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Патент USA US2412960

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Patented Dec. 24, 1946
POLYMERS or 'rn'ramuoaosrmnun
Kenneth L. Berry, Hockessln, Del., assignor to E. I.
du Pont de Nemours & Company, Wilmington,
Del., a corporation of Delaware
No Drawing. Application March 19, 1945,
Serial No. 583,640
2 Claims.
This invention relates to compositions of mat
ter and more particularly to new and useful ?uid
compositions comprising tetra?uoroethylene co
Copolymers of tetra?uoroethylene and ethyl
ene, particularly those containing a high propor
tion of tetrafiuoroethylene, are characterized by
(01. 260-32)
?uoroethylene/ethylene of 1:0.78 (82% tetra
?uoroethylene) and 9 parts of diisobutyl adipate
was heated while stirring at 260 to 265° C. where
upon a. clear solution resulted. Upon cooling the
solution gelation occurred.
The tetra?uoroethylene/ethylene copolymers
can be obtained by polymerizing a mixture of
tetrailuoroethylene and ethylene, containing at
least 50% of tetra?uoroethylene under pressures
bility in the common organic solvents. Such gen
erally useful solvents as dimethyl succinate or 10 substantially above atmospheric pressure at a
temperature in the range of 40 to 150° C. in the
dimethyl phthalate will not dissolve copc‘ymers
presence of water or a mixture of water and a
of tetrafluoroethylene and ethylene containing a
non-reactive diluent and oxygen or a peroxy cat
high proportion of the former constituent.
alyst. The polymer used in the foregoing ex
These copolymers are also soluble only s‘ ,litly or
to a, limited degree in the high boiling ketones 15 ample was prepared by the following procedure:
A stainless steel high pressure reactor was flushed
such as isofenchone, acetophenone, benzophe
with oxygen-free nitrogen and charged with 150
none, and isophorone. Somewhat better solu
parts of deoxygenated water, 50 parts of tertiary
bility is obtained in a complex mixture of unsat
butyl alcohol and 0.3 part of benzoyl peroxide.
urated cyclic ketones boiling within the range
of 250° C. to 325° C., and containing from twelve 20 The reactor was then closed and further charged
with 100 parts of a mixture of tetra?uoroethyl
to eighteen carbon atoms. Although the high
ene and ethylene (mole ratio 1:1.28). The poly
melting point and general insolubility of the co- ‘
merization was then carried out by heating the
polymers of tetra?uoroethylene with ethylene is
reactor at 80° C. while maintaining an internal
desirable for many applications, these same prop
erties make the polymers unavailable for other 25 pressure of 1600-1800 lbs/sq. in. by the periodic
high melting points, non-workability and insolu
uses. For many applications there are advan
tages in the use of solutions rather than molten
compositions to achieve the ?uid state necessary
in lacquers, coating compositions, and dopes suit
. injection of additional quantities of the above in
dicated tetra?uoroethylene-ethylene monomer
mixture. The sum of individual pressure drops
during the reaction period of 19 hours was 1005
able for use in forming various objects, such as 30 lbs. The reactor was cooled, the pressure release
?lms, sheets, ribbons, bristles and ?laments. A
and the copolymer discharged.
methyl hexahydrophthalate. Dialkyl esters of
saturated acyclic hydrocarbon dicarboxylic acids
Solutions similar to that described in the above
still further advantage in the use of solutions lies
example were obtained by heating the copolymer
in the ease with which they can be cast into films
with the following esters: dimethyl glutarate, di
or coatings of uniform thickness, which is me
chanically more di?icult to accomplish with a 35 methyl adipate, diethyl adipate, dimethyl azelate,
dibutyl seba-cate, dimethyl methadipate and di
molten composition due to its relatively high vis
This invention has as an object new and use
in which the alkyl groups each contain from 1
ful compositions of matter. A further object is a
method for preparing new and improved tetra 40 to 4 carbon atoms and the dicarboxylic acid con
tains from 5 to 10 carbon atoms are preferred
iluoroethylene copolymer compositions useful in
making ?laments, bristles, ribbons, ?lms, sheets
and coatings on various materials such as metal.
Other objects will appear hereinafter.
since in general they yield solutions having the
highest polymer content.
This invention is applicable to and is usually
The above objects are accomplished by dissolv 46 practiced with copolymers consisting essentially
of the reaction product of 50 to 85% tetra?uoro
ing a tetra?uoroethylene/ethylene copolymer
ethylene and 50 to 15% ethylene.
containing from 50 to 85% of tetra?uoroethylene
The polymer solution can be conveniently pre
in a neutral ester of a saturated dicarboxylic acid
pared by agitating the polymer with the solvent
containing at least 5 carbon atoms, such ester
being free of multiple carbon to carbon linkages 50 at temperatures ranging from approximately
200“ up to the boiling point of the solvent. Solu
and containing from '7 to 18 carbon atoms.
tions prepared in this manner will gel 'upon cool
The following example is further illustrative of ing to temperatures somewhat below that used
the practice of the invention:
A mixture of 1 part of tetra?uoroethylene/
in the preparation of the solution. The tem
perature of gelation is dependent somewhat upon
ethylene copolymer having a mole ratio oi tetra
the solvent, the concentration of the solution and
the viscosity of the polymer. Thus, highly con=
centrated solutions, e. g. about 40% solids, usu
ally gel at higher temperatures than do solutions
and porous objects such as fabrics, paper, regen
erated cellulose and wood.
As many apparently widely di?'erent embodi
ments of this invention may be made without de
parting iromthe spirit and scope thereof, it is to
_ Similarly solutions of polymer containing high
be understood that I do not limit myself to the
viscosity polymer gel at higher temperatures than
speci?c embodiments thereof except as de?ned in
do solutions containing lower viscosity polymers.
the appended claims.
In general, the solubility of the polymer is de»
I claim:
creased and the gel temperature of polymer sclu= 10
1. A composition oi’ matter comprising a solu
tions is raised as the percentage of tetra?uorm ‘
' tion in organic solvent of a copoiymer of tetra
ethylene in the polymer is increased.
containing > lower concentration
of ; polymer.
. By employing the neutral esters of dicarboxylic
?uoroethylene and ethylene containing from 50%
acids of the type hereinbefore described, solu
to_85% tetrajfiuoroethylene, said solvent being a
tion ranges from 1 up to approximately 40%.
The present process is of particular value in that
the solutions can be obtained with copolymers
free of multiple carbon to carbon linkages and
containing from 7 to 18 carbon atoms.
ester of a saturated dicarboxylic acid con
tions of tetra?uoroethylene/ethylene copolymers 15 neutral
taining at least 5 carbon atoms, said ester being
can be obtained in which the polymer concentra=
2. A process for obtaininga solution in an or~
ganic solvent of a copolymer of tetra?uoroethyl
made from tetraiiuoroethylene and ethylene 20 one
and ethylene containing from 50% to 85%
alone, and without including in the polymer re
said process comprising heat»
action mixture any modifying agent designed. to
ing said polymer with a neutral ester at a tem
improve solubility.
perature of from 200° C. to that of the boiling
The new solutions of tetra?uoroethylene/eth
of said ester, said ester being an ester of a
ylene copolymers disclosed herein are advanta 25 saturated
dicarboxylic acid containing at least 5
geously used in a number of applications, for ex
carbon atoms, said ester being free of multiple
ample for the preparation of the polymer disper
carbon to carbon linkages and containing from
sions, for coating metal objects such as wire, for
7 to 18 carbon atoms. '
casting ?lms and iorimpregnating glass ?bers
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