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2,408,608
Patented Oct. 1, 1946 1
UNITED‘ 'smrss PATENT" OFFICE’
cmionmnrnn nnsms
Oliver W. Cass, Niagara Falls, N. Y., assignor to
E. Lida Pont de Nemours & Company. ‘Wil
mington, Del., a corporation oi’ Delaware
No Drawing. Application May 24, 1943, v
, Serial No. 488,214
2- Claims._ (Cl. 260-436)
This invention relates to the preparation of
certain new and useful chlorine-containing resin
ous materials.
More particularly, it relates to '
2
nation. ‘Another object of this invention is the
conversion of those vinylidene chloride-vinyl
chloride copolymers of low softening points which
are commercially valueless into valuable resinous
polymeric materials by subjecting these resins to '
the action of chlorine whereby their chlorine con
tents are raised with an appreciable increase in
their softening point. Still another object of this
invention is the improvement of the heat sta
the preparation of new and valuable resins ‘by
introducing chlorine into resins previously pre
pared by copolymerizing vinylidene chloride and
‘ vinyl chloride ("Saran” type resins).
Vinylidene chloride and vinyl chloride when
mixed and subjected to polymerizing conditions
form copolymers throughout the entire range of 10 blity and solubility characteristics of vinylidene
' chloride-vinyl chloride copolymers by the intro
possible mixtures. These copolymers will vary in
duction of chlorine thereinto, thereby increasing
chlorine content from those of high vinyl chloride
the chlorine content of these copolymer resins.
content containing approximately 57% chlorine
'These and still further objects of this invention
to those of high vinylidene chloride content con
taining approximately 73% vchlorine.
Unfor
- 1.5
'will be apparent from the ensuing disclosure of
certain preferred embodiments thereof.
tunately all resins containing chlorine within this
I have now discovered that both the low sof- .
range, 57% chlorine content to 73% chlorine con
'tening point characteristic of some of the vinyli
tent, are not commercially utilizable because, as
dene chlorideevinyl chloride copolymers, and the
the chlorine content of these resins'increases the
softening point ‘ of the copolymer changes, de 20 inherent ‘instability toward heat of these resins,
can be overcome by subjecting these copolymers
creasing from a, softening point of approximately‘
to a chlorination treatment. In this way it is
78° C. for a copolymer containing 95% vinyl
possible to increase the chlorine content of the
chloride-5% vinylidene "chloride to a softening
copolymers thus markedly improving their prop
point of approximately 5° C. for a copolymer con
taining 45% vinyl chloride--55% vinylidene 25 erties when subjectedto high temperatures, both
' when stabilizers of the previously mentioned type
chloride. As the amount of vinyl chloride is still
are present in the resins, and when such stabi
further reduced, thereby increasing the chlorine
lizers are not so present. I have further dis-‘
content of the resulting vinyl chloride-vinylidene
covered that the solubility characteristics, of the.
chloride resin still further, the softening point
again rises until, fora polymer containing 10% 30 copolymers'are increased by the chlorination
treatment in such a manner as to render the
of vinyl chloride and 90% vinylidene chloride, the
resins more useful and general in application.
softening point is about 135° C. Those copoly
The extent of chlorination required to secure
mers of low softening point covering the middle
these advantageous results will generally vary
range in chlorine contents are practically use
35 depending upon the individual vinylidene chlo
less from the commercial point of view.
ride-vinyl chloride copolymer being considered.
In addition to’ this disadvantage characteris
However, I have found that the introduction'of
tic of some of the vinylidene chloride-vinyl
from 4 to 5% of chlorine for those copolymers ‘
chloride copolymers, all of these copolymers suf
containing relatively large amounts of vinylidene
fer from inherent instability toward heat and for
chloride, and the introduction of from 8 to 10%
that reason tend to discolor to a substantial ex
of chlorine into those copolymers containing rel
tent and liberate hydrogen chloride when sub
atively small amounts of vinylidene chloride willv .
jected to high temperatures such~ as those en
e?ect the desired improvements. Generally,
countered in molding operations. While thia
therefore, I prefer to introduce from about ‘3% to
thermal instability may be counteracted to‘ a‘
greater or less extent by the incorporation with 45 15% of chlorine'into the vinylidene chloride
the copolymers'oi various stabilizers, even under
the very best of conditions copolymers 'of' the
vinyl chloride copolymer, the larger amounts be
ing introduced into those copolymers containing
high vinyl chloride contents such as amounts of
the order of 95%, while the lower amounts of
One of the objects of this invention is the im-' 50 chlorine are introduced into those resins con
vinyl chloride-vinylidene chloride type‘ mustgbe
regarded as unstable to heat. .
.
,
"
provementwi resins of the vinylidene chloride
vinyl chloride copolymer type whereby the low
softening points of some of these resins are’ ele
vated and all are rendered more stable to heat
by subjecting thecopolymeric material‘to chlori
taining relatively high amounts of vinylidene
chloride such as amounts of the order of 90%, for'
example.
,
.
The chlorination may ordinarily be carried out
by suspending the copoiymeric ‘material in an ap
2,408,608,
3
of methanol to the cool solution, followed by ?l
tration in order’to recover the product.
propriate organic liquid such as carbon tetra
chloride, which organic liquid may contain, if de
sired, a, small amount of water as catalyst. The
The chlorinated copolymer containing 64.5%
suspension of the copolymer in the organic liquid
chlorine was then subjected to the identical mold
ing conditions previously described. There re
sulted a clear light brown molded product in
is then heated to a temperature high enough to
initiate the reaction, temperatures in the range _
_ 60 to 70° 0. being generally suitable. Gaseous
place of the black molded product resulting when
the unchlorinated material was used. The mold
chlorine is then passed into the suspension of
ing temperature had to be increased approxi
copolymer while this suspensionis subjected to
the action of actinic radiation. The chlorinated 10 mately 20° C., moreover, in order to secure satis
factory molding and equivalent material ?ow,
polymers may be isolated as dry powders after
this increase in temperature ‘being necessitated
the desired amount of chlorine has been intro
by the elevated softening point of the resin.
duced or. in those instances wherein the copoly
When 2% of the same typical stabilizer was in
mer has been softened or dissolved by the sol
vent, methanol or other‘ precipitant may be added 15 troduced into the chlorinated copolymer as pre
viously utilized for the unchlorinated material,
to the cooled reaction mixture ‘and the precip
and the mixture ‘molded under identical condi
itated chlorinated copolymer removed by ?ltra
tions, an optically clear colorless molded product
tion. While these conditions of chlorination are
was secured. Here again temperatures consid
given as illustrative, it is of course evident that
other procedures may be utilized as will be ap 20 erably above those required for molding the un
chlorinated copolymer were necessitated by the.
preciated by those skilled in the chlorination of
increased softening point of the resin. , In both
cases the chromium-plated surfaces of the mold '
were not in any way attacked during the molding
' organic compounds. The following examples are
illustrative-of certain preferred methods of car
rying out my invention.
-
-
25 operation and retained their mirror-like ?nish
Example 1
950 parts of vinyl chloride and _50 parts of
throughout
The unchlorinated
repeated molding
copolymeric
cycles.material
‘
dis
solved in methyl ethyl ketone only' to the extent of 10 to 12% at room temperature, while the
vinylidene chloride were introduced into a pres
sure vessel provided with means for agitation, 30 solubility of the chlorinated copolymeric material
in the same solvent was increased to."15%.' This
heating, and cooling. In addition to this mono
meric mixture the pressure vessel was charged
with 3000 parts of water containing 5 parts am
monium persulfate and 5 parts of sodium bi
35
sul?te as polymerization catalyst!
The contents of the pressure vessel were.
agitated with heating .until a temperature of 35°_
C. was attained. At this point polymerization
began and the reaction vessel and its contents
illustrates the superior solubility characteristics
of the chlorinated copolymeric-material. Films
of the chlorinated copolymer containing 64.5%
chlorine as cast from solvents werevtransparent
and
colorless.
. >
0
‘
'
'
Example 2
By following the procedure describedin Exam
ple l a copolymer was prepared by utilizing as
were maintained at a temperature within ‘the’ 40 the monomeric material a mixture of 750 parts
range 40 to 45° C. until polymerization was com=
of vinylidene chloride and 750 parts of vinyl chlo
plete. After about 2%. hours the contents of the
ride. The resulting copolymer softened at room
reactor were discharged and the polymerized
temperature and was practically valueless inso
mixture precipitated, ?ltered, and dried in the
far as molding operations were concerned. when
45
usual fashion. The yield 7 of vinyl chloride
subjected to temperatures above room tempera
vinylidene chloride copolymer was 87.2% of the
ture the soft copolymeric resin turned blwk,
theoretical and the product‘had a chlorine con
simultaneously liberating large quantities of hy
tent oi’ 57.7%.
drogen chloride.
The resulting copolymer when subjected to an
. The copolymer was then subjected to chlorina- .
50
elevated temperature of 135° C. under molding
tion under conditions identical with those given
conditions for two minutes gave a black ‘brittle
in Example 1. .The chlorination was continued
molding. The chromium-plated surfaces on the ' until the resulting product had a chlorine con“
mold were badly discolored and attacked by the
tent of 73.3% compared with an initial chlorine
hydrogen chloride released. When a ‘typical
content of 64 to. 65%. The resulting copolymer
chlorc=resin stabilizer was incorporated in 2% 65 of higher chlorine content was now capable of
concentration with the copolymeric' product and
being molded at an elevated temperature yield
the materialthen subjected to molding conditions
ing, even when agents tending to stabilize against
the product was still dark brown in color and the
the action of heat were not present, a light yel
plates of the mold were stained by the liberation
low
somewhat brittle molded product. When the
till usual stabilizers were incorporated the molding
of corrosive fumes during the molding.
300 parts of the copolymer produced in accord
was colorless and transparent. 'Ingreither case
ance with the foregoing method was suspended
was there any evidence of corrosion of the chro
in 4286 parts of carbon tetrachloride containing
mium-plated surfaces of they mold. The result
7.5 parts of water. Chlorine gas was introduced
ing
chlorinated copolymer, moreover, possessed
into this stirred slurry over a period of thirteen 85 improved solubility in the customary ketone sol
hours, the material being brought into contact
vents commercially utilized, both in regard to
with actinic radiation by means of a light bulb.
maximum solubility therein and to ease of solu
At the end of this period suiilcient chlorine had
tion.
been absorbed to raise the chlorine content of the 1
vinyl chloridewinylidene chloride copolymer from 70
,
Example 3
By following the same procedure described in
an initial value of 57.7% chlorine to 64.5% chlo
rine. At this point chlorination was stopped and
Example 1 a mixture of 1200 parts of vinylidene'
residual chlorine and hydrogen chloride blown -
chloride and 300 parts of vinyl chloride was co
polymerized. 'The resulting copolymerhad a
material was then precipitated by the additionv 75 chlorine content of 68.8% and unstabllized mold
from the solution. The chlorinated copolymeric
2,408,608
p
ingg prepared at 145' C. were dark brown in
color.
By following the chlorination procedure de
, crlbed in Example. 1, 300 parts of this copolymer
were chlorinated until the chlorine content had
6
‘
rinatlon o! a copolymer 0! vinyl chloride and
vinylidene chloride containing between 10% and
95% by weight .0! vinyl chloride .with the re- '
mainder of said copolymer being vinylidene chlo
ride, said polymer,’ as a result of said chlorina
tion, having an increased percentage content oi
chlorine and an increased resistance to darken
ing at elevated temperatures.
been raised to 72.5%. When a stabilizer against
heat instability was not present molded samples
of this chlorinated resin were optically clear but
2. Apolymeric product obtained by the chlo
light yellow in color. When 2% of a typical sta
rination of a copolymer of vinyl chloride and‘
10
bilizer against heat instability was present in the
vinylidene chloride containing between 10% and
‘chlorinated copolymer, the resulting products
95% by weight of vinyl chloride with the re—
prepared by molding at an elevated temperature
mainder of said copolymer being vinylidene chic“
were optically clear and water white in color.
ride, said polymer, as a result of said chlorina
As various changes may be made in the pro
tion, having 3% to 15% increase in content of
cedure as described without departing from the 15- chlorine, and an increased resistance to dark
scope of my invention, it is intended that its pur
ening at elevated temperatures.
view should be determined in accordance with
the appended claims.
I claim:
-
1. A polymeric product obtained by the chlo
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