Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
~ 1 7~0 ~ ~
.
s The invention relates to filaments and fibers
of polyacryloni-trile or polyacrylonitrile copolymers,
which are predominan-tly buil-t up from acryloni-trile
elements and which have an initial modulu~ - based on
100 % elongation - of greater than 1,300 cN/tex,
process for -the production of such filaments and fibers
is also described.
'It is known that polyacrylonitrile filament tow
can be produced by combined wet and contac-t stretching.
10 Thus, for e~ample, a process in which the filamen-ts are
dried, with free shrinkage allowed, after wet stretching
to four to five times their length is claimed, for
example, in ~erman Offenlegungsschrift 2,156,88l~.
~uring this drying in a heated gas at 135 to 145C,
15 experience shows that the filaments shrink by more than
30 %. Thereafter, dry stretching to at least 1.4 times
their length is envisaged, As proved by -the examples
of this previous literature, it is possible, under -these
conditions. to obtain indivldual ~ilament s-trengths of
4.8 g/den ~-42,4 cN/tex (Example 1 f) or an initial
modulus of 107.2 g/den - 946 cN/tex (Example 1 h)~
The maxim~n e~fective stretching in the exampIes was
abou-t 1:6,8; effective stret;ching is to be understood
as the actual s~retching effec-tive, for example, on the
denier of t'rlr;~ individual filaznen-ts~ I-t can be calcul-
ated from the individuaL stre-tch values, bu-t these must
also be corrected by the shrink~lge during slack clrying.
7~
3 --
The texti.le values of the ~ilaments procluced
according -to the previ.ous li-terature rnust still be
regarded as inadequa-te for industrial fields of use.
There have t7nerefore been attempts, in par-ticular~ to
increase the initial modulus of such :Cibers s-til].
further.
Thus, for example, German O~fenlegungsschrif-t
2,851,273 describes a process in which, direc-tly af-ter
wet stretching, the filaments are s-tretched further in
a "steam pressure s-~etching zone" at-temperatures from
110 to 140 C under the action of sa-turated steam under
pressure. In the case of a continuous procedure,
such a process is very expensive from an industrial poin-t
of view~ in particular because of the sealing problems
of the hot pressure chamber. The best fibers produced
by this process have a strength of 12.8 g1den ~ 113 cN/-tex
- a-t an elongation of 30%, and the initial modulus Of
these filamen-ts is 140 g/den - 1,236 c~/tex. These
values have been -taken from Example 10, in which filaments
with an indlvidual denier of only 0.32 den - 0.3~ dtex
, ~ere obtained.
However, these good tex-tile values are achieved
only with very fine individual filament deniers~ During
spinning of customary deniers according to Examples 1 -to
7 of the previous literature, -these hi.gh fiber values
cannot be achieved by a long way~
A simi].ar stre,tch1.ng process a-t elevated terr,pera-
tures under stearn pressure is al,so described in German
Democratic Repub:l.ic Patent Speciflca-tion 135,509. The
. .
best filaments (according to Ex~mple 3) ha~e a strength
of 73.8 p/tex ~ 72.4 cN/tcx at 9.2 % elonga-l;ion. The
nitial modulus was detel~nined as 17250 p/tex ~ 1,226
cN/-tex, In this patent specification9 i-t is expressly
5 indicated -that the quality of the spinning solution
largely deterlnines -the stretching properties. Fibers
with the sta-ted data can only be ob-tained if'-the spinning
solu-tions ha~e been prepared from solution pol~ners, which
have furthermore also been ripened at temperatures from
10 15 to 40C for at leas-t 20 to 100 hours. ~ccording to
statemen-ts made by the authors, spi.nning solutions o.f
precipi-tation polymers have a poorer s-tate of solution
and thus- enable .only relatively low stretching factors
to be applied. Filaments with relatively high inltial
15 moduli cannot be produced from precipitation pol~mers.
There was therefore still -the object of providing
. filaments and fibers of polyacrylonitrile or acrylonitrile
copolymers, ~Jhich have inl-tial moduli grea-ter -than
1,300 cN/tex and ~or which the production process difers
20 as little as possible ~rom the normal spinning process,
: and in par-ticular does no-t require th~ use of steam
stre-tching zonesor the like or any special ripening pro-
. ce,s,s for -the spin dope, or -the use of par-ticular
solution polymers~
I-t has now bee-n ~ound~ surprisingly, that it is
possible to produce filaments and fibers with such proper-
ties by a spinning process whicn is :;ndustrially si.mple
and can be carried ou-t on conven-tio-nal units, by which
means i-t was possible -to spin fi.].amen-t.s and fibers with
0 1 1
5 -- .
considerably be-tter properties than are described in
-the li-terature both from spinning solutions of precipi- ~
tatioll pol~ners and from spinning solutions vf solu-tion
polymers. The filamen-ts according -to the invention
5 have an initial modulus of over 1,300 cN/tex in -the
customary denier range (about 1.5 to about 15 d-tex).
These values are preferably between 1,400 and 2,500 cN/
tex. The filaments and fibers wi-th -these high ini-tial
moduli are particularly suitable for indus-trial fields
of use, such.as, for example 9 for -the production of
filaments intended for conversion to carbon fibers or
as rein.forcing fibers or filaments, or, in the form of
woven-fabrics, kn.it-ted fabrics or non~wovens of fi.bers or
filamen-ts~ for the production of reinforced organic or
- 15 inorganic materials. Other fi.elds of use which may be
~en-tioned are the production of ~ilters or fil-ter fabrics~
and their use as the substrate fabric for -the production
of coated fabrics such as, for example, -the production of
translucent materials, a~rnings and sails, and also for
20 the produc-ti.on of sewing yarns and -the like . The fibers
and filaments can be used in crimped or tex-turized ~orm.
Excellent results~are obtained in these fields of use
with fibers or filaments which have a tenacity between
1,500 and 2,500 cN/tex. The high tensile strength
25 achieved of at:leas-t 50 cN/tex, which can be associated
with elongations at break o~ at most 15 %, complete.the
good pattern of properties of the filamen-ts and fibers
according to -the invention.
The invention is also based on a process for the
. . .
,
--` il170~1
~ 6 --
produc-tion of these fibcrs and filaments by a wet or dry
spinning process, in which wet stretching of the spun
filaments is to take place during -the washing -treatment,
and the filaments are subsequently dried and then subjec-
5 ted -to hot s-tre-tchin~. The process according to the
invention comprises drying the filaments under tbnsion
on hot. drums, if appropriate in -to~ or hank form, and
then subjecting it to con-tact stretching of at least
1-1 5, in which the effective overall stre-tchin~ must be
10 at least l:9. By cont;act stretchin~ there is to be
understood, in -this contex~t, stre-tching in the dry, ho-t
state, for example using flat heating elemen-ts.
- The preci.pitation or solution polymers prepared
by customary proce`sses can be employed as the polymeric
15 raw materials. Both homopolymers and copolymers of
acrylonitrile can be used, depending on the requirement
for the fields of use. It should be ensured tha-t the
puri-~y of the monomers employed i.s as high as possible.
Suitable comonomers are all the unsatura-ted compounds
. 20 which can be copolymerized wi-th acrylon~rile, of which
the ~ollowing may be men-tioned here as examples: acryl--
amid~, acrylic acid and esters thereof, vinyl esters and
ethers~ such as vinyl acetate, vinyl stearate, vinyl butyl
- ether and vinyl halogenoacetates 9 suGh as vinyl bromoace-t-
25 ate, vinyl dichloroacetate and vinyl trichloroace-ta-t.e~
styrene, maleimide, vinyl hali.des, such asJ for example,
.inyl chlori.de, vinyli.den.e chloride and vinyl bromide,
and unsaturated compounds whi.ch carry su]fonate groups,
and the like.
., , ' '
~3~
Po~ymers which have relative solution viscosi-
ties - mcasured in 0.5 % s-trength dimethylIorlnamide
solutions - in the range from 1.7 to 6.0 can be employed.
Good results are achieved under economical condi-tions
using polymers within a viscosity range f'rom abou-t 1.~5
to 3.5, and polymers within -t~e viscosi-ty range frorn 2.5
to 3.5 give particularly good resul-ts.
The polymers employed should preferably contain
a-t least 90 % o~ acrylonitrile ~mits. Particularly
good tex'tile ~alues are achieved with polymers ~^Jhich are
built up ~rom acrylonitrile units to -the exten-t of a-t
least 99 %.
The solution condi-tions for the preparation of
the spinning solutions should be chosen such that spin-
ning so]u-tions which are as far as possible homogeneous
and free from gel par-ticles are ob-tained. Light
scattering measuremcnts using a laser as the ligh-t source
are particularly suitable for checking -the quality of the
spinning solution. Only high-cluality spinning solu-tions
~/hich exhibit very low ligh-t scat-tering values make
possible the high stretchings required according to -the
invention. The spinning solvtions can be run either
con-tinuously or discontinuously~ Inorganic or organic
additives, such as, f'or example, delus-tering agen-ts,
stabilizers, ~lameproofing additives and the like, c~n
be incorporated into the spinning solu-tionO
The splnning process according to the invention
is dis-tinguished by a high effec-tive overall stre-tching
o~ at leas-t l:9~ As alreac1y nlen-tioned above, in
.
3 ~ 70(~
-- 8
detel~li.ning -the effec-tive overall stretching, on~Ly the
we-t s-tre-tchillg within -the washing process and the con
tac-t stre-tchi.ng are -taken in-to considera-tion, and shrink--
age of -the fi.laments is allowed for. The spin draw ratio or
5 spinneret attenuation is not included i.n the overall streching
values; rather, -the fresh spun filamen-ts obtained after
a dry or wet spinning process are evaluated as unstretched
materialO ln -the process according -to the invention,
the effective overall stretching should be a-t least 1:9.
10 ~ffective overall stretching ratios of 1:10 to 1:25 are
preferred, and effective overall stre-tching ratios
between about 1:12 and 1:22 a~e particularly preferred.
. The process according to the inventi.on ca~ be
carried out on conven-tional filament- or fiber-spinning
-15 units. New -tech~i~ues ~hich were not hi-therto cus-tom-
ary are not required. In particular, it is no-t necessary
to employ a special stretching chamber in which the fila- :
.. ments, for exarnple in tow form, are exposed to the action
of s-team under pressure. The process is distinguished
~0 by high overall stre-tching values for -the freshly 5pun
filaments, an effective minimum s-tretching of 900 ~
being required. This effective overall stre-tching is
carried out in several stages. The filaments are first
subjected to wet stre-tching in one or step~ise in several
25 hot baths, before or af-ter the resi.dual con-tent o~ solven-t
has been washed ou-t~ The tel~perature of the stretching
bath media, which generally comprise mix-tures of water
and -the solv~n-t, should be kept as high as possible
Temperatv.resslightly below -the.boiling poi.n-t o~ -the ba.-th
t 1 7 ~
_ g ~
liquid are preferred. However, baths ~hich con-tain
other stretchi.ng bath rnedia, ~or example gl.ycol or
glycerol, i~ appropriate mixed with the polymer solvent,
are also possi.ble, and in -the case of -these baths
5 stretching -temperatures above 100C can also be chosen
A~-ter the s-tre-tching operation ancl after -the residual
content of solvent has been washed out, it also being
possible firs-t to wash out the solvent and then to
stretch -the filaments, the filaments arefinished in a
10 finishing ba-th and are then as far as possible largely
freed from .adhering water in the customary manner b~J the
action of rota-ting nip roller pairs. The finish applied
i.n thefinishing bath can influence the stretching proper
ties of the ~ilaments. Of the known finishing mixtures,
15 that ~hich gi.ves a low filamen-t/~ilament friction shoul.d
be chosen.
. The filaments are then dried under tenslon on
hot drums. Slight shrinkage, which ~requen-tly proves
to be advantageous for subsequent stretching; can be
20 permi-tted during drying; in adjusting -the shrinkage,
however, it must be ensured that -the tow always runs over
the dryi.ng drums under tension The temperatures o~
. the drv~s should be chosen such tha-t the tow leaves -the
drier with a very low resid1la1 moisture o~, as far as
25 possib:Le, less than 1 ~0. Temperatures in the range
~rom 140 to 220C have proved -to be ad.van-tageous for -these
dl~ums, bu-t th:i.x does notpreclude the use of higher or
].ower tempera-tures. I-t is also possi.ble to dry the
f.i.laments on the drums at graduated tempera-tures~
" .
1 ~ 70 0 ~ :1
After drying, the -tow is stretched once more
to at least 1.5 times it.s length with the application
of dry heat. This stretching can also be effected in
one or more stages. The t~w can be heated by the pro~
cesses cus-tomary in the ar-t, for example by being passed
around hot drums, by contac-t over hot pla-tes, in a ho-t
air -tunnel or by radia-tion, in par-ticular inf`rared
radiation. Stepwise stretching in which the various
heating processes can be applied can also be used.
Combina-tions which are always particularly advantageous
are -thosein which -the filament is s-tretched by or be-t-
ween hot drums in the ~irs-t s-tretching s-tage and one of
the three o-ther processes described is applied in the
second s-tage. The s-tre-tching -tempera-tures are influ~
enced by -the nature of -the polymers employed and to some
extent by the preceding stretching and the drying con-
ditions~ In general, a temperature range from about
- 120 to 250C is sui-table, and the range from 140 to
200C is par-ti.cularly advantageousO
Af-ter the stre-tching, the fil.aments are cooled
and are either wound by kno~m processes -to give
continuous ma-terial or are cut to fibers wi-th the
desired cut leng-th by kno~m processes. If required
by the field of` use, the filamen-ts or fibers can also be
subjected -to a special finish before or after -the
cut-ting.
The following examples serve to illustrate -the
i.nven-tion ~nless indicated o-therwise, the percen-tage
data and parts relate to units by weigh-t.
) Q 1 ~
_ ..~
1~700 g of a suspenslon precipi-ta-tion po:lymer of
99.50b of acrylonitrile and 0.5% of methyl acryla-te wi-th
a relative viscosi.-ty of 2.85 are dispersed in 8,300 g of
dimethylforrnamide at ~30C and are dissolved at 90C for
90 minutes, with s-tirring, to give a homogeneous spinning
solu-tion. After ~eing filtered, the solution is forced,
at a feed rate of 16.2 ml/min~-te through a 100-hole jet
with a ho:Le diameter of 0.06 mrn into a coagulating ba-th
~0 which cormprises 50 % of dimethylformamide and 50 % of
wa-ter and has a -tempera-ture of 50C. When -the resulting
filaments have reached an im~ersed length of 50 cm, -they
are drawn off at a rate o~ 5.5 m/minute. The yarn
is stretched by raisi-n~ the speed to 29.3 m/minu-te in
2 stretching baths comprising 60 % of dimethylforrnamicle
and 40 % of water a-t a -tempera-ture of 99C, washed in wa-ter
at a tempera-ture of 85C in further baths and, after
passing -through a finishing ba-th, is dried on 2 hea-ted
duos with surface temperatures of 140 and 185C respec-
tively, a shrinkage to a speed reduced by 0,7 m/minutebeing allowed. The residence time on the first duo
with a temperature of 140C is chosen such that the
yarn is lus-trous when it lea~Jes -the duo, t'nat
iS -to say -i-t no longer contains vacuoles. The
yarn is .drawn off from -the second dUo at
33.3 rn/minute and is s-tretched by raising the speed to
95 m/rn:inu-te, ~ri-th the aid of an unheated duo, over 4
heated plates which touch the yarn alternately from
below and above, at temperatures o~ 5, 1459 165 and
-- 12 -
168 C, and is then wound on to bobbins O The ef:fc?c-tive
overall stre tching ratio is calcula-ted as 1:17 . 3 in -this
case . The filaments -thus ob-tainecl had the :l~o] lowing
properties: deni.er: 275 dtex; tensile s-trength. 61 cl~/tex;
5 elongati.on at break: 6 %.; ini-tial modullls: 1, 836 cN/teY;
kno-t s treng-th of the i~dividual cap:illaries: 10 ~ 6 cN/ tex .
Exampl e 2
2 ~ 600 gr of a precipitation polymer o~ 93 . 7 %
of acrylonitrile~ 5.8 % OI methyl acryla-te and 0. 5 % of
10 sodium methallylsulfonate i,rith a relative viscosity OI
1.92 are dissolved in 7, 400 g of dimethylformamide -to
give a homogeneous spinning solution. AI-ter -this solu-
tion has been .îiltered, it is forced, at a feed rate of
19 ml/minu-te5 ~a jetwith 300 holes with a holè dia-
15 me-ter of 0.06 mm into.a coagulating bath comprising 65 %
of dimethylformamide and 35 % of water a-t 50C When
the resul-ting yarrl has reached an immersed length OI
50 cm5 i-t is dra~n off from -the coagula-ting bath
a t 5 . 5 m/minute, stre-tc hed by raising the speed
. 20 -tG 50.0 m/minute in 2 stretching ba-ths containing 6G ~0
o~ dime thy-Lformamide and 40 % of water a-t 99C,
washed with wa-ter at ~35C and, after passing through a
~inishing bath, dried on 2 heated duos 5 no shrinkage
being allo~re(l, The suri~ace tempera-tures OI duo 1 ~rere
25 120 C and those o:E duo 2 were 165C. The clried
yarn was then passed over 4 pla-tes heated -to 145C
whi:Lc? béing s-tre-tched. a t a final ra-te. o: 79 . 0 m~f
miml-tc-? with the aid o~ a .îur ther duo ~ : The
individ.ual filaments OI the yarn thus produced
~ 13 -
had the fol:lowing properties: denier: 2.1 d-tex; -tensile
s-trength- 74 cN/~tex; elongatiorl a-t break: 9 ~'; initial
modulus ~ 95 cN/-texO
Example_3
2,500 g of a precipitation polymPr of 99.5 %
of acrylonitrile,and 0.5 % of me-thyl acryla-te wi-th a
relative viscosity of 1.92 were dissolved in 7,500 g of
dimethylformamide, and, after being filtered, -the solu-
tion was forcedJ at a ~eed rate of 16.4 ml/minute, -through
10 a 300 hole je-t with a hole diameter of 0.06 ~m into a
coagulating bath ~hich comprised 70 % of dimethylformamide
and 30 % of wa-ter and had a tempera-ture of 30C
A~ter tne resul-ti.ng yarn had reached an immer-
sed length of 50 cm, it was drawn o~f ~t 5 0 m/
15 minute and stretched by raising the speed to 33 m/minu-te
in a stretching bath containing 60 ~0 of dime-thylformamide
and 40 % of l~a-ter at 9~C and then washed wi-th wa-ter and7
after passing through a finishing bath, dried on 2 duos,
no shrinkage being allowed. The surface tempera-tures
20 of the duos were 120 and 140C. l`he yarn was then
stretched by raising the speed to 68 m/minute, corres--
ponding to an effective overall s-tretching ratio of
1:13 6, over 4 plates heatecl -to 135C. The individual
filaments of the yarn had the following properties:
25 denier: 2.0 dtex; tensile s-trength: 58 cNjtex; elongation
at break: 8 %, initial ~odulus: 1,500 cN/tex
E~am~ 4
.~ _
1,400 g of a precipita-tion polymer of 100 %.o~
acrylonitrile wlth a relative viscosity of 3.0 were
,
7~
- 14 -
dissolved in 8,600 g of dimethylformamide -to gi.ve a
spinning solu-tion and the so~Lu-ti.on was fil-tf.;red and
forced, at afeed ra-te of 16 ml/mi.nu-te, through a lOO hole
jet wi-th a ho]e diameter of o.o6 mm in-to a coagula-ting
ba-Lh cornpr.ising 55 % of dime-thy]fo~namide and 45 % o~
wa-ter at 50 C. The resulting filament was drawn of~
from the coagulating bath at 5.5 m/mi.nu-te and stre-tched
by raislng the speed to 29.~ m/minute in a s-tretching
bath comprising 60 % of dime-thylformamide and 40 % of
wa-ter at 99 C. The filament was -then washed in water
at 85C and subsequen-tly passed -through a fir1i~hin~
bath9 and thereafter dried on 2 duos which had surface
temperatures of 140 and 165C respectively. A shrink-
age to a speed reduced by 2.5 m/minute was permitted on
-the duos, but the yarn was drawn off from the second
duo a-t 30 3 m/rninute and stretched by raising the speed
to 72 m/minute over 4 hot plates wi-th surface tempera-tv.res
140, 140, 150 and 150 C. The individual filamen-ts
of the yarn . -thus obtained had the following properties:
denier: 3.1 dtex; tensile strength: 65 cNltex; elongation
at break: 8 ~0; ini.tial modulus: l,400 cN/tex D
~ ' .
In a conti.nuous procedure, 80 g per minute of a
precipi.tation polymer of 9~ 7 % of acry]oni-trile, 5.8 %
of methyl acrylate and 0.5 % of sodium methallylsulfona-te
were dissolved in dime-thy:Lformamide to g.ive a 26 % by
weight spi.nning soLution, and the solu-tion was fil-tered
and .~orced through a jet wi-th 5,000 holes with a hole
diame-ter of 0.06 r~n into a coagula-ting ba-th, which com~
D !~0
5 --
prised 60 ~' of dirnethylformamlde and 40 % of wa-ter a-t
45 c. A~-ter a ba-th zone of 13 cm, -the -tow was dra~m
off at 6.5 m/mimlte, . drawn by raislng -the speed -to
39.0 m/minute in 2 s~re~tching baths containing 45 % of
dimethyl:Eormamide and 55 % of wa-ter a-t 99C and -then
washed wi-th wa-ter a-t 90C, and simul-taneously shrunk
back to a speed reduced to 35.2 m/minu-te, and subsequently
dried on drum driers In the drum drier, ~the -tow
was dried at 165C in a first stage, no shrinkage being
permit-te(d, and after-treated at 180C in a second s-tage,
the tow being drawn by raîsing the speed to
63.9 m/minute between the first and second s-tage. The
tow then passed into a third stage of -the drum
drier, whlch was opera-ted at 175C, the ~ow being
.15 dra~m again,- by raising the speed -to 69.2 m./minute,
be-tween the second and third stage, Finally9 the
tow pas3ed over 8 hot pla-tes which were arranged alter-
na.tely above and below and had a surface tempera-ture of
180 C, -the tow being drawn between the plates by rais-
20 ing the speed to 77.2 m/minu-te, correspondin~ to an
ef~ec-ti.ve overall drawing of 1:11.9. After the tow
had been cu-t into staple fibers, the ~ollowing -tex-l;ile
proper-ties were measured: denier: 2.2 dtex; tensile
strength: 73 cN/tex; elon~ation at break: 10 %; initial
modulus : 1,373 cN/te~.
Exa~ple 6
.~
Example 1 was repeated, bu-t 5 %, rela-ti~e -to the
polymer, o~ -titaniurn dioxide was added to the spi~ling
solution as a delus-tering agent. The individual
-16-
filaments of the yarn had the following properties:
denier: 3.6 dtex; tensile strength: 61 cN/tex; elongation
at break: 7 %; initial modulus: 1,389 cN/tex.
Example 7
In a continuous procedure, a polymer such as has
already been described in Example 2 was dissolved in
dimethylformamide to give a 30.5% strength spinning
solution, and, after it had been filtered, the solution
was forced, at a feed rate of 72 ml/minute, through a 50-
hole jet with a hole diameter of 0.15 mm into a dry-
spinning tunnel. Hot air at 360°C was blown in the
filament direction at a tunnel temperature of 200°C.
The take-off rate of the filaments was 220ml/minute.
In each case 11 of the strands thus obtained
were collected to form a tow and the tow was stretched
to 606 times its length in 2 stretching baths, which
comprise 6 % of dimethylformamide and 94 % of water at
99°C, washed with water at 80 to 85°C, a shrinkage of
11 % being allowed, and, after passing through a finish-
ing bath, dried on 2 duos with surface temperatures of
140 and 160°C, a shrinkage of 5 % being allowed. The
filaments were drawn off from the second drier duo at
a stretching ratio of 1:1.07 and stretched at 1:1.64
over four hot plates at 140°C. The following textile
properties were measured on individual filaments of the
resulting tow: denier: 2.0 dtex; tensile strength: 65
cN/tex; elongation at break: 9 %; initial modulus:
1,491 cN/tex.
- 17 -
Examp].e 8
_~ .
In a continuous procedure, a polymer~ as already
descri.bed in Example 3 9 was dissolved to give a 26 % .
strength spinning solu-tion and -this solu-tion ~.as subjec-
ted to dry spinni..ng, at a feed rate of 85.2 ml/minute,under -the condi-tions described in EY.ample 7.
In each case 11 of the strand~ thus ob-tained
were collected to form a -tow and the tow was stretched
to five times its length in 2 stre-tching ba-~.hs, which
comprise~ 6 % of dime-thylformamide and 94 % of wa-ter at
99C 9 washed wi-th water a-t 80 to 85C 9 a shri.nkage of
7 % being allowed, and9 after passing -through a finish~
ing ba-th, dried on. 2 duos at 140 and 160C~ a shri.nlsage
of 5 ~0 being allowed, The tow was drawn off from the
second drying duo with a stretching ratio of 1:1.02 and
s-tretched at 1:2.65 over -four hot plates a-t 140C. The
individual filamen-ts had the following proper-ti.es:
. denier: 1.7 dtex7 tensile streng-th: 81 cN/tex; elongation
at break: 9 %; initial modulus: 1,482 cN/tex.
.Ex.ample 9
ln a continuous procedure, a pol~ner, as described
in Example 1, was dissolved to ~ive an 18 % s-trength
spinning solution and this solution was spun, at a feed
rate of 58,8 cm3/minuteS through a jet wi-th 18 holes with
a hoJ.e diameter of 00250 mm in-to a dry-spinning tunnel
which had a tunnel wall tempera-ture of 240C. Air
heated to 3~0C was blown in the f.ilamen-t direc-tion.
The fllaments were drawn off at 200 m/minute
ln each case 20 of these s~r~nds were collected
1 1 7~) Q ,g 1 ,
- 18 ~
and the resu]ting -tow was stretched from 10 m/minute by
raising the speed -to 60 m/minu-te in 2 stre-tching baths
which con-tain 6 % of dime-thylformamide and 94 ,'0 of water
at 99G, washed in water at 85C, finished and -then dried
on 3 duos at a -temperat.ure of 140, 170 and 200C, a
shrinkage to a speed reduced by 7 m/minu-te bein~ allowed.
The tow was then stre-tched by raising -the speed -to 120.2
m/minute over four plates heated -to 165C. The é~fec-
tive overall stretching ratio was thus 1:1.2Ø The
resu].tir~g indi.vidual fllaments had the following proper-
ti.es: denier: 2.~ dtex; tensile strength: 7~ cN/tex7
elongation at break: 8 % 9 initial modulus: 1,600 cN/-tex;
. knot strength: 13.6 cN/tex.
Exam~æ_e 10
Three of the dry-~spun filaments spv.n according
to Example ~ were plied and -the tow was s-tretched
from 7.5 b~- rais-ing the speed to 30.7 m/minute in 2
stretching baths which contain 60 % of dimethylformamide
and 40 % of water a-t 99C, and then washed with wa-ter at
-. . 20 85C, a shri~age to a speed redu.ced by 1 m/minu-te bei.ng
allowed, ~inished dried on 2 duos wi-th a surface -tem-
perature o~ 140 and 185C respec-tively, a shrinkage -to a
speed reduced by 2 m/minute being al-l.owed, drawn off from
the second duo, which was heated -to 185C, at 30.5 m/ .
mi.nu-te and stretched by raising -thc speed -to 120.7 m/
minute over four plates hea-tecl -to 160, 160, 166 and 166C.
The plied yarn thus obta].ned had the fol:Lowing
properties: deni.er: 93 dtex; -tensile strength: 68 cN/tex;
elongation at break: 6 /0; initial rnodulus: 1,989 cN/tex.
~ 3 7 (~
- lg
E~ ~e 11
. ~_ .
1~500 g of a pol~ner of 99.5 % o~ acrylonitrile
and 0.5 % of methyl acryla-te wi-th a rela-tive viscosi-ty
o~ 3,3 were dissolved in 8,500 g of dimethylformamide.
5 This solution was filtered, and forced, at a feed rate of
18 ml/minute, through a jet wi-th 100 holes with a hole
diame-ter o~ 0.06 mm in-to a coagula-ting bath which com--
prised 55 % of dimethylformamide and 45 % of water at
50C, After the filamen-t had reached an ir~nersed
10 leng-th of 45 cm, it was drawn o~ a-t a ra-te of 5.0 ~1/
minu-te, stretched by raising the speed to 29.3 m/mi.nute
in two s-tretching baths which contained 60 % o~ dimethyl-
- formamide and 40 % of water at 99C, washed at 85C,
finished , dried on 2 duos at 140 and 165C, a shrinkage
15 to a speed reducedby 2.9 m~inute being allowed, drawn off
~rom the second duo at 30.3 m/rninu-te and s-tretched by
raising the speed to 100 m/minute on four hot plates at
140, 150, 167 and 177C. The effective overall stretch-
ing ratio in this case was thus 1:20.00 The yarn
20 spun in this way had the following proper-ties: denier:
270 dte~; tensile s-trength: 67 cN/tex; elongation a-t
break: 7 % 7 initial :modulus: 1,981 cN/tex~
,
. .
