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Патент USA US2404723

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, July 23, 1946- I
Filed Nov. 10, 1944
Patented July 23, 1.946
Richard R. Merner, Deer?eld, Ill., assignor't‘o E. I.
du Pont de Nemours & CompannWilmington,
Del., a corporation of Delaware
Application November 10, 1944, Serial ‘No. 562,857
11 Claims.
This invention‘relates to a new composition
of matter and shaped articles produced therefrom.
More particularly, this invention relates to an
organic solvent solution of polyacrylonitrile, i. e.
posed (including such non-solvents for'acrylonl
trile as water, dilute acid, dilute salt'solutions,
ble substances, for example vinyl or acrylic com
pounds in which at least 85% by weight "of the
polymer is acrylonitrile have been known for
some time and recognized as possessing desirable
it is attempted to form a multi?lament yarnby
extruding, for example the proposed aqueous so
extrusion into coagulating baths of the type pro
etc.) result in the formation of shaped articles
polymerized acrylonitrile or polymerized vinyl
that contain large amounts of the inorganic salt
cyanide (CH2=CHCN)¢, and copolymers and in
of the proposed solvent." These salts are distrib
terpolymers of acrylonitrile in which at least 85%
uted throughout the structure ‘and destroy the
by weight of the polymer is acrylonitrile; .and the
continuity of the polyacrylonitrile phase and the
production of shaped articles from. said organic
structure possesses poor physical properties. Re
solvent solution of said polymers of acrylonitrile. 10 moval of these salts, when possible, results in the
Polyacrylonitrile, and copolymers ‘and inter
formation of a porous-spongy, weak, undesirable
polymers of acrylonitrile with other polymeriza
structure that is very brittle and completely ‘un
physical and chemical properties including tough
suited for use as a'yarn or ?lm. Moreover, when
dium sulfocyanide polyacrylonitrile composition,
into a. dilute acid bath, it is found that .the indi
ness and insolubility in and insensitivity to com
‘mon organic solvents such as methyl or ethyl ‘al
' vidua1 ?laments obtained stick together-Ito. form
cohol, acetone, ethyl ether, ethyl acetate, hydro
20 tremely brittle and'cannot be bent'br ‘worked
carbon solvents, chlorinated hydrocarbons and
the like. Because of these facts, numerous at
tempts have been made to form these polymeric
an essentially mono?lament structurethat‘is ex
without breaking.
U. S. Patent No. 2,167,537 to Tobis points out
that certain copolymers of acrylonitrile and an
materials into yarns, ?lms and other shaped
acrylic acid ester (those copolymers containing
25 not more than 65% of acrylonitrile) are soluble
The copending application of George IL Lath
in mixtures of organic solvents such as dioxan,
am, Serial NO. 562,012, ?led November 4, 1944
cyclohexanone, etc. However,
discloses solutions of ‘polyacrylonitrile in di
these liquids are incapable Of dissolving or even
methyl‘ carbamyl compounds and the produc
swelling polyacrylonitrile or copolymers of acry
tion of extruded and otherwise shaped articles 30 lonitrile containing higher percentages of acry
and structuresfrom such solutions. The above
lonitrile, i. e. acrylonitrile polymers 01.’ the type
" said application of George H. Latham represents
the ?rst successful dissolution of polyacryloni
trile in a solvent to produce a solution which is
suitable for the production of commercially use
ful textile yarns or wrapping tissue ?lms, and
similar tough, ?exible structures.
The present application relates to a similarly
satisfactory dissolution of polyacrylonitrile in an
‘organic solvent taken from a different class of
organic compounds and the polyacrylonitrile
solutions produced thereby are similarly satis
factory for the production of tough, ?exible,
with which this invention is concerned. As pre
viously mentioned, polymers containing such high
percentages (at least 85% by weight) of acrylo
nitrile are especially desirable for use because
of their good physical properties and excellent
chemical resistance.
It has also been proposed (Rein U. S. Patent
No. 2,117,210) to dissolve polyacrylonitrile in mol
ten quaternary ammonium salts such as benzyl
pyridinum chloride, an ionizable salt. Although
the resulting solution can allegedlybe used to
form yarns or ?lms of polyacrylonitrile, the solu
dense, colorless yarns and ?lms which are suit
tion itself is dark red to brown in color, indicat
able for use in practically all general commercial 45 ing that some decomposition of the polyacryloni
applications of such products.
trile or some reaction between the polyacryloni
It has been known heretofore that concen
trile'and the molten salt ‘has probably taken
trated, aqueous solutions of inorganic salts such
place. 1 Such solutions are not satisfactory for
as lithium bromide, zinc chloride and sodium sul
the production of commercially useful, shaped
focyanide will dissolve polyacrylonitrile‘and it 50 articles of polyacrylonitrile. Here again, it has
has been proposed (Rein U. S. Patent No. 2,140,
been found practically impossible to obtain ?la
921). to employ the resulting ‘solutions in the
mentary structures such as yarns from the com
formation of yarns and ?lms. However, it has ' position. Films or ?laments, when obtainable,
been found substantially impossible to use the
are extremely brittle; they are highly colored
resulting compositions in such a manner. Their 55 and very weak, presumably because of the pres
material which will undergo hydrogen bonding
with the active hydrogen-bonding groups of the
polymer molecules and thus weaken the strong
hydrogen bond within the polymer molecules and
ence within them of residual quaternary am
monium salt. Removal of this salt is difficult
and the resulting structures contain numerous
and large voids that make the structures sub
stantially useless for commercial purposes.
It is therefore an object of this invention to
cause the hydrogen-bonding forces to be shared
between molecules. of the polymer and the sol
vent. In this manner, it is possible to form a
molecular dispersion of the polymer within the
dissolve polyacrylonitrile or a copolymer or in- "
terpolymer of acrylonitrile in which at least 85%
solvent and thus form a solution.
by weight of the polymer is acrylonitrile, in a
solvent whlich does not react with or decompose 0 _ However, the strength of the hydrogen-bond
ing capacity cannot be taken as the sole criterion
the polymer and which may be substantially
as to whether or not a compound will function
to dissolve an acrylonitrile polymer. It is also
necessary that, in order to function as a solvent
completely removed from the structures formed
of such a solution.
It is another object of this invention to pro
for an acrylonitrile polymer, the compound con
tain certain groups which will be capable of cat
isfactorily sharing a hydrogen bonding force
with the particular active group of the acrylo
trile polymer. In most instances, these groups
duce a solution of polyacrylonitrile or a copoly
mer or interpolymer of acrylonitrile in which at
least 85% by weight of the polymer is acryloni
trile, in a solvent which does {not react with or
decompose the polymer, the solution being suit-,
able for the formation of commercially useful, 20 require the presence of a hydrogen atom on a
carbon atom to which the group is attached (des
void free articles ofvpolyacrylonitrile, for exam
ignated as an alpha-hydrogen atom). Such
groups as require the alpha-hydrogen atom are
ineffective to impart solvent power if the alpha
ple yarns which are suitable as textile yarns and
?lms which are, suitable as wrapping tissue.
It is another object of this invention to pro
duce a solution of polya'crylonitrile, or a copoly 25 hydrogen atom is missing.
It has now been found that groups capable of
mer or interpolymer of acrylonitrile in which at
conferring solvent power include dimethyl car
trile, in a volatile organic solvent, which solution
is stable over'extended periods of time and is
eminently suited for use in the manufacture of 30'
least 85% by weight of the polymer is acryloni- . ‘
shaped articles such as' yarns, ?lms. tubes, straws,‘
arti?cial horsehair, bristles and ribbons, or when
highly concentrated, for use in the manufacture
of molded articles. '
I formyl imido
It is a still further object of thisinvention to 35
produce shaped articles and structures of poly
acrylonitrile, or copolymers or interpolymers of
cyano (45m, thiocyano (-s-o-Em and
acrylonitrile in which at least 85% by weight of
the polymer is acrylonitrile.
It is still another object of this invention to 40
produce a shaped article or structure of poly
acrylonitrile or copolymers or interpolymers of
acrylonitrile in which at least 85% by weight of
groups, provided however that the cyano, thiocyano
the polymer is acrylonitrile, for example a yarn,
?lm, tube, bristle or the like which is tough, ?ex 45 and sulfoxy groups require attachment (through
their respective unsatis?ed carbon and sulfur
ible, tenacious and free from voids.
valences) to a carbon, atom which is in turn at
Other objects of the invention will appear
tached to at least one hydrogen atom (alpha
hydrogen) in order to render them effective.
‘The objects of the invention may be accom
The dimethyl carbamyl and the formyl imido
plished in general by dissolving polyacrylonitrile,
or a copolymer or interpolymerof acrylonitrile in
which at least 85% by weight of the polymer is ,
acrylonitrile in di-substituted formamide of the ‘
type more speci?cally de?ned hereinafter.
If the solvent has a relatively low boiling point 55
(less than about 250° C.), the solution of poly
acrylonitrile may then be formed into‘ a shaped
structure, for example a yarn or film and the sol
groups are effective in the absence of the alpha
hydrogen atom. (It is possible that they con
tain the equivalent of an alpha-hydrogen atom
within their own structures.) Thus, the groups
dimethyl carbamyl
[ Cg:
vent removed from the shaped structure. ‘When
the solvent is relatively non-volatile and has a 60 formyl imido (HCON<) , cyanomethylene
boiling point of about 300° C. or more, shaped
articles may be made from the solution and at
thiocyanomethylene (>CHSCN) and’ sulfoxy
least a portion of the solvent may be retained
therein as a plasticizer for the articles.
and >CHSO2O—) shall hereinafter be referred to
as solvogenic groups and compounds containing
them are frequently capable of dissolving an
It has been recognized in recent years ‘that
under certain conditions, an atom of hydrogen
is attracted by rather strong forces to two atoms
instead of only one so that it may be considered
to be acting as a bond between them. This is
called the hydrogen bond.
acrylonitrile polymer containing at least 85% by
weight of acrylonitrile.
The di?lculty of dissolving polymers containingv
at least 85% by weight of acrylonitrile is due to
the presence within the molecules of strong hy
drogen-bonding forces and in order to dissolve
In the event that two or more groups requiring
the presence of an alpha-hydrogen atom in order
to render them soivogenic are attached to the
same carbon atom and compete with each other
for an available'alpha-hydrogen atom, the sul- .
one of these polymers, it is necessary to ?nd a 75 foxyogroup, the cyano group and the thiocyano
group take preference over each other in the order
Representative compounds coming within the
named to form the solvogenic group. the lower
ranking group or groups present assuming merely
the nature of an inert substituent on the carbon
scope of the above formula and suitable for use
as solvents for the above-mentioned acrylonitrile
polymers include:
It has furthermore been found that compounds
/ m
groups will be solvents for the above-mentioned
polymers only if the carbon content of the com
pound be within certain limits as given below. If 10
N'N'biswymm‘athyl) “mm”
the ratio of carbon to solvogenic groupings is
maintained within the said limits, the compounds
will retain solvent properties of the polymer even
though the molecule be of considerable size and
complexity._ 'Ifhe solvent power of the compound 15
for acrylomtrile polymers 15 increased if add1
N'Nmis (bemwmoethyl) Mmmide
tional solvogenic groups are present in the molec-
ular structure of the compound, the effect of
these groups being additive.
_ H
It has now been found that formamide (formyl 20
imido) derivatives which are fusible without de-
N_ b t
composition, preferably those having a melting
N 0-0111‘? I
th l_N_ ta th In"
( e Hyanoe yibmg?id-ee H
1 th I
We y)
point below ‘250° 0., in which both valences of
the N-atom of the amide are satis?ed by hydro-
carbon carbon atoms and which are embraced by 25
the following empirical formula will dissolve poly-
acrylonitrile and copolymers and mterpolymers
in which at least 85% by Weight of the polymer is
[o.(—lo~N/ ) ][0,(><|2~05N) ][C,(:/?-S—CEN) 10.x. o. N—g—N .
\CHa ,.
wherein X represents
omgmsmcmom (H
\OH—g—O—, \CH——g—O—. \oH-zL, or\CH—-g—/
No-omo ,
the free valance of the sulfoxy group being at- 40
tached also to carbon;
formamide cmcmomsoiomcm 0
t is an integer equal to or greater than 1;
m, q, u and w are integers equal to or greater than
m+q+u+w+t is equal to or greater than‘2;
n, p, r, v and k are mtegers
equal to or greater
than zero;
provided always that
k/t is equal to or less than 3;
omomsocmom 3
Nc-cmo 1
12/10 is equal to or less than 2;
N-<betamn°ethylggiggiggw WWW)
r/u is equal to or less than 0.5; Y
p/q is equal to or less than 1.5 and
n/m is equal to or less than 1.5.
These compounds are not salts but may be 55
cyclic or acyclic and may possess one or more
ethylenic or acetylenic linkages. Valences other
CEMHSO 0155015“ 0
cyano, thiocyano or sulfoxy groups; the total
thiocyano and sulfoxy groups not exceeding the
sum m+q+u+w+t. The respective tolerances of
(carbonyl or thiocarbonyl) or within the chain
sum m+l1+u+w+t and the number of cyano, 65
gen or sulfur atoms may appear in the compound as bivalent groups either as a side group
number of such halogen, oxygen, hydroxyl' and
are independent of each other and members of
both groups may be present in the molecule up 70
to their group tolerances. The substituent oxy-
_ _
N (bem_cym°ethy1)fo§m(:g§igmthylsumnylethyl)
than those contained. in carbon-to-carbon linkages and not shown as satis?ed in the above for
mula must be satis?ed by hydrogen, halogen, oxy- 60
gen or bivalent sulfur atoms or by hydroxyl, thiol,
thiol substituents not exceeding one half the
‘I? '
g "0"}!
above room temperature. Shaped structures and
articles can be produced, by extruding many of
iractory in which is embedded an electrical heat
such solutions into an evaporative or coagulativev
medium. By forming the structures in an evapo
rative medium, the solvent must be evaporated
therefrom and by forming the structures in a
ing coil I9. The spinning cell can thus be oper
ated at any desired temperature. A plurality of conduits 2| are provided adjacent the bottom of
the device for passing evaporative medium
through the cell so as to evaporate the solvent
from the extruded ?laments IS. The evaporative
medium is removed from the cell through outlet
coagulative medium, the solvent should be re
moved by selective solution in a non-solvent for
the polymer.
openings 23. The yarn comprising the plurality
The solutions are prepared by dissolving the 10 of ?laments I5 is passed from the bottom 01' the
polyacrylonitrile, or copolymer or interpolymer of
spinning cell around guide roller 25 and is wound
acrylonitrile with one or a mixture of the above
on a. bobbin 21.
mentioned solvents. Some of these solvents are
solid at ordinary temperatures and dissolve or re
Referring to Figure 2 of the drawing, the yarn
I5 is removed from the bobbin package 2‘! and
tain the polymer in clear solution only at elevated 15 passed about draw roller 29 and separating roller
temperatures, for example at temperatures of
3|. From draw roller 29, the yarn is passed to a
100° C. or higher, below which temperature-the
second draw roller 33 and separating roller 35.
composition resembles a gel. In all cases when
the polymer is dissolved in a solvent of the above
The yarn is passed around the two sets of draw
rollers including-their separating rollers a su?l
class, the resulting composition while hot has the 20 cient number of turns to prevent slippage of the
appearance of a true solution.
When cooled to
yarn. Draw roller 33 is- rotated at a greater
speed, for example three to ten times the speed .
of draw roller 29. In this manner, the yarn I5
room temperature, the composition generally
takes on the appearance of a gel, which gel may,
on standing, undergo syneresis.
Reheating of
is stretched between the two draw rollers.
this gel or syneresed mass however causes it to 25 the yarn passes between the two draw rollers, a
again return to solution form.
heating medium is brought into contact with the
In view of the relatively high melting points of
yarn through blower nozzles 31 and 39. The
some of the solvents of this invention, they would
yarn passing from the draw roller 33 is wound
have comparatively little use in the production of
on bobbin 4|. The drawingor stretching of the
a polyacrylonitrile spinning or casting solution. 80 spun yarn as described is not claimed as part of
‘Such solvents are, however, excellent solvent
the present invention, but is claimed in the co
plasticizers for polyacrylonitrile since they are
pending application of Daniel T. Meloon, Serial
soluble in a wide range of proportions with the
No. 496,397, ?led July 28, 1943.
said acrylonitrile polymers. The present inven
Figure 3 of the drawing illustrates a wet spin
tion therefore contemplates solid solutions of 85 ning apparatus for the production of yarn, The
acrylonitrile polymers containing at least 85% by
acrylonitrile polymer solution is passed through
weight of acrylonitrile as well as liquid solutions
conduit -5I and is extruded through spinneret 53
to form a multi?lament yarn 54. The yarn 54 is
Shaped articles obtained from solvent solutions
passed about guide roller 51 which is positioned
of polyacrylonitrile in accordance with the inven 40 within the coagulating liquid in tank 55. The
tion and from which. the solvent is subsequently
yarn is then passed about guide roller 59 and is
removed are substantially free of foreign matter
wound on bobbin 6|.
and voids and substantially undecomposed and
The organic solvent solution of polyacrylonitrile
chemically unchanged from the simple polymer
may be cast in the form of a ?lm as illustrated
prior to its solution.
in Figure 4. In accordance with this apparatus,
The above-described organic solvent solutions
the polymer solution is passed from hopper ‘H on
of acrylonitrile polymer may be shaped in the
to the endless steel band 13 where it is smoothed
form of ?laments, yarns, ?lms, tubes and like
by means of a doctor knife 15. The band, to
structures by apparatus and processes generally
gether with the ?lm, is passed under a means 11
known in the art, the detailed operating condi 50 for bringing a heated drying medium into con
tions being suitably modi?ed.
tact with the ?lm. The ?lm 8| is pulled from
Suitable methods and apparatus for the pro
the band 13 and collected on a mill roll 83..
duction of shaped articles of the polymers of this
The polyacrylonitrile for use with the invention
invention will be readily apparent by reference to
is preferably prepared by the ammonium persul
the following detailed description when taken in 55 fate catalyzed polymerization of monomeric
connection with the accompanying illustrations
acrylonitrile dissolved or emulsi?ed in water. It
,in which:
can, however, be prepared by any other suitable
Figure 1 is a diagrammatic vertical sectional
type of polymerization reaction such as, for ex
view showing a dry spinning cell suitable for use
ample, the emulsion type reaction disclosed by
in accordance with the invention;
‘ 60 U. 8. Patent No. 2,160,054 to Bauer et al. The
Figure 2 is a diagrammatic perspective view
polymer preferably possesses a molecular weight
showing a yarn drawing device for use in con
within the range of 15,000 to 250,000 or even high
nection with the invention:
er, as calculated from viscosity measurements by
Figure 3 is a diagrammatic perspective view
the Staudinger equation:
showing a wet spinning apparatus for use in the 65
Molecular weight=klyi%,
invention; and
Figure 4 is a diagrammatic side elevational view,
showing a suitable ?lm casting apparatus for use
in accordance with the invention.
K,,, = 1.5 X 10-4
Referring to Figure 1 of the drawing, reference 70 N,,,=speci?c viscosity= viscosity of solution. 1
viscosity of solvent
numeral H designates a spinneret through which
a plurality of ?laments l5 are formed by extrud
ing a ?lament-forming solution supplied to the
spinneret by means of conduit l3. The spinning
cell is jacketed with a material I‘! such as a re
Czconcentration of thesolution expressed as the
number of moles of the monomer (calculated) per
liter of solution.
The molecular weight of the polymer obtained
is dependent on such factors as the concentra
tion of the monomer in the water, the amount
and type of catalyst present, the temperature
of the reaction, etc. For example, polyacryloni
trile, having a molecular weight of approximately
60,000 can be prepared as follows: To 94 pounds
of distilled water heated to 40° 0. add 40 grams
of ammonium persulfate catalyst and 80 grams
of sodium ,bisul?te activator.
acrylonitrile of Example I were intimately mixed
with 25 parts of solid N,N'-diformyl piperazine '
and heated to a temperature of 170° 0., to form a
viscous, homogeneous mass or solution. Subse
quent cooling of this solution to room tempera
ture resulted in the formation of a gel-like mass
.of high viscosity which‘ could be molded to a
strong, tough, rod-like structure.
‘As indicated in the above examples, it is' pos
Then add 16 10 sible by the practice of this invention to obtain
pounds of acrylonitrile slowly with stirring over
a period of two hours. The polyacrylonitrile hav
a solution of polyacrylonitrile, or'a copolymer or
' in-terpolymer of acrylonitrile which iseminently
suited for use in the manufacture of shaped arti
ing the above said molecular weight will precipi- ‘
tate from the solution. Increasing or decreasing ' cles such as yarns, ?lms, or molded, articles.
the amount of the catalyst, while maintaining the 15 These solutions are also suited for use as lacquers
or coating compositions. ,They are ‘especially.
other conditions constant, decreases or increases
.useful in the coating of wire and electrical parts the molecular weight of the polymer. Acryloni
where the high chemical and electrical resistance
trile copolymers and interpolymers containing at
of the polymer is important.
least 85% by weight of acrylonitrile and likewise
preferably having .a molecular weight of 15,000 20 For the purpose of de?nition, a solvent is a ma
terial which, when in, the liquid state, is capable
to 250,000 or- higher'can be prepared in a similar
of forming solutions in which the polymer is
present in a concentration by weight of 5% or
The following examples in which parts, pro
more. In most instances, the polymer is soluble
portions and percentages are by weight unless
otherwise speci?ed illustrate preferred methods of 25 in almost all proportions although the miscibility
preparing solutions of polymers in accordance
with the principles of this invention and of em
ploying these solutions in the manufacture of
commercially satisfactory shaped articles of the
' may take place at elevatedktemperatures in the
case of certain compounds.
As also shown, the solvents of the invention are
useful not only in connection with polyacrylo
The invention is not to be limited by 30 nitrile, but also with copolymers and interpoly
mers of acrylonitrile and other polymerizable
the details set forth in the examples.
_ polymer.
Example I
Fifteen (15) parts of ,a polyacrylonitrile pre- '
substances such as, for example, compounds con
taining one or more ethylenic linkages including
vinyl and acrylic compounds as well as ole?nic
pared by the polymerization of monomeric acrylo 35 or diole?nic hydrocarbons such as isobutylene,
butadiene, etc. They are eminently satisfactory
nitrile in accordance with the teachings of U. S.
Patent No. 2,160,054 to Bauer et a1. and possess
ing an average molecular weight of 120,000 as
determined by the Staudinger equation from vis
cosity data are ground to an average particle size
of 200 mesh and mixed with_85 parts of N-beta
for use with’ those polymers that contain an ap
preciable amount of acrylonitrile, for example,
polymers, copolymers and interpolymers that
contain at least 85% by weight of acrylonitrile
and that have generally been regarded by the art
as being completely insoluble in all common or
ganic solvents. Nor are these solvents limited to
mixture being heated within a period of ?fteen
use with a polyacrylonitrile of any given molecu
minutes to a temperature of 150° C. to form a
clear, viscous solution which may be used at this 46 lar weight. They can be used with a polymer of
almost any given molecular weight and are espe
temperature for the casting of ?lms. If subse
. cially satisfactory for use with those polymers
quently cooled, the solution becomes more vis
having an average molecular weight within the
range 15,000 to 250,000 as determined by viscosity ‘
The solution was heated to a temperature of
data using the Staudinger equation and intended
175° 0., cast on to a surface heated to 175° C. and
for use in the manufacture of yarns or ?lms.
dried to form a thin, transparent film of acrylo
The solution of acrylonitrile polymer dissolved
nitrile polymer, the ?lm being tough, ?exible and
in an organic solvent in accordancev with this in
tear resistant. 7
vention must be of such a concentration that its
cyanoethyl-N-methyl formamide, the resulting
Example 11
65 viscosity at the operating temperature is within a
workable‘range. When it is to be employed in
Twenty (20) parts of a copolymer consisting of
the spinning of yarn or the casting of ?lm, the
90% of acrylonitrile and 10% of vinyl thiolace
solution should preferably have aviscosity within
tate prepared by the aqueous emulsion polymer
the range 25 to 750 poises. When the polymer
ization of acrylonitrileand vinyl thiolacetate in
has a molecular weight of 250,000 or more, this
the presence of 0.5% ammonium persulfate were
requires that the maximum concentration of
dissolved in 80 parts of N,N'-dimethyl-N,N'-di
polymer in the spinning solution be of the order
formyl tetramethylene diamine by warming.
of 10%. Generally, it is preferred that the spin
The resulting clear solution was extruded at a
ning solution contain at least 10% of the poly
temperature of 175° 0. into a bath-comprising
mer because of the di?iculty of rapidly removing
glycerol heated to 150° C. to form a 15-fllament
large amounts of solvent from the solution in
yarn having a total denier of 150. A bath travel
of 24 inches was employed, the yarn being sub
the spinning operation. , Moreover, it is economi
.jected to a tension of 0.7 gram per denier (based
cally undesirable to use such large amounts of
solvent for the spinning of a given amount of
on the ?nal yarn denier) during its travel through
the bath. The solvent was removed ,from the 70 polymer although it'is true that the solvent can
yarn by the glycerol, thereby coagulating the co
be completely recovered from the spinning opera
polymer. ,
tion and reused. For these reasons, it is pre
ferred to employ a polymer having an average
Example l1!
molecular weight of between 40,000 and 150,000'
Seventy-?ve ('75) parts of the powdered poly 76 since such a polymer ‘forms a solution of the de
sired viscosity in concentrations of the order of
the article without the application of heat, for
example by stretchingfat room temperature.
15% to 25% and at a desirable spinning tempera
ture of the order of 100° to 150° C.
01’ course,
In addition to acting as solvents for polyacrylo
nitrile, or copolymers of acrylonitrile, the ali
phatic or arylaliphatic nitrile compounds of this
invention, when present in small amounts, can,
also be used as plasticizing agents for the polymer
and the higher boiling compounds of the inven
it is within the scope of the invention to heat the
solution to a higher temperature, even to above
the normal boiling point of the solvent, for the
actual spinning operation. Here again, the con
trolling factor with regard to the temperature of
the spinning solution is the viscosity of the solu
tion are especially suited for such use. At the '
10 same time, it is, of course. to be understood that
The evaporative medium employed in the dry
non-solvent softeners, such as glycerol, can also
spinning of ?laments and yarns or the dry cast
be incorporated in the solutions of the invention,
ing of ?lms in accordance with this invention
may be any vapor inert to the ?lm- or ?lament
forming solution such as air, nitrogen, steam, etc.,
these materials remaining in the subsequently
or any suitable mixture thereof. The tempera
ture of the evaporative medium is dependent on
such factors as the dimensions of the spinning
cell, the composition and rate of extrusion of the
spinning solution and the rate of flow of the 20
evaporative medium. It is only'necessary that
these several factors be so correlated that the
yarn or other shaped article leaving the spinning
cell be su?iciently freed of the solvent so that it is
formed articlesto impart a softening effect. If it
is desired to use such plasticizing or softening
agents with polyacrylonitrile, they are preferably
added in the desired amount to an already formed
solution of the polymer in a lower boiling solvent,
for example to a solution of the polymer ‘in di
methyl formamide,
This invention is primarily concerned with the
steps or dissolving polyacrylonitrile in a suitable
solvent to form a stable solution adapted for use
in the manufacture of shaped articles of poly
25 acrylonitrile. It is characteristic of the invention
age form or otherwise collecte .
that the solutions provided by it are stable; the
As indicated in Example II above, shaped ar
solvents do not cause a decomposition or chemical
ticles of acrylonitrile polymer can also be formed
of the dissolved acrylonitrile polymer.
by extruding the spinning solution into a suitable
solidi?ed and capable of being wound into pack
precipitating bath comprising a liquid that is mis 30 At the same time, it is also characteristic that
the solvents provided by the invention are also
cible with the solvent but is a chemically inert
covers the use of glycerol and aqueous solutions
useful in the dissolving of mixtures of polyaerylo.
nitrile and adluvants such as dye modiriers, linear
polyamides such as nylon, derivatives of cellulose
including cellulose ethers and esters, polymers of
vinyl compounds such as vinyl chloride, vinyl ace
sate, acrylic acid, etc., which adjuvants may be
incorporated in the acrylonitrile polymer solution
of salts as baths, preferably at elevated tempera
tures, for the wet spinning of acrylonitrile poly
physical; of the resulting shaped articles.
non-solvent for the acrylonitrile polymer, iAS ex
amples of such a liquid maybe mentioned water,
glycerin, organic solvents such as alcohol, ether,
etc., or aqueous solutions of salts, alkalies or 35
acids, The copending application of William W.
Watkins, Serial No. 496,376, ?led‘ July 28, 1943,
mer yarn, from solutions of the polymer, prefer
ably with substantial tension and stretch being
to niodify the properties, both chemical ' and
This invention provides a class of solvents for
polyacryionitrile, andcopolymers and interpoly
applied during spinning.
mers of acrylonitrile which were heretofore con
The article of acrylonitrile polymer thus ob
sidered substantially insoluble. The solvents are
tained can advantageously be subjected to a 45 capable of forming with the polymer clear solu
stretching operation of the type employed in the
tions that are stable for extended periods of time
above examples. This stretching is preferably
and are admirably suited for use as lacquers or
performed by passing the yarn between two posi
coating compositions or in the manufacture of
tively driven rollers, the peripheral speeds of
shaped articles of the polymer, for example by
which are so adjusted that the article is stretched
50 extrusion into an evaporative or coagulative
from two to ten times its original length, prefer
medium, orby the use of a molding technique.
ably approximately six times its original length.
The invention also provides a class of materials
This stretching of the formed article may be per.
that is eminently suited for use in plasticizing
formed at any suitable time. However, in the
structures comprising the acrylonitrile polymers.
case of articles formed by the wet spinning or 55 The materials provided by this invention are ap
casting technique, it is preferably performed be
fore the article has been completely dried. The
orientation of the structure thus obtained im
parently true solvents for the above-mentioned
acrylonitrile polymers. They do not tend to
react with or decompose the polymer, the poly
proves the physical properties of the structure in
meric material obtained from the solution of this
cluding its tenacity, its resilience, etc.
00 invention apparently being the same identical
This stretching of the shaped article can also
chemical composition as the initial polymer.
be accomplished by causing the article, while
Yarns, ?lms and similar articles of polyacrylo
passing between stretching rollers, to contact a
nitrile prepared from the solutions of this inven-‘
heated stationary pin or to pass through an inert
tion can be stretched to yield oriented structures
medium such as air, water, glycerin, etc., heated
that possess a high tenacity, a desirable elonga
to a high temperature, Obviously, the article
tion and a high elastic recovery that compares
must not be exposed to this high temperature for
favorably with that of silk. The articles are not
a period su?'iciently long to decompose the poly
contaminated with undesirable salts and they are
mer. In general however, the time of contact of
substantially free of void spaces.
the article with the heated medium is so short 70
Reference throughout the speci?cation and
that temperatures up to 250° C. can be employed.
claims, to acrylonitrile polymers, polymers of
Although it is generally preferred to heat the ar
ticle to a temperature of at least 100° C. during
the‘st-retching operation, this is not essential.
Desirable results can be obtained by stretching
acrylonitrile, and co-polymers and interpolymers
of acrylonitrile "containing at least 85% by
weight of acrylonitrile" signifies polymers con
taining in their molecules at least 85% by weight
‘of the acrylonitrila unit which is considered to
be present in the polymer molecule as the group
0H;- E-0N
‘ 5. A new composition of matter -as de?ned in
claim 1, in which the polymer solution has a
viscosity within the range 25 to 750 poises.
8. As a new composition of matter, a polymer
that is. at least 85% by weight of the reactant 6 of acrylonitrile containing-in the polymer mole
material converted into and forming the polymer
cule atleast 85% by weight Of ecrylonitrile dis
is acrylonitrile.
solved in N-beta-cyanoethyl-N-methyl forma
Since it is obvious that many changes and
modi?cations can be made in the above described
7- A8 a new composition of ‘matter, a polymer
details without departing from the nature and 10 of acrylonitrile containing in the polymer mole
spirit of the invention, it is to be understood that
cule at least 85% by weight of‘jacrylonitrile and
the invention is notto be limited to the details
an organic compound embrwed by the formula;
‘ wherein it is a member of the class consisting of
. described herein except as ‘set forth in the ap
pended claims.
I claim:
1. As a new composition of matter, a polymer
CH- —0—,
_ 0
CH- —-O—', /(?n— -, and/OE- -
of acrylonitrile containing in the polymer mole
cule at least 85% by weight of acrylonitrile dis
the free valences of the's'ulfoxy group being at
solved in an organic compound embraced by the
25 tached also to carbon; both valences' of the ni
wherein X is a member of the class consisting‘ of
- 0
trogen atom of the formyl imido group are at
tached to hydrocarbon carbon atoms; t is an in
teger at least equal to 1; m. 11. u and w are in
- _'_
°H‘H"°_' PEA-0"’ (In-L’ “d cn'g
tegers at least equal to zero; m+q+u+w+t is at
.' 35 least/equal to 2; n, p, r, v and 7c are integers at
least equal to zero; k/t does not exceed 3; 12/10 '
the free valences of the sulioxy group being at
tached also to carbon; both valences ofthe vnitroge‘nv atom of the formyl imido group are at-
does not exceed 2;)‘lu does not exceed 0.5; p/q
does not exceed 1.5 and 11/111 does not exceed 1.5,
tached to hydrocarbon carbon atoms; t is an in- - all valenoes of said compound other than those
teger at leastequal to 1; m, q, u. and w are in- ‘0 contained in carbon-to-carbon linkages and not
tegers at least equal to zero; m+q+u+w+t is at
shown as satis?ed in the formula being satis?ed
least equal to 2; n. p. 1'. v and k are integers at
- by a substituent taken from the group consisting
least equal to zero; k/t does not exceed 3; 12/10‘
of hydrogen, halogen, Oxygen, bivalent sulfur,
does not exceed '2; 'r/u does not exceed 0.5; PM 45 hydroxyl; thiol, cyano. thiocyano. and sulfoxy;
does not exceed 1.5 and n/m does not exceed 1.5.
the total number 01 such halogen, oxygen, sulfur,
all valences of said‘compound other than those,
hydroxyl and thiol substituents not exceeding
contained in carbon-to-carbon linkages and not
‘one half m-i-q+u+w+t and the total number of
shown as satis?ed in the formula, being satis?ed
cyano, thiocyano and sulfoxy substituents not
by a substituent taken from the group consisting so exceeding m+q+u+w+t_
8. The composition of claim 1 in which the Q
of hydrogen, halogen, oxygen, bivalent sulfur,
hydroxyl, thiol,‘ cyano, thiocyano and sulfoxy;
solution contains at least 10% of said polymer
the total number of such halogen; oxygen, sul- ‘
of acrylonitrile.
~ fur, hydroxyl and thiol substituents not exceed9- The composition 01 claim 1 in which the
ing one half m+q+u+w+t and the total num- u polymer of acrylonitrlle is polyacrylonitrile hav
ber of cyano, thiocyano and sulfoxy substituents
ing a molecular weight between 15,000 and
not exceeding m+q+u+‘w+t.
2. A new composition of matter as de?ned in '
10. The composition of claim 1 in which the
claim 1, in which the polymer is polyacrylonitrile.
polymer of acrylonitrile is polyacrylonitrile hav
3. A new composition of matter as defined in so ing ‘a molecular weight between 40,000 and
claim 1, in which the polymer has a molecular
weight of between 15,000 and 250,000. _
11. The composition of claim 'U'in which the
4. A new composition of matter as de?ned inpolymer of acrylonitrile is polyacrylonitrile.
claim 1, in which the polymer has a. molecular
weight of- between 40,000 and 150,000.
- i
21 '
Patent No. 2,404,723.
Certi?cate of Correction
July 23, 1946.
, It is hereby certi?ed that errors appear in the printed s eci?cation of the above
numbered patent requiring correction as follows: Column 2, ine 41, for “pyridinum”
read ?yridinium; column 5, lines "32 to 34 and column 19, lines 27 to 29 inclusive,
right an(1 portion of the formula, for the last ?ve indistinct subletters read u, v, w, k
and t respectively; column 5, lines 30 to 32, right hand portion of the formula, for
column 7, line 56, for “aminoethyl)” read aminoethyl]; column 10, line 57, for
“CHQCHQCN” read 0H20H20N; column 20, line 17, in the formula, for the indistinct
subletter before the last double bracket read u; line 15 same formula, after “C”
between the last pair of brackets, for the indistinct subletter read 1); and that the ~
said Letters Patent should be read with these corrections therein that the same may
conform to the record of the case in the Patent O?ice.
Signed and sealed this 15th day of October, A. D. 1946.
First Assistant Commissioner of Pafc'nta.
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