The fibres are preferably-chopped into lengths in the range from 0.8mm to 4.00mm and preferably have a diameter in the order of 12uιι. KEVLAR (RTM) is particularly preferred in that the random orientation and physical entanglement of the fibres and fibrils thereof align in the direction of applied shear thus increasing the viscosity of the polymer. Alternatively fused silica may be used as a thixotrope.
The polymer is preferably thermoset. Polyurethane is preferred.
In order that the present invention may be more readily understood a specific embodiment thereof will now be described by way of example only with reference to the single accompanying drawing which shows one apparatus for making papermachine clothing in accordance with the present invention.
Referring to the drawing an apparatus 10 for making papermachine clothing such as a shoe press belt comprises a horizontally mounted rotatable drum 11 and a plurality of rollers 12 which define a path over which an endless base cloth 13 travels. A series of infra-red heaters 14 are provided adjacent the drum 11 on the side of the base cloth 13 which is remote from the drum 11. A polyurethane coating may be applied to the base cloth 13 by utilising a feed nozzle to project the heat softened polymer into the nip 15 between the base cloth 13 and the top of the drum 11. The polyurethane coating is impregnated with chopped aramid fibres in order to prevent sagging of the polymer on the drum and to improve the abrasion resistance of the belt.
In order to impregnate the polyurethane coating with the chopped aramid fibres the fibres are added in substantially equal amounts to the thermoset precursor material. The aramid containing precursors (e.g. polyol and isocyanate) are mixed immediately prior to applying the impregnated coating to the base cloth. The amount of aramid fibre added is preferably less than 3% by weight.
The strength of a prior art polyurethane coated belt "A" was tested. Similarly the strength of a belt incorporating 0.17% KEVLAR (RTM) was tested. The results are set out below. Average Strength (Kg/2.5cm)
"A* Polyurethane (Prior Art) 91.3 •B' Polyurethane 94.5
+ 0.17% Kevlar
It can be seen that the incorporation of very small amounts of KEVLAR fibres significantly increases the strength of the press belt.
It is to be understood that the above described embodiment is by way of illustration only. Many modifications and variations are possible.

Claims

1. A method of making papermachine clothing comprising the step of feeding a base cloth over a rotating body and applying a polymer coating to the base cloth as the base cloth is fed over the rotating body, wherein the polymer coating is impregnated with a thixotrope.
2. A method of making papermachine clothing as claimed in claim 1, wherein the thixotrope comprises an aramid.
3. A method of making papermachine clothing as claimed in claim 1 or claim 2, wherein the thixotrope comprises aramid fibres.
4. A method of making papermachine clothing as claimed in claim 3, wherein the length of the fibres is in the range from 0.8mm to 4.0mm.
5. A method of making papermachine clothing as claimed in claim 3 or claim 4, wherein the fibres have a diameter of substantially 12 μm.
6. A method of making papermachine clothing as claimed in claim 1, wherein the thixotrope comprises fused silica.
7. A method of making papermachine clothing as claimed in any preceding claim, wherein the polymer is a ther osetting polymer.
8. A method as claimed in any preceding claim, wherein the polymer comprises polyurethane.
9. A method of making a shoe press belt using the method of any of claims 1 to 8.
10. Papermachine clothing comprising a base cloth having a polymer coating thereon, wherein the polymer is impregnated with a thixotrope.
11. Papermachine clothing as claimed in claim 10, wherein the thixotrope comprises an aramid.
12. Papermachine clothing as claimed in claim 10 or claim 11, wherein the thixotrope comprises aramid fibres.
13. Papermachine clothing as claimed in claim 12, wherein the length of the fibres is in the range from 0.08mm to 4.0mm.
14. Papermachine clothing as claimed in claim 12 or claim 13, wherein the fibres have a diameter of substantially 12jjra.
15. Papermachine clothing as claimed in claim 10, wherein the thixotrope comprises fused silica.
16. Papermachine clothing as claimed in any of claims 10 to 15, wherein the polymer is thermoset.
17. Papermachine clothing as claimed in any of claims 10 to 15, wherein the polymer comprises polyurethane.
18. The use of the papermachine clothing of any of claims 10 to 17 as a shoe press belt.
EP95902897A 1993-12-15 1994-12-14 Papermachine clothing Withdrawn EP0734471A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
GB9325608A GB2284772B (en) 1993-12-15 1993-12-15 Papermachine clothing
GB9325608 1993-12-15
PCT/GB1994/002731 WO1995016820A1 (en) 1993-12-15 1994-12-14 Papermachine clothing

Publications (1)

Publication Number Publication Date
EP0734471A1 true EP0734471A1 (en) 1996-10-02

Family

ID=10746614

Family Applications (1)

Application Number Title Priority Date Filing Date
EP95902897A Withdrawn EP0734471A1 (en) 1993-12-15 1994-12-14 Papermachine clothing

Country Status (7)

Country Link
EP (1) EP0734471A1 (en)
JP (1) JPH09507534A (en)
AU (1) AU1215995A (en)
CA (1) CA2179172A1 (en)
FI (1) FI962458A (en)
GB (1) GB2284772B (en)
WO (1) WO1995016820A1 (en)

Families Citing this family (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5792323A (en) * 1995-09-07 1998-08-11 Albany International Corp. Spiral base structres for long nip paper machine press belts
US6447648B1 (en) * 1996-08-13 2002-09-10 Metso Paper, Inc. Anisotropic reinforced ribbon-cast blanket for extended nip press
FI103209B2 (en) † 1998-01-02 2005-04-04 Valmet Corp Method for surface coating of press or conveyor belts and corresponding surface-coated belt
ATE364750T1 (en) 2001-04-18 2007-07-15 Stowe Woodward Ag SHOE PRESS BELT
EP1293601A1 (en) 2001-09-17 2003-03-19 Stowe Woodward Aktiengesellschaft Belt for shoe press
JP3803071B2 (en) * 2002-06-11 2006-08-02 ヤマウチ株式会社 Elastic belt for paper industry and method for producing the same
US7011730B2 (en) 2002-12-30 2006-03-14 Albany International Corp. Structure for process belt
DE102004011665A1 (en) * 2004-03-10 2005-10-06 Stowe Woodward Ag Integral shoe press belt
ES2514466T3 (en) 2005-12-02 2014-10-28 Heimbach Gmbh & Co. Kg Procedure for manufacturing liquid impervious paper machine belts and coating device for the same
JP4616403B1 (en) * 2009-11-27 2011-01-19 イチカワ株式会社 Process belt for papermaking

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4287115A (en) 1979-11-13 1981-09-01 The Dow Chemical Company Filler mixtures and thermoset resins containing same
US4299868A (en) 1978-04-01 1981-11-10 Bayer Aktiengesellschaft Coating compositions
US4308184A (en) 1978-04-01 1981-12-29 Bayer Aktiengesellschaft Heat cross linkable polyurethane coating compositions
FR2543150A1 (en) 1983-03-21 1984-09-28 Altulor Sa Acrylic polymer coating compositions and finished products thus coated
US4640950A (en) 1983-06-22 1987-02-03 Takeda Chemical Industries, Ltd. Thixotropic polyurethane resin compositions
US4752519A (en) 1986-12-10 1988-06-21 Albany International Corp. Papermakers felt with a resin matrix surface
US4795480A (en) 1986-12-10 1989-01-03 Albany International Corp. Papermakers felt with a resin matrix surface
EP0336876A2 (en) 1988-04-08 1989-10-11 Beloit Corporation A blanket for an extended nip press
US4944844A (en) 1989-07-11 1990-07-31 Beloit Corporation Polyurethane extended nip press blanket

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4251928A (en) * 1978-05-30 1981-02-24 Asten Group Inc. Metal impregnated dryer fabric
US5073235A (en) * 1990-04-12 1991-12-17 The Procter & Gamble Company Process for chemically treating papermaking belts
US5207873A (en) * 1992-04-17 1993-05-04 Huyck Corporation Anti-contaminant treatment for papermaking fabrics

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4299868A (en) 1978-04-01 1981-11-10 Bayer Aktiengesellschaft Coating compositions
US4308184A (en) 1978-04-01 1981-12-29 Bayer Aktiengesellschaft Heat cross linkable polyurethane coating compositions
US4287115A (en) 1979-11-13 1981-09-01 The Dow Chemical Company Filler mixtures and thermoset resins containing same
FR2543150A1 (en) 1983-03-21 1984-09-28 Altulor Sa Acrylic polymer coating compositions and finished products thus coated
US4640950A (en) 1983-06-22 1987-02-03 Takeda Chemical Industries, Ltd. Thixotropic polyurethane resin compositions
US4752519A (en) 1986-12-10 1988-06-21 Albany International Corp. Papermakers felt with a resin matrix surface
US4795480A (en) 1986-12-10 1989-01-03 Albany International Corp. Papermakers felt with a resin matrix surface
EP0336876A2 (en) 1988-04-08 1989-10-11 Beloit Corporation A blanket for an extended nip press
US4944820A (en) 1988-04-08 1990-07-31 Beloit Corporation Method for making a blanket for an extended nip press
US4944844A (en) 1989-07-11 1990-07-31 Beloit Corporation Polyurethane extended nip press blanket

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of WO9516820A1

Also Published As

Publication number Publication date
GB2284772A (en) 1995-06-21
FI962458A0 (en) 1996-06-13
GB2284772B (en) 1997-11-26
CA2179172A1 (en) 1995-06-22
AU1215995A (en) 1995-07-03
WO1995016820A1 (en) 1995-06-22
JPH09507534A (en) 1997-07-29
FI962458A (en) 1996-06-13
GB9325608D0 (en) 1994-02-16

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