U.S. patent application number 13/356838 was filed with the patent office on 2012-07-26 for manufacturing a papery article.
This patent application is currently assigned to BASF SE. Invention is credited to Stefan Fassbender, Christoph Lessig.
Application Number | 20120186766 13/356838 |
Document ID | / |
Family ID | 46543279 |
Filed Date | 2012-07-26 |
United States Patent
Application |
20120186766 |
Kind Code |
A1 |
Fassbender; Stefan ; et
al. |
July 26, 2012 |
MANUFACTURING A PAPERY ARTICLE
Abstract
The present invention relates to a process for manufacturing
papery articles, such as paper, card and board, comprising the pH
adjustment of an aqueous composition comprising at least one fiber
stock by addition of methanesulfonic acid (MSA).
Inventors: |
Fassbender; Stefan; (Speyer,
DE) ; Lessig; Christoph; (Dachau, DE) |
Assignee: |
BASF SE
Ludwigshafen
DE
|
Family ID: |
46543279 |
Appl. No.: |
13/356838 |
Filed: |
January 24, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61435812 |
Jan 25, 2011 |
|
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|
Current U.S.
Class: |
162/181.3 ;
162/158; 162/181.1; 162/181.2; 162/181.5; 162/181.8 |
Current CPC
Class: |
D21H 17/68 20130101;
D21H 17/09 20130101; D21H 17/66 20130101; D21H 17/63 20130101 |
Class at
Publication: |
162/181.3 ;
162/158; 162/181.2; 162/181.1; 162/181.5; 162/181.8 |
International
Class: |
D21H 17/66 20060101
D21H017/66; D21H 17/63 20060101 D21H017/63; D21H 17/68 20060101
D21H017/68; D21H 17/09 20060101 D21H017/09 |
Claims
1-12. (canceled)
13. A process for manufacturing a papery article comprising the
steps of: a) providing an aqueous composition comprising at least
one fiber stock; b) adding methanesulfonic acid to the aqueous
composition comprising at least one fiber stock to adjust the pH;
and c) draining the aqueous composition comprising at least one
fiber stock.
14. The process according to claim 13, wherein the step of draining
the aqueous composition (step c) results in the formation of a
fibrous web which is pressed and/or dried in one or more further
process steps.
15. The process according to claim 13, wherein the fiber stock used
is at least one fiber stock selected from the group consisting of
sulfate pulp (SA), sulfate semi-pulp, sulfite pulp (SI), groundwood
(HS), pressurized groundwood (PGW), refiner mechanical pulp (RMP),
thermomechanical pulp (TMP), chemical thermomechanical pulp (CTMP),
thermomechanical pulp with caustic/peroxide pretreatment (BCTMP),
waste paper (AP) and deinked waste pulp (DIP).
16. The process according to claim 13, wherein the aqueous
composition comprises at least one fiber stock which has been
alkali-oxidatively bleached.
17. The process according to claim 13, wherein at least one
secondary fiber stock is used.
18. The process according to claim 13, wherein the aqueous
composition comprising at least one fiber stock has a stock density
in the range from 0.01 to 5%.
19. The process according to claim 13, wherein the aqueous
composition additionally comprises at least one further additive
selected from the group consisting of aluminum sulfate, aluminum
nitrate, polyaluminum chloride (PAC), aluminum hydroxide chloride,
organic precipitant, biocide, deaerator, defoamer, dispersant,
adsorbent, fixative, retention aid, drainage accelerant, dye,
optical brightener, internal sizing agent, wet strength agent, dry
strength enhancer and internal wet web strength polymer (IWWS).
20. The process according to claim 13, wherein the aqueous
composition additionally comprises at least one inorganic filler
selected from the group consisting of ground calcium carbonate
(GCC), precipitated calcium carbonate (PCC), kaolin, titanium
dioxide and barium sulfate.
21. The process according to claim 13, wherein the pH of the
aqueous composition comprising at least one fiber stock is adjusted
to a value in the range from 4 to 11.
22. The process according to claim 13, wherein the step of adding
methanesulfonic acid to the aqueous composition comprising at least
one fiber stock takes place in a paper machine approach flow.
23. The process according to claim 13, wherein the papery article
is selected from graphic paper, office communication paper,
packaging paper, board, card, hygiene paper and specialty
paper.
24. The process according to claim 13, wherein the papery article
is a packaging material for the food sector.
Description
[0001] The present invention relates to a process for manufacturing
papery articles, such as paper, card and board, comprising the
addition of methanesulfonic acid (MSA) to an aqueous composition
comprising at least one fiber stock to set the pH.
[0002] The present invention further relates to the use of
methanesulfonic acid in the manufacture of a papery article, more
particularly for setting the pH of an aqueous composition
comprising at least one fiber stock in the paper/board machine
approach flow.
[0003] Paper and papery article for the purposes of the present
invention refer to sheetlike articles manufactured from fibers,
more particularly from chemically or mechanically uncovered
vegetable fibers, which are formed by dewatering a fiber stock
suspension using at least one wire screen usually under addition of
fillers and further additives.
[0004] The manufacture of papery articles on state of the art
paper/board machines generally comprises the dewatering of a fiber
stock suspension, for example a chemical pulp, mechanical pulp
and/or waste paper suspension, on at least one moving wire screen
to form a paper web. The term paper or board machine typically
subsumes the following assemblies: approach flow system, head box,
wire section, press section, dry end, size press (surface sizing),
film press, smoothing cylinder, smoothing system, online calender,
online coating assembly and windup. Often, the manufacture of
papery articles comprises downstream steps of surface treatment
(e.g., calendering, coating) and comprises finishing (e.g., roll
cutting, format cutting, packing). A general description of the
process steps and equipment parts involved in the manufacture of
papery articles is described for example in "Papiermacher
Taschenbuch, 8.sup.th edition, Dr. Curt Haefner-Verlag GmbH,
Heidelberg".
[0005] The approach flow system is where the fiber stock suspension
is made machine-ready for the subsequent sheet forming in the wire
section. It is where, for example, the final/compensatory beating
of the fiber stock is carried out, the stock amounts and stock
densities are regulated, and also the regulation of the flow rates
is carried out. Within the approach flow system, it is also
possible for the metered addition of fillers, process chemicals
and/or performance chemicals to take place. The approach flow
system is generally held to include all equipment parts and
pipework between the mixing and machine chest and the head box of
the paper/board machine. The approach flow system of the
paper/board machine is generally also where the pH of the fiber
stock suspension is set.
[0006] In the head box, the fiber suspension having a stock density
of generally less than 1.4% is applied to at least one moving
endless wire screen (machine wire). In the subsequent wire section
as it is known, the fiber stock suspension is drained to a stock
density of about 12 to 24% (augmented by application of vacuum or
pressure for example) and the fibers become interfelted together to
form a still wet fibrous web (sheet formation). This fibrous web is
removed from the wire using a pickup felt (felt band) for example,
and passes into the subsequent wet presses where the stock density
is further increased to about 50%.
[0007] Thereafter, the fibrous web is generally dried in the dryer
section using drying cylinders. For certain end uses, the paper can
then be subjected to further processing steps (e.g., smoothing,
coating, calendering).
[0008] The fiber stock suspensions used for paper or board
manufacture, in addition to fibers, usually comprise fillers, more
particularly inorganic fillers such as calcium carbonate, kaolin,
titanium dioxide, barium sulfate and multiple process and/or
performance chemicals, for example sizing agents to increase the
hydrophilicity and printability of the paper, and also, for
example, retention aids, drainage aids, dyes, optical brighteners,
wet strength agents, dry strength enhancers, defoamers,
biocide.
[0009] Possible fiber stocks for the manufacture of papery articles
are generally primary fiber stocks and also secondary fiber stocks.
Primary fiber stocks used are more particularly wood-free fiber
stocks, more particularly chemical pulps such as sulfate pulp (SA)
(also known as kraft pulp), sulfate semi-pulp, sulfite pulp (SI) of
hard- and/or softwoods. However, wood-containing fiber stocks, more
particularly mechanical pulps such as groundwood (HS) (also known
as stone groundwood SGW), pressurized groundwood (PGW), refiner
mechanical pulp (RMP), thermomechanical pulp (TMP), chemical
thermal mechanical pulp (CTMP) and thermomechanical pulp with
caustic-peroxide pretreatment (BCTMP) may also be used. Secondary
fiber stocks include various waste paper varieties recycled into
paper/board and card production, and also deinked pulp (DIP). DIP
is produced by a waste paper recovery process in which a large
proportion of the printing ink is removed from the fiber stock
suspension. In the deinking process, the slurried, defibered waste
paper is commonly admixed with caustic, water glass, complexing
agent, surfactant and hydrogen peroxide. The printing inks detach
from the fiber surface and are removed from the fiber stock
suspension by flotation. Chemical pulp, such as goundwood,
pressurized groundwood, TMP, RMP, but also chemical pulp are
typically bleached in the course of production and/or before use. A
distinction is generally made between oxidative and reductive
bleaching stages, although these bleaching stages are often
combined into bleaching sequences. Bleaching frequently comprises a
treatment with hydrogen peroxide under alkaline conditions. When
the bleaching process concludes with an alkaline stage, it is
generally necessary for the fiber stock suspension to be acidified.
In order to establish the pH necessary for paper production, it is
therefore generally necessary to add an acid to regulate the
pH.
[0010] Depending on the pH of the fiber stock suspension used for
paper formation, a general distinction is made between the
conventional acidic process (pH in the range from 4.5 to 6.8)
comprising generally the addition of acidic aluminum salts and the
neutral process in the pH range from 6.8 to 10.8. In the ideal case
of a neutral process, the pH is adjusted to a value between 7.0 to
7.5. In recent decades, the neutral process has become more and
more established, particularly because it enables calcium carbonate
(CaCO.sub.3) to be used as a filler, for example in the form of
ground calcium carbonate (GCC) or precipitated calcium carbonate
(PCC).
[0011] Fiber stock suspension pH is of decisive importance for
paper production and has a direct influence on paper/board machine
runnability. A high pH leads to increased swelling of the fibers
and impedes fiber stock suspension drainage. Accurate and reliable
pH setting further contributes to preserving the whiteness of the
papery articles and to preventing yellowing by alkalis. The choice
of suitable acids for setting the pH as part of the manufacture of
papery articles is very limited. Owing to the requirements of
availability, price and stability, a person skilled in the art
chooses from a very limited number of acids suitable for paper
production. The use of phosphoric acid, or of a combination of
phosphoric acid and phosphonates, or the use of carbon dioxide for
pH setting is described in the prior art. It is further known to
use sulfuric acid and/or bisulfite to set the pH in paper
production. It has also been written that the pH of a fiber stock
suspension can be adjusted by adding an electrolyte, such as
aluminum sulfate, aluminum nitrate, polyaluminum chloride (PAC) and
aluminum hydroxide chloride.
[0012] The WO 98/56988 document describes a process for stabilizing
the pH of a pulp suspension for paper production using a
combination of an alkali metal hydroxide and carbon dioxide.
[0013] The US 2010/0175839 document describes a multi-stage process
for adjusting the pH of a cellulosic pulp suspension wherein the
pulp is treated at least twice with carbon dioxide and at least
once with a strong acid, e.g., sulfuric acid, sulfurous acid or
bisulfite, and wherein a step for carbonate removal is
included.
[0014] The WO 2009/003770 document discloses a process for making
paper wherein a fiber stock suspension comprising a mechanical pulp
is subjected to an acid-base treatment to avoid reducing the
brightness. In the process, the fiber stock suspension is treated
initially with a strong acid, more particularly sulfuric acid,
sulfurous acid, hydrochloric acid and bisulfite, and then with a
weak base (e.g., an alkali metal bicarbonate or alkali metal
carbonate).
[0015] The prior art use of phosphoric acid and phosphonates
results in increased formation and deposition of calcium phosphates
in various parts of the paper machine. The paper/board machine thus
has to be increasingly idled to allow for cleaning.
[0016] Many state of the art paper machines operate at very high
speeds of up to 1800 meters per minute and outputs of up to 1000 t
of paper per 24 h to increase the production of paper/card.
Paper/board machine idling and the increased production of broke
are therefore the decisive factors for the efficiency and economics
of the production process.
[0017] Furthermore, phosphorus compounds pollute the wastewater
cleaning facilities of paper mills which, unlike communal water
treatment facilities, generally have no phosphorus-eliminating
stage.
[0018] One particular problem with using carbon dioxide for pH
regulation of fiber stock suspensions is the outgassing of carbon
dioxide in the wire water circuit and also the attendant
fluctuations in the pH. In addition, metering the gaseous additive
carbon dioxide requires costlier metering devices.
[0019] It is an object of the present invention to provide a
pH-regulating additive, more particularly an acid, for fiber stock
suspensions in paper production, and/or an improved process for
paper production. The process should firstly meet all
wastewater-relevant and environmental requirements as well as
provide for an efficient, simple and inexpensive operation. Simple
metering, minimal introduction of additional salt content into the
wire water/wastewater of the paper machine and also good drainage
behavior of the fiber stock suspension should be ensured for
instance.
[0020] We have found that, surprisingly, adding methanesulfonic
acid (MSA) is a particularly effective way to adjust the pH of
fiber stock suspensions in papermaking. Methanesulfonic acid has a
pK.sub.a value of about -0.6 and so is a strong or very strong
acid. Methanesulfonic acid is generally non-oxidizing and is marked
by heat and hydrolysis resistance in particular. Methanesulfonates
are used in washing and cleaning compositions for example.
Methanesulfonic acid is further used in acidic electroplating
solutions for metal coatings.
[0021] The present application is directed to a process for
manufacturing a papery article, such as paper, card and board,
comprising the steps of: [0022] a) providing an aqueous composition
comprising at least one fiber stock; [0023] b) adding
methanesulfonic acid to the aqueous composition comprising at least
one fiber stock to adjust the pH; [0024] c) draining the aqueous
composition comprising at least one fiber stock.
[0025] The use of methanesulfonic acid is associated with the
following advantages in particular: [0026] Methanesulfonic acid is
readily biodegradable and is halogen-free and thus reduces the
burden on the wastewater treatment of the production process.
Moreover, no or distinctly less phosphorus/phosphate ends up in the
wastewater of the paper/board machine. [0027] There is less, if
any, formation of deposits of calcium phosphate, for example, in
the parts of the paper/board machine. [0028] Owing to the high acid
constant of methanesulfonic acid, comparatively low quantities need
to be added. The salt burden of process waters in papermaking can
accordingly be reduced. [0029] Economic viability/efficiency of the
manufacturing process is improved. [0030] Methanesulfonic acid is
colorless, odorless and available in high purity, hence there is no
alien impact on the manufacturing system (process water,
wastewater, circuit water, papery articles). Therefore,
methanesulfonic acid is particularly suitable for use in the
manufacture of papery articles (packaging materials for example)
which are used in the food sector. [0031] Methanesulfonic acid has
high thermal stability, a low vapor pressure, hydrolysis resistance
and unlimited miscibility with water, hence handling and metering
are simple. [0032] Methanesulfonic acid is halogen-free and has
minimal corrosivity compared with sulfuric acid for example.
[0033] The use of methanesulfonic acid is thus able to provide a
distinct improvement in the economics of manufacturing papery
articles.
[0034] Paper and papery article for the purposes of the present
invention refer to sheetlike articles manufactured from fibers,
more particularly from chemically or mechanically uncovered
vegetable fibers, which are formed by dewatering a fiber stock
suspension using at least one wire screen usually under addition of
fillers and further additives. Additives are generally
distinguished into process chemicals (e.g., biocides, deaerators,
retention aids) and performance chemicals (e.g., dyes, optical
brighteners, wet strength agents). Paper and papery articles for
the purposes of the present invention are more particularly graphic
papers, office communications papers, packaging papers, hygiene
papers and specialty papers. Graphic papers for the purposes of the
invention are all papers used for printing in flexographic
printing, letterpress, offset printing or gravure printing for
example, e.g., news print. Office communication papers are writing,
printing and copying papers, for example photoprint and digital
printing papers. Packaging papers are papers, card and board for
packaging purposes, for example corrugated fiberboard. Hygiene
papers for the purposes of the invention are papers of high
specific volume and high absorbency, which are typically used in
the sanitary or kitchen sector or in the industrial sector. The
term specialty papers identifies papers and paperboards for
specific technical uses, for example decor papers and filter
papers.
[0035] Papery articles can be classified, according to their mass
per unit area, as paper, card or board. According to German
standard specification DIN 6730, a mass per unit area of not more
than 225 g/m.sup.2 is indicative of paper and above 225 g/m.sup.2
of board. Papery articles having a mass per unit area in the range
from 7 to 150 g/m.sup.2 are often also referred to as paper, in the
range from 150 to 600 g/m.sup.2 as cardboard and from 600 g/m.sup.2
as paperboard. Cardboard and paperboard typically consist of
multiple layers.
[0036] The present invention more particularly provides a process
as described above, wherein the step of draining the aqueous
composition (step c) results in the formation of a fibrous web
which is pressed and/or dried in one or more further process
steps.
[0037] The aqueous composition more particularly is a suspension
(slurry) of a fiber stock in water. The aqueous composition may
comprise further dissolved, colloidally dissolved or solid
constituents. The constituents in question are more particularly
known to a person skilled in the art and used/generated in the
course of manufacturing papery articles.
[0038] The fiber stock can be more particularly selected from:
[0039] chemical pulp (ZS), such as sulfate pulp (SA) (also called
kraft pulp), sulfate semichemical pulp, sulfite pulp (SI); [0040]
mechanical pulp, such as groundwood (HS) (also called stone
groundwood SGW), pressurized groundwood (PGW), refiner mechanical
pulp (RMP), thermomechanical pulp (TMP), chemical thermomechanical
pulp (CTMP), thermomechanical pulp with caustic/peroxide
pretreatment (BCTMP); [0041] secondary fiber stock, such as waste
paper (AP) and deinked pulp (DIP).
[0042] Fiber stocks used can be more particularly the
above-described bleached and/or unbleached pulps and/or fiber
stocks from hard- or softwoods. Preference is given to using beech
sulfite pulp and/or long fiber sulfate pulp.
[0043] More particularly, the aqueous composition comprises at
least one fiber stock selected from the group consisting of sulfate
pulp (SA), sulfate semi-pulp, sulfite pulp (SI), groundwood (HS),
pressurized groundwood (PGW), refiner mechanical pulp (RMP),
thermomechanical pulp (TMP), chemical thermomechanical pulp (CTMP),
thermomechanical pulp with caustic/peroxide pretreatment (BCTMP),
waste paper (AP) and deinked waste pulp (DIP).
[0044] In a preferred embodiment, the fiber stock used is at least
one secondary fiber stock, more particularly waste paper and/or
deinked pulp (DIP).
[0045] More preferably, the aqueous composition comprises at least
one fiber stock which has been alkali-oxidatively bleached.
[0046] Preferably, the aqueous composition comprising at least one
fiber stock has a stock density in the range from 0.01 to 5%,
preferably in the range from 0.1 to 5% and more preferably in the
range from 0.2 to 1.4%.
[0047] The stock density of an aqueous composition comprising at
least one fiber stock (fiber stock suspension) is the percentage of
the dry mass of the filterable solids in the composition relative
to the mass of the entire composition. Commonly, the dry mass is
reported as absolute dry mass or as dry mass on drying under
standard conditions (oven dry, otro). The determination of the
stock density of fiber stock suspensions is described in DIN 54359
(EN ISO 4119) for example.
[0048] By further constituents, the aqueous composition may
comprise at least one customary additive (process and performance
chemicals) known to a person skilled in the art. The additive may
be selected from: [0049] process chemicals, such as [0050]
electrolyte, for example aluminum sulfate, aluminum nitrate,
polyaluminum chloride (PAC), aluminum hydroxide chloride, inorganic
precipitants [0051] organic precipitant [0052] biocide (e.g., slime
control agent) [0053] deaerator [0054] defoamer [0055] dispersant
[0056] adsorbent (e.g., talc) [0057] fixative (e.g., short-chain
cationic polymers) [0058] retention aid (e.g., long-chain anionic
and cationic polymers, also partially crosslinked) [0059] drainage
accelerant [0060] and performance chemicals, such as [0061] dye
[0062] optical brightener [0063] internal sizing agent (resin size,
AKD, ASA, polymer size) [0064] surface sizing agent [0065] wet
strength agent [0066] dry strength enhancer [0067] internal wet web
strength polymer (IWWS)
[0068] More particularly, the aqueous composition additionally
comprises at least one further additive selected from the group
consisting of aluminum sulfate, aluminum nitrate, polyaluminum
chloride (PAC), aluminum hydroxide chloride, organic precipitant,
biocide, deaerator, defoamer, dispersant, adsorbent, fixative,
retention aid, drainage accelerant, dye, optical brightener,
internal sizing agent, wet strength agent, dry strength enhancer
and internal wet web strength polymer (IWWS).
[0069] Preferably, the aqueous composition additionally comprises
at least one inorganic filler selected from the group consisting of
ground calcium carbonate (GCC), precipitated calcium carbonate
(PCC), kaolin, titanium dioxide and barium sulfate, preferably
selected from the group consisting of ground calcium carbonate
(GCC) and precipitated calcium carbonate (PCC).
[0070] Adjusting the pH of an aqueous composition comprising at
least one fiber stock is more particularly effected by adding
methanesulfonic acid until the desired pH value or the desired pH
range is reached. A person skilled in the art is familiar with
common methods of pH control. The amount of methanesulfonic acid
added depends on the type of the aqueous composition comprising at
least one fiber stock and its original pH and also the desired pH
target value.
[0071] Adjusting the pH of the aqueous composition comprising at
least one fiber stock can be effected by adding a mixture of acids
comprising methanesulfonic acid. It is further conceivable to use a
mixture of methanesulfonic acid and carbon dioxide, or a mixture of
acids comprising methanesulfonic acid and carbon dioxide. More
particularly, methanesulfonic acid is added as sole acid to adjust
and/or stabilize the pH. It is further conceivable to
adjust/regulate the pH of the aqueous composition by additionally
adding a base known to a person skilled in the art.
[0072] The present invention provides more particularly a process
for manufacturing a papery article as described above, wherein the
pH of the aqueous composition comprising at least one fiber stock
is adjusted to a value in the range from 4 to 11, more particularly
in the range from 4.5 to 6.8 and more particularly in the range
from 6.8 to 10.8.
[0073] When the process of the present invention relates to a
process for manufacturing a papery article using the acidic method,
it is particularly a pH in the range from 4.5 to 6.8 which is set
by adding methanesulfonic acid. When the process of the present
invention relates to a process for manufacturing a papery article
using the so-called neutral method (usually with use of calcium
carbonate as filler), the pH of the aqueous composition comprising
at least one fiber stock is preferably adjusted to a range from 6.8
to 10.8 and more particularly from 7.0 to 7.5.
[0074] The process described in the present application for
manufacturing a papery article may comprise further common process
steps of paper/board production, for example steps in stock
preparation comprising dispersing, sorting, beating of the fiber
stock, steps downstream of drying, such as calendering, coating,
cutting, and also steps concerning finishing.
[0075] The addition of methanesulfonic acid to the aqueous
composition comprising at least one fiber stock can take place at
one or more different process sections of the manufacturing process
of the papery article. More particularly, the addition of
methanesulfonic acid to the aqueous composition comprising at least
one fiber stock takes place in a paper machine approach flow.
[0076] The approach flow system for the purposes of the present
invention is generally held to include all equipment parts and
pipework between the mixing and machine chest and the head box of
the paper/board machine. The approach flow system is where the
fiber stock suspension is made machine-ready for the subsequent
sheet forming in the wire section. It is where, for example, the
final/compensatory beating of the fiber stock is carried out, the
stock amounts and stock densities are regulated, and also the
regulation of the flow rates is carried out. The approach flow
system of the paper/board machine is where more particularly the
aqueous composition comprising at least one fiber stock (fiber
stock suspension) is uniformly diluted from about 3 to 5% stock
density (thick stock) to about 0.2 to 1.4% stock density. In
addition, the fiber stock suspension can be cleaned of fiber
bundles, sand, plastics, etc. This is done more particularly in the
so-called stock fine screening via centrifugal, pressure and/or
vibration screeners for example. The approach flow system is also
where fillers, process chemicals and/or performance chemicals can
be added. The approach flow system of the paper/board machine is
generally also where the pH of the fiber stock suspension is
set.
[0077] It is particularly preferable for the addition of
methanesulfonic acid for adjusting the pH to take place before,
after and/or during the stock fine screening of the aqueous
composition comprising at least one fiber stock. Stock fine
screening is more particularly effected using common screening
assemblies, for example centrifugal, pressure and/or vibration
screeners. It is preferable to add methanesulfonic acid before the
last screening assembly before the head box.
[0078] The process of the present invention can generally be used
for manufacturing any papery articles known to a person skilled in
the art. The process of the present invention relates more
particularly to the manufacture of a papery article selected from
graphic paper, office communication paper, packaging paper, card,
board, hygiene paper and specialty paper, preferably a process for
manufacturing a graphic paper or an office communication paper. In
a preferred embodiment, the invention provides a process for
manufacturing a papery article wherein the papery article is a
packaging material for the food sector.
[0079] The present application is further directed to the use of
methanesulfonic acid in the manufacture of a papery article.
[0080] More particularly, the use which the present invention
provides for methanesulfonic acid in the manufacture of a papery
article comprises adjusting the pH of an aqueous composition
comprising at least one fiber stock.
[0081] More particularly, the present invention provides for the
use of methanesulfonic acid in the manufacture of papery articles
on industrially common paper and/or board machines. Preferably, the
use of methanesulfonic acid comprises adjusting the pH of an
aqueous composition comprising at least one fiber stock in a paper
and/or board machine approach flow. The methanesulfonic acid may be
more preferably used before the head box.
[0082] More particularly, the present invention provides for the
use of methanesulfonic acid in the manufacture of a papery article
selected from graphic paper, office communication paper, packaging
paper, board, card, hygiene paper and specialty paper, more
particularly a packaging material for the food sector.
* * * * *