FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See section 10, rule 13)
"METHOD FOR PRODUCING A CELLULOSIC
MOLDED BODY"
LENZING AKTIENGESELLSCHAFT, an Austrian company of
Werkstrasse 2, A-4860 Lenzing, Austria
The following specification particularly describes the invention and the manner in
which it is to be performed.
1
Process for the production of a cellulosic moulded body
The invention relates to a process for the production of cellulosic moulded bodies according
to the viscose process.
In particular, the invention relates to the production of fibres and filaments.
The production of viscose fibres according to the viscose process comprises the following
steps
• alkalizing a cellulose starting material, in particular pulp (slurry, ripening of the
alkali cellulose)
• converting the alkalized cellulose starting material („alkali cellulose") into cellulose
xanthogenate
• dissolving the cellulose xanthogenate with alkali, whereby the so-called viscose is
obtained as a spinning mass
• optionally adding modifiers to the viscose for producing a spinning mass for modal
fibres
• spinning the viscose into continuous moulded bodies
• regenerating the cellulose from the continuous moulded bodies in a precipitation bath
• aftertreatment as well as drying
• optionally cutting the continuous moulded bodies into staple fibres.
The fibres produced by this process are known under the generic term (standard) viscose
fibres and modal fibres. The modal process differs from the standard viscose process by an
altered composition of the spinning mass, additional modifiers in the spinning mass and an
altered spinning bath composition.
The pulp used in the viscose process must meet certain criteria in order to enable appropriate
fibre qualities.
The pulp used in the viscose process has an alpha-cellulose content of more than 90% and
exhibits only small amounts of secondary compounds such as xylan and other hemicelluloses
(such as mannan). For the most part, those compounds are broken down and dissolved out
during the alkalization of the pulp at the beginning of the viscose process (Fig. 1).
Hemicelluloses remaining in the pulp are depolymerized during the ripening of the alkali
cellulose along with the cellulose and, therefore, have a much lower average molecular
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weight than in the starting pulp. This applies both to the use of chemical conversion pulps
and to the use of paper pulps.
The markedly lower molecular weight of hemicelluloses which are introduced into the
viscose process along with the pulp and are then subject to degradation in the slurry and the
ripening of the alkali cellulose becomes apparent in Fig. 2. In contrast thereto, the molar
mass distributions of hemicelluloses which have been extracted from a softwood and a
hardwood paper pulp without degradation are depicted.
WO 95/00698 describes a process in which, during the production of kraft pulp, a substantial
portion of hemicellulose is at first removed from the production stream and is reprecipitated
on the pulp at a later stage.
From US 7,390,566 B2 as well as from WO 2007/128026, the use of pulp with a relatively
high amount of xylan for the production of viscose fibres is known. The use of a pulp rich in
hemicellulose for the production of Lyocell fibres is known from WO 99/47733 Al as well
as from WO 01/88236 A2.
WO 2005/118950 describes the separation of beta-cellulose from a lye which has
accumulated by squeezing a pulp upon cold or hot caustic extraction (CCE, HCE).
There is still a need to increase the yield of the viscose process, with the quality of the final
products being consistent. Furthermore, the need exists to provide novel viscose fibres
having modified properties, in particular an increased absorbing capacity.
In one aspect, the object of the present invention is achieved by a process for the production
of a cellulosic moulded body according to the viscose process by shaping a spinning mass
containing cellulose xanthogenate, which is characterized in that xylan in an amount of at
least 1% by weight, based on the cellulose, preferably from 1% by weight to 20% by weight,
particularly preferably from 3% by weight to 15% by weight, is added to the cellulose
xanthogenate.
In a further aspect, the invention relates to a cellulosic moulded body obtained according to
the viscose process and having an amount of high-molecular xylan with an average degree of
polymerization (DP) of from 75 to 350, preferably of from 110 to 220, of at least 0.5% by
weight, based on cellulose, preferably of 2% by weight to 8% by weight.
3
Short description of the figures
Fig. 1 shows the depletion of low-molecular components in the viscose process.
Fig. 2 shows the molar mass distributions of high-molecular hemicelluloses from pulps as
well as of degraded hemicellulose from the slurry in the viscose process.
Fig. 3 shows fibre strengths of viscose fibres with an increased content of high-molecular
xylan in comparison to a standard fibre without any further xylan addition.
Fig. 4 shows the development of the water retention capacity (WRV) of viscose fibres as a
result of the addition of high-molecular xylan in the dissolving lye.
Fig. 5 shows the molar mass distribution of xylan precipitated upon a CCE treatment of an
eucalyptus kraft pulp and the molar mass distribution of a viscose fibre upon addition of said
high-molecular xylan.
Fig. 6 shows the molar mass distribution of a viscose fibre having an amount of 4.8% of
high-molecular xylan and the molar mass distribution thereof after removal of the proportion
of high-molecular xylan by way of calculation.
Detailed description of the invention
Unless indicated otherwise, percentage figures hereinafter always mean values in percent by
weight.
Surprisingly, it has been found that, by adding xylan to the cellulose xanthogenate in the
viscose process, an increase in the production yield can be achieved, with the properties of
the resulting cellulose moulded bodies staying the same or even being improved,
respectively.
Unlike in the prior art in which the xylans contained in the pulp are, for the most part,
dissolved out during the alkalization of the pulp and accumulate as a waste product, the
xylan is added to the cellulose xanthogenate in accordance with the invention. In the
subsequent steps of the viscose process (spinning, regeneration etc.), a substantial
degradation or dissolving of the xylan does not take place anymore so that it is largely
preserved in the moulded body which has been formed.
According to the invention, the xylan is preferably added in the form of an alkaline solution.
The alkaline solution may exhibit an amount of xylan of from 1 to 60 g/l.
4
In particular, the xylan may be added to the cellulose xanthogenate as a component of an
alkaline dissolving lye.
It is known that, for the dissolution of the cellulose xanthogenate for producing the spinning
dope, an alkaline dissolving lye is used. According to the preferred embodiment of the
present invention, the added xylan may be contained in said lye.
Particularly preferably, the xylan originates from a press lye accumulating during the
squeezing of alkalized pulp at the beginning of the viscose process. In particular, the press
lye accumulating during the squeezing of alkalized pulp may be added to the cellulose
xanthogenate.
As mentioned initially, the pulp is alkalized at the beginning of the viscose process. During
the squeezing of the alkalized pulp, an alkaline press lye accumulates which contains a high
amount of xylan which has been dissolved out of the pulp via the alkalization.
If said press lye is now used as a dissolving lye for dissolving the cellulose xanthogenate, the
xylan which, beforehand, has been dissolved out of the pulp is reintroduced into the process,
thus increasing the yield thereof.
Said xylan is relatively low-molecular. A person skilled in the art would expect an addition
of low-molecular xylan to have a negative impact on the strength properties of the resulting
fibre. However, it has been shown that the addition of low-molecular xylan does not
negatively affect the strength of the fibres and, hence, a yield increase is possible with no
change in strength properties.
According to a particularly preferred embodiment of the process according to the invention,
at least a portion of the added xylan is a high-molecular xylan with an average degree of
polymerization (DP) of from 75 to 350, preferably of from 110 to 220.
As already mentioned, the xylan originating, in the above-described embodiment, from the
press lye of the alkalization of the pulp in the viscose process is comparatively lowmolecular
due to the degradation during alkalization (see Fig. 2). It has been shown that
viscose fibres which are obtained by adding such a low-molecular xylan do not fall short of
conventional viscose fibres with regard to their properties such as, e.g., strength and
elongation.
5
Surprisingly, it has been shown that the result of adding high-molecular xylan to the
cellulose xanthogenate are comparable strength values and, additionally, an increased water
retention capacity as well as also a better stability of the contained xylan as compared to
further process steps.
In doing so, also the high-molecular xylan is added in an amount of from 1% to 20%,
preferably from 3% to 15%, based on cellulose.
The high-molecular xylan may preferably originate from a mass flow rich in hemicellulose
which accumulates in the course of an extraction step during the production of a pulp.
Methods of extracting pulps in the course of their production, such as, e.g., an alkaline preextraction
directly from the wood chips prior to pulping or a cold caustic extraction (CCE),
are known. Non-alkaline methods of extraction involving complexing agents such as, e.g.,
nitrenes or organic solvents such as DMSO are also presented in the literature. In those
extraction methods, the xylan is indeed dissolved out of the pulp, but is essentially not
broken down, in contrast to the alkalization of the (finished) pulp at the beginning of the
viscose process.
If the press lye obtained by squeezing the pulp after the extraction is concentrated by
appropriate methods, e.g., membrane filtration such as in WO 2005/118050, a mass flow
with a high proportion of high-molecular xylan is thereby generated. Said lye may, for
example, be re-added to the cellulose xanthogenate directly as a dissolving lye or,
respectively, as a part thereof.
This involves a yield increase in particular in an integrated viscose plant where the starting
pulp for the viscose process itself is produced in the same plant, since the xylan, which
otherwise would acccrue as a waste stream, is reintroduced into the process.
The present invention also relates to a cellulosic moulded body obtained according to the
viscose process and having an amount of high-molecular xylan with an average degree of
polymerization (DP) of from 75 to 350, preferably of from 110 to 220, of at least 0.5%,
based on cellulose, preferably of 2% to 8%.
The moulded body according to the invention is novel since, in the conventional viscose
process — without the addition of high-molecular xylan to the cellulose xanthogenate as
envisaged according to the invention — no high-molecular xylan is contained anymore in the
6
moulded body which has been formed because of the degradation as well as the dissolving of
xylan.
The cellulosic moulded body according to the invention is preferably provided in the form of
a fibre, e.g., a staple fibre or a filament fibre.
The invention also relates to the use of the cellulosic moulded body according to the
invention in absorbent products.
Examples
The invention is illustrated in further detail by way of the following examples:
Up to the production of the cellulose xanthogenate, the manufacturing process follows the
conventional viscose process. According to the invention, a pure lye which has been
enriched with xylan or a lye which already contains xylan is used as the dissolving lye.
The lye may contain low-molecular and/or high-molecular xylans.
If a lye with only low-molecular xylans is used, the lye may be added together with a
dissolving water, which may be optionally used.
In a lye with high-molecular xylans, the lye should be added initially to the cellulose
xanthogenate in order to prevent the xylans from precipitating, and optional addition of
dissolving water should occur separately.
In the following Examples 2 to 6, a lye containing high-molecular xylans was used.
In order to obtain the lye rich in high-molecular xylan, which is used in those examples, a
paper pulp from eucalyptus wood produced according to the kraft process was treated with
90 g/I of NaOH for 30 min at a consistency of 10%. The accruing lye was used as a
dissolving lye either in an unchanged state or after a concentration process, e.g., by means of
membrane filtration.
The dissolving lye contained between 1 and 66 g/1 of dissolved xylan. Upon xanthation, the
xylan was added to the xanthogenate together with the alkaline dissolving lye and admixed
homogeneously. The xylan exhibited the following molecular weight distribution:
Mw Mn PDI DP
kg/mol kg/mol
7
Xylan 22 13 1.7 167
Table 1: Molecular weight of the employed xylan from a CCE lye
In Fig. 2, the molecular weight distribution of high-molecular xylan is depicted, as it is
produced from a CCE lye of softwood and hardwood pulps, respectively. It can be seen
clearly that the xylan obtained after the application of a CCE stage has a much higher
average molecular weight than the xylan which has already been broken down in the slurry
of the viscose process.
The xylan was added to the xanthogenate from a conventional beech sulfite pulp and,
therefore, was not present during sulfidation, but only in the subsequent process step, the
dissolution of the xanthogenate. Thus, the xylan is not xanthated, but dissolved in NaOH.
The fibres were spun out in the laboratory. In this way, fibres having a markedly higher
content of xylan were produced (see Table 2 below).
Example 1 (comparative example):
A pulp (beech sulfite pulp) was mixed with approx. 18% NaOH, squeezed and subjected to a
ripening of the alkali cellulose at approx. 34°C for a duration of 19 hours. A spinning mass
with a basic composition of 32% CS2, 8.6 to 8.9% cellulose and 5.2 to 5.6% alkali was
produced. The trial was repeated with the same set-up (Examples 1-1 and 1-2, respectively).
The dissolving lye contained 0% xylan. The spinning mass thus obtained was spun into
fibres having the properties as shown in Table 2, Example 1, in a conventional manner. The
(low-molecular) xylan provided in the fibres and amounting to 0.6 or 0.7%, respectively,
originates from the pulp used.
Example 2
A dissolving lye with 8.5 g/I of high-molecular xylan was added to a xanthogenate according
to Example 1. The spinning mass thus obtained was spun into fibres having the properties as
8
shown in Table 2, Example 2. The xylan absorption amounted to 63% of the high-molecular
xylan provided in the dissolving lye, which corresponds to a proportion of high-molecular
xylan of 0.7%, based on the fibre.
Example 3
A dissolving lye with 22.0 g/1 of high-molecular xylan was added to a xanthogenate
according to Example 1. The spinning mass thus obtained was spun into fibres having the
properties as shown in Table 2, Example 3. The xylan absorption amounted to 79.2% of the
high-molecular xylan provided in the dissolving lye, which corresponds to a proportion of
high-molecular xylan of 2.7%, based on the fibre.
Example 4
A dissolving lye with 39.0 g/1 of high-molecular xylan was added to a xanthogenate
according to Example 1. The spinning mass thus obtained was spun into fibres having the
properties as shown in Table 2, Example 4. The xylan absorption amounted to 77.2% of the
high-molecular xylan provided in the dissolving lye, which corresponds to a proportion of
high-molecular xylan of 4.8%, based on the fibre.
In order to detect the high-molecular xylan on the fibre, the molar mass distributions of the
fibre enriched with xylan and that of the employed CCE xylan were determined by size
exclusion chromatography (Fig. 5). In the area of the xylan peak, a shoulder at the fibre is
clearly visible, which is indicative of a concentration of the added xylan in the fibre. If this
xylan portion is subtracted by way of calculation, a curve of a standard viscose fibre emerges
as illustrated in Fig. 6. The xylan content of 5.5% as indicated in Figs. 5 and 6 thereby refers
to the total content of xylan in the fibre (i.e., xylan from the pulp used, plus the added highmolecular
xylan).
Example 5
A dissolving lye with 31.7 g/1 of xylan was added to a xanthogenate according to Example 1.
The spinning mass thus obtained was spun into fibres having the properties as shown in
Table 2, Example 5. The xylan absorption amounted to 60.2% of the high-molecular xylan
provided in the dissolving lye, which corresponds to a proportion of high-molecular xylan of
6.9%, based on the fibre.
9
Example 6
A dissolving lye with 66.3 g/I of xylan was added to a xanthogenate according to Example 1.
The spinning mass thus obtained was spun into fibres. The xylan absorption amounted to
54.4% of the high-molecular xylan provided in the dissolving lye, which corresponds to a
proportion of high-molecular xylan of 10.0%, based on the fibre.
In this example, the dissolving lye containing the xylan was added to the cellulose
xanthogenate together with dissolving water. Obviously as a result thereof, a partial
precipitation of the xylan in the spinning mass occurred so that the quality of the spinning
dope (filter value etc.) as well as that of the spun fibres fell short of those of Examples 2 to 5.
Example 7 (comparative example)
In a pilot plant, the same beech sulfite pulp was used for the production of viscose fibres.
After the slurry of the pulp, a press lye enriched with low-molecular xylan was obtained by
squeezing. Said lye was subjected to nanofiltration. The permeate from the nanofiltration,
which exhibits only a small content of low-molecular xylan, was subsequently used as a
dissolving lye in the pilot plant.
Due to the low supply of 0.38% of xylan (based on cellulose in the spinning mass) resulting
therefrom, and the low molecular weight thereof, no additional xylan was precipitated on the
viscose fibre. The xylan content of the fibre spun out amounted to 0.5%. Said xylan
originates from the pulp used.
Example 8
In a pilot plant, the same beech sulfite pulp was used for the production of viscose fibres.
The retentate rich in low-molecular xylan from the nanofiltration as described in Example 7
was used as a dissolving lye.
The xylan supply in the spinning mass amounted to 5.67%, based on cellulose. 30.0% of that
was spun into the fibre. A fibre with 2.2% of xylan was obtained.
Testing methods
Determination of the sugars in the fibre:
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After a two-stage total hydrolysis with sulphuric acid H2SO4, the sugar monomers were
determined by anion exchange chromatography (AEC) with a pulsed amperometric detector
(PAD). The method was described in the following publication: Sixta H, Schelosky N,
Milacher W, Baldinger T, Roder T (2001) Characterization of alkali-soluble pulp fractions
by chromatography. Proceedings of the 11th ISWPC, Nice, France: 655-658.
Determination of the molecular weight distribution in the fibre:
The molecular weight distribution in fibres was determined by size exclusion
chromatography (SEC). The samples were dissolved in DMAc-LiC1 (dimethylacetamide/
lithium chloride). A MALLS detector (multi-angle laser light scattering) was used. Further
details were published by Schelosky N, Roder T, Baldinger T (1999), Molmassenverteilung
cellulosischer Produkte mittels Grol3enausschlusschromatographie in DMAc/LiC1, Das
Papier 53, 12:728-738.
Determination of the molecular weight distribution of the added high-molecular xylan:
The xylan was precipitated from the CCE lye under acidic conditions, analogously to the
standard method Tappi T 203 om-93: 1993 for the determination of beta and gamma
fractions. Subsequently, the process was continued with the SEC method, similarly as for the
determination of the molecular weight distribution of fibres.
List of abbreviations:
CCE cold caustic extraction
C S2 carbon disulphide
DP degree of polymerization
MW molecular weight
Mw weight average molecular weight
Mn number average molecular weight
SEC size exclusion chromatography
WRV water retention capacity
PDI polydispersity index Mw/Mn
The properties of the viscose spinning masses obtained in each case as well as of the
obtained fibres according to Examples 2 to 5 are summarized in the following Table 2:
11
Example 1-1 1-2 2 3 4 5
Filter value
Particle
Xylan in the dissolving lye
Xylan absorption
Low-molecular xylan in the
fibre
High-molecular xylan in the
-
ppm
g/1
%
% od
358
14.7
0.0
0.0
0.6
374
17.7
0.0
0.0
0.7
353
22.0
8.5
63.0
0.7
330
13.6
22.0
79.2
0.7
372
15.3
39.0
77.2
0.7
364
15.6
31.7
60.2
0.7
fibre % od 0 0 0.7 2.7 4.8 6.9
Total xylan in the fibre % od 0.6 0.7 1.4 3.4 5.5 7.5
Molecular weight
distribution of the viscose
fibre:
Number average Mn kg/mol 26.5 28.5 29.3 27.6 27.5 26.6
Weight average Mw kg/mol 63 65 66 66 63 61.5
Polydispersity index PDI
(Mw/Mn) - 2.4 3.3 2.2 2.4 2.3 2.3
Percent by weight of
polymers with DP<50 % 5.6 5.0 4.8 5,2 5.1 5.6
Percent by weight of
polymers DP<100 % 11.7 11.7 11.5 12.8 13.0 13.8
Titre dtex 1.30 1.29 1.34 1.37 1.34 1.34
Strength conditioned,
60% stretching cN/tex 26.0 25.0 26.5 24.8 24.8 23.8
Elongation conditioned,
60% stretching % 17.8 17.7 16.0 18.0 16.6 15.5
Working capacity %cN/tex 465 443 424 447 412 370
Water retention capacity
WRV % 90.0 92.4 94.5 95.6 98.5 97.1
Table 2: Properties of viscose fibres from a beech sulfite pulp with xylan from a CCE stage
spun in as a copolymer
The high-molecular xylan was absorbed by the fibre in an unexpectedly high amount. The
absorption into the viscose fibre amounted to 63% to 79% of the xylan provided in the
dissolving dye. From the filter value and the particle number, it becomes apparent that the
quality of the spinning mass and the processability did not suffer at all from the addition of
said copolymer.
In contrast, xylan which is introduced into the process merely with a dissolving pulp or paper
pulp is broken down and, as a result, is removed by 63 to 80% during the alkali ripening and
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in the spinning bath (see Table 3 below). Also, the filter value and the particle content of the
viscose spinning mass are significantly reduced — in particular with a high input of xylan
from a paper pulp.
Pulp process xylan in
the pulp
[%]
filter
value [-]
particle
content
[ppm]
xylan in the
spinning
mass/fibre [%]
loss of
xylan
[%]
Dissolving
pulp
beech
sulfite
3.1 364 15.6 0.6 80.6
Paper pulp eucalyptus
kraft
22.1 8 671 8.1 63.3
Paper pulp poplar
kraft
19.8 69 118 7.3 63.1
Table 3: loss of xylan introduced with the pulp in the viscose process
Surprisingly, it has been shown that the textile-mechanical properties of the produced fibres
remain almost constant (see Fig. 3). In this connection, the xylan contents indicated in Fig. 3
again refer to the total content of xylan in the fibre (i.e., xylan from the pulp used, plus the
added xylan).
Also, the water retention capacity WRV could be increased significantly by incorporating
the xylan into the viscose fibre (see Table 2 and Fig. 4). That is to say, the absorption of
water and the capacity to adsorb water could not only be increased, but also adjusted
selectively via the xylan content of the fibre. This is a completely new possibility of shaping
product properties, for example, for an application in absorbent products.
The abscissa (xylan content) in Fig. 4 again refers to the total content of xylan in the fibre.
In Fig. 4, the water retention capacity of the fibre produced according to Example 6 (content
of high-molecular xylan: 10.0%) is shown as well. It amounted to 106.0%.
The properties of the viscose spinning masses obtained in each case as well as of the
obtained fibres according to Examples 7 and 8 are summarized in the following Table 4:
Example 7 8
Filter value 389 401
Particle 4.5 5.0
Total xylan absorption % 0 30.0
Total xylan in the fibre % od 0.5 2.2
Molecular weight
distribution of the viscose
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Example 7 8
fibre:
Number average Mn kg/mol 22.1 22.0
Weight average Mw kg/mol 60.1 66.7
Polydispersity index PDI
(Mw/Mn) -
2.7 3.0
Percent by weight of
polymers with DP<50 %
7.1 8.0
Percent by weight of
polymers DP<100 %
15.3 15.1
Titre dtex 1.40 1.45
Strength conditioned,
60% stretching cN/tex
26.8 25.8
Elongation conditioned,
60% stretching %
17.0 15.9
Working capacity %cN/tex 455.6 410.2
Table 4. Properties of viscose fibres produced by adding xylan from the viscose production
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Claims:
1. A process for the production of a cellulosic moulded body according to the viscose
process by shaping a spinning mass containing cellulose xanthogenate, characterized in
that xylan in an amount of at least 1% by weight, based on cellulose, preferably from
1% by weight to 20% by weight, particularly preferably from 3% by weight to 15% by
weight, is added to the cellulose xanthogenate.
2. A process according to claim 1, characterized in that the xylan is added in the form of
an alkaline solution.
3. A process according to claim 1 or 2, characterized in that the xylan is added to the
cellulose xanthogenate as a component of an alkaline dissolving lye.
4. A process according to any of claims 2 or 3, characterized in that the xylan originates
from a press lye accumulating during the squeezing of alkalized pulp at the beginning
of the viscose process.
5. A process according to claim 4, characterized in that a press lye accumulating during
the squeezing of alkalized pulp at the beginning of the viscose process is added to the
cellulose xanthogenate.
6. A process according to any of claims 1 to 5, characterized in that at least a portion of
the added xylan is a high-molecular xylan with an average degree of polymerization
(DP) of from 75 to 350, preferably of from 110 to 220.
7. A process according to claim 6, characterized in that the high-molecular xylan is added
in an amount of from 1% by weight to 20% by weight, preferably from 3% by weight to
15% by weight, based on cellulose.
8. A process according to claim 6 or 7, characterized in that the high-molecular xylan
originates from a mass flow rich in hemicellulose which accumulates in the course of an
extraction step during the production of a pulp.
9. A cellulosic moulded body obtained according to the viscose process and having an
amount of high-molecular xylan with an average degree of polymerization (DP) of from
15
75 to 350, preferably of from 110 to 220, of at least 0.5% by weight, based on cellulose,
preferably of 2% by weight to 8% by weight.
10. A cellulosic moulded body according to claim 9 in the form of a fibre.
11. The use of a cellulosic moulded body according to any of claims 9 or 10 in absorbent
products.
Dated this 12th day of May, 2015.
PRIYA KA CHOPRA
OF K S PARTNERS
ATTORNEY FOR THE APPLICANT(S)
16
Abstract
The invention relates to a process for the production of a cellulosic moulded body according
to the viscose process by shaping a spinning mass containing cellulose xanthogenate, which
is characterized in that xylan in an amount of at least 1% by weight, based on cellulose,
preferably from 1% by weight to 20% by weight, particularly preferably from 3% by weight
to 15% by weight, is added to the cellulose xanthogenate. Furthermore, the invention relates
to cellulosic moulded bodies obtained according to the viscose process and having an
amount of high-molecular xylan with an average degree of polymerization (DP) of from 75
to 350, preferably of from 110 to 220, of at least 0.5% by weight, preferably of 2% by
weight to 8% by weight.
(Fig. 3)