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Патент USA US2411722

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,_ Patented Nov. '26, ‘1946 V‘ I‘
,.
~ UNITED. ‘STATES’ PATENT ' OFFICE ' Q I
2,411,722
1 ' SULFUR-DIOXIDE MODIFTED 'ra'rm- .
. FLUOROETHYLENE POLYMER
_ Jesse Harmon and Robert M. Joyce, Jr., Wilming-‘
ton, Del., assig'nors to E. I. du Pont de Nemours
, & Company, Wilmington, Del., a corporation of Delaware}
'
Y = No "Drawing.
,
v
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I
Application September 21-, 1945,
Serial No. 617,930
. 4 Claims.
_
. ‘
-
.
(.01. 260-801]
1.
sulfuric acid. vIt contained 0.47% sulfur, or an '
This invention relates to'polymeric materials
average ratiosof one sulfur dioxide unit to 67.4
and more particularly to sulfur dioxide-modified _
tetra?uoroethylene polymers.
Polytetra?uoroethylene is a hard, tough, in-=_
tetra?uoroethylene units.
. ‘
The sulfur dioxide-modi?ed tetra?uoroethylene.
fusible solid which is insoluble in and'unattacked 5 polymers of this invention are macromolecular
by inorganic acids, alkalies and organic solvents. ' polymers having the empirical formula’
'
While this combination of propertiesis very de-
"
-
.
sirable for a great many applications, many of‘
(Oink-(80?”
these properties make the polymer unsuitable for
wherein Z and 1, are integers, the ratio of “z to 1,
“her “868-
,
'-
'
10 being within the range of from 1:1 to 125:1;
This invention has as an'object new and useful
Those of greatest utility have the .empirical ‘for
comPOsitlonS of matter- A further object is the
preparation of sulfur dioxide-modi?ed 'tetra?uoroethylene polymers.
mula (CzFt) e.(S02)y, as hereinbefore de?ned, in
which the ratio of x to y is ‘within the range or
A still further object re-
‘from 6:1 to 125:1.
sides m the sulfur dioxide-modi?ed polymers 15
‘which 9'1‘ 9 characterized by lower menu? pom.“
and improved workability. ‘Additional obJects will
‘
-
The ratio of S0: to C2F4 in the polymers of this
invention may be varied within the above limits
by varying the mol ratio of Sulfur dioxide to tetrag
?uomethylehe in the reaction mixture_ Thus’
become apparent from an examination of the following descnption and claims‘
said ratio in the reaction mixture may be varied
These and 0th!” objects and advantages are 20 widely; although usually the mol ratio of sulfur
accomplished according to the herein described ‘- dioxide to tetra?uoroethylene m the reaction
mvenuon which comprises polymerizing tetra‘
mixture is within the range of from 1:10 to 10:1.
?uoroethylene in the presence of sulfur dioxide
The catalysts used in the practice‘ of, this m_
under substantially anhydrous conditions and in - -
Vehtion are organicheroxy compounds e_ g" thhse
the absence of diluents using an organic peroxy 2.5 organic compounds which contain a’, ___o__o_
compound as catalyst as more fully described
structura Examples of’ thesev compounds are:
heremafter' ,
_
diacyl peroxides, such as benzoyl peroxide, di- J ,
The followmg example’ in whichPmmr'Fions
lauroyl peroxide; dialkyl' peroxides, such as di- ,
are in Parts by Weight unless Otherwlse weaned,
ethyl peroxide, di(tert. butyDperoxide; and alkyl '
is given for illustrative purposes and is not in- 30 hydropemxides, such as tam hutylhydmpemxidep
tended t°_p1a°e any restrictions .on ,the herein
Appreciable e?ects are had when the amount of
described mYentmn'
‘
Example
l
'
'
catalyst employed‘ is as low as 0.001% and when
it is as high as 5% ofthe sum of the weights of
the sulfur dioxide and tetra?uoroethylene in the
A silver-lined shaker tube was swept with nitro- 35 reaction mixture. The use of amounts of catalyst, ;
gen and. charged with one part of benzoyl perlower than 0.001% and higher than 5% is not oxide. The head was fastened to the tube and
recommended for economic reasons since inferior‘
the tube was evacuated and chargedvwith 128
results ‘are obtained when the catalyst is em-l .
parts of sulfur dioxide and _50 parts of tetra-
' plOyed outside the indicated range.
Optimum
fluoroethylene through a valve. Thevalve was 40 results are obtained when the amount of catalyst
closed and the tube was ‘shaken ?rst at room tememployed is within the range of from 0.01% to 1%.
perature for three hours and then for four hours
based upon the total weight of the sulfur dioxide
at 80° C. The tube was then cooled and the
and tetra?uoroethylene in the reaction mixture. ‘
unreacted sulfur dioxide and tetra?uoroethylene
,
- The process of this invention .can be carried
were removed by releasing the pressure. The 45 out at atemperature within the range of from
product consisted of 21 parts of a hard, brittle,
0° C. to 200° C. The reaction is generallycarried
tan-colored solid.
The product when fused was
a mobile liquid, whereas unmodi?ed polytetra-
out within the range offrom 25° C. to 150° C. ‘ .
The polymerization is carried out under super- _
?uoroethylene retained its form when heated at
atmospheric pressure, generally 'autogenous pres
temperatures as high as 400° C. The sulfur di- 50 sure,,and usually within the range'of from three
oxide-modi?ed tetra?uoroethylene polymer was
non-?ammable, melted at 310° C., was insoluble
in water, dioxane, acetic acid, ethanol, xylene and
. atmospheres up to'1000'atmospheres. The maxi
mum possible pressure apparently is limitedonly
by the apparatus available.
.'
acetone. It was unaffected by hot dilute alkali
The products of this'invention'are character
or acid but was darkened by hot concentrated 55 ized'by improved workability and lower softening
2,411,722
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'
4
.
modified tetraiiuoroethylene polymer which com
temperatures compared to those of unmodi?
tetra?uoroethyiene polymers. They may be used _
prises subjecting to superatmospheric pressure
as molding plastics, ?lms,‘?bers and adhesives
'and a temperature’ within the range of from 0°
C.‘to 200? C. a mixture consisting of sulfur diox
ide, tetra?uoroethylene and as catalyst an or
and as electrical insulation.
.
'
As manyapparently widely‘ diiferent embodi- '
ments of this invention'may be made without de-,
parting from the spirit and scopejthereof, it is
ganic peroxy compound.
_
, ‘ 4. The process for obtaining
a sulfur‘ dioxide-v
to be understood that we do not limit ourselves
' modi?ed tetra?uoroethylene polymer which com- _‘
to the speci?c embodiments thereof except-as
prises subjecting-to a pressure within the range
-
of from three atmospheres to 1000 atmospheres
Having described the present invention,. the
following is claimed as new and useful:
and a temperature within the range of from 25°
C. to .150‘ C., a mixture consisting of sulfur di
1. A macromolecular polymer having the em-‘
oxide; tetra?uoroethylene and benzoyl peroxide,
de?ned in the appended claims.
-
pirical formula (CaF4)=.(SO:') y, wherein wand 11 ' -- the moi ratio of ‘sulfur dioxide to tetrafiuoro- '
are integers, the ratio of xto 14 being within the 1s ethylene'belng within. the range of from 1:10 to v
range of from 1:1 to 125:1.- v .' g ‘I
- >
10:1 and" the benzoyl peroxide being present'in
-‘
2. A macromolecular polymer having the em- '
pirical formula (C2F4)=.(SO2)y, wherein a: and y
are integers, the ratio of :c to 1/ being within the
range of from 6:1 to 125:1.
'
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3. The process for obtaining a sulfur dioxide
‘an amount within the range of from 0.01% to 1%
' of the sum of the weights of the sulfur dioxide
- and tetra?uoroethylene.
20
JESSE mos.
_
ROBERT M. JOYCE, .n.
‘
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