U.S. patent application number 13/942173 was filed with the patent office on 2013-11-14 for headbox for the production of paper or paperboard.
The applicant listed for this patent is Stora Enso AB. Invention is credited to Jan-Erik Nordstrom.
Application Number | 20130299113 13/942173 |
Document ID | / |
Family ID | 42561971 |
Filed Date | 2013-11-14 |
United States Patent
Application |
20130299113 |
Kind Code |
A1 |
Nordstrom; Jan-Erik |
November 14, 2013 |
HEADBOX FOR THE PRODUCTION OF PAPER OR PAPERBOARD
Abstract
A headbox is provided that comprises at least one first inlet
channel adapted to receive furnish comprising fibres, at least one
turbulence generator connected to the first inlet channel, a second
inlet channel adapted to receive a non-fibrous high consistency
composition, and a sliced cone connected to the turbulence
generator and the second inlet channel. The first inlet channel and
the turbulence generator are arranged so that the furnish is passed
through the first inlet channel and further to the turbulence
generator and thereafter to the sliced cone. The second inlet
channel is arranged so that the non-fibrous high consistency
composition is passed through the second inlet channel and directly
to the sliced cone bypassing the turbulence generator.
Inventors: |
Nordstrom; Jan-Erik; (Nacka,
SE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Stora Enso AB |
Falun |
|
SE |
|
|
Family ID: |
42561971 |
Appl. No.: |
13/942173 |
Filed: |
July 15, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13144025 |
Jul 11, 2011 |
8512517 |
|
|
PCT/SE2010/050096 |
Jan 29, 2010 |
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13942173 |
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Current U.S.
Class: |
162/341 |
Current CPC
Class: |
B32B 2307/7265 20130101;
B32B 2307/75 20130101; B32B 2255/26 20130101; D21H 27/32 20130101;
D21F 1/026 20130101; D21F 9/006 20130101; D21F 11/04 20130101; B32B
2255/20 20130101; B32B 2255/28 20130101; B32B 2250/26 20130101;
B32B 29/005 20130101; B32B 29/06 20130101; D21F 1/02 20130101; B32B
2255/12 20130101; B32B 2307/7242 20130101; D21H 27/30 20130101;
B32B 2255/24 20130101; B32B 2307/41 20130101; B32B 2307/4023
20130101; B32B 2553/00 20130101 |
Class at
Publication: |
162/341 |
International
Class: |
D21F 1/02 20060101
D21F001/02 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 16, 2009 |
SE |
0900191-8 |
Claims
1. A headbox comprising at least first and second inlet channels,
at least one turbulence generator and a sliced cone, wherein the
first inlet channel and the at least one turbulence generator are
adapted to receive a furnish comprising fibres and wherein the
first inlet channel and the turbulence generator are arranged so
that the furnish is passed through the first inlet channel and
further to the turbulence generator and thereafter to the sliced
cone, and wherein the second inlet channel is adapted to receive a
non-fibrous high consistency composition and wherein the second
inlet channel is arranged so that the non-fibrous high consistency
composition is passed through the second inlet channel and directly
to the sliced cone bypassing the turbulence generator.
2. The headbox according to claim 1 wherein the headbox comprises
three inlet channels wherein two of the channels are adapted to
receive the furnish comprising fibres and one of the channels is
adapted to receive the non-fibrous high consistency
composition.
3. The headbox according to claim 2 wherein the inlet channels
adapted to receive furnish comprising fibres feeds the furnish to
at least one turbulence generator and the inlet channel which is
adapted to receive the non-fibrous high consistency composition
feeds the non-fibrous high consistency composition directly to the
sliced cone without subjecting the non-fibrous high consistency
composition to turbulence generation.
4. A multilayer headbox comprising at least one first inlet channel
adapted to receive furnish comprising fibres, at least one
turbulence generator connected to the first inlet channel, a second
inlet channel adapted to receive a non-fibrous high consistency
composition, a sliced cone connected to the turbulence generator
and the second inlet channel, wherein the first inlet channel and
the turbulence generator are arranged so that the furnish is passed
through the first inlet channel and further to the turbulence
generator and thereafter to the sliced cone, and wherein the second
inlet channel is arranged so that the non-fibrous high consistency
composition is passed through the second inlet channel and directly
to the sliced cone bypassing the turbulence generator.
5. The headbox according to claim 4 wherein the headbox comprises
three inlet channels wherein two of the channels are adapted to
receive the furnish comprising fibres and one of the channels is
adapted to receive the non-fibrous high consistency
composition.
6. The headbox according to claim 5 wherein the inlet channels
adapted to receive the furnish comprising fibres feeds the furnish
to at least one turbulence generator and the inlet channel which is
adapted to receive the non-fibrous high consistency composition
feeds the non-fibrous high consistency composition directly to the
sliced cone without subjecting the non-fibrous high consistency
composition to turbulence generation.
7. The headbox according to claim 5 wherein the channel adapted to
receive the non-fibrous high consistency composition is in the
middle of the headbox and the two inlet channels adapted to receive
furnish comprising fibres are outer inlet channels of the headbox.
Description
CROSS REFERENCE
[0001] This application is a division of U.S. Ser. No. 13/144,025
filed Jul. 11, 2011, which is a U.S. National Stage under 35 U.S.C.
.sctn.371 of International Application No. PCT/SE2010/050096, filed
Jan. 29, 2010, which claims priority from Swedish Patent
Application No. 0900191-8, filed Feb. 16, 2009.
FIELD OF THE INVENTION
[0002] The present invention relates to a process for producing a
multilayer paper or paperboard product comprising a non-fibrous
high consistency layer.
[0003] The invention further relates to a paper or paperboard
produced according to the process and a headbox used in the
process.
BACKGROUND
[0004] Production of multilayer papers can either be done by the
use of a head-box in a single step or by the use of several
headboxes and wires or forming units. The challenge is to produce
smooth fibre layers without streaks or fibre flocks, i.e. layers
with good formation.
[0005] The consistency of a furnish in the headbox is of great
importance for obtaining a fibre web with good formation. Higher
consistency makes it much more difficult to produce a smooth fibre
web since the fibres tend to flock, which can be seen as a cloudy
visual appearance in the fibre web sheet, i.e. the formation is not
good. The normal consistency of a furnish in a headbox is about
0.5-2%, but some examples of higher consistency has also been
described in prior art. One example can be seen in U.S. Pat. No.
4,376,012 which discloses usage of a consistency of about 2-5%.
[0006] In papermaking processes there is an ongoing concern to find
ways to produce paper or paperboard at reduced costs. One way is to
reduce the energy needed for the produced paper or paperboard. Many
steps in a production line demands high amounts of energy and
reducing the energy demand also decreases the production cost. By
increasing the consistency, i.e. by reducing the water content, the
dewatering and drying demand is reduced, and thus also the energy
needed.
[0007] Another way to decrease the production cost is to decrease
the amount of the expensive raw material, i.e. fibres in the
product. In papermaking, fillers are often added in order to
improve the properties of the paper but also to reduce the raw
material content and thus also the total cost. When making
paperboard, there is an ongoing development to produce a paperboard
with high bulk and thus decreased raw material content but without
decreasing the strength and thickness of the paperboard to maintain
the stiffness in the produced paperboard.
[0008] There is, however, a need for an improved process to make a
paper or paperboard product which decreases the production cost by
reducing both the energy demand and the raw material content.
SUMMARY OF THE INVENTION
[0009] It is an object of the present invention to provide a
process for production of a paper or paperboard product in an
energy efficient way.
[0010] Another object of the invention is to produce a paper or
paperboard at a decreased cost.
[0011] These objects and other advantages are achieved by the
process according to claim 1, By adding a non-fibrous high
consistency composition in the headbox during production of a paper
or paperboard product, it is possible to decrease the drying demand
of the produced product as well as affect the raw material content
and thus also the production cost. This is achieved by the
independent claims. Preferred embodiments of the process are
defined in the dependent claims.
[0012] The invention relates to a process for producing a
multilayer paper or paperboard product, which process comprises the
steps of providing a first headbox with a furnish comprising
fibres, which furnish forms at least one layer of the paper or
paperboard product, providing the headbox with a non-fibrous high
consistency composition, which composition forms at least one
additional layer of the paper or paperboard product and conducting
the layers onto a wire forming a multilayer web which is further
dewatered and dried forming the paper or paperboard product.
[0013] The non-fibrous high consistency composition may have a dry
content of 5-70% by weight, preferably 10-40% by weight. The high
dry content of this layer increases the total dry content of the
multilayer web which reduces the need for dewatering in the forming
and in the press sections and gives easier and faster drying.
[0014] The content of the non-fibrous high consistency composition
may be increased and the content may be 10-80% by weight of the
total content of the paper or paperboard product. In this way the
drying efficiency increases and the cost decreases.
[0015] The non-fibrous high consistency composition may be a
coating colour. In this way it is possible to add a coating
composition already in the headbox which both increases the dry
content of the formed fibre web and also improves the opacity and
printability of the formed paper or paperboard product.
[0016] The multilayer web preferably has a dry content above 1.5%
by weight when conducted onto the wire before dewatering, i.e. on
the forming section. This is higher compared to fibre webs
described in prior art, which means that the drying demands of the
fibre web according to the invention is decreased.
[0017] The paper or paperboard product preferably consists of at
least three layers and it is most preferred that a non-fibrous high
consistency layer forms the middle layer of the paper or paperboard
product. Even more preferable, the outer layers are fibre layers
and the middle layer is a non-fibrous high consistency layer,
preferable a coating layer. In this way, the formed paper or
paperboard product will have improved or remained quality at
decreased raw material content and/or cost.
[0018] The process may also provide a second headbox with a furnish
comprising fibres forming at least one additional layer of the
paper or paperboard product and providing the second headbox with a
non-fibrous high consistency composition forming at least one
additional layer of the paper or paperboard product and conducting
the layers onto at least one wire forming a multilayer web which is
further dewatered and dried to form the paper or paperboard
product. It is common, when making for example multilayer
paperboard products, to use more than one headbox.
[0019] The invention further relates to a paper or paperboard
product produced according to the process mentioned above.
[0020] The invention also relates to a headbox for use in the
process mentioned above wherein the headbox comprises at least a
first and a second inlet channel, at least one turbulence generator
and a sliced cone, wherein the first inlet channel and the at least
one turbulence generator are adapted to receive a furnish
comprising fibres and wherein the first inlet channel and the
turbulence generator are arranged so that the furnish is passed
through the first inlet channel and further to the turbulence
generator and thereafter to the sliced cone, and wherein the second
inlet channel is adapted to receive a non-fibrous high consistency
composition and wherein the second inlet channel is arranged so
that the non-fibrous high consistency composition is passed through
the second inlet channel and directly to the sliced cone.
[0021] The headbox preferably comprises three inlet channels
wherein two is adapted to receive furnish and one is adapted to
receive a non-fibrous high consistency composition. In this way a
three layer paper or paperboard product is produced wherein one
layer of the product is a non-fibrous high consistency layer and
two layers are fibre layers.
[0022] It is preferred that the inlet channels adapted to receive
furnish conducts the furnish to at least one turbulence generator
and the inlet channel which is adapted to receive the non-fibrous
high consistency composition conducts the non-fibrous high
consistency composition directly to a sliced cone. In order to get
a good formation on a fibre layer it is necessary to have a
turbulence generator which prevents the fibres from flocking. The
high consistency layer does not contain fibres and it may thus not
be necessary to have a turbulence generator in order to get a
homogen layer. The headbox can thus be made smaller due to the lack
of turbulence generator for the high consistency layer. Thus, the
non-fibrous high consistency composition may be conducted from the
inlet channel directly to the sliced cone without passing a
turbulence generator.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] The present invention will by way of example be described in
more detail with reference to the appended schematic drawing, which
shows an embodiment of the present invention.
[0024] FIG. 1 shows a headbox according to the invention.
DETAILED DESCRIPTION
[0025] The invention describes a totally new process which results
in a new type of paper or paperboard product. The process reduces
both the energy demands and the raw material content, i.e. fibre
demand of the produced product. The invention also gives an
existing paper or paperboard machine the potential to increase
production capacity, i.e. no major modifications of the paper or
paperboard machine is necessary in order produce this high quality
product.
[0026] The non-fibrous high consistency composition preferably has
a dry content of about 5-70% by weight, preferably 10-40% by weight
or even more preferably 25-40% by weight. Higher dry content
decreases the amount of water which needs to be removed from the
formed paper or paperboard product. The optimal dry content depends
on the construction of the forming section, on the properties of
the composition and on the capacities of the pumps which conducts
the composition to the headbox and further on to the wire/wires.
Due to high consistency of the non-fibrous high consistency
composition, the resulting multilayer product will have a higher
consistency during production compared to multilayer fibre products
produced according to prior art.
[0027] The non-fibrous high consistency composition does preferably
not contain any fibres. However, small amounts of fibres or fines
from fibres may be present. The composition contains drained water
from the forming process which may partially or completely be
recycled and then fractions of fibres or fines from fibres might
also be present. However, the major part of the composition, i.e.
more than 90% by weight and preferably more than 97% by weight is
non-fibrous material.
[0028] Furthermore, by adding a non-fibrous high consistency
composition already in the headbox it is possible to increase the
total content of the non-fibrous composition in the paper or
paperboard and thus also to decrease the fibre content. The
non-fibrous high consistency composition content may be 10-80%,
preferably 30-60% by weight of the total content of the paper or
paperboard produced. In this way the drying demands decreases since
it takes more energy to dry fibres compared to, for example fillers
or coating colour, which are two examples of non-fibrous high
consistency composition. Furthermore, the cost decreases both since
the drying demand decreases and since most non-fibrous high
consistency compositions are much cheaper compared to fibres.
[0029] According to the invention the water content in the head-box
is minimized. The at least one layer with fibres has a consistency
of 0.1-5% by weight, preferable between 0.2-2% by weight or even
more preferably 1-1.4% by weight. The consistency of the fibres is
chosen in a way so that the best formation of the fibre layer is
achieved. Conventionally used dilution techniques may be used to
better control the cross direction profiles in any, or all, of the
layers to be formed.
[0030] The non-fibrous high consistency composition is preferably a
coating colour. The invention thus combines the forming area with
the coating area by putting the coating layer into the head-box of
a paper or paperboard machine.
[0031] The coating layer increases the quality of the paper or
paperboard product, such as the printability and the opacity. It is
also possible to produce a smooth coating layer from a high
consistency coating colour at high speed.
[0032] The coating colour may be a composition with a certain
predetermined recipe comprising inorganic or organic pigments,
binder and if necessary additional additives. Common pigments which
can be used are clay (kaolin), calcium carbonate, titan dioxide,
talc, calcium sulphate (gypsum) and granules of starch or other
organic pigments. The binder is added in order to bind the pigments
together and can for example be starch, carboxymethylcellulose
(CMC) or a synthetic binder such as latex e.g. styrene-butadien
latex or acrylic-copolymer latex. Other additives can for example
be wet strength agents, surfactants or dispersion agents. The
pigments, binder and other additives are chosen based on the
desired properties of the produced paper or paperboard product. The
coating colour may also contain small amounts of fibres or fines
from fibres, which mainly come from the drained recirculated water
during the forming or pressing, e.g. from the short or long
circulation in a paper or paperboard machine.
[0033] The paper or paperboard product according to the invention
can have the coating layer as a surface layer and the coating layer
can thus be printed in a conventional way. The coating layer can
also be surrounded by at least two fibre layers, i.e. at least one
fibre layer on each side of the coating layer. The printability of
the paper or paperboard product is still improved due to the
presence of the coating layer in-between the fibre layers, for
example problems with print bleeding or showing through the paper
or paperboard product are decreased.
[0034] Furthermore, the opacity of the paper or paperboard product
is improved, i.e. increased, since the coating colour consists of
pigments which diffract the light more efficiently than fibres and
thus prevent seeing through the paper or paperboard product.
[0035] The non-fibrous high consistency composition may also be a
homogen polymer solution which can form a barrier in order to
create an impermeable layer against liquids, gases etc in or on the
formed paper or paperboard product.
[0036] The produced paper or paperboard product also has a
decreased raw material demand. Normally, fillers are added to the
furnish which makes it possible to decrease the amount of raw
material. However, fillers are mixed together with fibres and it is
not possible to increase the dry content of a fibre/filler mixture
in the headbox since it then will not be possible to produce a
smooth paper or paperboard product. This is due to the fact that
high solid contents of fibres tend to flocculate and thus give an
uneven sheet structure.
[0037] The produced paper or paperboard according to this invention
has both decreased dewatering demands as well as decreased raw
material content and the non-fibrous content of the paper or
paperboard is thus increased. The non-fibrous content of the
produced paper or paperboard product can, as previously mentioned,
be increased and preferred values are approximately 35% by weight
or more, preferably 50% by weight or more of the total content of
the product.
[0038] The paper or paperboard produced according to the invention
will be of a completely new type with high amount of non-fibrous
high consistency composition, for example coating colour, within
the product and thus the product will have remained or better
properties, even at lower grammages.
[0039] The produced paper or paperboard product will also have
other improved properties as various layers can be added within the
sheet to enhance different properties. In this way it is possible
to produce a paper or paperboard product with totally new
properties. Examples of non-fibrous high consistency compositions
can, besides coating colours, also be polymers or materials as
could be seen as smell-taste driven, i.e. increasing or decreasing
smell or taste properties in a product covered or packaged within
this paper or paperboard, or materials adding a specific
authenticity to the produced product in order to be able to trace
the product and make sure that it is genuine.
[0040] The furnish comprising fibres and the non-fibrous high
consistency composition are separately caused to flow through the
headbox onto a wire to form a multiply web. The formation of the
web, i.e. the distribution of the fibres are controlled and
regulated and the web is dewatered to a consistency of above 1.5%
by weight, preferable above 1.6% by weight but consistencies as
high as 10% by weight may be possible. However, the normal
consistency is 1.6% by weight which is typically when the web
contains fibres (60%) of 1% consistency and filler (40%) at 20%
consistency. The web is thereafter further dewatered in a press
section, and the web receives a dry content of about 50-60% by
weight before entering the drying section. Conventionally used
dilution techniques may be used to better control the cross
direction profiles in any, or all, of the layers to be formed.
[0041] The increased dry content at an early stage means that the
drying section can be shortened and/or the temperature of the
drying rolls can be decreased and/or the production capacity, i.e.
machine speed, can be increased. The dry content of the finished
paper or paperboard product is about 85-99%.
[0042] The fibre web may be dried using conventional drying
techniques. The web is often dried, by heating cylinders which the
fibre web is in contact with. Normally, steam heated drying
cylinders are used in order to dry the wet web but gas or
electrical fired, infrared or induction heating can also be
used.
[0043] Furthermore, the web may also be dried using new drying
technology, such as impingement drying, impulse drying, or other
drying techniques performed with very hot surfaces. On-line
calendering would also diminish calendering needs off-line since a
smooth surface may already be achieved after drying.
[0044] The produced paper or paperboard product comprises at least
two layers, one layer comprising fibres and one layer comprising a
non-fibrous high consistency composition. The product can also
comprise three, four, five, six or even more layers. The product
may consist of more than one fibre layer with the same or different
composition and one non-fibrous high consistency layer. The product
may also consist of more than one non-fibrous high consistency
layers with the same or different compositions and one fibre layer.
The product may also consist of more than one fibre layers and more
than one non-fibrous high consistency layers with the same or
different compositions. The non-fibrous high consistency layers may
either be located on each other or the non-fibrous high consistency
layer can be located in between fibre layers. In the same way, the
fibre layers can either be located on each other or they can be in
between non-fibrous high consistency layers.
[0045] If necessary, at least one additional coating layer can be
added to the surface of the produced paper or paperboard product
prior to or after the drying section. This coating layer can be
added by any conventional known technique in order to further
improve the surface properties and above all the printing
properties of the produced paper or paperboard product.
[0046] One very big advantage with the current invention is that no
major changes in the equipment are needed. The paper or paperboard
machine can be used with only some modifications of the headbox.
The paper or paperboard machine must of course be runned in a
different way due to the decreased demand of drying and due to the
changed properties of the produced paper or paperboard product.
[0047] One example of a headbox (1) according to the invention can
be seen in FIG. 1. Furnish is conducted to the headbox (1) through
two conduits (2, 4) which further conducts the furnish to two inlet
channels (5, 7). These inlet channels (5, 7) are the outer inlet
channels of the headbox (1). The furnish is thereafter conducted to
two turbulence generators (8, 9) and thereafter to a sliced cone
(10). A coating colour is conducted to the headbox (1) through a
conduit (3) and further to an inlet channel (6) located it the
middle of headbox (1). The coating colour is thereafter directly
conducted to the sliced cone (10).
[0048] The headbox can be of any kind of headbox for the production
of multilayer products. Other embodiments and variation than the
ones described above are possible within the scope of the invention
as defined in the independent claims. For example, more than one
headbox can be used.
[0049] When providing a second headbox with a furnish comprising
fibers forming at least one additional layer and providing the
second headbox with a non-fibrous high consistency composition
forming at least one additional layer, a paper or paperboard
product with at least two fibre layers and at least two non-fibrous
high consistency composition layers is formed.
[0050] Even though the invention is directed towards production of
paper or paperboard it should be mentioned that it could be
possible to produce other products such as gypsum boards or MDF's
(medium density fibreboard) or similar building materials with new
constructions and properties (e.g. water proof, gas proof or fire
proof boards), or various bases for composites to polymer industry
pressing moulds, e.g. replace common polymers originating from the
petrochemical industries, such as polyvinylchloride (PVC) and
LDPE/HDPE (low/high density polyethylene) used as raw materials in
mould forming products today.
* * * * *