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Патент USA US2404721

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July 23, 1946.
Filed NOV. 4, 1944
Lsw w.
-,u .
{1521 4
BY f27' a?!‘
Gila/2&4 5r’ ‘6%,?
Patented July 23, 1946
a " ‘ 5
ass Fort‘
> , 9r‘, ‘ Q‘POLYMER
at Clyde,Houtzf,,Snyder,
PRODUCTS‘ N.‘IY;1,"a"ssi'gn6r~to?E.
‘ ‘
du Pont‘dc‘Nemoui-s 8: Company; Wilmington
>“_Del.,§a:corporatlon of Delaware;
Application November 4, last:
,jni‘olaunsi (01. 260-32)
This invention relatesito anew ‘composition of
matter and shaped articles-producedtherefrom.‘
More particularly, this invention’ relates to an or
substantially impossible'fit
ganic solvent solution - of ' polyacrylonitrlle, ‘ i. .e.
positionsv in such ‘a’ manner
polymerized acrylonitrile wort‘ polymerized vinyl
cyanide (CH2=CHCN) 1, ,and copolymers; and ‘in
mg such-‘inon?‘solvents To
terpolymers of acrylonitrile inwhichv atgleast “85%
by weight of the polymer is acrylonitrile, {and to
the fonnationi'l'dflishape ‘art "
. »the production of ‘shaped articles from saidor
large amounts of the-vruiorga
ganic solvent solution of ‘said polymersof acrylo-j 10
This application ‘is a‘ continuation-vin‘ipartl of
‘ tinu'ity: “0ft? ther'apolyacryldnitrile ‘ei’pha'se _-a ‘d ‘the?
the copending application of‘RayClyde 'Houtz,
or ;.these.
i<salts;;;,when‘; ‘:spos'slble; result~I‘ in‘
Serial No. 447,446, ?led June 17,1942. ; t ‘
Polyacrylonitrile, and copolymers and inter?‘
polymers of acrylonitrile‘with otherrytpolymeriz
able substances, for examplevinylor acryliccom
15 theiformation'lof a“porous';,»spon‘gy; weak, un‘de‘siri
pounds, in which at‘ leastv85%yby weight of ‘the
polymer is acrylonitrile» ‘have-“jbeen known ‘,for
when ittisvatte‘mptedlto Iormaamulti?lament-yam
able' structure ithatl :is we 2 brittle-1 and 1 completely
unsuitedzaforrl useless at
om?lmi. Moreover;
bypextruding. :io‘r exampleiithezrproposed an aqueous
some time and recognized as ‘possessingdesirable 20 sodium sulfocyanlde polyacryloriitrileZ'coxnposis
physical and chemical properties including tough
tion,‘ into‘aa ;di1ute\acid=lb.ath;-i spfound thatsthe
ness and insolubility in and insensitivity to com
mon organic solvents such. as methyl or ethyl
. alcohol, acetone, ethyl‘ether, ethyl acetate, ‘hy
is" extremelytbrittlejand cann
drocarbon solvents, chlorinated hydrocarbons and 25 without breaking.
the like. Because of-these‘factsrsnumerous at
tempts have been made to form these polymeric
materials into yarns,e?lms and‘ other shaped var
The copending
Serial No. application
562,012, “?ledoimevennatie
oi =qeorgef
herewith discloses solutions, of'polyacrylonitrile
in dimethyl carbamyl compoundsandthe. pro
duction of extruded and otherwise shaped articles
containing ‘whi'gli'e
and structures from such solutions. 1 ‘The above- .
acrylonitrilel i e. acrylonitril
said application of George H. Lathalnlrepresents
the ?rst successful dissolution‘of.polyacrylonitrile " ‘
in a solvent to produce a solution which ‘is‘fsuit
able for the production‘oi commerciallyluseful
textile yarns or wrapping tissue ?lmsiand‘ similar
tough, ?exible structures.
The present applicationsrelaltesrtoasimilarly ‘
satisfactory, dissolution of,‘polyacrylonitrileiin an
organic solvent taken ‘fror‘n'ja different classof
organic compounds and the polyacrylonitrile solu
tions produced thereby arefsvijmilarly ‘satisfactory ‘ ‘
for the production of'tou‘gh, ‘?exible‘,,dense, color?‘
less yarns and ?lms “ which’ are‘suitable‘ior use
in ‘practically all general“ commercial‘s‘k‘applicw‘
It has suchproducts,
been known heretofore th?ti‘c‘on‘c‘
‘ k
aqueous solutions of inorganic‘ salts‘ sucl'itfas' lith
ium bromide, zinc chloride‘ and‘sodiu'm ‘"s‘uIfQc‘Iy-j
anide will dissolve polyacryl‘onitrilei andhfitj has
been proposed (minors. I'a intNo.l'2‘,1f4'0;921l)d
tick" togetheiwzpto
formianess vtviallyrsmpne?la ent t1:
- 2,404,721
the above-mentioned acrylonitrile polymers in
mentary structures such as yarns from the com
clude :
position. Films or ?lamentswhen obtainable,
are extremely brittle; they are highly colored and
very weak, presumably because of the presence
within them of residual quaternary ammonium
salt. Removal of this salt is di?lcult and'the“
resulting structures contain numerous and large
voids that make the structures substantially use
less for commercial purposes.
It is therefore an object of this invention to dis 10
solve polyacrylonitrile or a‘ copolymer or inter
acrylonitrile polymer solutions formed by the
polymer of acrylonitrile in which at least 85% by
weight of the polymer is acrylonitrile, in a solvent
‘use of the solvents described above are stable at
room temperature (approximately 20° C.) and at
which does not react with or decompose the poly- -
temperatures considerably above room tempera
mer and which may be substantially completely 15 ture. Shaped structures and articles can be pro
removed from the structures formed of such a
duced by extruding such solutions into an evapo
rative or coagulative medium. By forming the
It is another object of this invention to produce
structures in an evaporative medium, the solvent
a solution of polyacrylonitrile or a copolymer or
must be evaporated therefrom and by forming
interpolymer of acrylonitrile in which at least 20 the structures in a coagulative medium, the sol
85% by weight of the polymer is acrylonitrile, in
vent should be removed by selective solution in a
a solvent which does not react with or decompose
non-solvent for the polymer.
the polymer, the solution being suitable for the
The solutions are prepared by dissolving the
formation of commercially useful, void free arti
polyacrylonltrile, or copolymer or interpolymer of '
cles of polyacrylonitrile, for example yarns which 25 acrylonitrile with one or a mixture of the above
are suitable as textile yarns and ?lms which are
mentioned solvents. Some of these solvents are
suitable as wrapping tissue.
solid at ordinary temperatures and dissolve or re
It is another object of this invention to pro
tain the polymer in clear solution only at ele
duce a solution of polyacrylonitrile, or a copoly
vated temperature, for example at temperatures
mer or interpolymer. of acrylonitrile in which at 30 of 100° C. or higher, below which temperature the
least 85% by weight of the polymer is acryloni
trile, in a volatile organic solvent, which solution
composition resembles a gel.
In all cases when
the polymer or copolymer is dissolved in a sol
is stable over extended periods of time and is
vent of the above class, the resulting composition,
eminently suited for use in the manufacture of
while hot, has the appearance of a true solution.
shaped articles such as yarns, ?lms, tubes, straws. 35 When cooled to room temperature, the composi
tion generally takes on the appearance of a gel,
arti?cial horsehair, bristles and ribbons, or when
which gel may, on prolonged standing, undergo
highly concentrated, for use in the manufacture
syneresis. Reheating of this gel or syneresed
of molded articles.
mass however causes it to again return to solution
It is a still further object of this invention to
produceshaped articles and structures of poly 40
acrylonitrile, or copolymers or interpolymers of
acrylonitrile in which at least 85% by weight of
the polymer is acrylonitrile.
In view of the relatively high melting points
of some of the solvents of this invention, they
would have comparatively little use in the pro
duction of a polyacrylonitrile spinning or casting
It is still another object of this invention to pro
duce a shaped article or structure of polyacrylo 45 solution. Such solvents are however excellent
solvent plasticizers for polyacrylonitrile since
nitrile or copolymers or interpolymers oi’ acrylo
nitrile in which at least 85% by weight of the I they are soluble in a. wide range of proportions
polymer is acrylonitrile, for example a yam, ?lm,
tube, bristle or the like which is tough, ?exible,
tenacious and free from voids.
Other objects of the invention will appear here
The objects of the invention may be accom
plished in general by dissolving polyacrylonitrile,
or copolymers or interpolymers of acrylonitrile
in which at least 85% by weight of the polymer
is acrylonitrile, in an aromatic compound which
with the said acrylonitrile polymers. The present
invention therefore contemplates solid solutions
60 of acrylonitrile polymers containing at least 85%
by weight of acrylonitrile as well as liquid solu
tions thereof.
Shaped articles obtained from solvent solutions
of polyacrylonitrile in accordance with the in
vention and from which the solvent is subse
quently removed are substantially free of foreign
matter and voids and substantially undecomposed
and I chemically unchanged from the polymer
is not a salt and which contains at least one hy
droxyl group and one nitro group attached to the 00 prior to its solution.
The above-described organic solvent solutions
same ring, the valcnces of the ring members be
of acrylonitrile polymer may be shaped in the
form of filaments, yarns, ?lms, tubes and like
If the solvent has a relatively low boiling point
structures by apparatus and processes generally
(less than about 250° C.), the solution of acrylo
nitrile polymer may then be formed into a shaped 65 known in the art, the detailed operating condi
tions being suitably modi?ed.
structure, for example a yarn or ?lm, and the sol
Suitable methods and apparatus for the pro
vent removed from the shaped structure. When
duction of shaped articles of the polymers of this
the solvent is relatively non-volatile and has a I
invention will be readily apparent by reference
boiling point of about 300° C. or more, shaped
articles may be made from the solution and at 70 to the following detailed descriptionwhen taken
in connection with the accompanying illustrations
least a portion of the solvent may be retained
in which:
therein as a plasticizer for the articles.
Figure 1 is a diagrammatic vertical sectional
Representative compounds coming within the
view showing a dry spinning cell suitable for use '
scope of the above-mentioned type of aromatic
compounds, and suitable for use as solvents for 75 in accordance with the invention;
ing otherwise satis?ed by hydrogen atoms.
. Figure 2 is a diagrammatic perspective view
showing a yarn drawing device for use in con
polymer preferably possesses a molecular weight
within the range of 15.000 to 250,000 or even
higher, as calculated from viscosity measure
nection with the invention;
Figure 3 is a diagrammatic perspective‘ view
showing a wet spinning apparatus for use in the
invention; and
Figure 4 is a diagrammatic side elevational view
showing a suitable ?lm casting apparatus for use
ments by the Staudinger equation:
Molecular weight=eKALzv
_ in accordance with the invention.
- Referring to Figure l of the drawing, reference 10
numeral I l designates a spinneret through which
a plurality oi’ ?laments II are formed by extrud
ing a ?lament-forming solution supplied to the
spinneret by means of conduit I 3. The spinning
cell is jacketed with a material I 1 such as a re
K... = 1.5 X 10-4
of solution_
N,,,=speci?c viscosity= viscosity
viscosity of solvent
C=concentration of the solution expressed as the
number of moles of the monomer (calculated) per
liter of solution.
fractory in which is embedded an electrical heat
The molecular weight of the polymer obtained’
ing coil IS. The spinning cell can thus be op
is dependent on such factors. as the concentra
erated at any desired temperature. A plurality
tion 'of the monomer in the water, the amount
of conduits H are provided adjacent the bottom
and type of catalyst present, the- temperature
of the device for passing evaporative medium 20 of
the reaction, etc. For example, polyacrylo
through the cell so as to evaporate the solvent
having a molecular weight of approxi
from the extruded ?laments l5. The evaporative
mately 60,000 can be prepared as follows: To 94
medium is removed from the cell through outlet
pounds of distilled water heated to 40° C. add 40
openings 23. The yarn comprising the plurality
grams of ammonium persulfate catalyst and 80
of ?laments i5 is passed from the bottom of the
grams of sodium bisul?te activator. Then add
spinning cell around guide roller 25 and is wound
16 pounds of acrylonitrile slowly with stirring
on bobbin 2 ‘i .
over a period of two hours. The polyacrylonitrile
Referring to Figure 2 of the drawing, the yarn
having the above said molecular weight will pre
I5 is removed from the bobbin package 21 and
cipitate from the solution. Increasing or de
passed about draw roller 29 and separating roller 30 creasing the amount of the catalyst, while main
3|. From draw roller 29, the yarn is passed to a
taining the other conditions constant, decreases
second draw roller 33 and separating roller 35.
or increases the molecular weight of the polymer.
The yarn is passed around the two sets of draw
Acrylonitrile copolymers and interpolymers con
rollers including their separating rollers a suffi
taining at least 85% by weight of acrylonitrile
cient number of turns to prevent slippage of the 35 and likewise preferably having a molecular
yarn. Draw roller 33 is rotated at a greater speed,
weight of 15,000 to 250,000 or higher can be pre
for example three to ten times the speed of draw
pared in a similar manner.
roller 29. In this manner, the yarn I5 is stretched
The following examples in which parts, pro
between the two draw rollers. As the yarn passes
portions and percentages are by weight unless
between the two draw rollers, a heating medium
otherwise speci?ed illustrate preferred methods
is brought into contact with the yarn through
of preparing solutions of polyacrylonitrile, and
blower nozzles 31 and 39. The yarn passingv from
copolymers of acrylonitrile in accordance with
the draw roller 33 is wound on-bobbin 4|. The
the principles of this invention and of employing
drawing. or stretching of the spun yarn as de
these solutions in the manufacture of commer
scribed is not claimed as part of the present in 45 cially satisfactory shaped articles of the polymer.
vention, but is claimed in the copending applica
The invention is not to be limited by the details
tion of Daniel T. Meloon, Serial No. 496,397, ?led
set forth in the examples.
July 28, 1943.
Figure 3 of the drawing illustrates a wet spin
Example I
ning apparatus for the production of yarn. The 50
Thirty (30) parts of an acrylonitrile polymer
acrylonitrile polymer. solution is passed through
prepared by the polymerization of monomeric
conduit 5| and is extruded through spinneret 53
acrylonitrile in accordance with the teachings
to form a multi?lament yarn 54. The yarn 54 is
of U. S. Patent No. 2,160,054 to Bauer et a1. and
passed about guide roller 51 which is positioned
possessing an average molecular weight of 120,000
Within the coagulating liquid in tank 55. The
are ground to an average particle size of 200 mesh
yarn is then passed about guide roller 59 and is
wound on bobbin 6| .
The organic solvent solution of polyacryloni
.. and intimately mixed with 70 parts of p-nitro
phenol ground to a similar particle size. The
mixture is heated over a period of thirty minutes
trile may be cast in the form of a ?lm as illus
trated in Figure 4; In accordance with this ap 60 to a temperature of 140° C. to form a ?uid, homo
geneous mass or solution which, on cooling to
paratus, the polymer solution is passed from hop
room temperature, forms into a solid mass that
per 1| on to the endless steel band ‘I3 where it is
smoothed by means of a doctor knife 15.
band, together with the ?lm, is passed under a
could be hot rolled or pressed into sheet form.
Example II
means 11 for bringing a heated drying medium
into contact with the ?lm. The ?lm 3| is pulled
from the band 13 and collected on a mill roll 83.
The polyacrylonitrile for use with the inven
Six (6) parts of 4-nitro_-alpha-naphthol are
dissolved in a solution prepared by heating 20
parts of the acrylonitrile ‘polymer of Example I
tion is preferably prepared by the ammonium
persulfate catalyzed polymerization of mono
and 80 parts of N-formyl morpholine to a tem
perature of 140° C. The resulting solution is
meric acrylonitrile dissolved or emulsi?ed in
cast on to a chromium surfaced plate maintained
at a temperature of 95° C. to form a thin, trans
water. It can, however, be prepared by any other
suitable type of polymerization reaction such as,
for example, the emulsion type reaction disclosed
by U. S. Patent No. 2,160,054 to Bauer et al. The
parent ?lm that is substantially free of haze.
The ?lm is tough and much more durable and .
?exible at low temperatures (0° F.) than ?lms
2,404,721 -
prepared from similar solutions but containing
suitable mixture thereof. The temperature of
the evaporative medium is dependent on such
factors as the dimensions of the spinning cell,
none of the nitro-naphthol of this invention.»
As above indicated, it is possible by the prac
tice of this invention to obtain a solution of poly-.
the composition and rate of extrusion of the spin
acrylonitrile, or a copolymer or interpolymer of
ning solution and the rate of flow of the evapora- I
tive medium. It is only necessary that these sev- ‘
acrylonitrile which is eminently suited for use
in the manufacture of shaped articles such as
yarns, ?lms or molded articles. These solutions
eral factors be so correlated that the yarn or
other shaped article leaving the spinning cell be
are also suited for use as lacquers or coating
sufficiently freed of the solvent so that it is so
compositions. They are especially useful in the 10 lidified and capable of being wound into package
coating of wire and electrical parts where the
form or otherwise collected.
high chemical and electrical resistance of the
Shaped articles of acrylonitrile polymer can
polymer is important.
also be formed by extruding the spinning solution
As also shown, the solvents of the invention
into a suitable precipitating bath comprising a
are useful not only in connection with the poly 15 liquid that is miscible with the solvent but is a
acrylonltrile, but also with copolymers and inter
chemically inert non-solvent for the acrylonitrile
polymers of acrylonitrile with other polymeriza
polymer. As examples of such a liquid may be
ble substances such as, for example, compounds
mentioned water, glycerin, organic solvents such
containing one or more ethylenic linkages in
as alcohol, ether, etc., or aqueous solutions of
cluding vinyl and acrylic compounds as well as 20 salts, alkalies or acids. The copending applica
ole?nic or diole?nic hydrocarbons such as iso
tion of William W. Watkins, Serial No. 496,376,
butylene, butadiene, etc. They are eminently
?led July 28, 1943, covers the use of glycerol and
satisfactory for use with those polymers that
aqueous solutions of salts as baths, ‘preferably at
elevated temperatures, for the wet spinning of
contain a large amount of acrylonitrile, for ex
ample polymers or copolymers that contain at 25 acrylonitrile polymer yarn, from solutions of the
polymer, preferably with substantial tension and
least 85% by weight of acrylonitrile and that
have generally been regarded by the art as being
stretch being applied during spinning. .
The article of acrylonitrile polymer thus ob
tained can advantageously be subjected to a
completely insoluble in all common organic sol
vents. Nor are these solvents limited to use with
a p'olyacrylonitrile of any given molecular weight. 30 stretching operation of the type employed in the
above examples. This stretching is preferably
They can be used with a polymer of almost any
performed by passing the yarn between two posi
tively driven rollers, the peripheral speeds of
given molecular-weight and are ‘especially satis
factory for use with those polymers having an
average molecular weight within the range 15,000
which are so adjusted that the article is stretched
to 250,000 as determined by viscosity data using 35 to from two to tentimes its original length, pref
erably approximately six times its original length.
This stretching of the formed article may be per
formed at any suitable time. However,in the
The solution of acrylonitrile polymer dissolved
case of articles formed by the wet spinning _or
in an organic solvent in accordance with this in
vention must be of such a concentration that its 40 casting technique, it is preferably performed be
fore the article has been completely dried. The
viscosity at the operating temperature is within
orientation of the structure thus obtained greatly
a workable range. When it is to be employed in
improved the physical properties of the structure
the spinning of yarn or the- casting of ?lm, the
including its tenacity, its resilience, etc.
solution should preferably have a viscosity within
the range of 25 to 750 poises. When the polymer 45 This stretching of the shaped article can also
be accomplished by causing the article, while
has a. molecular weight of 250,000 or more, this
passing between stretching rollers, to contact a
requires that the maximum concentration of poly
the Staudinger equation and intended for use in
the manufacture of yarns or ?lms.
heated stationary pin, or to pass through an inert
mer in the spinning solution be of the order of
10%. Generally, it is preferred that the spinning
medium such as air, water, glycerin, etc., heated
solution contain at least 10% of the polymer be 50 to a high temperature. Obviously, the article
must not be exposed to this high temperature for
cause of the di?iculty of rapidly removing large
a period su?iciently long to decompose the poly—
amounts of solvent from the solution in the spin
ning operation. Moreover, it is economically un
mer. In general however, the time of contact of
the article with the heated medium is so short.
desirable to use such large amounts of solvent for
the spinning of a given amount of polymer al
though it is true that the solvent can be com
55 that temperatures up to 250° C; can be employed.
It is generally preferred to heat the article to a
pletely recovered from the spinning operation and
temperature of at least 100° C. during the stretch
reused. For these reasons, it is preferred to em
ploy a polymer having an average molecular
ing operation.
In addition to acting as solvents for poly
weight of between 40,000 and 150,000 since such 60 acrylonitrile, or copolymers or interpolymers of
acrylonitrile, the aromatic compounds of this in
a polymer forms a solution of the desired vis
cosity in concentrations of the order of 15% to
25% and at a desirable spinning temperature of
the order of 100° to 150° C. Of course, it is with
in the scope of the invention to heat the solution 65
to a higher temperature, even to above the nor
mal boiling point of thesolvent, for the actual
spinning operation. Here again, the controlling
vention containing hydroxyl and nitro groups,
when present in small amounts, can also be used
as plasticizing agents for the polymer, and the
higher boiling compounds of the invention are
especially suited for such use. At the same time,
it is, of course, to be understood that non-solvent
softeners such as glycerol, etc., can also be in
corporated in the solutions of this invention, these
factor with regard to the temperature of the spin
ning solution is the viscosity of the solution.
70 materials remaining in~the subsequently formed
The evaporative medium employed in the dry
articles to impart a softening effect. If it is de
spinning of ?laments and yarns or the dry casting
sired to use such plasticizing or softening agents
of ?lms in accordance with this invention may be
with polyacrylonitrile, they are preferably-added
any vapor inert to the ?lm- or ?lament-forming '
in the desired amount to an already formed solu
solution such as air, nitrogen,_steam, etc, or any
tion of the polymer in a lower boiling solvent.
This invention is primarily concerned with the
steps of dissolving polyacrylonitrile in a suitable
Since it is obvious that many changes and
modifications can be made in the above described
details without departing from the nature and
spirit of the invention, it is to be understood that
solvent to form a stable solution adapted for use
in the manufacture of shaped articles of polyac
rylonitrile. It is characteristic of the invention 6 the invention is not to be limited to the details
that the solutions provided by it are stable; the
described herein except as set forth in the ap
solvents do not cause a decomposition or chemical
pended claims.
alteration oi’ the dissolved acrylonitrile polymer.
I claim:
At the same time, it is also characteristic that the
1. As a new composition of matter, a polymer
solvents provided by the invention are also use 10 of acrylonitrile containing in the polymer mole
ml in the dissolving of mixtures of polyacrylo
cule at least 85% by weight of acrylonitrile dis
nitrile and adiuvants such as dye modi?ers, linear
solved in an aromatic compound taken from the
polyamides such as nylon, derivatives 01.’ cellulose
group consisting of: '
including cellulose ethers and esters, polymers of
vinyl compounds such as vinyl chloride, vinyl 15
acetate, acrylic acid, etc., which adjuvants may
be incorporated in the acrylonitrile polymer solu
tion to modify the properties, both chemical and
physical, oi the resulting shaped articles,
This invention provides a class of solvents for 20
polyacrylonitrile, and copolymers and interpoly
mers of acrylonitrile which were heretofore con
2. A new composition of matter as defined in
sidered substantially insoluble, i. e. compounds
which, when liquid, will form solutions containing
claim 1, in which said polymer is polyacryloni
an appreciable amount, e. g. 5% or more by 25
3. A new composition of matter as de?ned in
weight of the polymer. The solvents are capable
of forming with the polymer clear solutions that
are stable for extended periods of time at both
claim 1,‘ in which said polymer of acrylonitrile ls
non-reactive with said aromatic compound.
4. A new composition of matter as de?ned in
room and elevated temperatures and are admira
bly suited for use as lacquers or coating composi.. 30 claim 1, in which said polymer is non-reactive
with said aromatic compound but is soluble in all
tions or in the manufacture of shaped articles of
proportions therewith.
the polymer, for example by extrusion into an
evaporative or coagulative medium, or by the use
or a molding technique.
5. A new composition of matter as de?ned in
claim 1, in which said polymer has a molecular
The invention also provides a class or materials 35 weight of between 15,000 and 250,000.
6. A new composition of matter as de?ned in
that is eminently suited for use in plasticizing
claim 1, in which said polymer has a molecular
structures comprising the acrylonitrile polymers.
weight of between 40,000 and 150,000.
The materials provided by this invention are ap
'7. As a new composition of matter, a polymer
parently true solvents ior‘the above-mentioned
acrylonitrile polymers. They do not tend to react 40 of acrylonitrile containing in the polymer mole
cuie‘at least 85% by weight of acrylonitrile and
with or decompose the polymer, the polmeric ma
an aromatic compound taken from the group
terial obtained from the solution of this invention
consisting of:
apparently being of the same identical chemical
composition as the initial polymer,
Yarns, ?lms and similar articles of polyacrylo 45
nitrile prepared from the solutions of this inven
tion can be stretched to yield oriented structures
that possess a high tenacity, a desirable elonga
tion and a high elastic recovery that compares
favorably with that of silk. The articles are not 50
contaminated with undesirable salts and they are
substantially tree of void spaces.
8. The composition of claim 1 in which the
Reference, throughout the speci?cation and
solution contains at least 10% of said polymer oi’
claims, to acrylonitrile polymers, polymers of ac
rylonitrile, and copolymers and interpolymers of 55 9. The composition of claim 1 in which the
acrylonitrile “containing at least 85% by weight
has a viscosity within the range 25 to
of acrylonitrile" signi?es polymers containing in . solution
750 pcises.
their molecules at least 85% by weight of the
10. The composition of claim 1 in which the.
acrylonitrile unit which is considered to be pres
polymer is polyacrylonitrile having a molecular
ent in the polymer molecule as the group
60 weight of between 15,000 and 250,000. '
11. The composition of claim 1 in which the
polymer is polyacrylonitrile having a molecular
that is. at least 85% by weight of the reactant '
material converted into and forming the polymer
is acrylonitrile.
weight of between 40,000 and 150,000.
an carom no'u‘m.
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