U.S. patent application number 10/489057 was filed with the patent office on 2004-12-23 for backing fabrics for papermaking machine convering materials.
Invention is credited to Budenbender, Jurgen, Onder de Linden, Thierry.
Application Number | 20040259449 10/489057 |
Document ID | / |
Family ID | 7698343 |
Filed Date | 2004-12-23 |
United States Patent
Application |
20040259449 |
Kind Code |
A1 |
Onder de Linden, Thierry ;
et al. |
December 23, 2004 |
Backing fabrics for papermaking machine convering materials
Abstract
Backing fabric for paper machine felts, based on yarn made of
polyamide 6 and polyamide 6.10, polyamide 6.11, polyamide 11 and/or
polyamide 12.
Inventors: |
Onder de Linden, Thierry;
(Dormagen, DE) ; Budenbender, Jurgen; (Dormagen,
DE) |
Correspondence
Address: |
NORRIS, MCLAUGHLIN & MARCUS, P.A.
875 THIRD AVE
18TH FLOOR
NEW YORK
NY
10022
US
|
Family ID: |
7698343 |
Appl. No.: |
10/489057 |
Filed: |
August 16, 2004 |
PCT Filed: |
August 29, 2002 |
PCT NO: |
PCT/EP02/09624 |
Current U.S.
Class: |
442/181 |
Current CPC
Class: |
D10B 2331/02 20130101;
D10B 2331/04 20130101; D21F 7/08 20130101; Y02W 30/62 20150501;
D10B 2211/02 20130101; B29L 2031/7092 20130101; B29B 17/00
20130101; B29K 2277/00 20130101; Y10T 442/30 20150401; D03D 7/00
20130101 |
Class at
Publication: |
442/181 |
International
Class: |
D03D 015/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 10, 2001 |
DE |
10144307.2 |
Claims
1. Backing fabric for papermaking machine covering materials,
having a base fabric which comprises combination twisted yarns of
monofilaments of polyamide 6 and monofilaments of polyamide 6.10,
in the warp direction.
2. Backing fabric for papermaking machine covering materials,
having a base fabric which comprises combination twisted fabrics of
monofilaments of polyamide 6 and monofilaments of polyamide 6.12,
polyamide 11 or polyamide 12 in the warp direction.
3. Backing fabric according to claim 1, wherein the twisted yarns
contain 1 to 20 monofilaments of polyamide 6 and 20 to 1
monofilaments of polyamide 6.10.
4. Backing fabric according to claim 2, wherein the twisted yarns
contain 1 to 20, monofilaments of polyamide 6 and 20 to 1
monofilaments of polyamide 6.12, polyamide 11 or polyamide 12.
5. Backing fabric according to any one of claims 1 to 4, wherein
said monofilaments of said base fabrics have a diameter of 0.08 to
0.3 mm.
6. Process for the production of base fabrics of papermaking
machine covering materials, which comprises forming a combination
twisted yarn of polyamide 6 monofilaments with monofilaments of
polyamide 6.10, polyamide 6.12, polyamide 11 or polyamide 12 and
forming the warp of a base fabric with said combination twisted
yarn.
7. Backing fabric according to claim 3, wherein said twisted yarns
contain 1 to 6 monofilaments of polyamide 6 and 6 to 1
monofilaments of polyamide 6.10.
8. Backing fabric according to claim 4, wherein said twisted yarns
contain 1 to 6 monofilaments of polyamide 6 and 6 to 1
monofilaments of polyamide 6.12, polyamide 11 or polyamide 12.
Description
[0001] The present invention relates to backing fabrics for
papermaking machine felt with improved properties, preferably
improved wear resistance and in particular improved dimensional
stability during paper manufacture.
[0002] Processes for the production of monofilaments from
thermoplastic polymers are in principle known (c.f. Handbuch der
Kunststofftechnik II, C. Hanser Verlag, Munich 1986, pp.
295-319).
[0003] Paper production on modern papermaking machines involving
sheet forming (forming part), mechanical dewatering (pressing part)
and thermal dewatering (drying part), smoothing and rolling is
known from Lehrbuch der Papier- und Kartonerzeugung (VEB
Fachbuchverlag 1987, p. 190 ff).
[0004] Fabrics employed in the forming part consist predominantly
of polyester monofilaments. In order to improve the abrasion
resistance monofilaments of polyamides together with polyester
monofilaments in an alternating pick-and-shot arrangement on the
machine side are also used.
[0005] In the pressing part the basic fabrics for the pressing felt
or wet pressing felt are produced almost exclusively from polyamide
fibres and polyamide monofilaments, preferably from pure
polyamide-6 but also from polyamide-66. A nonwoven layer of
polyamide fibres is needled onto the base fabrics consisting of
polyamide monofilaments in a second processing stage and this layer
is thereby mechanically anchored in the said base fabric.
[0006] Dry screens on the other hand normally consist of polyester
monofilaments that are largely stabilised by means of suitable
products, for example Stabaxol (a commercial product available from
Rheinchemie, Mannheim), against hydrolytic decomposition.
[0007] The commercially available press felts made from polyamide-6
monofilaments have on account of their high abrasion resistance,
compressibility and very good recovery of the felts after passing
through the press nip major advantages compared to press felts of
other materials, e.g. polypropylene, polyester, wool or other types
of polyamide (e.g. PA 6.10, PA 6.12).
[0008] A significant disadvantage of these press felts is however
the lack of dimensional stability in the event of machine
downtimes. The materials polyamide-6 and polyamide-66 absorb up to
10 wt. % of water in a wet environment. The length and thickness of
the monofilaments changes with the absorption of water. In
particular the change in length means that in the event of
malfunctions or downtimes of the papermaking machine due to other
causes the felts have a different weight and fabric density in the
wet zones than in the dry zones. After dealing with the
malfunctions and starting up the papermaking machine again no
high-quality paper can be produced with these felts until the felts
have re-established the same water content and the same density and
width over the whole area.
[0009] Furthermore the change in width often means that the full
working width of the papermaking machine cannot be utilised since
the felts extend beyond the maximum width of the machine and are
damaged at their edges.
[0010] There has therefore been no lack of attempts to improve the
dimensional stability of press felts in wet/dry cycles.
[0011] One possibility is to use other fabric constructions.
[0012] The use of other materials in the warp of the fabrics is
widespread, for example the replacement of polyamide-6 or
polyamide-66 monofilaments by filaments which absorb substantially
less moisture under high ambient moisture conditions and in which
the dimensions of the fabrics consequently change only slightly.
Monofilaments of polyamide 6.10 and polyamide 6.12 have proved
suitable.
[0013] A disadvantage of these fabrics and of the felt produced
therefrom is however the significantly reduced wear resistance when
used in papermaking machines compared to fabrics of polyamide-6
monofilaments and felts produced therefrom.
[0014] It has now surprisingly been found that the disadvantages of
the lack of wear resistance can be avoided and can be replaced by
the advantages of a good dimensional stability if the warp of the
basic fabric consists of combination twisted yarns that contain
monofilaments of polyamide-6 as well as also monofilaments of
polyamide 6.10 or polyamide 6.12.
[0015] The object of the invention is achieved if in the production
of the backing fabric there are used combination twisted yarns with
1 to 20 monofilaments of polyamide-6 and 20 to 1 monofilaments of
polyamide 6.10, polyamide 6.12, polyamide 11 or polyamide 12 in the
warp instead of twisted yarns of polyamide-6 monofilaments.
[0016] Moreover, the fabrics produced in this way also have a
significantly improved economic utility since the raw materials
polyamide-6 and polyamide-66 are industrially more readily
available and can be re-used in many recycling systems after
economic utilisation.
[0017] A particular advantage of the process according to the
invention is that twisted yarns of an even number of the materials
used as well as also an odd number of these materials can be
twisted with one another. In this way specific, calculable
dimensional changes of the twisted yarns or fabrics produced
therefrom can be established and the economic utility can
optionally also be improved.
[0018] The following examples demonstrate the advantages according
to the invention of the combination twisted yarns, without
restricting the possibilities of these combinations.
EXAMPLES
[0019]
1 Monofilament Commercial Product Diameter Polyamide 6 X 201 0.20
mm Polyamide 6.10 ATF 2311 0.20 mm Polyamide 6.12 ATF 23 0.20
mm
[0020] Manufacturer: Bayer Faser GmbH
[0021] Pre-Twisted Yarns
[0022] Pre-twisted yarns of construction 0.20 mm.times.2 were
produced on an Allma Saurer AZB-T type yarn twisting machine at 304
revolutions/metre
[0023] Experimental part V 1: X 201/X 201, 0.20 mm.times.2, S 304
revolutions/metre
[0024] Experimental part V 2: X 201/ATF 2311, 0.20 mm.times.2, S
304 revolutions/metre
[0025] Experimental part V 3: ATF 2311, 0.20 mm.times.2, S 304
revolutions/metre
[0026] Experimental part V 4: ATF 2300 0.20 mm.times.2, S 304
revolutions/metre
Comparison Example 1
[0027] Pre-twisted yarns of polyamide 6, experimental part V 1,
were processed on an Allma Saurer AZB-T type yarn twisting machine
to form a balanced annular twisted yarn of construction 0.2
mm.times.2.times.2 with S 304/Z 260 revolutions.
[0028] The twisted yarn was then fixed tension-free in a heating
cabinet for 5 minutes at 160.degree. C. and cut into pieces of
length 1.00 m. The exact length and the weight of the sample pieces
was determined. Following this the samples were then stored
tension-free for 24 hours in a water bath at 20.degree. C., removed
from the water, dried, and the change in length as well as the
weight were determined.
[0029] The twisted yarn was then dried for 24 hours at 80.degree.
C. in a circulating air drying cabinet and the change in length and
weight loss were again determined. This cycle was repeated three
times. The changes in length between the wet/dry cycles are
summarised in Table 1.
[0030] The abrasion resistance of the twisted yarns was determined
by an abrasion test developed in-house. For this, the monofilaments
and twisted yarns are drawn cyclically under a defined load over a
grinding roller until they break. The number of grinding cycles is
a measure of the abrasion resistance.
Comparison Example 2
[0031] Pre-twisted yarns of polyamide 6.10 (ATF 2311), experimental
part V 3, 0.20 mm were processed into an annular twisted yarn as
described in comparison example 1. The change in length after
wet/dry alternating cycles as well as the abrasion resistance were
also determined as described in comparison example 1. The results
are summarised in Table 1.
Example 1
[0032] Pre-twisted yarn V 1 and pre-twisted yarn V 2 were processed
into an annular twisted yarn as described in comparison example 1.
The annular twisted yarn had a proportion of PA 6.10 of 25%. The
change in length after wet/dry alternating cycles as well as the
abrasion resistance was also determined as described in comparison
example 1. The results are summarised in Table 1.
Example 2
[0033] Pre-twisted yarn V 1 and pre-twisted yarn V 3 were processed
into an annular twisted yarn as described in comparison example 1.
The annular twisted yarn had a proportion of PA 6.10 of 50%. The
change in length after wet/dry alternating cycles as well as the
abrasion resistance was also determined as described in comparison
example 1. The results are summarised in Table 1.
Example 3
[0034] Pre-twisted yarn V 2 and pre-twisted yarn V 2 were processed
into an annular twisted yarn as described in comparison example 1.
The annular twisted yarn had a proportion of PA 6.10 of 50%. The
change in length after wet/dry alternating cycles as well as the
abrasion resistance was also determined as described in comparison
example 1. The results are summarised in Table 1.
Example 4
[0035] Pre-twisted yarn V 3 and pre-twisted yarn V 2 were processed
into an annular twisted yarn as described in comparison example 1.
The annular twisted yarn had a proportion of PA 6.10 of 75%. The
change in length after wet/dry alternating cycles as well as the
abrasion resistance was also determined as described in comparison
example 1. The results are summarised in Table 1.
Example 5
[0036] Pre-twisted yarn V 4 and pre-twisted yarn V 1 were processed
into an annular twisted yarn as described in comparison example 1.
The annular twisted yarn had a proportion of PA 6.12 of 50%. The
change in length after wet/dry alternating cycles as well as the
abrasion resistance was also determined as described in comparison
example 1. The results are summarised in Table 1.
2 TABLE 1 Abrasion Propn. Propn. Water Water Behaviour PA 6 PA 6.10
Absorption .sup.1) Elongation .sup.1) min-max % % % % Cycles Comp.
Ex. 1 100 0 6.8 3.0 260-350 Comp. Ex. 2 0 100 2.8 1.2 220-290
Example 1 75 25 6.0 2.7 260-320 Example 2 50 50 5.2 2.0 250-295
Example 3 50 50 4.9 1.9 255-305 Example 4 25 75 3.8 1.6 225-290
Propn. PA 6.12 Example 5 50 50 5.1 2.1 245-300 .sup.1) Mean value
from three measurement cycles
* * * * *