U.S. patent application number 11/654298 was filed with the patent office on 2007-07-19 for paper machine fabric with release coating.
This patent application is currently assigned to Voith Paper GmbH. Invention is credited to Robert Crook, Sanjay Patel.
Application Number | 20070167099 11/654298 |
Document ID | / |
Family ID | 37930923 |
Filed Date | 2007-07-19 |
United States Patent
Application |
20070167099 |
Kind Code |
A1 |
Patel; Sanjay ; et
al. |
July 19, 2007 |
Paper machine fabric with release coating
Abstract
A paper machine fabric INCLUDES A fabric having a roll side and
a paper side and a surface matrix on the paper side; and a chrome
complex treatment in the surface matrix. The chrome complex
treatment chemically reacts with the surface matrix and orients
hydrophobic organic chains away from the surface of the fabric and
thereby provides enhanced release property.
Inventors: |
Patel; Sanjay; (Summerville,
SC) ; Crook; Robert; (Wilson, NC) |
Correspondence
Address: |
BACHMAN & LAPOINTE, P.C.
900 CHAPEL STREET, SUITE 1201
NEW HAVEN
CT
06510
US
|
Assignee: |
Voith Paper GmbH
|
Family ID: |
37930923 |
Appl. No.: |
11/654298 |
Filed: |
January 17, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60759650 |
Jan 17, 2006 |
|
|
|
Current U.S.
Class: |
442/327 ;
156/181; 162/348; 162/358.1; 162/901; 162/902 |
Current CPC
Class: |
D21F 7/086 20130101;
Y10T 442/60 20150401; D21F 1/0027 20130101; D21F 1/0036 20130101;
D21F 7/083 20130101 |
Class at
Publication: |
442/327 ;
162/348; 162/358.1; 162/901; 162/902; 156/181 |
International
Class: |
D04H 1/00 20060101
D04H001/00; D21F 1/10 20060101 D21F001/10 |
Claims
1. A paper machine fabric, comprising: a fabric having a roll side
and a paper side and a surface matrix on the paper side; and a
chrome complex treatment in the surface matrix.
2. The fabric of claim 1, wherein the fabric comprises a fabric
base, a roll side batt layer on the roll side of the fabric base,
and a paper side batt layer on the paper side of the fabric base,
wherein the surface matrix is attached to the paper side batt
layer.
3. The fabric of claim 1, wherein the chrome complex treatment is
chemically bonded with the surface matrix.
4. The fabric of claim 1, wherein the chrome complex comprises a
polymerized chromium network chemically bonded with the surface
matrix.
5. The fabric of claim 1, wherein the fabric is at least one of a
forming fabric, a press fabric, a dryer fabric, an impermeable
press belt and a through-air dryer fabric.
6. A method for providing release properties to a papermaking
machine fabric, comprising the steps of: applying a solution of
chemically reactive chrome complex to a surface of a papermaking
machine fabric; and drying and curing the fabric so that the
complex reacts with the surface and produces a polymerized chromium
network chemically bonded to the fabric.
7. The method of claim 6, wherein the drying and curing step
orients hydrophobic fatty chains from the complex so that the
chains are oriented away from the fabric.
Description
CROSS REFERENCE TO PROVISIONAL APPLICATION
[0001] This application claims the benefit of the filing date of
provisional patent application 60/759,650 filed Jan. 17, 2006.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to paper machine fabrics.
Paper machine fabrics are conventionally used in the manufacture of
paper towels, facial tissue, bathroom tissue, table napkins and the
like.
[0003] U.S. Pat. Nos. 6,017,417 and 6,331,230 and Publication WO
01/44568 describe the manufacture of tissue and the like using
through-air drying. Typically, in such processes, a slurry of
cellulosic fibers is fed onto a forming fabric or between two
forming fabrics, where the paper web is formed and partially
dewatered before the web is transferred, often via a transfer
fabric, to a through-air drying (TAD) fabric for further water
removal by way of one or multiple TAD units. The web is then fed by
way of the TAD fabric to a presser roll where a nip is formed
between the TAD fabric and a Yankee cylinder. Here the paper web
transfers to the Yankee cylinder where further drying and creping
takes place. In one variation of this process, the Yankee cylinder
is removed, thus eliminating the pressing nip. In this case, the
web is transferred from the TAD fabric to a further fabric.
[0004] It is conventional to spray a chemical release agent, e.g.
silicone oil onto the paper machine fabrics in order to provide
good sheet release, whether it be to aid the transfer of the sheet
on to another fabric or on to the Yankee cylinder, after exiting
the presser roll nip. There are a number of potential problems
associated with using a chemical release agent in the TAD process,
two of these being that they are messy to utilize and very
expensive.
[0005] A significant problem with the use of a chemical release
agent is the fact that the agent remains in the recycled white
water system. Most modern paper machines tend to have closed water
systems, and so the water that is removed from the cellulosic stock
during the papermaking process and the reclaimed fabric shower
water is collected, recycled and then reused as shower water and
also to dilute the new cellulosic stock. In the interim period, the
water is stored in holding tanks. In these tanks, minute beads of
chemical release agent coalesce into larger globules. It is
extremely difficult to separate the chemical release agent from the
water and the globules end up coating these tanks, which finally
make their way back into the system. When the globules find their
way into the cellulosic stock, there are potentially a number of
problems, all of which result in a reduction of paper quality and
machine operating efficiency.
[0006] Another approach to improve release is to coat the fabric,
and typical coatings include thermoset polyurethane (TPU),
hydrophobic materials and the like.
[0007] It is clear that the need remains for an environmentally
friendly system which can be applied to paper making machine fabric
and other belts or rolls to improve release behavior without
adversely impacting other performance attributes.
SUMMARY OF THE INVENTION
[0008] According to the invention, the foregoing need has been
met.
[0009] According to the invention, a paper machine fabric is
provided which comprises a fabric having a roll side and a paper
side and a surface matrix on the paper side; and a chrome complex
treatment on the surface matrix. The chrome complex treatment
serves to enhance release properties of the fabric without
requiring sanding of the fabric and without using materials which
interfere with the complex paper system and/or the paper making
machine itself. Further, the treatment is applied in a water based
system, and chemically reacts with the surface of the fabric.
[0010] According to the invention, the chrome complex treatment can
preferably be an organic metal complex, preferably a fatty acid
metal complex.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] A detailed description of preferred embodiments of the
present invention follows, with reference to the attached drawings,
wherein:
[0012] FIG. 1 schematically illustrates a fabric having a coating
according to the invention.
DETAILED DESCRIPTION
[0013] The invention relates to fabric for papermaking machines
and, more particularly, to a treatment for such fabric which
improves the release properties of the fabric.
[0014] The treatment according to the invention is applied to the
paper side of a fabric, preferably a fabric 10 having a base 12 and
batt layers 14, 16 attached at each side of base 12. A surface
matrix 18 can be attached to or otherwise defined on a surface of
batt layer 14, and the treatment 20 according to the invention is
preferably applied at least to surface matrix 18.
[0015] According to the invention, the surface treatment comprises
a water based system containing a chrome complex. One example of
particularly suitable chrome complexes is a family of products
marketed by Dupont under the trademark Quillon.RTM., certain
examples of which include chromium pentahydroxy(tetradecanoato)di-;
tetradecanoato chromic chloride hydroxide; octadecanoato chromic
chloride hydroxide and others.
[0016] The treatment composition can be applied in relatively low
concentrations, for example at concentrations of less than 10%
volume, preferably at concentrations of less than 2% volume. The
composition can be applied using known techniques such as spray or
kiss roll application. After application to the fabric, the
composition is preferably dried and cured, preferably at a
temperature of about 100.degree. C. plus or minus about 50.degree.
C. This leads to chemical reaction of the composition with the
fabric which leads to desirable release properties of the fabric.
It is believed that the composition reacts with the polar groups of
the fabric, and when cured the complex forms an insoluble layer of
a polymerized chromium network chemically bonded to the substrate.
Hydrophobic fatty acid chains of the composition are left oriented
away from the surface of the substrate, giving rise to a unique and
unexpected release property.
[0017] The treatment according to the present invention can
advantageously be applied to various papermaking machine clothing
or fabric and other industrial fabrics, for example including
forming fabrics, press fabrics, impermeable press belts, dryer
fabrics, TAD and other industrial fabrics, and can be applied to
rolls and sleeves.
[0018] The composition of the present invention can also be
engineered with other aqueous polymer systems such as poly vinyl
alcohol (PVA) or poly vinyl acetate (PVAc) to provide control over
surface energy, wetting behavior and the like.
[0019] A particular advantage of the present invention is that the
fabric does not need to be sanded or ground or otherwise treated in
a potentially harmful way in order to apply the composition.
[0020] The water based system which is preferably used to apply the
composition is environmentally friendly, and does not contaminate
the white water of the process or the wet cellulosic material.
EXAMPLE
[0021] An impermeable press belt having a 1.0 mm thick surface
matrix consisting of TPU and embedded nylon fibers is treated using
Quilon S and/or Quilon L solution. The solution is applied by spray
and/or kiss roll application at concentrations of 0-10% by volume,
and then dried and cured at 100.degree. C. Following this
treatment, the treated fabrics were tested and surface energy
dropped by approximately 20% as compared to the normal TPU. Thus,
the treated fabric has a marked improvement in release
properties.
[0022] It is to be understood that the invention is not limited to
the illustrations described and shown herein, which are deemed to
be merely illustrative of the best modes of carrying out the
invention, and which are susceptible of modification of form, size,
arrangement of parts and details of operation. The invention rather
is intended to encompass all such modifications which are within
its spirit and scope as defined by the claims.
* * * * *