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Патент USA US2403966

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2,403,966
Patented July 16, 1946
UNITED STATES PATENT OFFICE
2,403,966
POLYMER SLURRY PROCESS
and Irving E.
John R. Brown, Jr., West?eld,
to Stand
Lightbown, Cranford, N. J ., assignors
ard Oil Development Company, a corporation
of Delaware
No Drawing. Application October 14, 1942,
Serial No. 461,986
8 Claims.
This invention relates to polymerization proc
esses and rubber-like polymers; relates particu
larly to processes for the interpolymerization of
iso-ole?ns and diole?ns; and relates especially
to the polymerization of ole?nic material in the
presence of non-reactive components for main
taining the solid polymer in a ?nely dispersed
(Cl. 260-8)
2
When the polymer is prepared in the presence
of substantial quantities of a diluent or diluent
refrigerant such as liquid ethylene, it is only
slightly sticky at the polymerization temperature,
and is only slightly sticky at room temperature
when moistened with water; but at temperatures .
in the range from about -55° C. to about -—20“
C., it is extremely sticky and it shows a very
great tendency to coalesce into large coherent
masses, and to adhere to surfaces with which
like polymers are produced by the polymerization 10 it comes into contact. In other methods of prep
or 'interpolymerization of an iso-ole?n such asiso
aration, where small quantities only of diluent.
butylene, with or without a diole?n such as bu
or no diluents are present, the material is ex
tadiene, isoprene, pentadiene, dimethyl butadi
tremely sticky at the polymerization temperature,
condition.
'.
.
It is known in the art that synthetic rubber
ene, or the like.
The polymerization reaction is
and at the intermediate intervening tempera
conducted at temperatures ranging from about 15 tures and is troublesomely sticky at room tem
C.
or
lower,
and
—40° C. or —78° C. to -l60°'
perature in water. These characteristics of the
consists in the mixing of the lique?ed ole?ns with
newly polymerized material interfere seriously
a lique?ed diluent-refrigerant such as liquid eth
with the handling of the product and with the
ylene or with a refrigerant such as solid carbon
complete removal of spent and surplus catalysts,
20
dioxide with or without a higher boiling diluent.
since the sticky character 01' the interpolymer
To the rapidly stirred mixture is then added,
causes it to adhere to the treating apparatus,
preferably by spraying onto the surface, a cat
and to cohere in relatively large lumps, contain
alyst consisting of aluminum chloride or similar
ing occluded catalysts which cannot be washed
metal halide dissolved in a suitable solvent such
out or removed in subsequent operations.
as carbon disul?de or the low-freezing alkyl
It is anobject of the invention to eliminate
halides. The resulting polymer has a molecular
these undesirable characteristics from the inter
weight ranging from 20,000 to 150,000 or above,
polymer and to obtain fine particle suspensions
has an iodine number ranging from 0.1 to 40,
or slurries by adding into the reaction mixture.
preferably between 0.5 and 10, depending upon 30 either prior to the polymerization reaction or
the quantity of diole?n interpolymerized into the
prior to the fiashring operation but preferably
polymer; and in addition the polymer has the
prior to the polymerization reaction, a small
capability of reacting with sulfur, in spite of its
quantity of an inert material in order to coat
very ‘low iodine number, to develop an elastic
the solid particles of interpolymer formed so as
limit in the material, a tensile strength ranging
to keep them in a dispersed condition during the
from 2500 lbs. to 4500 lbs/sq. in., an ultimate 35 subsequent operations; which material may later
elongation ranging from 500% to 1200%, and a
be washed out of the polymer if desired. This
high abrasion and fiexure resistance. The result
material serves as a' de?oculating agent to pre
ing material, while not a true synthetic rubber
vent the undesired cohesion and adhesion of the
in any way, is a high-grade substitute for rub
40 polymer throughout its processing.
ber, possessing many advantages over rubber.
A further object of the present invention is to
The polymer is a plastic, elastic solid, but it
provide a new and useful combination of proc
has been found exceedingly diiilcult to obtain
essing steps for the treatment of low tempera
the solid polymer during the interpolymerization
ture interpolymers to obtain and maintain the
reaction in the form of small particle aggregates
solid interpolymers in the form of ?ne-grained
with a physical structure adapted for eii‘lcient 45 slurries. A further object is the slurrying of the
and convenient processing through such subse
interpolymers in water, and the maintenance of
quent steps as the ?ashing of! of unreacted ole
the slurry during subsequent processing, includ
?nic material, diluent and refrigerant; and wash
ing dry and subsequent mechanical working and
ing out of spent catalyst or residual catalyst.
milling operations.
Likewise, it is dimcult to prevent cohesion be 60 The objects of the invention are accomplished
tween the particles 01' the interpolymer, and to ' by the incorporation into the reaction mixture
prevent adhesion of the particles or interpoly
prior to the interpolymerization reaction or an
mer to the reactor, to the supporting screen in
inert de?occulating material in the form of a
the drier, and other metal objects with which 55 fine powder which may comprise inert powders
the interpolymer comes in contact.
' 9,408,988
4
such as talc, whiting, zinc oxide, other pigments
or various inorganic ?llers, colloidal clays, such
/
other means; the water being preferably quite
warm to supply the necessary heat of vaporiza
as bentonlte, kieselguhr and the like; and other
tion for the residual volatile components of the
swellable materials such as powdered gelatine,
reaction mixture. This process step results in
powdered gum tragacanth, gum arabic and the
the formation of a relatively ?ne-grained slurry
like. Other objects and details of the invention
of , the polymer in water, which is particularly
will be apparent from the following description.
advantageous to handle, since the de?occulating
In practicing the present invention, the steps
agent prevents coalescence of the particles dur
of preparing a reactive mixture of the desired ole
ing the warming-up procedure, and similarly pre
?nic material at the desired low temperature is in 10 vents adhesion of the particles to the container.
accordance with the steps as taught in Australian
The resulting polymer slurry in water is readily
Patent No. 112,875, issued to R. M. Thomas and
processed by any of a number of subsequent steps.
W. J. Sparks or in the corresponding U, S. Patent
The polymer slurry is readily separated from the
2,356,128, issued Aug. 22, 1944 to Thomas and
water merely by straining out the polymer, and
sparks.
15 the fine grains of polymer are readily dried to re
Broadly these steps comprise mixing in the
move both the water and residual traces of dilu
proper proportions an iso-ole?n containing 4 to 8
ent and reactants, by treatment in a drying oven.
Alternatively. the polymer may be washed in a
capable of interpolymerization with an isoole?n
kneader or on the mill as desired, using substan
and containing 4 to 12 carbon atoms such as bu 20 tial quantities of water (preferably warm), to
tadiene, isoprene, 2,3-dimethyl-l,3 butadiene; pi
remove the deflocculating agent and the residual
perylene, or a non-conjugated diole?n such as 2~
traces of reaction mixture; as well as to destroy
methyl-hexadiene-1,5; 2,6-dimethyl - hexadiene~
any residual traces of catalyst. When gelatine or
1,5; or triole?ns such as hexatriene, myrcene; 1,6
other aqueous colloids are used, they are water
dimethyl-heptatriene-l,3,5 and 2,4,6-trimethyl 25 soluble and are very readily removed from the
carbon atoms such as isobutylene with a diole?n
' 1,3,5-hexatriene, or the like and cooling the mix
ture by internal refrigeration by means of solid
carbon dioxide or external refrigeration, e. g., by
liquid ethylene, to a temperature ranging from
-80° C. to —-100° C. or as low as —160° C.
polymer, together with the catalyst and volatile
reaction mixture components by a relatively
short, simple and easy washing operation. In
the case of the pigment type of de?occulating
30 agent, the removal is not so readily accomplished,
To this mixture there is then added a small _ although, particularly in the case of the bentonlte
quantity of a pulverant or comminuted, inert, de
type of clays and the talc, a major portion of the
?occulating material selected from the class con
pigment may be removed by a reasonable amount
sisting of inert powders such as talc, whiting, cal
of washing in the kneader or on the mill.
cium silicates, zinc oxide pigments, inorganic ?ll 35 It is of course advantageous to use pigments
ers, colloidal clays such as bentonlte, kieselguhr
which may be retained in the polymer to avoid
and the like; or a swellable aqueous colloid such
the necessity of prolonged washing; or, if a poly--'
as gelatine or gum tragacanth or gum arable or
mer free from de?occulating agents is desired, it
powdered agar or the like. The inert material
is of course preferable to use the aqueous colloid
may be added as such in a pulverant form or may 40 type of material. In either instance, the poly
be dispersed in methyl chloride or in the feed.
mer may be dried and milled to prepare it for
After the inert material has been thoroughly dis
further use.
persed in the reaction mixture, there is then
added a Friedel-Crafts type catalyst; which may
be boron ?uoride or aluminum chloride in solu
tion in an inert low-freezing solvent such as ethyl
or methyl chloride or other similar active halide
materials. This polymerization reaction is con
ducted under conditions to give a ?nely grained
form of interpolymer which is highly desirable,
in order to permit the maximum speed of process
log the solid interpolymer in subsequent oper- -
Era'mple I
An ole?nic mixture consisting of 495 parts by
volume of isobutylene and 5 parts by volume of
isoprene (70% purity) was diluted with 1000 parts
by volume of liquid ethylene. To this mixture
there was then added 10 parts (by weight) of a
good grade of talc in the form of a hydrous mag-‘
nesium silicate having a soft, greasy touch, which
is available in various grades; such as potstone,
ations.
steatite or French chalk. The mixture was pre
The catalyst may be any convenient Friedel
pared in a reactor equipped with stirring means,
Crafts catalyst as is indicated by N. 0. Calloway 55 and provided with a cover to avoid contact with
in his article on the “Friedel-Crafts synthesis”
the air and to confine the volatilized portions of
printed in the issue of "Chemical Reviews,” pub
the mixture. The reactor was carefully insulated
lished for the American Chemical Society at Bal
to reduce the rate of heat in?ow and to reduce
timore in 1935; volume XVII, No. 3, the article
the volatilization of the ethylene refrigerant.
beginning on page 327; the list of useful Friedel 60 The catalyst was prepared by dissolving commer
Crafts catalysts being particularly well shown on
cial anhydrous aluminum chloride in methyl
page 375. For the solvent, any of the mono- or
poly-aliphatic halides having less than about_
three or four carbon atoms are useful; the com
pounds having carbon atoms above about 2, re
quiring special low-temperature technique to pro
duce a satisfactory catalyst solution, and the
mono~halides being preferred. In addition, such
solvents as carbon disul?de are also useful.
chloride at the boiling point of the methyl chlo
ride to yield a nearly saturated solution contain
ing about 1.0% of materials calculatedas alumi
num chloride. This solution was then diluted
with an additional amount of methyl chloride to
produce a, solution containing 0.5% of dissolved
aluminum chloride. This solution was then pre
cooled to -'78° C. and applied through a spray
When the polymerization reaction has reached 70 nozzle'onto the surface of the vigorously stirred
ole?nic mixture. The polymerization proceeded
rapidly and was approximately 80% complete in
about 5 to 7 minutes.
entire reaction mixture may be mixed quickly
The intenpolymer was formed in the reactor as
with water, in a vigorously stirred tank, or by 75 a ?ne-particle slurry in the residual liquid, par
a desired stage of completion, the unreacted ma
terials are separated from the residual polymer
ization mixture in any convenient manner. The
' 2,408,900
5
of tine, inert powders, which will serve to prevent
agglomeration of the polymer particles. The
tlcularly in the ethylene. The slurry was then
dumped into a ?ash tank for the final separation
group includes such substances as rouge, clay,
or the interpolymer and the diluent-refrigerant,
whiting, zinc oxide, chromite. vermiilion, and
many other inert, ?nely powdered pigments. Ex
and it was found to retain its fine-particle char
acter with no perceptible tendency to coalesce in
ample III shows a second class of substances
to large aggregates. The solid interpolymer.
after thorough washing with water and drying
which, like the colloidal class, tends to swell up
and disperse the material in the presence of
was found to have a molecular weight of 80,000.
This molecular weight was satisfactory, and the
polymer was suitable for compounding and our
water. These materials are the mineral ?llers
prepared from such substances as the diatoma
ceous earth materials of silicious origin known to
the trade as “Celite”; and include the intusorial
ing with non-sulfur vulcanizing agents of the
type of qulnone dioxime to give desirable vulcan
earths and clays oi the hydrous-silicate-of-alu
izates: and the interpolymer material was found
mina type. Example IV shows an organic col
to be in a particularly advantageous form for
loid having powerful swelling properties which
15
subsequent processing. including such steps as
is representative of a considerable number oi! sub
drying with hot air and for mechanical working
stances including gelatine, gum tragacanth, gum
on the mill.
arabic, agar-agar, and tannin.
Example I!
Other inert anticoalescing materials, enumer
ated above and illustrated by the present
Example I was repeated with the following 20 invention, include such substances as kieselguhr,
variation: no talc was added to the polymeriza
abestine, infusorlal earth, whiting, calcium sili
tion reaction mixture. After the polymerization
cate, magnesium carbonate, Kalite, lithophone,
reaction was completed, it was noted that the in
titanium
pigment, zinc oxide, Zinc sul?de,
terpolymer particles formed agglomerated into a
organic toners and various waxes such as car
large bulky mass, quite di?'erent from Example I.
nauba, montan and rubber wax. These are the
The solid polymer, after thorough water washing
preferred species to be added severally or in
and drying was found to have a molecular weight
admixture
in a pulverant comminuted form to
of 80,000. This molecular weight was satisfac
the reaction mixture prior to the commencement
tory, and the solid polymer was suitable for com
the interpolynierization reaction, since they
pounding and curing to give a vulcanizate pos 30 of
impart highly advantageous and desirable
The
sessing desirable physical characteristics.
physical properties -to the vulcanizate. Since
tendency of the interpolymer material, however,
some of the materials enumerated above
to coalesce or agglomerate after the completion.
particularly the waxes are soluble in the alkyl
of the polymerization reaction and in the washing
halides, they may be incorporated in the form
steps was highly undesirable, since the coalesced
of a solution or supension and used as such in
material was di?icult to handle and was not suit
distributing the inert materials into the inter
able ior plant operations such as hot air drying
polymerization reaction mixture.
and mechanical working on mill rolls.
Example III
40
A similar mixture to that in Example I was pre
pared, and to it was added approximately 10 parts
by weight of the weight of the ole?nic material
of bentonite. The polymerization was then con
ducted, as in Example I. and an excellent poly
mer well filled with the bentonite was obtained.
The polymer showed only a minor tendency to
agglomerate while in the cold liquid; coalesced
only slightly during the warming up; and formed
an excellent slurry in water at room temperature. '
The small amount of coalescence which occurred
during the warming up was readily overcome,
These anticoalescing materials may, in some
instances, remain in the polymer through
subsequent compounding, molding, and curing
operations to serve as ?lters and colorants.
Alternatively some of them may be more or less
completely washed out by kneading the polymer
in water in equipment such as the Werner and
P?eiderer kneader.
Relatively short time , oi.’
kneading in water will remove nine-tenths or
more of the aqueous colloids and substantially all
can be washed out by a reasonable length of time
of kneading. In this respect, these materials are
sharply different from other types of pigments.
such as the reinforcing pigments, which cannot
be washed out but become an integral part or the
merely by vigorous stirring, since, in water, the
polymer mass.
bentonite swells up and disperses the polymer
These examples‘ and the practicing of this
very effectively in the water.
invention show that the broad class of inert
Example IV
pulverant, comminuted, inert materials-such as
talc,‘ inorganic pigments, clays, organic colloids,
A similar mixture to that in Example I was
etc.—will function to control and reduce the
prepared, and to it was added approximately 2
parts by weight on the ole?nic mixture of ?nely 60 coalescing tendency of the slurry of interpolymer
in the reaction medium as anticoalescing agents
powdered gelatine. Gelatine as an amino acid is,
at room temperature, strongly reactive with
and serve as internal inert extenders when added
aluminum chloride; but at polymerization tem
to the interpolymers in the process of their for
peratures below about -40° C. the material is
mation in order to decrease the extent oi’
wholly inert and non-reactive. Nevertheless the 65 agglomeration, and to reduce the tendency of the
particles serve as polymerization nuclei, and as
interpolymer to adhere to metal and to coalesce
a dispersing and de?occulating agent for the par
in the intermediate drying and processing
ticles of polymer; and, when the material was
operations.
'
brought up to room temperature in water, the
Thus the invention consists of the steps, in
gelatine substance swelled very rapidly and yield 70 combination, of adding to the interpolymerization
ed a very thorough dispersion of the polymer.
mixture of ole?nic or ole?nic-polyole?nic mate
These examples are representative of three
rials at low temperatures an inert anticoalescing
groups of addition agents according to the inven
and ?ller material, polymerizing the ole?ns in
tion. Example I shows an inert powder; talc,
the presence of anticoalescing material and. then
which is representative oi.’ a considerable number 76
2 2,403,966
7
slurrying the solid polymer in water by the aid
of the anticoalescing material.
perature, separating the polymer in dispersed
from from the polymerization mixture, slurrying
the polymer in water, and maintaining the poly
mer in dispersed form after polymerization by
the action of the de?occulating agent.
While there are above disclosed but a limited
number of embodiments of the invention, it is
possible to provide still other embodiments With
out departing from the inventive concept here
disclosed; and it is therefore desired that only
5. A polymerization process comprising the
steps in combination of mixing a major propor
such limitations be imposed upon the appended
tion of isobutylene with a minor proportion of
claims as are stated therein or required by the
a diole?n having 4 to 12 carbon atoms, inclue
10
prior art.
sive, cooling the mixture to a temperature with
The invention claimed is:
in the range of —20° 0. to —160° 0., adding to
1. In a polymerization process in which a
the mixture an inert de?occulating agent, poly
major quantity of an isoole?n of 4 to 8 carbon . merizing the mixture by the addition of a Friedel~
atoms is polymerized with a minor quantity of
Crafts catalyst dissolved in a non-complex-form
a diole?n of 4 to 12 carbon atoms at a tempera 15 ing solvent which is liquid at the polymerization
ture of from —'-20° to —160° 0.. bymeans of a
temperature, separating the polymer in dispersed
solution of a Friedel-Crafts catalyst dissolved in
form from the polymerization mixture, slurrying
an alkyl halide which is liquid at polymerization
temperatures, the step of conducting the poly
merization in the presence of an inert de?occu
lating agent, then separating the polymer in a
the polymer in water, and maintaining the poly
mer in dispersed form after polymerization by
20 the action of the de?occulating agent.
6. A polymerization process comprising the
steps in combination of mixing a major pro
portion of isobutylene and a minor proportion
it in a dispersed form after polymerization by
of
butadiene, cooling the mixture to a tempera
the action of the de?occulating agent.
25
ture within the range of —20° C, to —160° 0.,
2. A polymerization process comprising the
adding to the mixture an inert de?occulating
steps in combination of mixing a major propor
agent, polymerizing the mixture by the addition
tion of an isoole?n having 4 to 8 carbon atoms,
of a Friedel-Crafts catalyst dissolved in a non
inclusive. with a minor proportion of a diole?n
complex-forming solvent which is liquid at the
dispersed form from the polymerization mixture,
slurrying the polymer in water, and maintaining
- having 4 to 12 carbon atoms, inclusive, cooling 30 polymerization temperature, separating the poly
the mixture to a temperature within the range
mer in dispersed form from the polymerization
of --20° 0. to —160° 0., adding to the mixture an
mixture, slurrying the polymer in water, and
inert de?occulating agent comprising bentonite,
maintaining the polymer in dispersed form after
polymerizing the mixture by the addition of a
polymerization by the action of the de?occulating
Friedel-Crafts catalyst dissolved in an alkyl 35 agent.
halide solvent which is liquid at the polymeriza
7. A polymerization process comprising the
tion temperature, separating the polymer in
steps in combination of mixing a major propor
dispersed form from the polymerization mixture,
tion of isobutylene and a minor proportion of
slurrying the polymer in water, and maintaining
the polymer in dispersed form after polymeriza 40 'isoprene, cooling the mixture to a temperature
within the range of —20° 0. to —160° 0., add
tion by the action of the de?occulating agent.
ing to the mixture an inert de?occulating agent.
3. A polymerization process comprising the
polymerizing the mixture by the addition of a
steps in combination of mixing a major propor.
Friedel-Crafts
catalyst dissolved in a non-com
tion of an isoole?n having 4 to 8 carbon atoms,
inclusive, with a minor proportion of a diole?n 45 plex-forming solvent which is liquid at the poly
merization temperature, separating the polymer
having 4 to 12 carbon atoms, inclusive, cooling
in dispersed form from the polymerization mix
the mixture to a temperature within the range.
ture, slurrying the polymer in water, and main
of -20° C. to —160° 0., adding to the mixture an
taining the polymer in dispersed form after poly
inert de?occulating agent, polymerizing the mix
merization by the action of the de?occulating
ture by the addition of a Friedel-Crafts catalyst
agent.
dissolved in an alkyl halide solvent which is
8. A polymerization process comprising the
liquid at the polymerization temperature, sepa
steps in combination of mixing a major propor
rating the polymer in dispersed form from the
tion of isobutylene and a minor proportion of
polymerization mixture adding the polymer to
dimethyl butadiene, cooling the mixture to a
water, and maintaining the polymer in dispersed
temperature within the range of —-20° C. to —160°
form after polymerization by the action of the
0., adding to the mixture an inert de?occulating
de?occulating agent.
agent, polymerizing the mixture by the addition
4. A polymerization process comprising the
of a FriedeI-Crafts catalyst dissolved in a non
steps in combination of mixing a major propor
complex-forming solvent which is liquid at the
tion of an isoole?n having 4 to 8 carbon atoms,
60
inclusive, with a minor proportion of a diole?n
having 4 to 12 carbon atoms, inclusive, cooling
the mixture to a temperature within the range
of —20" 0. to —160° 0., adding to the mixture
an inert de?occulating agent comprising gela
tine, polymerizing the mixture by the addition of
a Friedel-Crafts catalyst dissolved in an alkyl
halide which is liquid at the polymerization tem
polymerization temperature, separating the poly_
mer indispersed form from the polymerization
mixture, slurrying the polymer in water, and
maintaining the polymer in dispersed form after
polymerization by the action of the de?occulating
agent.
>' "JOHN R. BROWN, JR.
IRVING E. HGH'I‘BOWN.
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