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Патент USA US2404717

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July 23, 1946.
R. c. HouTz
Filed Nov. 4, 1944
Patented July 23, 1946
2,4„311 '
Bay Glyde Hauts, Snyder, N. Y., assigner to E. I.
du Pont de Nemours à 0cm
Del., a corporation of Delaware
Application November 4, 1944, Serial No. 562,015
15Claims. (Cl. 26o-32)
This invention relates to a new composition oi'
matter and shaped articles produced therefrom.
More particularly. this invention relates to an
organic solvent solution of polyacrylonitrile, i. e.
polymerlzed acrylonitrlle or polymerized vinyl
cyanide (CHFCHCN) s, and copolymers and in
terpolymers of acrylonitrile in which at least 85 %
by weight of the polymer is acrylonitrile, and to
the production of shaped articles from said or
ganic solvent solution of said polymers of acrylo
This application is a continuation-impart of
the copending application of Ray Clyde Houtz,
to employ the resulting solutions in the formation
of yarns and films. However. it has been found
substantially impossible to use the resulting com
positions in‘such a manner. Their extrusion into
coagulating baths of the type proposed (including
such non-solvents for acrylonltrile as water, di
lute acid, dilute salt solutions. etc.) result in the
formation of shaped articles that contain large
amounts of the inorganic salt of the proposed sol
10 vent. These salts are distributed throughout the
structure and destroy the continuity of the poly
acrylonitrile phase and the structure
poor physical properties. Removal of these salts.
when possible, results in the formation of a po
15 rous, spongy, weak, undesirable structure that is
very brittle and completely unsalted for use as a
yarn or nlm. Moreover, when it is attempted to
able substances, for example vinyl or acrylic com
form a multi-mament yarn by extruding, for ex
pounds, in which at least 85% by weight of the
ample the proposed aqueous sodium sulfocyanlde
Serial No. 447,446, ñled June l‘l', 1942.
Polyacrylonltrile and copolymers and inter
polymers of acrylonitrile with other polymeriz
polymer is acrylonitrile have been known for
some time and recognized as possessing desirable 20 polyacrylonitrile composition, into a dilute acid
bath, it is found that the individual filaments ob
physical and chemical properties including tough
tained stick together to form an essentially mono
ness and insoiubility in and insensitivity to com
ñlament structure that is extremely brittle and
mon organic solvents such as methyl or ethyl al
cannot be bent or worked without breaklns.
cohol, acetone. ethyl ether, ethyl acetate, hydro
U. S. Patent No. 2,167,537 to Tobls points out
carbon solvents, chlorinated hydrocarbons and 25 that
certain copolymers of acrylonitrile and an
the like. Because of these facts, numerous at
acrylic acid ester (those copolymers containing
tempts-have been made to form these polymeric
not more than 65% of acrylonitrile) are soluble
materials into yarns. iilms and other shaped
in mixtures of organic solvents such es dioxan,
monochlorbenzene, cyclohexanone, etc. How
The copending application of George H.
ever, thesc liquids are incapable of dissolving or
Latham, Serial No. 562,012, filed of even date
even swelling poiyacrylonltrile or copolymers of
herewith disclom solutions of polyacrylonitrlle
in dimethyl carbamyl compounds and the pro
duction of extruded and otherwise shaped articles
and structures from such solutions. The above
said application of George H. Latham represents
the first succesiul dissolution of polyacrylonitrile
acrylonitrile containing higher percentages of
aorylonitrile, i. e. acrylonitrlle polymers of the
type with which this invention is concerned. As
previously mentioned, polymers containing such
high percentages (at least 65% by weight) of
acrylonitrile are especially desirable for use be
of their good physical properties and ex
able for the production of commercially useful
chemical resistance.
textile yarns or wrapping tissue films and similar 40 cellent
It has also been proposed (Rein U. S. Patent
tough, nexible struc
No. 2,117,210) to dissolve polyacrylonitrile in
The present application relates to a similarly
molten Quaternary ammonium salts such as
satisfactory dissolution of polyacrylonitrile in an
benzyl pyridinium chloride, an ionisable salt.
organic solvent taken from a diiiîerent class of
the resulting solution can allegedly be
organic compounds and the polyacrylonitrlle so 45 Although
used to form yarns or iilms oi polyacrylonitrlle,
lutions produced thereby are similarly satisfac
the solution itself is dark red to brown in color.
tory for the production of tough, flexible, dense,
indicating that some decomposition of the poly
colorless yarns and mms which are suitable for
acrylonltrile or some reaction between the poly
use in practically all general commercial applica
acrylonitrile and the molten salt has probably
tions of such products.
taken piace. Such solutions are not satisfactory
It has been known heretofore that concentrated
the production of commercially useful, shaped
aqueous solutions of inorganic salts such as
in a solvent to produce a solution which is suit
articles of polyacrylonitrile. Here again, it has
lithium bromide, zinc chloride and sodium sulfo~
been found practically impossible to obtain lila
cyanide will dissolve polyacryionitrile and it has
mentary structures such as yarns from the com
been proposed (Bein U. B. Patent No. 2,140,921)
position` Hlms or illaments, when obtainable,
are extremely brittle: they are highly colored and
very weak.
because of the presence
within them of residual quaternary ammonium
salt. Removal of this salt is dlmcult and the re
sulting structures contain numerous and large
voids that make the structures substantially use
less for commercial 12111110688.
It is therefore an object of this invention to
to be acting as s bond between them. This is
called the hydrogen bond.
The dimculty of dissolving polymers contain
ing at least 85% by weight of acrylonitrile is due
to the presence within the polymer molecules oi'
strong hydrogen bonding forces. and in order to
dissolve one of these polymers, it is n
und. a material which will undergo hydrogen
dissolve polyacrylmitrile or a. copolymer or inter
bonding with the active hydrogen bonding groups
by weight oi' the polymer is acrylonitrile. in a
strong hydrogen bond within the polymer mole
lll of the polymer molecules and thus weaken the
polymer o1' acryionitrile in which at least 85%
cule and cause the hydrogen bonding forces to
shared between molecules of the polymer and
the polymer and which may be substantially ccm
solvent. In this manner. it is possible to form
pletely removed from the structures formed of 15 a molecular
dispersion of the polymer within the
solvent and thus form a solution.
It is another object of this invention to produce
However. the strength of the hydrogen bonding
a solution of polyacrylonitrile or a copolymer or
cannot be taken as the sole criterion as
lnterpolymer of acrylonitrile in which at least
solvent which does not react with or decompose
to whether or not a cœnpound will function to
85% by weight oi' the polymer is acrylonitrile, in 20 dissolve
an acrylonitriie polymer. It is also
that in order to function as s solvent
the polymer, the solution being suitable for the
for an acrylonitrile polymer, the compound con
formation of commercially useful, void free
tain certain groups which will be capable of satis~
articles of polyacrylonitrile. for example yarns
i'actorily sharing a hydrogen bonding force with
which are suitable as textile yarns and lllxns
the particular active group of the acrylonitriie
which are suitable as mapping tissue.
In most instances. theœ groups require
It is another object of this invention to pro
a solvent which does not react with or decompose
the presence of a hydrogen atom on a carbon
duce a solution of polyacrylonitrile or a copoly
atom to which the active group ls attached
(designated as an alpha-hydrogen atom). Buch
least 85% by weight ci’ the polymer is acrylont 30 active
groups as require the alpha-hydrogen atom
trile, in a volatile organic solvent. which solution
are ineilective to impart solvent power ii’ the
alpha-hydrogen atom is
eminently suited for use in the manufacture oi'
capable of
shaped articles such as yarns, mms, tubes, straws,
conferring solvent power include dimethyl
artificial horsehalr. bristles and ribbons. or when 35 carbamyl
highly concentrated, for use in the manufacture
oi molded articles.
It is a still further object of this invention to
produce shaped articles and structures ci’ poly
acrylonitrile or copolymers or interpolymers of
formyl imido
acrylonitrile in which at least 85% by weight of
the polymer is acrylonitrile.
It is still another object oi this invention to
produce a shaped article or structure oi' poly
acrylonitrile or copolymers or interpolymers of
ßyano (-CEN), thiocyano (-B-Cs) and sulf~
acrylonitrlie in which at least 85% by weight of_
the polymer is acrylonitrile, for example a yarn.
mer or interpolymer of acrylonltrile in which at
[CíaCiti` ]
nlm, tube, bristle or the like which is tough`
ilexible, tenacious and free from voids.
so, _i.,
i _E_o., _3-0.)
Other objects of the invention will appear 60
'I'he objects oi' the invention may be accom
groups. provided however that the cyano. thio
plished in general by dissolving polyacrylonitrile,
cyano and suli'oxy groups require attachment
or a copolymer or interpolymer oi' acrylonitrile in
(through their unsatisfied carbon and sulfur
which at least 85% by weight of the polymer is 65 valences) to a carbon atom which is in turn at
acrylonitrile in a compound containing a sulfoxy
tached to at least one hydrogen atom (alpha
methylene group (in which ‘v‘sulfoxy” is as donned
hydrogen) in order to render them eil'ective.
The dimethyl carbamyl and the formyl imido
in Patent Oillce Classiiication Bulletin 74, page
30) and which compound is not a sait, for ex
groups are eil'ective in the absence oi' the alpha
ample dimethyl nili'oxide.
60 hydrogen atom. (It is possible that they con
tain the equivalent oi' an alpha-hydrogen atom
Ii' the solvent has a relatively low boiling point
(less than about 250° C.) , the solution of acryloni
within their own structures.) Thus, the groups
dimethyl carbamyl
trile polymer may then be formed into a shaped
structure, for example a yarn or i‘ilm, and the
solvent removed from the shaped structure to 85
coagulate the saine.> When the solvent is rela
tively non-volatile and has a boiling point of
about 300° C. or more. shaped articles may be
iormyl lmido (HCON<), cyanomethylene
the solvent may be retained therein as a plasti
ciser for the articles.
under certain conditions. an atom of hydrogen is
attracted by rather strong forces to two atoms
(>CHCN), thiocyanomethylene (>CHSCN) and
>CHSOO--, and >CHSGa0-l shall hereinafter
be referred to as solvogenic groups and com
pounds containing them are frequently capable
of dissolving an acrylonitrile polymer containing
insteadofonlyone, sothatitmaybc considered 75 at least 85% by weight of acrylonitrlle.
In the event that two or more groups requir
ing the presence of an alpha-hydrogen atom in
order to render them solvogenic are attached to
the same carbon atom and compete with each
other for an available alpha-hydrogen atom, the
sulroxy group, the cyano group and the thio
cyano group take preference over each other in
the order named. to form the solvogenic group,
the lower ranking group or groups present assum
ing merely the nature of an inert substituent 10
groups should equal at least the total number of
any combination of said halogen, oxygen and bi
valent sulfur atoms and the hydroxyl and thiol
radicals, and the number of said non-solvogenic
cyano, thiocyano and sulfoxy substituents not
exceeding the value of m+¢1+u+w. - ¿The two
respective tolerances for the two said groups of
substituents are independent oi each other and
members of both groups may be present in the
molecule up to their group tolerances. The said
oxygen or sulfur substituents may be present as
bivalent groups either as a side group (carbonyl
It has furthermore been found that compounds
or thiocarbonyl) or within the chain (ether or
containing the above-mentioned solvogenic
thlûether), as the case may be. It is preferred
groups will be solvents for the above»mentioned
polymers only if the carbon content of the com 15 that the carbon atoms in the Ca, Cp, Cr and Co
portions ot the above formula be joined to each
pound be within certain limits, the limits for the
other, hut this is not essential.
compounds of the present invention being given
Representative compounds coming within the
below. If the ratio o! carbon to solvogenic
of the above formula and suitable for use
groupings is maintained within the said limits,
the compounds will retain solvent properties of 20 as solvents for the above mentioned acrylonitrlle
polymers include:
the polymer even though the molecule be of con
siderable size and complexity. The solvent power
of the compound for acrylonltrile polymers is
Methane dlsulíonic acid, dimethyl ester
on the carbon atom.
generally increased ii' more than one of the solvo
genio groups is present in the molecular structure 25
of the compound, the effect of these groups being
It has now been found that sulfoxy methylene
compounds which are fusible without decompo
sition and particularly those sulfoxy methylene 30
compounds embraced by the following empirical
formula and preferably having a melting point
below 250° C.. will dissolve polyacrylonitrile and
copolymers and interpolymers of acrylonìtrile in
which at least 85% by weight of the polymer is 35
Ethane-l,2«disulfonic acid. dlethyl ester
Ethane-Lz-disulfonic acid, dimethyl ester
Qfpropanone-l ,l.3-tri.sulfonlo scid, trimethyl ester
»prepararme-1 .3-disulionic acid. dimethyl estar
wherein X represents
the tree valence of the sulioxy group being also
attached to carbon: m, q and u are integers
equal to or greater than zero; w is an integer 50
equal to or greater than 1; n, p, r and v are in
tegers of such value than n/m is equal to or less
than 1.5; p/q is equal to or less than 1.5; r/u
is equal to or less than 0.5 and v/w is equal to or
less than 2.
The compounds are not salts but may be cyclic
or acyclìc in nature and may posses one or more
ethylenic or acetylenic linkages. Valences other
than those contained in carbon-to-carbon link
ages and not shown to be satisfied in the above 60
empirical formula must be satisfied by a. sub
stituent taken from the group consisting of hy
drogen, halogen, oxygen, bivalent sulfur atoms
or by hydroxyl, thiol, cyano, thiocyano. or sulf
oxy radicals, the total number of said halogen, 65
oxygen, bivalent sulfur. hydroxyl and thiol sub
stituents not exceeding the sum (m-l-q-i-u-l-w),
i. e. the number of
Chloromethane disullonlc acid, dimethyl ester
Diethyl ether-2,7»disulfonic acid, dimethyl ester
(C HiSOaCHsCHz):
Butane-1,4-dlsu1ionle acid, dimethyl ester
(CHxSOlCHs) ,S
Thlo~bis (methane suli'onlc acid), dimethyl ester
Propane-1,3-disullonic acid, dimethyl ester
2-propenol-1,3-dlsulionlc acid, dimethyl ester
C H38 O :C H |
Methyl methane sultonste
Methyl athens sulilnate
C Erg-O -C Ha C H»
Ethyl methane suliinate
Methyl methane sulilnate
Dlmethyl sultano
oms olomomon
Bete-hydmxyethyl methyl lullen»
nnmumznylàuuonykmyl) »um
(CHICHJE 01h03;
Bistethyllullenyl) methane
1,1-bls (methylmllonyl) ethme
Lbbtsßthylsulionyl) ethme
L12-trl: (ethyllulfonyl) preme
C IHS 0101110»
'l‘rla(ethylsul1'ony1) methane
Bis(ethy1sullonyl) ehloromethme
( C B18001011;
Bla(methykn1lonyl) methane
801C Hl
2«thlooyenoethmemllente acid, methyl Itter
2-cyanoethsneeulfonle wld, methyl ester
S 0x0 IH»
l-bromo-Z-cylnoethnnesulfonle acid, methyl ester
l-methylsulfonyl-l-ethyl sullonyl athene
ßvyunoethanesullonic acid, ethyl esta:
Bln(methylsulfonylmethyl-sullonylmethyl) Iuliano
C He
2,2-bis(methylsulfonyl) butano
(C3010 (BOQCHm
2,2~bll(methylm1funyl) propina
Sultonyl bis(methanemlfonic wld), dimethyl ester
i C :H53 0x C Hl) l
1,2;bie(ethylsn1!onyl) ethane
2-(methylaulfonyl)ethnne-su1fon1c scid. ethyl alter
2-(methylsulñnyhethane-eulfonle acid, ethyl ester
8~(N.N-dimethylearbamyl)~l-prepeuasulfonte wld.
methyl ester
C Haß 0x C HxC Hl
1,2-bls(methylsul!onyl) ethane
Bulllnyl bll(methlneeu1fonio mld), dimethyl eater
I-(ethykulllnybethaneeullonle ecld, ethyl ester
CHnC (SOaCnHßhC (S 0|CxHùaC Ha
2,2.3,3-teh'akis(ethylsnltnnyl) butano
Methyl ethyl sullene
C HIIC H (S OsCxHl) |11
1,1.3,3»tetmkls (ethylsulfnnyl) propane
2-(ethyllul1onyDethanesultonlu mld, ethyl alter
l,1-hls(methyl.sul!onyl) propme
Bls(methylsul£onylmethyl) sullen»
(CaHaSOaC H018 Oa
ßlsœthylsulfonylmethyl) sullone
2-bromo-2-eymœthanesullfonic mld, ethyl eater
` calsmcmcomonm
(N,N-dlmethylearhamyl) methane-saliente wld.
methyl ester
CgBgSOxCHaC 0N (C El) s
(NN-dimethylœrbamyl) methane-summe acid.
ethyl eater
L15-ble (methylaulIonyD-Z-propmene
(N,N-dlmethylcarbnmyh meth ena-eulfnnlc uid.
l,2-hla(methyleulllnyl) ethnne
1,2-bls (ethylsumnyl) ethnne
n~propyl ester
(N,N-dimethyleerbamyl) methaneeulfonio ecld.
isopropyl ester
C ( C H150 C En) l
(C'H‘SO) ¿B80101111
Tetnkmmethylsumnylmethyl) methane
1-(ethyllh1nnylj-1-(ethyl-eulfonyl) ethm
Methyl ethyl sulroxlde
(01h80) :CH:
Blsûnethylsulßnyl) methane
( C RnB 0 )1C H Cl
Blumethylsulßnyl) ehlorometham
( CHahS 0
Dimethyl lulloxide
1-(methylaul?nyD-l-(methyl eulronyl) athene
\ /
omsoom‘cmdnc omen.)
'ir-(Betl’thlocynnosthylmlßnyl) butyronitrlte
C 5x60 CE1 BON
Alpllrthlooyam-beta-(mothylml?nyl) >proplmiltrlle
yhhmmmnpropylsullinyl) butyronitrile
omcmsoiomdnc Gluem).
-y-(N, -dlmothylearbanglllr’llethylsulfonylybutyronl
N ,N-dlmethylalpha-cyano-y-me thylsulionyl
Trlmethylene sulfoxlde
Hr- 0
Alpha eyanomethyl trlmethylene sull’one
2-|slplls-eyano-beta(N,N-dimethyl-cerbamyl) ethylsulflnyl]
ethanesullonio acid. ethyl ester
2-I -cysn‘owfN N-dlmethyl-carbnmyl) propylsulllnyll
ethânœulronm acid, ethyl @sur
Trlmethylene sulfone
lla-'cyano-bete-m N-dlmethylearbamyl) ethyl-enlfonyl]
ethanes'ulíonic acid, ethyl ester
Z-ITeyann-‘ym N-dlmethylœrbamyl) propylsulíonyl]
eth’anesulfonic acid, ethyl ester
In lieu ot the sterile groups, such as CN for
example, in certain of the above typical com
pounds, other groups in the sterile state may be
included in the molecule, e. g, SCN, sulfoxy, etc..
provided that the tolerance limits are observed
as explained above.
All of these compounds are misclble in a wide
range of proportions with polyacrylonitrile, and
copolymers and interpolymers o! acrylonltrile and
they do not appear to react with or decompose
them. Many of the compounds are also miscible
with (soluble in) such non-solvent liquids for the
polymeric materials as water, aqueous -salt solu
tions, alcohol, glycerol, etc. Solutions or an
acrylonitrile polymer ln many of the compounds
of this invention can therefore be extruded into
such liquids to form shaped articles such as yarns.
ñlms, etc. of the polymer with the solvent being
removed by selective solution in the liquid coagu
lant. Moreover, because many of the compounds
of the invention are volatile (vaporlzable without
decomposition at atmospheric pressure and at
temperatures not exceeding 250° CJ, solutions
of the polymer in such compounds are eminently
2-1 tlzl' moq-(MN-dlmetbyl-carbsmyl)propylsulßuyll
ethnneeull‘onlcacid, ethyl ester
ano-elphn-(N,Ndlmeth learbamyll propyl
:âï?nyll ethanesullonlc acidy, ethyl ester
suited for use in a dry spinning or casting process
for the preparation of a yarn or ñlm of the
For the purpose of definition, a solvent is a ma
terial which, when in the liquid state. is capable
of forming solutions in which the polymer is pres
ent in a concentration of 5% or more.
In most
70 instances, the solvent and polymer are misclble in
almost all proportions although the mlsclbility
may take place at elevated temperatures in the
case of certain compounds.
The solutions of the invention are prepared
by dissolving the polyacrylonitrile. or copolymer
or interpollrmer o! acrylonitrile with one or more
oi the compounds ot this invention. Some oi’
these compounds exist in the solid state at ordi
nary temperatures and dissolve or retain the
of filaments Il is passed from the bottom of the
spinning cell around lulde roller Il and is wound
on a bobbin 21.
Referring to Figure 2 of the drawing. the yarn
It is removed from the bobbin package 21 and
passed about draw roller 2l, and separating
roller l i. From draw roller 20, the yarn is passed
to a second draw roller Il and separating roller
il. The yarn is passed laround the two sets of
draw rollers including their separating rollers a
sum :lent number o! turns to prevent slippage ci
polymer in clear solution only at elevated tem
peratures, for example at temperatures oi' 100°
C, or higher, below which temperature the com
position takes on the appearance oi a gel. Even
in such a case however. there is usually no sub
stantial evidence of immediate separation oi' the
gel into two phases although after standing (i. e.
sometimes after a period of several weeks), the
the ya "n. Draw roller 3l is rotated at a greater
gels may undergo syneresis. This phenomenon of
speed, :or example three to ten times the speed
gel formation or syneresis is reversible however
draw roller 2l. In this manner, the yarn I8
and subsequent heating oi the gelled or syneresed 15 or
is stretched between the two draw rollers. As
mass causes it to revert to solution form.
the yarn passes between the two draw rollers, a
In view of the relatively high melting points of
heating medium is brought into contact with the
some of the solvents oi' this invention, they would
yarn through blower nozzles 31 and 3l. The yarn
have comparatively little use in the production of
passing from the draw roller 33 is wound on bob
an acrylonitrile polymer spinning or casting soin 20 bin
4|. The drawing or stretching oi the spun
tion. Such solvents are. however. excellent sol
yarn as described is not claimed as part oi the
vent plasticizers for acrylonitrile polymers since
present invention, but is claimed in the copend
they are soluble in a wide range of proportions
ing application of Daniel T. Meloon. Serial No.
with the said polymers. The present invention,
496,397, filed July 28, 1943.
therefore, contemplates solid solutions of acrylo 25 Figure 3 of the drawing illustrates a wet spin
nitrile polymers containing atleast 85% by weight
ning apparatus for the production of yarn. The
or acrylonitrile as well as liquid solutions thereof,
acrylonitrile polymer solution is passed through
Shaped articles obtained from solvent solutions
conduit ll and is extruded through spinneret Il
of acrylonitrile polymer prepared in accordance
to form a multii’ilament yarn II. The yarn 54 is
with the invention and from which the solvent is 30 passed about guide roller l1 which is positioned
subsequently removed are substantially free of
within the coagulating liquid in tank ll. The
foreign matter and voids alter removal oi' the sol
yarn is then passed about guide roller 59 and is
vents and the acrylonitrile polymer remains sub
wound on bobbin 0I.
stantially undecomposed and chemically un
The organic solvent solution of the acrylonitrile
changed irom the original acrylonitrlle polymer
35 polymer may be cast in the form of a iilm as
prior to its solution.
illustrated in Figure 4. In accordance with this
The above described organic solvent solutions
apparatus, the polymer solution is passed from
,of acrylonitrile polymer may be shaped in the
hopper 1| on to the endless steel band 13 where
form of filaments, yarns. nlms. tubes and like
it is smoothed by means o! a doctor knife 1B. The
structures by apparatus and processes generally 40 band, together with the illm, is passed under
known in the art, the detailed operating condi
a means 11 for bringing a heated drying medium
tions being suitably modined.
into contact with the nlm. The ñlm BI is pulled
Suitable methods and apparatus for the pro
from the band 1l and collected on a mill roll 8l.
duction of shaped articles oi' the polymers of this
The polyacrylonitrile for use with the inven
invention will be readily apparent by reference to 46 tion is preferably prepared by the ammonium
the following detailed description when taken in
persulfate catalyzed polymerization of mono
connection with the accompanying illustrations
meric acrylonitrile dissolved or emulsined in
in which:
water. It can, however, be prepared by any other
Figure l is a diagrammatic vertical sectional
suitable type oi' polymerization reaction, such as.
view showing a dry spinning cell suitable for use
for example. the emulsion type reaction disclosed
in accordance with the invention;
by U. S. 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 ci 15,000 to 250,000 or even
nection with the invention;
higher, as calculated from viscosity measure
Figure 3 is a diagrammatic perspective view
ments by the Staudinger equation:
showing a wet spinning apparatus for use in the
invention; and
Molecular weight- Ilfv‘ë
Figure 4 is a diagrammatic side elevational
view showing a suitable iilm casting apparatus for
use in accordance with the invention.
Referring to Figure l of the drawing, reference
numeral il designates a spinneret through which
a plurality oi’ filaments I5 are formed by extrud
ing a filament-forming solution supplied to the
spinneret by means oi' conduit il. The spinning
œil is _iacketed with a material i1 such as a re
i‘ractory in which is embedded an electrical heat
ing coil I9. The spinning cell can thus be oper
Bviscoslty of solution_
viscosity of solvent l
=concentration of the solution expressed as the
number of moles of the monomer (calculated) per
liter of solution.
The molecular weight of the polymer obtained is
ated at any desired temperature. A plurality of
dependent on such factors as the concentration
conduits 2l are provided adjacent the bottom of 70 of the monomer in the water,' the amount and
type of catalyst present, the temperature of the
the device for passing evaporative medium
through the cell so as to evaporate the solvent
reaction, ete. For example, polyacrylonitrile
having a molecular weight of approximately
from the extruded filaments il. The evaporative
medium is removed from the cell through outlet
60,000 can be prepared as follows: To 94 pounds
openings 23. 'I‘he yarn comprising the plurality
of distilled water heated to 40° C. add 40 grams oi
of two hours. The polyacrylonltrile having the
above said molecular weight will precipitate from
the solution.
(based on the final yarn denier) during its travel
through the bath. The dimethyl sulfone was
removed from the yarn by the glycerol, thereby
coagulating the copolymer. The yarn, which
I ammonium persulfate catalyst and B0 grams of
sodium bisultlte activator. Then add 16 pounds
of acrylonitriie slowly lwith stirring over a period
possessed a tenacity of 4.0 grams per denier and
an elongation of 12%, was colorless and lustrous
in appearance. It accepted acid and basic dyes
Increasing or decreasing the
amount oi’ the catalyst, while maintaining the
other conditions constant, decreases or increases
Example III
Seventy-iive (75) parts of the powdered poly
the molecular weight of the polymer. Acrylo
nltrile copolymers containing at least 85% by
weight Aof acrylonitrile and likewise preferably
possessing a molecular weight oi’ 15,000 to 250.000
acrylonitrile of Example I were intimately mixed
with 25 parts of solid bis(beta methylsulfonyl
ethyllether and heated to a temperature of 170°
or higher can be prepared in a similar manner.
The following examples in which parts, pro
C. to form a viscous, homogeneous mass or solu
portions and percentages are by Weight unless 16 tion.
Subsequent cooling of this solution to room .
otherwise specified illustrate preferred methods
temperature resulted in the formation of a gel
of preparing solutions in accordance with the
like mass oi’ high viscosity which could be molded
principles ot this invention and oi’ employing
to a strong, tough, rod-like structure.
these solutions in the manufacture of commer
solution of acrylonitrile polymer dissolved
cially satisfactory shaped articles of the polymer. 20 in The
an organic solvent in accordance with this
The invention is not to be limited by the details
invention must be of such a concentration that
set forth in the examples.
its viscosity at the operating temperature is
Example I
within a workable range. When it is to be em
Fifteen (15) parts of a polyacryionitrile pre
pared by the polymerization of monomeric
acrylonitrile in accordance with the teachings
ployed in the spinning of yarn or the casting of
nlm, the solution should preferably have a vis
cosity within the range of 25 to 750 poises. When
the polymer has a molecular weight of 250,000
of U. S. Patent No. 2,160,054 to Bauer et al. and
or more, this requires that the maximum con
possessing an average molecular weight of
120,000 as determined by the Staudinger equation 30 centration oi“ polymer in the spinning solution
be of the order oi 10%. Generally, it is pre
from viscosity data are ground to an average
ferred that the spinning solution contain at least
particle size of 200 mesh and mixed with 85 parts
10% of the polymer because of the difficulty of
oi dimethyl sulfoxlde, the resulting mixture being
rapidly removing large amounts of solvent from
heated Within a period of fifteen minutes to a
the solution in the spinning operation. More
temperature of 90° C. to form a clear solution over, it is economically undesirable to use such
possessing a viscosity oi 100 poises at this tem
large amounts of solvent for the spinning of a
perature. If subsequently cooled, the solution
given amount of polymer although it is true that
becomes more viscous.
the solvent can be completely recovered from the
The solution was heated to a temperature oi
spinning operation and reused. For these rea
90° C., cast on to a surface heated to 90° C. and
sons, it is preferred to employ a polymer having
dried to form a thin, transparent film of acrylo
an average molecular weight of between 40.000
nitriie polymer, the film being tough, flexible and
and 150.000 since such a polymer forms a solution
tear resistant. The iilm of acrylonitrile polymer
of the desired viscosity in concentrations of the
remaining on the plate is then removed from the
plate to yield a strong, transparent sheet of ap 45 order of 15% to 25%, and at a desirable spinning
temperature of the order of 100° to 150° C. 0i
proximately 0.001 inch in thickness. YThe sheet,
course, it is within the scope of the invention to
in addition to being flexible and resistant to tear
heat the solution to a higher temperature, even
ing, is insensitive to the common volatile organic
to above the normal boiling point of the solvent,
solvents. It is substantially impervious to oils,
hydrocarbons and common organic substances. 50 for the actual spinning operation. Here again,
the controlling factor with regard to the tem
It is approximately sixteen times as impervious
perature of the spinning solution is the viscosity
to the transmission therethrough ci’ moisture
of the solution.
vapor as a sheet of regenerated cellulose of the
The evaporative medium employed in the dry
same thickness. In addition, the sheet possesses
spinning of filaments and yarns or the dry cast
a brilliant clearness that makes it especially de
ing of illms in accordance with this invention
sirable for commercial use. The film can, ii' de~
sired, be stretched longitudinally and transversely
may be any vapor inert to the fllm- or filament
forming solution such as air, nitrogen, steam,
to improve its strength in these directions. It is
etc., or any suitable mixture thereof. The tem
characteristic of this stretched nlm that it does
not shrink greatly when subjected to elevated co perature of the evaporative medium is dependent
on such factors as the dimensions of the spinning
temperatures. For example, such a iilm, when
cell, the composition and rate of extrusion of
subjected to a temperature of 175° C.. will shrink
the spinning solution and the rate of ñow of the
approximately 10%.
Example II
evaporative medium. It is only necessary that
Twenty (20) parts of a copolymer consisting 65 these several factors be so correlated that the
yarn or other shaped article leaving the spinning
of 90% acrylonitrile and 10% vinyl thiolacetate
cell be sufilciently freed of the solvent so that
prepared by the aqueous emulsion polymerization
is solidified and capable of being wound into
of acrylonitrile and vinyl thiolacetate were dis
form or otherwise collected.
solved in 80 parts ci dimethyl sulfone by warm
As indicated in Example II above, shaped arti
lng. The resulting clear solution was extruded 70
cles of acrylonitrile polymer can also be formed
Vat a temperature of 115° C. into a bath compris
by extruding the spinning solution into a suitable
ing glycerol heated to 115° C. to form a lñ-iila
precipitating bath comprising a liquid that is
ment yarn having a total denier of 150. A bath
miscible with the solvent but is a chemically
@travel oi' 24 inches was employed, the yarn being
>subiected to a tension of 0.7 gram per denier 75 inert non-solvent for the acrylonitrile polymer.
As examples of such a liquid may be mentioned
water, glycerin, organic solvents, such as alcohol,
ether, etc.. or aqueous solutions of salts, alkalies
or acids. The co-pending application of William
W. Watkins. Serial No. 496.376, tiled July 2B,
1943, covers the use of glycerol and aqueous solu
tions of salts'as baths, preferably at elevated
temperatures, for the wet spinning of acrylo
nitrile polymer yarn, from solutions of the poly
mer, preferably with substantial tension and
stretch being applied during spinning.
The length of travel of the shaped article
through the precipitating or coagulating liquid
is not critical to the invention. provided only that
it be suiliciently long to solidify the acrylonitrile
polymer. When the precipitating bath is water.
the bath travel may be as short as l/g inch, or it
may be lll or more inches in length. When the
precipitating liquid is an aqueous salt solution
such as a 20% solution of calcium chloride, the
solidiiìcation of the acrylonitrile polymer struc
ture is generally more gradual than in the case
of water so that it is necessary to use a somewhat
longer bath travel than with water. If desired,
softening agents with poiyacrylonitrlle. 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 o! the
polymer in dimethyl suli'oxide.
Although the discussion thus far has been di
rected mainly toward the manufacture of yarns
and illms of acrylonitrile polymer, the solutions
provided by the invention and the evaporative
and wet spinning processes described above are
equally well adapted for' use in the manufacture
of other shaped articles of acrylonitrile polymer
such as arti?cial horsehair, straws, bristles, tubes,
bands and ribbons. For example, the solutions
may be extruded through a suitable die and into
a heated atmosphere or precipitating bath to
form a tubular structure. or they may be extruded
in any other desired manner. Moreover. because
the solvents of the invention are miscible in a
20 wide range of proportions with acrylonitrile poly
mer, the powdered polymers may be treated with
' small amounts of the solvent to yield a substance
suitable for use in the formation of molded arti
cles. This is a particularly important result in
suitable means such as guide rods or rollers may 26 asmuch as it has heretofore been difiicult to use
be placed in the bath to tension the yarn or other
shaped article during its formation.
The article of acrylonitrile polymer thus ob`
this material in molding operations. In this
same manner. a plurality of sheets of acrylo
nitrile polymer may be treated with small amounts
tained can advantageously be subjected to a
oi' solvents and Dressed together to form lami
stretching operation of the type employed in the 30 nated articles. When present in the shaped ar
above examples. This stretching is preferably
performed by passing the yarn between two posi
tively driven rollers, the peripheral speeds of
which are so adjusted that the article is stretched
ticle, the solvents of this invention (particularly
those of high boiling point) are excellent plas
Of course, the shaped articles may also
be treated with non-solvent softening agents. for
to from two to ten times its original length. pref 85 example glycerol. These plasticizing and soften
erably approximately six times its original length.
ing agents may be incorporated in the solution
This stretching of the formed article may be
performed at any suitable time. However, in the
case of articles formed by the wet spinning or
casting technique. it is preferably performed be
fore the article has been completely dried. The
orientation of the structure thus obtained greatly
improved the physical properties of the structure
including its tenacity, its resilience, etc.
of this invention or they may be applied to the
shaped article as an after-treatment; or they
may be added to the acrylonitrile polymer by a
milling operation wherein the agents and poly
mers are worked between rotating rollers until
a mass of the desired consistency is obtained.
This invention is primarily concerned with the
steps oi' dissolving acrylonitrile polymers in a
This stretching of the shaped arti le can also 45 suitable solvent to form a stable solution adapted
be accomplished by causing the article, while
for use in the manufacture of shaped articles.
passing between stretching rollers, to contact a
It is characteristic of the invention that the solu
heated stationary pin, or to pass through an inert
tions provided by it are stable; the solvents do
medium such as air, water, glycerin, etc., heated
not cause a decomposition or chemical alteration
to a high temperature. Obviously, the- article 50 of the dissolved acrylonitrile polymer. At the
must not be exposed to this high temperature
same time, it is also characteristic that the sol
for a period sufficiently long to decompose the
vents provided by the invention are also useful
polymer. In general however, the time of con
in the dissolving of mixtures of acrylonitrile poly
tact of the article with the heated medium is so
mer and adjuvants such as dye modifiers, linear
short that temperatures up to 250° C. can be 65 polyamides such as nylon, derivatives of cellulose
employed. Although it is generally preferred to
including cellulose ethers and esters, polymers of
vinyl compounds such as vinyl chloride, vinyl
C. during the stretching operation, this is not
acetate, acrylic acid, etc., which adjuvants may be
essential. Desirable results can be obtained by
incorporated in the acrylonitrile polymer solution
stretching the article without the application of 60 to modify the properties. both chemical and phys
heat, for example by stretching at room tem
ical, of the resulting shaped articles.
Although this invention has been described
In addition to acting as solvents for polyacrylo
with particular regard to polyacrylonitrile, i. e.
nitrile. or copolymers or interpolymers of acrylo
polymerized vinyl cyanide. the solvents and proc
nitrile, the sulfur-containing compounds of this 85 esses of this invention are equally useful in form
invention, when present in small amounts, can
ing clear, stable solutions oi’ such acrylonitrile
also be used as plasticizing agents for the polymer
copolymers and interpolymers as were considered
and the higher boiling compounds of the inven
heretofore to be insoluble in volatile organic sol
heat the article to a temperature of ` at least 100°
tion are especially suited for such use. At the
vents, i. e. acrylonitrile copolymers and inter
same time, it is, of course, to be understood that 70 polymers containing at least 85% by weight of
non-solvent softeners such as glycerol, etc., can
acrylonitrile; such solutions can be used in the
also be incorporated in the solutions of this in
same way and for the same purposes as described
vention. these materials remaining in the subse
herein with respect to polyacrlyonitrile. It is
quently formed articles to impart a softening
therefore considered to be within the scope of
eiîect. If it is desired to use such plasticizing or 75 this invention to dissolve in the above mentioned
solvents copolymers and inter-polymers in which
acrylonitrile is copolymerized or interpolymer
ized with polymerizable substances such as, for
example, compounds containing one or more
ethylenic linkages, e. g. vinyl acetate, vinyl chlo
ride, acrylic acid and its esters and homologues,
styrene, isobutylene and butadiene, as well as
other vinyl and acrylic compounds, other oleñnic
stance, acrylonitrile polymer-_articles produced
in accordance with the principles of this inven
tion find many important uses. While yarns
made from these polymers are capable of use
wherever yarns have previously been used with
more or less advantage. there are certain fields
where the properties of the polymer especially
commend them. For example, the high tenacity,
flexibility and resilience of the yarns of the in
or diolefinic hydrocarbons, etc. and polymers of
such substances. 'I‘he solvents of the present in 10 vention make them suitable for use in the manu
facture of hosiery and other articles oi' clothing
vention will also be useful as new solvents for
while the resistance to soiling and ease of clean
acrylonitrile polymers which have less than 85%
ing (common cleaning agents may be used on
«by weight of acrylonitrile and especially those
them without danger) make them desirable for
having an average molecular weight of 15,000
to 250,000 as determined by viscosity data using 15 use in flat fabrics and either as multiiilament
the Staudinger equation and intended particu
larly for use in the manufacture of yarns and
The invention also provides a class of mate
rials that is eminently suited for use in plasticiz 20
ing structures comprising the acrylonitrile poly
mers. The materials provided by this invention
are apparently true solvents for the above men
tioned acrylonitrile polymers. They do not tend
to react with or decompose the polymer, the
polymeric material obtained from the solution
oi' this invention apparently being of the same
identical chemical composition as the initial
polymer. Thus, the solvents and solutions of
acrylonitrile polymer provided by this invention Y
when used in relatively small amounts are cap
able oi’ softening and moistening solid particles
of polymers of acrylonitrile having at least 85%
by weight of acrylonitrile, whereby it is possible
to form molded articles of acrylonitrile polymer.
Such a process is especially adapted to the for
mation of laminated structures from films of
polyacrylonitrile, or even from ñlms of other
or monofilament yarns in the manufacture of
pile fabrics including velvets, plushes. upholstery
or carpeting. The yarns can be advantageously
used as either the pile and/or backing of such
fabrics. At the same time, their low water ab
sorption, high resistance to mold and bacteria
growth and pronounced resistance to ultra-Y
violet light make the yarns highly suited for use
in outdoor fabrics such as tents, awnings, tar
paulins, flags, sails and the like. These same
factors, taken together with the low density of
the yarn (specific gravity of 1.16 as compared
with 1.52 for cellulose), also permit the yarns
to Vbe manufactured into clothing and other
articles for use in tropical climates where light
weight, flexible fabrics that resist the action of
weather, direct sunlight and mold growth are
Other uses based on these same and
related properties include the manufacture of the
yarns into fishing lines, fish nets, cordage es
pecially for marine purposes, bathing suits, um
brellas and the like. It is, of course, to be
understood that the yarns of the invention can
be employed in these uses in the form of either
The invention provides practical methods for 40 continuous ñlaments or as staple fibers of any
given length. They can be formed into novelty
preparing shaped articles of polymers of acrylo
yarns with other fibers, both natural and syn
nitrile having at least 85% by weight of acrylo
thetic in character, and because of their high
nitrile, which articles are characterized by de
resilience, the staple fibers of the invention. par
sirable physical and chemical properties. For
example, the articles are resistant to the action 45 ticularly when crimped, are highly suited for
admixture with wool.
of water and the common organic solvents.
Still other uses, particularly for mcnofilamen
They are not ail'ected by prolonged contact with
tary structures of the polymer, include the manu
relatively concentrated solutions of sulfuric acid,
facture of rattan-like fabric for furniture, bristles
or other mineral acid, nor are they ail’ected by
dry cleaning solvents. etc. They diiîer from 50 and window screening wherein the light weight,
low water absorption and high resistance of the
articles of other polymerized vinyl compounds.
polymer to ultra-violet light, sulfur fumes and
such as polymerized vinyl chloride, in that they
salt air are important attributes. Moreover, the
do not shrink greatly when heated to high tem
high flexibility and durability of such structures
peratures. They possess a desirable high di
electric strength and are not harmed by pro
longed exposure to ultraviolet light. They are
also very 'resistant to the action of mold and
enable screens made oi' them to be rolled up when
not in use. thus permitting their incorporation
as an integral part of the window structure.
As previously mentioned, the acrylonitrile poly
mers with which this invention is concerned are
Yarns, films and similar articles oi polyacryla
nitrile prepared from the solutions of this inven 60 highly resistant to the action of acids and most
other chemical reagents including oils, greases
tion can be stretched to yield oriented structures
and the like and this fact, taken together with
that possess a high tenacity, a desirable elonga
their high softening point and controlled shrink
tion, and a high elastic recovery that compares
age, makes yarns of the polymer highly useful
favorably with that oi' silk. The articles are not
in industrial applications including such uses as
contaminated with undesirable salts and they are
filter cloths, covers for rayon spinning bobbins
substantially free of void spaces. The films,
and cakes, clothing for workers in areas where
tubings and similarly shaped articles are ap
acids and other corrosive fumes are present and
proximately sixteen times as impervious to the
the like. Still another important use, dependent
transmission of moisture vapor as are films,
mainly on its .resistance to acids, comprises the
tubings, etc. of regenerated cellulose of the same
manufacture of the yarn or other shaped articles
thickness. They are substantially impervious to
of the polymer including films and tubings into
oils and hydrocarbons including aviation gaso
separators or other protective parts for
storage batteries, particularly of the heavy duty
Because of these several unique properties
which may be combined here in a single sub 75 im.
bacteria growth.
The above uses are primarily concerned with f
yarns (either multi?lamentary or monoillamen
tary in character) of the polymer. However, it
group consisting oi’ hydrogen, halogen. oxygen,
bivalent sulfur, hydroxyl, thiol. cyano, thiocyano
and sulioxy; the total number 0I said halogen,
will be understood that the same desirable prop
oxygen, sulfur, hydroxyl and thiol substituents
erties (also present in other shaped articles of s not exceeding the sum im-l-q-l-u-i-w) and the4
the polymer such as film, tubing and the like)
make these other articles useful in similar appli
cations such as the protection of objects from the
eiiects of moisture. common organic solvents and
number oi cyano, thiocyano and suli'oxy groups
not exceeding the sum (m+q+u+w).
2. As a new composition oi' matter, a polymer
oi acrylonitrile containing in the polymer mole
chemical reagents and as containers or tubing for lu cule at least 85% by weight of acrylonitrlle dis
the packaging or transport o! liquids including
solved in a solvent comprising an organic sulfoxy
corrosive liquids, oils, greases and the like. More
compound, said compound embraced by the tor
over, because of their clarity and brilliance. illms
o! an acrylonitrile polymer prepared in accord
wherein X represents a member oi’ the class con
ance with this invention also ?nd an important 2o sisting of
use in the decorative art.
The solutions prepared in accordance with the
present‘invention are also suited tor use as lac
quers or coating compositions and are especially
suitable for use in the coating of wire and elec- 25 the free valence oi the suli'oxy group being also
trical parts where the high chemical and electrical
attached to carbon; m, q and u are integers at
resistance oi’ the polymer is important.
least equal to zero; w is an integer at least equal
Reference, throughout the specification and
to 1; 1i. P, r and v are integers of such value
claims, to acrylonitrile polymers, polymers oi.'
that n/m does not exceed 1.5; p/q does not exceed
acrylonitrile, and copolymers `and interpolymers 30 1.5; r/u does not exceed 0.5 and v/w does not
oi acrylonitrile “containing atleast 85% by weight
exceed 2; all valences of said compound other
of acrylonitrile" sigrilñes polymers containing in
than those contained in carbon-to-carbon link
their molecules at least 85% by weight'oi the
ages and not shown as satisñed in the formula
acrylonitrile unit which is considered to be pres- s being satisfied by a substituent taken from the
ent in the polymer molecule as the group
5 group consisting of hydrogen. halogen, Olufsen.
bivalent sulfur, hydroxyl, thiol, cyano, thiocyano
and sulfoxy: the total number of said halogen,
that is. at least 85% by weight oi' the reactant
oxygen, sulfur, hydroxyl and thiol substituents not
material converted into and forming the polymer
exceeding the sum fm-l-q-i-u-l-w) and the number
is acrylonitrile.
Since it is obvious that many changes and modl
iications can be made in the above described
of cyano. thiocyane and sulfoxy groups not ex
ceeding the sum (m-i-q-l-iH-w).
3. A new composition of matter as deñned in
details without departing from the nature and i
claim 2 in which the polymer iii polyacrylonitrile.
spirit of the invention. it is to be understood that
4. A new composition oi matter as defined in
the invention is not to be limited to the details ‘5 claim 2 in which the polymer has a molecular
described herein except as set forth in the ap
weight ot between 15.000 and 250,000.
pended claims.
5. A new composition of matter as deiined in
I claim:
claim 2 in which the polymer has a molecular
l. As a new composition of matter, a polymer
weight of between 40,000 and 150,000.
oi acrylonitrile containing in the polymer molecule 5o
6. A new composition of matter as defined in
at least 85% by weight of acrylonitrile and a
claim 2 in which the polymer solution has a vis
cosity within the range 25 to 750 poises.
compound embraced by the formula:
wherein Xrepresents a. member ci' the class oon- o»
sisting of ‘
\ CHS(Il
the free valence o! the suli'oxy group being also
attached to carbon; m, q and u. are integers at
least equal to zero; i w is an integer at least equal
to l; n, p, r and v are integers oi' such value that
7. As a new composition ot matter, a polymer
o! acrylonitrile containing in the polymer mole
cule at least 85% by weight of acrylonitrile dis
solved in dimethyl suli'oxide.
8. As a new composition of matter, a polymer
65 oi' acrylonitrile containing in the polymer mole
cule at least 85% by weight of acrylonitrile dis
solved in beta hydroxyethylmethyl sulfone.
9. As a new composition of matter, a polymer
of acryionitrile containing in the polymer mole
u/m does not exceed 1.5; p/q does not exceed 70 cule at least 85% by weight of acrylonitrile dis
1.5; r/u. does not exceed 0.5 and v/w does not
solved in dimethyl suli‘one,
exceed 2; all valences oi’ said compound other
10. The composition ot claim 2 in which the
than those contained in carbon-to-carbon link
solution contains at least 10% of said Polymer of
ases and not shown as satisiled in the formula
being satisiied by a substituent taken trom the 7l 11. The composition o! claim 2 in which the
polymer is polyacrylonitriie having a molecular
weight ot between 15,000 and 250,000.
14. The composition oi claim 0 in which the
polymer is poiyacryionitrile.
12. The composition of claim 2 in which the
i5. The composition oi claim 9 in which the
polymer is poiyacrylonitrile having a molecular
weight o! between 40,000 and 150,000.
13. The composition of claim ‘7 in which the
polymer is polyacrylonitrile.
Certificate of Correction
Patent No. 2,404,717.
July 23,1946.
It is hereby certiñed that errors appear in the rinted specification of the above
numbered patent requiring correction es follows: Co umn 4, line 46, for “(-S-C EY’
read (-S- CEN) ; column 11, lines 4 and 5, strike out the formula and insert instead
the following--
column 20, line 73, for “polyacrlyonitrile” read polyacrylonitrüe; 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 Office.
Signed and sealed this 15th day of October, A. D. 1946.
First Assistant Commissioner of Patents.
polymer is polyacrylonitriie having a molecular
weight ot between 15,000 and 250,000.
14. The composition oi claim 0 in which the
polymer is poiyacryionitrile.
12. The composition of claim 2 in which the
i5. The composition oi claim 9 in which the
polymer is poiyacrylonitrile having a molecular
weight o! between 40,000 and 150,000.
13. The composition of claim ‘7 in which the
polymer is polyacrylonitrile.
Certificate of Correction
Patent No. 2,404,717.
July 23,1946.
It is hereby certiñed that errors appear in the rinted specification of the above
numbered patent requiring correction es follows: Co umn 4, line 46, for “(-S-C EY’
read (-S- CEN) ; column 11, lines 4 and 5, strike out the formula and insert instead
the following--
column 20, line 73, for “polyacrlyonitrile” read polyacrylonitrüe; 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 Office.
Signed and sealed this 15th day of October, A. D. 1946.
First Assistant Commissioner of Patents.
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