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Патент USA US3032394

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United States atenr
1
3,032,384
PRODUCTION OF FTLAMENTARY MATERIAL
Jesse L. Riley, New Providence, N.J., and Charles E.
Kip, Chillicothe, Ohio, assignors to Celanese Corpora~
tion of America, New York, N.Y., a corporation of
Delaware
Filed Jan. 28, 1958, Ser. No. 711,647
17 Claims. (Cl. 18—54)
3,032,384
Patented May 1, 1962
may have boiling points below the “solution tempera
tures” of the polyole?ne, i.e. below the temperatures at
which the polyole?ne forms homogeneous solutions in
said solvents; these temperatures are all below the melt
ing point of the polyole?ne. Thus cyclohexane, which is
the preferred solvent for straight chain polyethylene, boils
at 80° C. and dissolves a straight chain polyethylene (of
MP. of about 140° C.) at a temperature of about 110°
C. N-octane and its isomers are also suitable solvents.
This application is a continuation-in-part of our earlier 10 Other solvents are methyl cyclohexane, toluene, xylene,
hi-?ash naphtha, tetrachloroethane and mixtures of any
of the solvents mentioned.
19, 1956, and now abandoned, the entire disclosure of
copending application Serial No. 617,024, ?led October
The solution being spun is relatively'viscous. Thus, in
which is hereby incorporated by reference.
the case of straight chain polyethylene of 50,000 molecu
This invention relates to the production of ?lamentary
material from polyole?ne resins, particularly from poly 15 lar weight (as determined by intrinsic viscosity measure
ments) a solution of about 20 to 25% concentration has
ole?ne resins having melting points above 130° C.
proved satisfactory. The viscosity of such solutions at
Polyole?ne resins having melting points above 130° C.
the spinning temperature is in the range of about 500 to
diifer from conventional polyole?ne resins in several im
portant respects.
Their molecular structures are more
5,000 poises (on Brook?eld synchroelectric viscometer).
The step of concentrating the relatively dilute solution
ordered and they show a greater crystallinity than the 20
obtained by polymerization may be carried out conveni
lower melting point polyole?ne resins. Thus in the case
ently by a ?ashing process in which the solution, under a
of polyethylene, the resins of high melting point have a
superatmospheric pressure and at a temperature above its
high degree of crystallinity, above 90% (as determined
atmospheric boiling point (e.g. above 120° C. in the case
by the method of Nielsen, Journal of Applied Physics,
vol. 25, pages 1210 and 1211, October 1954) and a high 25 of cyclohexane solutions) is fed into a zone of lower
superatmospheric pressure (e.g. 20-50 p.s.i.g.) and a por
density, generally above 0.955. They also have higher
tion of the solvent evaporated, preferably while the solu
impact strengths and greater tensile strengths than the
tion is agitated. In this manner a 2 to 10% polyole?ne
conventional polyethylene resins. One method for the
solution obtained in the polymerization process described
production of such straight chain polyole?ne resins is dis
closed in Belgian Patent 530,617 of January 24, 1955, 30 above may be brought easily to. the desired concentration.
wherein an ole?ne dissolved in a low-boiling hydrocarbon
solvent is brought into contact with a solid polymeriza
tion catalyst such as chromium oxide supported on silica
and alumina.
Other high melting polyole?ne resins include isotactic
polypropylene; isotactic poly-4-methyl pentene-l; iso
tactic poly-3-methyl butene-l; isotactic polymer of 4,4
dimethyl pentene-l; isotactic polyvinylcyclohexane; and
isotactic polystyrene.
In one convenient spinning arrangement, the concen
trated polyole?ne solution is maintained, under superat
mospheric pressure and at a temperature which is above
the atmospheric boiling point of the solvent and which is
35 at least as high as the “solution temperature” of the solu
tion, in a suitable pressure vessel which acts as a reser
voir. The hot solution is discharged continuously from
the reservoir, under the autogenous pressure of the hot
solvent, into a valved pipe or other conduit connected to‘
It is an object of this invention to produce ?bers of 40 the components of a conventional dry spinning apparatus
superior properties from polyole?ne resins having melting
(e.g. a metering pump. a suitable ?lter such as a candle
points above 130° C. and particularly from straight chain
?lter, and a spinning jet), all of which are maintained
at an elevated temperature sut?cient to keep the resin in
polyethylene resins.
'
Another object of this invention is the production, of
solution at all times (e.g. a temperature of 140 to 170° C.
?bers of polyole?ne resins from solutions thereof in low 45 for straight chain polyethylene). Preferably, the tem-.
perature in the reservoir is somewhat higher than that in
boiling solvents.
subsequent parts of the system, so that the pressure in
Still another object of this invention is the Production
of ?bers from solutions obtained on polymerization of
said reservoir is higher, said higher pressure tending to
ethylene, the ?bers being formed by a process in which
force the solution out of the reservoir into the spinning
the polymer is kept in liquid phase, without intermediate 50 lines. For example, the reservoir temperature may be
separation of the polymer from its solution prior to
150 to 170° C. while the balance of the system may be 'at
spinning.
140° C. for straight chain polyethylene.
"
Other objects of this invention will be apparent from
The spinning jet may be of the conventional type carry
the following detailed description and claims. In this de
ing therein a suitable jet ?lter. The ori?ces in the spin
scription and claims all proportions are by weight unless
ning jet should be of such dimensions that at the desired
rate of extrusion the pressure drop through the ori?ces is
otherwise indicated.
One important aspect of this invention involves the
in excess of the vapor pressure of the solution at the
polymerization of the ole?ne in relatively dilute solution
spinning temperature so that the pressure inside the jet is
in a low-boiling solvent, using a solid polymerization cata
maintained above said vapor pressure. Ori?ces whose
lyst. ‘After the removal of catalyst particles, the solution 60 diameters are about 30 to 60 microns and whose lengths
of high melting ole?ne polymer thus obtained is con
are one to two times their diameters have been found
centrated, as by evaporation of the solvent. The result
satisfactory at spinning rates of 0.1 to 1.5 cc. of solution
ing solution is maintained under superatmospheric pres;
per ori?ce per minute.
sure and at an elevated temperature, above the atmos
The spinning jet may be situated in a spinning cabinet
or spinning cell having provision for the admission of
pheric boiling point of the solvent, and is forced throughv
one or more ori?ces in a spinning jet at such a rate that
the pressure on the high pressure side of the jet is in ex
cess of the vapor pressure of the solution at said elevated
temperature (plus the pressure of any dissolved gas) even
heated air or other evaporative medium and for the ex
haust, into a suitable recovery system, of the evaporative
medium carrying the solvent released during the spinning
process. For ease of operation, the pressure in the spin
though the pressure on the discharge side of the jet is 70 ning cell should be about atmospheric. The evaporative
medium may be introduced so as to flow through the spin
substantially atmospheric.
The solvents employed in the practice of this invention
ning cell in the same direction as, or countercurrent to,
3,082,384
3
4
the ?laments being formed and it may be fed in at spaced
ning temperature and, ‘of course, in excess of the. tem-.
points along the path of the ?laments through the spin
ning cell. As the ?laments pass through the spinning cell
perature at which the resin dissolves in said solvent. Suit
able solvents for the purpose are, depending on the spin
the solvent in the outer surfaces of said ?laments vaporizes
ning temperature, for example, xylene, cumene, B-methyl
naphthalene, Z-methyl thiophene, chlorobenzene, decahy
dronaphthalene, tetrahydronaphthalene, dicyclohexyl, 1
decene, mineral oil, and para?‘in oil. The ori?ces in the
very rapidly so that the concentration of polymer in said
outer surfaces rises, while the temperature of said outer
surfaces falls due to evaporation. Thus there is formed
spinningjet are blocked by any suitable obstruction, such
about each ?lament a hard sheath of polymer surround
as a resilient gasket forced against the outer surface of
ing a superheated liquid core. The entire ?lament solidi
?es as it proceeds further through the evaporative at 10 the jet, until the system has attained the temperature de
sired for the spinning operation. Thereafter the res
mosphere in the spinning cell.
ervoir containing the spinning solution, comprising the
High melting polyole?ne resins have a strong tendency
resin in the low-boiling solvent, is connected to the spin
to crystallize and it is found that ?laments of best prop
ning lines, the spinning pump is started, and the obstruc
erties are obtained when the conditions of spinning are
such as to favor super-cooling of the solution of resin 15 tion to the spinning jet is partially removed so that the
high-boiling solvent is permitted to ooze out of the spin
and thus to delay crystallization thereof. Thus, the solu
ning jet. When substantially all of the high boiling sol
tion being spun should be well-?ltered and should be free
vent has been forced out of the spinning lines and the
of crystallite nuclei, and the rate at which solvent is lost
resin solution has begun to pass out of the spinning jet, the
during the process should be rapid in comparison to the
rate at which the polymer starts to crystallize. For ex 20 spinning pressure increases abruptly and the obstruction
is then removed entirely and spinning is commenced.
ample, when straight chain polyethylene resin is used,
In an alternative method for starting the spinning op
the solution should preferably be maintained at above the
eration, the high-boiling solvent'is replaced by the same
melting point of the straight chain polyethylene resin
low-boiling solvent as is present in the resin solution.
prior to and during spinning so as to insure that no crys
tallite nuclei are for-med, and-the temperature of the 25 The spinning lines are ?rst ?lled with this low-boiling
solvent, while cold, after which the spinning system is
evaporative medium into which the solution is spun should
sealed and then heated to the desired spinning tempera
preferably be maintained at as high a level as is possible
ture, which is, of course, above the boiling point of the
(e.g. 1l5—140° C.) without causing actual boiling of the
low-‘boiling solvent. The obstruction to the spinning jet
solution being spun. For example, when the solvent is
cyclohexane it is desirable that the air in the immediate 30 is then partially removed and the solvent is forced gradu
vicinity of the spinning jet be maintained at a tempera
ally out of said jet, and spinning commenced, all in a
ture of about 130 to 140° C. The actual temperature
of the ?laments being extruded is of course much less
manner similar to that described above in connection
with the use of high-boiling solvent.
One suitable spinning arrangement is illustrated sche
ing from evaporation of solvent.
35 matically in the accompanying drawing, in which refer
ence number 11 designates a polymerization zone, to
As the ?laments emerge from the spinning cell they are
than these temperatures, due to the cooling e?ect result
taken up in any suitable manner. Thus, the several ?la
ments my be brought together to form a multi?lament
which solid catalyst, solvent and ole?ne are supplied con
yarn which is wound on a bobbin or other yarn package
leaves the zone 11 and is fed to a catalyst-separation zone
tinuously. A mixture of polymer solution and catalyst
support. Generally the linear speed at which the ?la 40 12, from which ‘the polymer solution passes to a concen
ments are taken up is somewhat higher than the linear
tration zone 13. The resulting concentrated polymer
speed of extrusion so that some stretching of the ?la
solution then enters a reservoir 14, from which it passes
ments takes place during spinning. A suitable range of
through a metering pump 16, which may be a suitable
ratios of take up speed to extrusion speed is 1.01:1 to 3:1.
gear pump, then through a candle ?lter 17 and a spinning
The resulting ?laments. generally have relatively low
jet 18, from which it emerges in the form of a plurality
of ?laments into a heated spinning cabinet 19. Heated
tenacities and high extensibilities, e.g. tenacities of 0.4 to
0.6 gram per denier and extensibilities of 1200 to 2500%
air is passed through the spinning cabinet, the air being
for straight chain polyethylene. By drawing the ?laments,
introduced, in the embodiment shown in the drawing, at
either hot or cold, ?laments of very high tenacity are ob
the bottom of the spinning cabinet and being withdrawn
tained, e.g. 7 grams per denier or higher for straight chain
together with solvent vapors from the top of the cabinet.
polyethylene. If cold-drawing is used the rate of draw 50 The ?laments are brought together to ‘form a yarn, which
ing is generally lower, to avoid breakage of the ?laments.
is drawn from the cabinet by a driven roll 21 and taken
The drawn ?laments are very highly oriented as shown
by their X-ray di?ractions patterns, and their extensibility
up on a ring twister indicated generally at 22.
The following examples are given to illustrate this in
is relatively low. The extent of drawing, i.e. the draw
vention further.
ratio, may be varied over a wide range, depending on the 55
Example 1
properties desired; for example,vthe ?laments may be
A stream of ethylene is passed into a mixture of_cyclo
drawn 200% to 2000%.
hexane
and chromium oxide catalyst, supported on silica
It has been found that freshly spun yarn may be drawn
alumina, in the manner described in Belgian Patent 530,
at a much‘ more rapid rate than yarn which has been
aged for some time. If desired the freshly spun yarn 60 617. The resulting mixture of catalyst and solution of
straight chain polyethylene resin is ?ltered hot to remove
may be drawn without any intermediate step of winding
the catalyst and the solution is passed into an agitated
the yarn into .a package. For this purpose the yarn leav
?asher, operated under a superatmospheric pressure of
ing the ‘spinning cell may be passed directly to a ?rst draw
25 pounds per square inch gauge and a temperature of
roll and then to a second draw roll operating at a much 65 150° C. or above, where a portion of the solvent is
higher speed and thereafter wound on a bobbin or other
evaporated OE and the concentration of the polyethylene
yarn package support.
The'yarn produced has a high luster, is inert to water
and to most common chemicals, and is resistant to ver
resin in the solution is raised, from its initial value of 5%‘,
up to 23%. The resulting hot concentrated solution is
passed into a reservoir maintained at ‘a temperature of
min. It shows excellent impact strength.
70 170° C. and then, through a gear pump and candle ?lter,
One aspect of this invention relates to starting up the
to a spinning jet, all of which are maintained at a tem
perature of 145 ° C. The pressure of the solution in the
spinning operation.v To this end, prior to spinning, the
jet is 360 p.s.i.g. The jet has 13 ori?ces each 0.56 mm.
spinning lines, including the pumps, ?lters and spinning
in diameter and .0015" long, and the solution is pumped
jet are ?lled with a hot high-boiling solvent for the resin,
which‘ solvent has a :boiling point in excess of the spin 75 through these ori?ces at a rate of 4.68 cc. of said solution
3,032,384,
5
per minute, into a spinning cabinet supplied with air at
a temperature of 133° C. The resulting ?laments are
brought together to form a yarn, which is passed at
speed of 9.5 meters per minute, over a driven rotating
roll, this speed being so related to the speed of extru
sion that the drawndown of the ?laments in the cabinet
is about 5%. The yarn is then wound and given a twist
of 0.2 turn per inch on a ring twister. The yarn thus ob
tained has a total denier of 85, 7.3 denier per ?l, a te
6
and 128° C. at the bottom, the resulting S-?lament 190
denier yarn being taken up at the rate of 48 meters per
minute.
-'
>
The term “melting point” as used herein refers to the
temperature at which a powdered sample of the resin,
placed on a melting point block, begins to lose its prop
erty of birefringence; at the same time the sample begins
to become clear and lose its cry'stallinity. This tempera
ture is generally below that at which a ?uid melt is
_
nacity of 0.5 gram per denier,'and an elongation at break 10 obtained.
It is understood that the foregoing detailed description
of 1500% determined at a strain rate of 50% per minute.
is given merely by way of illustration and that many vari
The freshly spun yarn is then drawn 770% over a hot
ations may 'be made therein Without departing from the
metal shoe at a temperature of 95° C. The drawn yarn
spirit of our invention.
has a denier of 0.95 per ?l, a tenacity of 7.3 grams per
Having described our invention what we desire to se
15
denier, and an elongation at break of 10.4%.
Example 2
23 parts of isotactic poly-4-methyl pentene-l, having a
melting point of 230° C. and an intrinsic viscosity of 2.5
cure by Letters Patent is:
>
1. Process for the production of ?lamentary materials
which comprises extruding through a spinning ori?ce a
solution of a highly crystalline polyole?ne resin having a
measured in tetrahydronaphthalene at 130° C., and pre 20 melting point above 130° C., in a volatile solvent having
an atmospheric boiling point below the melting point of
pared in known manner by polymerization of 4-methyl
said polyole?ne resin and evaporating ‘said volatile sol
pentene-l in the presence of aluminum triiso‘butyl and ti
vent from said extruded solution without the boiling
tanium tetrachloride, is dissolved in 100 parts of xylene
thereof, said solution which is extruded being maintained
by tumbling a mixture of the polymer and xylene for 20
hours at a temperature of 170° C. The solution, in a 25 at a temperature above the atmospheric boiling point of
closed container under nitrogen at superatmospheric pres
said solvent.
2. Process for the production of ?lamentary materials
sure, is extruded, through a spinnerette having 1 hole
which comprises extruding through a spinning ori?ce a.
0.096 mm. in diameter, vertically upward into the sur
solution in a volatile solvent of a highly crystalline poly
rounding atmosphere, where the xylene evaporates, to
form a ?lament which is taken up on a driven pulley. 30 ole?ne resin having a melting point above 130° C. and
evaporating said volatile solvent from said extruded solu
The following results were obtained under the conditions
tion without the boiling thereof, the solution being ex
indicated below:
truded being maintained at a temperature above the solu
tion temperature of said polymer in said solvent and
TemperElonga 35 above the atmospheric boiling point of the solvent.
Extru- ature of Take Denier Modu- Tenac- tion of
Filament
sion
Solution
up
pressure,
and
speed,
p.s.i.g.
100
50
100
60
100
of
Fila-
lus of
?la-
ity of
?la-
Spinner- mJmin. ment
ette,° O.
ment,
gJd.
ment,
at
g./d. break,
175
180
193
195
185
8. 5
5. 0
8. 0
13.0
15. 0
12
16
25
10
11
17
15
13
17
16
?la
mcnt
gJd.
0. 82
0. 46
0. 40
0. 54
0.
38
130
151
115
95
3. Process as set forth in claim 2 in which the rate of
extrusion is such that the pressure drop through the spin
ning ori?ce is in excess of the vapor pressure of the solu
tion at the spinning temperature.
4. Process as set forth in claim 2- in which the resin
40
is a straight chain polymer of ethylene and the solution
being extruded is maintained at a temperature of at least
the melting point of said straight chain polyethylene.
5. Process as set forth in claim 2 in which the resin
45 is a straight chain polymer of ethylene and the solvent
The above ?laments were then drawn by stretching them
between two sets of rollers running at different speeds,
the ?laments passing over a heated shoe located between
the two sets of rolls.
The following results were ob
is cyclohexane and the solution ‘being extruded is main
tained at a temperature of about 140 to 170° C.
6. Process as set forth in claim 5 in which said extru
sion temperature is at least as high as the melting point of
tained at the temperature indicated below, the extent of 50 said straight chain polyethylene.
7. Process for the production of ?lamentary materials
drawing being varied to give the ?lament deniers set
which
comprises polymerizing an ole?n in a volatile sol
forth below:
vent in the presence of a highly crystalline polymerization
catalyst to form a solution of a polyole?n resin having a
Filament
Shoe
Denier of
Elonga
Tempera- Drawn Modulus, Tenacity, tion at
ture, ° 0. Filament g./d.
gJd.
break,
percent
150
135
150
155
155
125
3. 9
3. 5
5. 1
4. 6
3. 5
3. 7
26
25
24
27
29
26
2. 2
2. 4
2. 5
2. 6
2. 7
1. 8
22
25
25
24
23
24
55 melting point above 130° C. and above the solution tem
perature of said polyole?ne resin in said solvent, concen
trating said solution by removing a portion of said solvent,
extruding said solution through a spinning ori?ce of a
spinning jet while maintaining said solution at a temper
60 ature above said solution temperature and above the
atmospheric boiling point of said solvent, said solvent
having an atmospheric boiling point below the melting
point of said polyole?ne resin and evaporating said vola_
tile solvent from said extruded solution Without the boil
Example 3
65 ing thereof.
8. Process as set forth in claim 7 wherein said solution
An 18% solution in xylene of isotactic polypropylene
is concentrated by flashing at superatmospheric pressure
(having a melting point of 160~l65° C. and an intrinsic
until it has a viscosity of about 500 to 5,000 poises meas
viscosity of 7.0, as measured in tetrahydronaphthalene at
ured at said temperature of extrusion.
130° C.) said solution containing 0.1%, based on the
polymer, of the stabilizer, 2,6-di-t-butyl p-cresol, was ex 70 9. Process as set forth in claim 7 wherein said poly
ole?ne is a straight chain polymer of ethylene and said
truded at a temperature of 177 ° C. and under a pressure
solution is extruded at a temperature of at least the melt
of 260 p.s.i.g. through a spinnerette having 5 holes each
0.154 mm. in diameter, downwardly into air at atmos
ing point of said polyole?ne.
10. Process as set forth in claim 1 in which spinning
pheric pressure in a spinning cabinet 3 feet high, the
is
started
by ?lling said spinning jet with a liquid consist
75
air temperature being 140° C. ‘at the top of the cabinet
8,032,384
7
8
ing essentially of a solvent for said resin, extruding said
solvent through said jet at said extrusion temperature and
feeding said solution of resin to said spinning jet-under
17. Process'as set forth in claim 2 in which said poly
ole?ne-is an isotactic polymer of styrene.
pressure to displace said solvent therefrom.
11. Process as set forth in claim 2 in which said solu
tion is extruded into air at atmospheric pressure and at a
temperature of 115—140° C.
12. Process as set forth in claim 2 in which said poly
ole?ne is an isotactic polymer of propylene.
13. Process as set forth in claim 2 in which said poly
ole?ne is ‘an isotactic polymer of 4-methyl pentene-l.
14. Process as set forth in claim 2 in which said poly
ole?ne is an isotactic polymer of 3-methy1 butene-l.
15. Process as set forth in claim 2 in which said‘poly
ole?ne is an isotactic polymer of 4,4-dimethy1 pentene-1.
References (Iitedin the ?le of this patent
UNITEDv STATES PATENTS
2,210,771
Myles et al. _________ __ Aug. 6, 1940
2,330,932
2,648,647
Taylor et al. __________ __ Oct. 5, 1943
Stanton etal. ________ .. Aug. 11, 1953
2,716,049
2,762,791
2,816,883
2,825,721
2,858,290
Latour ______________ __ Aug. 23,
Pease et a1. __________ __ Sept. 11,
Larcher et al. ________ .._. Dec. 17,
Hoganet al. __________ __ Mar. 4,
Davis et al. __________ __ Oct. 28,
2,867,495
Myers ______ __'_‘ ______ __ Jan. 6, 1959
131,333
Australia ____________ __ Feb. 11, 1949
FOREIGN PA'PENTS
16. Process as set forth in claim 2 in which said poly
ole?ne is an isotactic polymer of vinyl cyclohexane.
1955
1956
1957
1958
1958
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