Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
WO 94/Q9~90 ~ ~ ~ y ~ ~ ~ P~LT/EP93/02782
- 1 -
'°~E~~~=E .AND PROCESS
~'O~t THE PROD'~CTI~N OF F~~RCIUS S'I9~,Y2~ D~°.~°ER.L~,S
°~
The present invention refers to a device and process for
. 5 production of fibrous starch materials particularly destined for
use in the production of pager and cardboard.
It is known that if aqueous colloid dispersions of starch
in typical concentrations of between 5 and 40% by weight of an-
hydrous solid, is brought into contact with non-solvents tfor
example a saline soluti~n of ammonium sulphate), it coagulates
forming flakes of gel.
US patent Info. 4,205,025 describes a process for the produ-
ction of fibrils used as paper pulp using film foaming polymers
including substantially water-soluble starches. By the term °~fi-
brils", materials showing a hybrid~mor~phology w~,ich is between a
film and a, fibre are ~.n~ezaded. The film forming ~olyaner is dis-
solved in water to f~rm a solution which is thin injected into a
precipitating means, preferably an organic non-solvent, such as
an alcohol or a~ketone, with the application of shearing utress
in order to obtain the fo~anati~n of fibrils which are then ren-
dered more hydrophobic through subsequent treatment in an inso-
ltiblising agent..
L?S Fatent I~o. 4, 340, 442 describes a process for the forma-
tion of fibrils which, in order to improve the hydrophobic pro-
parties of the.....fibrils, uses starch insoluble in grater having a
high amylose content (SO-~0%by weight), which ~.s coagulated in a
S'allne Solution, ~n ~art~L.CLllar ~IYtYifl(~Y1'i ttm ci~l r,hat-b o.. ~ a -~
_ __ _,_
' which is substantially insoluble in water, rec~ui.res a stage in
which it is dissolved in alkaline solution which causes problems
in the coagulation stage and problems with respect to disposal
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... ...., . . ,.':..' ':.' $ n,-:L "','. .. : ~.., . ~ ~..'~ :~i, ..';.~~~.
~.. '.' .. .'.' ... '.:::~ ~';~ ~ "" ,.'. ' .~ '~': '.
1
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, ,.: . .. '.. '
W~ 9~/~9190 ~ , ~. r PC: ('/EIP93/02'782
~1~~~~'~ ~
- 2 -
of sulphates different from ammonium salts, which are foxzned in
said stage.
US Patent No. 4,7.39,699 describes a process for the produ-
ction of a product having starch fibre morphology, through ex-
trusion of a colloidal starch dispersion having a high
amylopectin content in a coagulating agent. In the case v~here a
starch having a amylopectin content of less than approximately
95~ is used, it is necessary to chemically modify the starch to
ensure the colloidal dispersion thereof in the aqueous system
1~ or, alternatively, the starch must be dissolved in the presence
of alkaline hydraxides.
The use of alkaline hydroxides, particularly sodium
hydroxide, makes the industrial application of the process de-
scribed difficult, in that the coagulation stage carried out
~.5 using ammonium sulphate results in the production of ammonia and
formation of large quantities of sodium sulphate preventing coa-
gulation and causing problems with respect to disposal..
US Patent Ira. 4,~~3,450 describes a process that uses the
product obtained according to the process described an US Patent
20 No. 4,139,699, for the production of paper or cardboard accor
ding to conventional paper znakir~g technology. Said product has a
short fibre morphology having a diameter of between 10 and 50a
microns and a length of betvaeen CP.1 and 3 mm, obtained by extru
ding the starch dispersion via a die into a moving coagulation
25 bath. .
US Patent No. 4,x53,1.68 describes a process of the type w
described in US Patent No. 4,139,699, in which the colloidal
starch dispersion adapted to be eactrtided is obtained by cooking
an aqueous starch dispersion containing the coagulating saline
3Q solution.
WU 94/09190 ~ ~ ~ ~ ~ '~ d PC'f/EP93/02782
- 3 -
In the above cited patent literature and in practical expe-
rimentation, various known devices can be used in order to fi-
nely break down tht: starch solution or dispersion and therefore
favour a close contact with the coagulating agent, such as ato-
mization nozzles, ejectors, mixers with stirrers, spinnerets or
syringes. It has however~been demonstrated experimentally that
the type of device used strongly influences the final coagulated
product and its properties. Devices in which the starch is coa-
gulated in highl~~ turbulent conditions (such. as ejectors) or in
which there is no ordered speed profile (mixers with stirrers),
do not give rise to products with a fibrous structure, but some-
what provoke a fragmentation of the starch, with formation of
flat scales (rolled onto each other) or a three dimensional ag-
gregate.
The dimensions of these non fibrous products vary with the
operating conditions and influence the character~atics of them.
In the production process very small particles are lost during
the separation and slow down the filtering operat~.on, xn that
they block the cloth; if used in the production of _ paper, they
are not retained on the flat cloth ~aith consequential loss of
starch in the paper and an increase of COD in the paper factory
waste water. On the other hand, very large particles do not in-
tegrate with the cellulose matri~c fibres giva.ng wise to c~efeet~
in the produced paper.
~5 Other negative aspect, verif~.ed for fibrids obtained from
the previously described processes, consists of rather high wa-
ter retention and solubility values.
a
1~ further product obtained ~rom~starch by coagulation pro-
cesses, but having a fibre morphology, partly reduces the above
listed disadvantages in that, thanks to its fibrous structure,
WC) 9~1109~90 ~ ~ w ~Z ~ ! ~~ PCT/EP93/02782
- 4 -
it increases its compatibility with the cellulose fibres, redu-
ces the water retention in that it is more easily filterable and
reduces its solubility as it has a lower specific surface. ,
It would therefore be desirable to have a production of a
product having fibre morphology, with dimension, size distribu-
tion and physical chemical properties such to be suitable for
the production of paper and cardboard and in addition to be ob-
tainable from low cost starch such as starch from maize or pota-
to without adopting alkaline solutions of starch for the starch
used.
In light of such a purpose, the object of this invention is
a process for the production of fibrous starch materials through
extrusion of a dispersion. or aqueous solution of starch material
in a flow of saline coagulant agent characterised by the fact
that it comprises the operation of:
extruding the dispersion or aqueous solution through a
microporous tubular wall in a chamber circularly ringed
with said microporous wall in such a way to obtain an ex-
trusion flux of the starch material which surrounds the
said tubular walls and
- carry out the coagulation of the extrusion by feeding the
flow of the coagulation agent in the annular chamber paral-
lel to the extrusion surface.
d~.nother object of the invention is a fibre making device
2~ characterised..by the fact that it comprises:
- a tubular body comprising first means of entry for feeding
the flux of starch material,
- a feeding chamber for the stare material connecting the
said first means of entry,
v 0 - ' an annular outlet chamber of the starch material,
'~'VO 94/0990 ~ ~ ~ ~a ~ ~) ~ Pf'T/EP93/02782
- 5 -
- a tubular element with porous walls coaxially arranged with
said outlet chamber and interposed between this and the
feeding chamber, adapt to extrude through the said porous
walls in the said outlet chamber a variety of threads of
' 5 starch material forming a envelope around the said tubular
element,
- a second means of entry connecting the outlet chamber for
feeding the coagulating agent flow and
- means of discharge arranged downstream from the ar~nu~.ar
outlet chamnber.
It has been found that by using the process and device of
the present invention it is possible to obtain a product which
shows a shape ratio having a particularly narrow size distribu-
tion and centred in the range of 75-100 mierons and having a
water solubility, determined by the "l~nthrone 'Test" further de-
scribed later, of less than about 2~ and a low water retention.
Other advantages and characteristics of the process, device and
product obtained according to the present invention wall be fur-
ther illustrated in detail in the following with reference to
the enclosed drawings in which:
- figure 1 shows illustrates a flow chart of the plant for
a
carrying out the process,
- figure 2 shows a cross section view of the fibre making
device according to the invention,
- f figure 3~' shows a cross section view of another embodiment
of the fibre making device, and
- figure 4 is an enlarged detail of a part of figures 2~ and 3
~nl~.th reference to the drawing in, figure 1, 1 indicates a
stirred dispersion for the preparation of the starch suspension
in water with a dry weight typically from 5-to 50o by weight and
~O 9~/49~90 ~, ~, PCT/EP93/02782
- 6 -
preferably 10-40a by weight. The starch used for the preparation
of the suspension is preferably natural starch such as starch
from maize, rice, tapioca, potato having a amylopectin content
from 30 to 100%. Particularly prefered is maize starch, widely
S available on the market, having a typical amylopectin content of
from 64-80~ by weight. 4~lithin the scope of the invention, starch
with a high content of amylose, such as amylomaize and che-
mically or physically modified starch can be used.
The starch suspension can also contain additives such as
salts (e.g. sali.ne coagulating agents as described in L1S Patent
No. 4,853,168) alkaline agents, organic fillers or minerals,
crosslinking agents, plasticisers, polyoxyethylene, polyvinyl
alcohol, ionomeric polymers such as copolymers of ethylene and
acrylic acid and/or malefic anhydride, polyacrylates, polyamides,
lubricants such as lecithin, fatty acids, esters and amides of
fatty acids.
The suspension, maintained in the disperses under stirring
at ambient temperature, is then pumped via a gear pump 2 into a
jet cooker, itself indicated with 3, where it is mixed in a co-
current with steam in such a way as to reach the desired cooking
temperature. The jet cooking process is known per se and invol_
ves instantaneous heating of the aqueous suspension with process
steam and then maintaining the heated liquid for a predetermined
period. The cooking temperature, generally between 90 and 180°C,
is selected according to the specific starch used in the course
of the process. 7Cn particular, care should be taken to avoid an
excessively high temperature causing degradation of the starch
material, while ensuring that the temperature, the shearing time
applied and the standing time are such that it is possible to
.30 obtain a dispersion close to complete gelation.
_~ N P~ ~ s 1~ P~/EP93/02782
WO 94/09190
At tree outlet of the j et cooker, the starch dispersion or
solution subject to cooking is collected whilst stirring in a
lined stirred reactor 4, water circulating at a temperature of
about 100°C in the casing thereof. A flash is effected in this
lined tank in order to free the excess steam and to return the
starch/water concentrations close to the initial concentrations.
Frown reactor 4 the starch is pumped via a pump 5, in a heat
exchanger & where it is brought to a. temperature of between 20
and 100°C, preferably from ~0 to 7~D°C. From the heat exchanger,
the starch is fed to a fibre making device of the types il-
lustrated in figures 2 and 3, described in the following, in
which a saline coagulating solution is also injected. The salts
that can be used in the scope of 'the present invention comprise
ammonium sulphate, magnesium sulphate, aluminium sulphate, ammo-
nium phosphate, potassium chloride, sodium sulphate, sodium car
bonate, sodium bicarbonate, and agnmonium chloride. The preferred
saline solution is a saturated solution of anunonium sulphate,
although it is not necessary to reach saturated levels of the
above mentioned salts and it is equally possible to use concen
trations lower than saturation levels.
The starch fibres obtained from the fibre making device are
collected in a stirred reactor 8 in order to be subjected to
maturing and subsequently decanting. Once the decanting h.as been
effected the clarified substance is recycled, by means of a pump
9, and 7nixed with a saturated saline solution of the coagulating
agent before being reused for drawing the starch.
The clarified substance which circulates in the installa-
Lion as a coagulating agent, contains the saline solution and
the finest fibres which, due to their small dimensions are not
decanted in the collecting container.
W(7 ~A/U~al9i) l _~ s) ~T ~ ~ ~~ PC'f/EP~3/~02782
_ g _
The mass of fibres from reactor 8 is pumped by means of
pump 10 on to filter 11. The fibres are then collected in a con-
tainer 12, while the filtrate is fed to container 13 where .it is
mixed with the clarified substance from pump 9, with subsequent
addition of sulphate in order to recycle the saline solution
adapted to be fed into fibre making device °7.
By using an appropriate number of reactors 8 for the matu-
ring and decanting, it is possible for the prodess to be carried
out continuously, thereby obtaining starch fibres which can be
washed directly on the filter or simply filtered and s~_
sequently washed.
The fibre making device 7, in the embodiement in figure 2,
comprises a tubular body 14 having at least one inlet 15 whieh,
under norgnal conditions, is usedl for feeding the starch ma-
serial, an inlet 16 designed to feed the coagulating agent and a
outlet 27 for discharging the starch fibres produced after the
coagulation.
From the inlet ~.5 the starch anaterial is immersed in a tu~
bular duct 18 which partially terminates in a wall l9 supplied
with radial holes. The holey wall part ~.9 acts as the distribu
tor of the starch material fl~w towards a feeding chamber 21.
r
'With the reference 22, the tubular element with microporous
walls suitable for eactrudi~ag the starch material from the fee-
ding chamber 21 unto the annular chamber 23 coaxially thereto is
indicated. The.~chamber 23 is separated from the radially exter-
nal surface of the element 22 and the radially internal surface
of body 14.
The tubular element 22 can consist of a body of porous sin
tered metal material in which the distribution of the porous
dimension is preferably comprised between 10 and 500 microns.
Wsp 9~i/dD919t) PCT/Ef93/02782
Alternatively the tubular element 22 is a body of metal
material, for example stainless steel, provided with a number of
radially passing holes obtained by mechanical working and having
at least a narrow flow section with openings having a dimension
~ 5 preferably comprised between 10 and 500 microns. Preferably said
radial holes have a cross section as illustrated in figure 4
with a portion 24 of the inlet for the starch material having a
narrow opening, typically from 10 to 500 microns, and a portion
25 on the outlet of the starch material with an larger sire ope
ning, preferably comprised between 0.5 and ~..5 mm.
The opening density on the extrusi~n surface (intended as
the surface of the tubular element in contact with the coagula-
ting agent), expressed as a ratio of number of holes to surface
area is preferably comprised between 4 and 0,05 holes/mm~.
1,5 The coagulating agent fed through the inlet opening 16,
flows through the annular element 26 having a crown of axial
holes 27, acting as distributor, end is fed into the first annu-
lar chamber 2~ defined by the walls 14 of the Fibre making derri-
ce and a tubular element coaxial to the body 29. From chamber 2~
the flow is fed into the annular chamber of outlet 23; parallel
to the radially external surface of the microgorous tubular cle-
ment 22, where the flow of coagulating agent interacts with the
extrusion flow of the starch material.
The starch material is extruded in the form of a variety of
threads which..surround the extrusion surface in the guise of a
tubular film.
Preferably the flow speed of the saline coagulating agent
in the annular section of the outlet chamber 23 is maintained
between ~. and 15 m/s .
wo ~)aio~~~.~c~ Pcri~~3ioz~sz
~o. ~-~~ ~'.. ..~'~~' ~~ 'fir
The drawing ratio, intended as ratio of flow speed of the
coagulating agent in the annular section of the chamber 23 and
the speed of the starch mater ial at the outlet of the holes of
the microporous wall (defined as the ratio between the flow rate
of the starch material and the total section in the hales of the
outlet) is generally comprised between 1-x.000, preferably betwe-
en 100-1000. Preferably the axial length of the cutlet chamber
23 is such that a stay tame of the starch material comprised
between 5 and 15 milliseconds is obtained. In any case the axial
length of the chamber 23 in which the starch material undergoes
drawing must be such to cause an orientation of the starch mate-
rial allowing at the same time a complete phase inversion.
At the outlet of chamber 23 the extnaded flow is fed into a
annular chamber 30 at a progressively increasing cross section
in the flow direction.
In the embodiment of the fibre making device illustrated in
figure 3, the flow of starch materials is fed through an inlet
31 to an annular chamber 32 defined by the walls of body ~.~ and
the microporous walled tubular element 33. The flow of the
starch material follows the radial direction towards the inside
through the walls of element 33 into the annular outlet chamber
34= comprised between the tubular element 33 and a central
nucleus 35 coaxial to the body. The flow of the coagulating
agent is fed across an inlet 36 and into a prechamber 37, it
flows into a chamber 40 across holes 3~ of an annular element 38
and from chamber 40 is fed to the outlet chamber 34 having a
narrow crass section in the flaw direction.
In this embodiment the section of~holes of the microporous
element 33 remains the same as figure 4. 7Cn this case, however,
the flow of- the starch material advances from a bigger to a
WCa )4/o9l~lD ~ ~. ~ ~~ ~ ! d Pcr~E~93~oz7s2
- 11 -
smaller cross section, which brings an increase in the starch
flow speed and necking down of the starch threads. The material
leaving the holes is coagulated by the coagulation agent flow in
the annular chamber 34. It has been observed that the best con-
ditions of coagulation are when the drawing ratio is comprised
preferably between 1 and 1.50, with an emission speed of the
starch material from the holes ~.n the microporous walls 33 eom-
prises preferably between 0.1 and 1 m/s.
The fibre'making device subject of the present invention
presents notab7le advantages such as:
it supplies, through coagulation of a starch material, a
product having a fibrous structure;
its structure having a cylindrical symmetry guarantees uni
formity of fluid mechanic conditions thus excluding possi
~.5 ble border effects;
its geometry is coar~pletely known and therefore project cri-
teria are available.
the knowledge of the above mentioned criteria permits its
scale-up.
~ther advantages deriving from the use of the above fibre
making device, will be highlighted by the following examples.
1. a 1.
BY using a plant as described with reference to figure 1
maize starch fibres have been obtained working under the follo-
wing conditionss
- starch concentration in the dispers~.on . 15% by weight
(anhydrous starch)
- maximuxtl cooking temperature in 'the j et cooker : 115 ° C ~pre-
ferred temperature range is hetween x.00-130°C)
W~ 94/09190 ~ .~ ~ ~ ~ ~ ,~ PC'~°/EE93/027H2
- 12
- temperature of the starch at the inlet of the fibre making
device: 60°C
- saline solution: ammonium sulphate: 41% by weight
- temperature of the saline solution at the fibre making
device inlet: 21°C
maximum speed of the saline solution in the outlet chamber
of the fibre making device: 7 m/s
- flow rate of the starch after cooking 4g 1/h
- fibre making device as illustrated in figure 2 having a
In extrusion sinter. consisting of a sintered metal with a po
rosity of 40 microns (average diameter raf the pores)
- length of the outlet chamber (23,24) of the fibre making
device: 10 cm
- average maturing time before ;filtering . ~ hours
25 Carr~ring out the process acccarding to the above mentioned
conditions starch fibres were obta:~ned having the following size
distribution measured according t~o the Bauer i~TcNett apparatus
expressed in percent by weight:
595 ~.tm (2~ mesh) % . 0. 3
20 297 pimm (~0 mesh) % . 3 .1
1~9 ~.tm ( 100 mesh} % . 68 . ~
"74 ~Cm (200 mesh) % . 21. 3
above 200 mesh ~C 100 . 6 . H
The determination of the characteristics of the salability
25 and the fibxe._...obtained has been carried out using the following
procedure:
washing of the filtration panels coming from the plant;
100 g of the filtration cake are dispersed in s~rater (500 ml) by
mechanical stirring with a glass anchor stirrer under the folio
30 wing conditions: w
WU 94/09190 ~ ~, ~ ~ ~ ~ ~ PC.'T/EP93/02782
- 13 -
Becker with diameter 10 cm and height 20 cm; mechanical
glass anchor stirrer (1=40 cm with stirring blade with 1= 8 cm,
height 8 cm);
Temperature - 20°C; stirring time 30 minx; rotation speed
' S 500 rpm.
The dispersion obtained is filtered on ~ruckner with. a dia-
meter of 30 cm in the presence of a paper filter under vacuum of
mm ~Ig .
The liquid is filtered twice on the same panel. The panel
10 is then washed with 500 ml of HaO. The ratio of starch to water
in °the washing is 1:10.
The solubility determination is carried out on the filtered
product, in order to separate it from the water and washed to
remove the coagulant. The product is dispersed in water in a
conventional laboratory pulper (dry coneentr~tion 0.2% rotation
speed 3000 rp~n)a a sample was removed after 4 h~urs and after
filtered oxx a ~ micron filter paper, the starch is measured in
solution with the reagent "ANTHIZ.O~TE°~ (solution 0.2~ of HR.ONE
in 96% H2S0~) .
The solubility value, determined by the above cited method
on the filter panels obtained according to the example, is less
them 1.5~.
The morphological characteristics of the fibre obt~.ined are
illustrated in figure 4.
~e .~ ._. .
~ The test according to example 1 has been repeated varying
only the characteristics of the microporous sintered filtex° con-
sisted, i.n this case of a sintered metal tube with pores having
an average diameter of 100 ~Sm. Fibres were obtained having the
.~ ~> ,~~ ~.
WO 9~t10)1 )0 ~ ~" ~'' " ~ ~ ~ PCT/Ep'93/~~7~2
- 14
following size distribution expressed in terms of percentage by
weight:
595 dun(28 mesh) % .
0.3
297 ~,m(40 mesh) % .
0.9
149 Nxn( 100 mesh) % .
63
74 ~Cm(200 mesh) % .
25.2
above .
200 10.6
mesh
X
100
The results demonstrate that the average diameter of the
pores does not influence in a relevant way the fibre dis
tribution that is maintained on a 100 and 200 mesh.
The solubility values obtained according to the method of
example 1 are once again less than 1.5% like in tine preceding
case.
Ex..axxuple 3 fcoa~rar~ti~re'~
The characteristics of the fibres obtained by the test in
example 1 are connpared to the f i,~rids obtained with the other
fibre making devices, in particular ejector and spinneret.
The process conditions are the same as for example 1.
The first fibre making device consists of an ejector equip
ped with 8 holes in a ~. n~ diameter, far the starch inlet with
an a.nclination of 45~ with respect to ejector axis placed in the
p
groove. The speed of the coagulating agent (ammonium sulph te).
in the thinner section is equal to ~1 m/s and the draw ratio,
(defined as the ratio between the maximum speed of the sulphate
to that of the~starch leaving the holes) is equal to 47.
The second fibre making device consists of a spinneret
equipped with 113 holes having a diameter of 0.5mm; this
spinneret is placed in a circular duct and the annular cro~rn
separated from the external surface of the spinneret and the
internal walls of the circular duct is fed with the coagulating
f . ~1 ~ .,;
VV~ 9~d/A9it)0 ~ A. ~ _~ a x d PCf/EP93/02782
- 15
agent, ammonium sulphate: the speed of the ammonium sulphate and
that of the starch material exiting the holes are parallel. At
the holes outlet, the starch material is contacted with the coa-
.
gulating agent; the suspension formed then enters in a conver
S gent (having a minimum diameter of 4 mm which corresponds to a
sulphate speed of 30 m/s) in which the high turbulence completes
the coagulation.
Table 1 reports the comparison of the fibre distribution
for the various products; as can be noted, with the ejection
fibres there is a high percentage of fine particles (80~) which
reduces when passing to the spinneret and the tubular. The di-
stribution curve is also different for these two fibre making
device: very narrow for the tubular (900 of the particles betwe-
en 100 and 200 mesh), larger for t;he spinneret.
This sire distribution, comxaaned with the particle form
(similar to fibres with a marked form ratio such as for tubular;
with high film content, furled and without a preferred direction
in the case of the spinneret) is responsible for the different
behaviour of the two products in the paper preparation together
with the cellulose fibres. In fact it has been experimentally
verified that the products obtained from the tubular fibre ma-
king device does not give rise to problems (of moulding or de-
siccation) in the preparation of sheets in the laboratory while
the use of the product from the spinneret, starting from a cer-
twin percentage, gives sheets with surface defects and with a
tendency to stick to the sheet forming plate.
Table 2 reports the percentage of starch retained on the
sheet of paper prepared in the laboratory with the Rapid-Koethen
apparatus, after dispersion of the cellulose - starch material
paste (at 10 % of the latter) in the pulper for 2 hours at 3000
W~ 94/0h190 w~ ~ ~.~ ~ r~ r. i''CT/EP93/027~2
~: _~ l,~ ,.~ t~ 4
- 16 -
rpm at ambient temperature. As noted the highest retention is
with the product from the tubular fibre making device.
Table 3 finally highlights the behaviour of the two diffe
rent products when filtered from the slurry after the
coagulation and washing until the ammonium sulphate has been
eliminated, the concentrations of the slurry and the maturing
time being equal. .d.~s shovrn the products obtained frown the tubu-
lar fibre making device show a double productivity with respect
to those of the spinneret.
~.0 Moreover another subj ect of the present invention are the
starch fibres obtainable through the previously described method
that present the characteristic of having a solubility of less
than 2~ and a dimension distribution as such of 90% has a dimen
sion such as to enter in the rar.~ge of from 100 to 200 mesh,
after classification by the Bauer-IMfcI~ett apparatus.
1 1- ~~- r' l n with various fibre making devi~~e
Fibre making Distribution
d ($ w/w)
i
ev l
ce 28 50 100 200 >200
spinneret 0.2 7.6 35.3 32.0_ 26
ejector 0.3 0.4 4.2 14.6- 80<5
tubular 0.3 3.1 68.5 _ 21.3 6.8
WO 94/09190 ~ .,~. ~ :.~ ~ ~ ' F'CT/E~'93/02782
- 17 -
Table 2 - Retention of starch fibres/fibrids in the ~a~er
Fibre making device Retention o
Spinneret g7.~
Ejector
Tabular
T 1e 3 - Fil ra.n a a it f v rio s tar h fibres fibri s
Fibre making device Filtered solid (Kg/h)
tubular
spinneret 10
P
P
