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Patented Sept. 24, 1946
2,408,007
UNITED ‘ STATES PATENT OFFICE
‘ 2,408,007
METHOD FOR RECOVERY OF LOW-TEMPER
ATURE POLYMERIZATION PRODUCTS
Robert M. Thomas, Union, and Donald 0. Field,
Linden, N. J ., assignors, by mesne assignments, '
to Jason, Incorporated, a corporation of Loui
siana
No Drawing. Application August 30,1941,
1
Serial No. 408,994
9 Claims. (01. 260-—93)
This application relates to polymeric materials;
rial. Also, the occluded catalyst has harmful and
relates particularly to processes for the produc
destructive effects upon the‘solid polymer, and, it
tion of high quality ole?nic polymers and‘ inter
appears‘ to‘ be a contributing factor in the de
polymers; and relates especially to methods for
terioration of the material during storage, upon
purifying the polymer and interpolymer, and si- 5 milling and upon heating, and to be a contribut
multaneously quenching and removing the cataing factor in the formation of blisters and vacu
lyst from the polymer.
oles in the interpolymer material upon curing.
In prior processes for the making of high molecThe present invention provides a new and use
ular weight ole?nic polymers and interpolymers,
ful combination of steps for the processing of low
such as polyisobutylene and the interpolymers of 10 temperature polymerizates to produce the solid
isobutylene with a, diole?n, the reaction, during
, polymer or interpolymer in the form of .a line
the latterstages as conducted at low temperatures,‘yields a mixture composed of the refrigerant, usually liquid ethylene, or solid carbon di-
grained slurry; to halt the polymerization reao~
tion at a desired stage; to purify the Polymer OI‘
interpolymer; and to improve its physical and
oxide, with a substantial quantity of methyl 15 chemical’ ‘characteristics during storage, during
chloride, portions of unreacted iso-ole?n and diheating and during mechanical working or mill
ole?n, together with excess aluminum chloride, or
111%.
other catalyst, and the solid polymer in the form
Broadly, the present invention consists of the
of chunks or aggregate This mixture is at the
steps of preparing a reactant mixture of the de
reaction temperature as set by the refrigerant, 20 sired ole?nic material at the desired low tem
and it is necessary to separate the solid polymer
perature, the material being preferably iSObll
from the other components of this mixture.
tylene, or‘other 10W molecular weight iso-ole?n,
‘ It, is known that the molecular weight, of the
either with or without a ldiole?n such as butadi
polymer produced by the reaction is an inverse
ene, ieoprene, pentadiene-L3; 2,3-dimethyl—1,3
function of the temperature, that is, the lower 25 butadiene 2-methy1 3-buty1 1,3-butadiene, or with
the temperature, the higher the molecular Weight.
cyclopehtadiene, OI’ non-wnjug-ated diole?ns Sueh
Furthermore, it is fund that if the reaction mixas 2-methyl hexadiene-l,5; 2,6-dimethyl hexadi
ture is allowed to warm up to room temperature
(?ne-1,5, 2,6-dimethyl-4-methylehe 2,5-hepte’diene
to remove the volatile constituents, polymerizaor triole?ns such as hexatriene, myrcene, 1,6
tion of the remaining reactants continues, under 30 dimethyl heptatriehe 1-3-5 and 2,4,6-t1‘imethy1
the influence of the residual and excess catalyst
1,3,5-hePtetrie11e 01‘ the like; and 600E118‘ vthe miX
during the warming up. But a polymer of much
lower molecular Weight is produced at the higher
ture to a temperature ranging from -l0° to —l00°
or —150° C. To this mixture, there i5 then added
temperature during the warming up; which poly-
a Friedel-Crafts type active halide catalyst;
mer has diiferent characteristics from the low 35 which may be boron ?uoride or may be aluminum
temperature polymer and is exceedingly dif?cult
to remove from the desired polymer; yet, if left
in, it is exceedingly harmful, or even ‘fatal, to
the desired characteristics of the" low temperature polymer.
‘
‘
‘
chloride in solution in an inert low-freezing sol
vent or may be other similar catalyst materials.
This polymerization reaction is conducted under
conditions-to give a ?nely pulverulent form of
40 polymer or interpolymer particle, which is high
‘ ‘In the prior art, it has been the practice to
“quench” the residual catalyst‘bythe addition of
small amounts of alcohol or other hydroxy or oxy-
‘ly desirable in order to permit the maximum
speed of solution of the solid polymer in subse
quen-t processes. When the polymerization reac
genated liquids to the cold polymerization mix-
tion has reached the desired stage of completion,
ture when the desired stage in the reaction is 45 the whole reaction mixture is discharged into
reached, before the mixture is allowed to warm
an excess of solvent, such as petroleum naphtha
up; ‘It is found that this procedure destroys the
containing: a small percentage of oxygenated
excess’catalyst in the liquid portion of the mixcompound, such as alkali, water, ammonia, an
ture, but ‘it does not affect those portions of the
ether, an organic acid, or preferably a low molec
catalyst which are occluded in the solid polymer. 5o ular weight alcohol. The, naphtha or other sol
This residual catalyst is still active, and, ‘since
vent material is provided in su?icient excess to
the ole?nic reactants are soluble in the solid polyinsure solution of the entire quantity of polymer
iners, it promotes an'undesirable polymerization
reaction of the-reactants which are dissolved in
or interpolymer andsuf?cient alcohol is present
to react with and, destroy all of the catalyst. This
the solid polymer to yield further‘harmful mate- 55 solution is then preferably Washed with water to
2,408,00?
4
3
remove the hydrolytic products arising from
the polyolefin, which latter is characterized by
quenching the catalyst, and to free the polymer
a molecular Weight ranging from 15,000 to
150,000, or higher; by an iodine number ranging
from 1 to 40 or 50, preferably between 1 and 9;
and the property of reactivity with sulfur to yield
a curing reaction. It is usually desirable to halt
or interpolymer of practically all inorganic ma
.terials.
The solid polymer or interpolymer is
then recovered from solution by any one of sev
eral methods. It may be precipitated from the
solution by the addition of appropriate quantities
of oxygenated solvent, such as an alcohol, ether,
aldehyde, organic acid or the like, either all at
the reaction short of 100% polymerization, the
preferable yield being from 60% to 80%.
This polymerization reaction is, as above point
once, or in steps, to effect a fractionationof the m ed out, conducted with the conditions adjusted
in such manner as to obtain a slurry of the small
solid polymer or interpolymer; or the naphtha
solution may be heated at ordinary vorre'duced
pressure and the naphtha ?ashed off from the
solid polymer or interpolymer by releasing the
pressure at an elevated temperature, or the solu
tion may be sprayed into a polar liquid main
tained at a temperature above the boiling point
of the solvent; or the solution may be emulsi?ed
in water in the presence of suitable emulsifying
agents, and if desired, the solvent volatilized from ~
the water emulsion by appropriate ‘heating while
retaining the solid polymer or interpolymer in
emulsion form for later use.
Thus an object of the invention is to produce,
by low temperature ‘polymerization, ‘an ole?nic
polymer and ole?nic-polyol‘e'?nic interpolymer of
improved quality by ‘modifying the steps used in
quenching the catalyst, by ‘removal of the cata
lyst andca'talyst breakdown products; and at
ease of the interpolymers Which'a-re capable of ¢
est possible particle‘ size of solid polymer or inter
polymer in the reaction mixture, A considerable
number of factors are involved in obtaining the
?ne particle size in the slurry which is desirable
for maximum speed of solution of the polymer in
the solvent.
The ?rst of these factors is the quantity of
diluent or diluent refrigerant. Ordinarily, the
polymerization reaction has been conducted with
1 or 2 volumes of diluent-refrigerant per volume
of polymerizable ole?nic or ole?nic-polyole??lc
material. In order to obtain reasonably small
particle size in the slurry, it is essential under
conditions of limited agitation that more than'g2
volumes of diluent per volume of ‘reactant ‘be
present; and evenlarger quantities, ‘up ‘to4'or' 5
volumes or" diluent per volume of reactant, are
sometimes preferable.
'
.
'
'
Secondly, it is desirable that the ‘diluentwor
being'vulcanized, to free the'int'erpolyme‘r from
the troublesome effects of blister-producing
diluent-refrigrant have as low a solubility for the
solid polymer or i'nterpolymer as possible and as
agentslx Other objects and "details of the "inven
low a solubility in the solid polymer as possible,
in order to minimize the softening effect of the
diluent upon the particles, thereby reducing. the
tendency towards cohesion. of the particles to a
tion will “be apparent from ‘the followingdescrip
tio‘i’i.
‘
'
'
‘
,
Tr‘i' practicing the invention, "an ole?’nic mixture
is prepared, preferably containing isobutylene in
minimum value. I For this purpose, liquid-ethyl
the proportion of vote 99 parts with'a'polyole?n,
one has a satisfactorily low solubility factor.
Thirdiy, the temperature of the mixture is an
preferably a’ conjugated diblé?h, in‘ the propor
tion of 30 parts to 1 part, the'diol'efin preferably 40 important item. At temperatures below about
being buta'diene 'or 'isoprene‘ or pentadiene-‘l, 3 or
—80° C. and in ‘the absence of- .plasticizing. mate
2,3l'dim‘ethyl ‘but'adi'erie-l? or other low molecu
1ar weight ‘similar ‘conjugated diole?n having
fl'om"four to ‘eight carbon atoms per ‘molecule
or other non-conjugated di‘ol'e?n,‘ triole?n or
polyele?npreviou'siymentioned. ‘This mixture is
then cooled to a low temperature, below —50° ‘C.
to —'1j00° or —15'0° ‘C(by mixing therewith a suit
rials, the polymer or interpolymer particles are
hard and sandy in character and do not cohere,
but at temperatures above about —-'75°
the
particles are rubber-like and show a strong tend
ency to eohere and agglo'mer'ate, 'This-e?ectis
well shown by the fact that when solid carbon
dioxide is used as an external refrigerant, the
able diluent-refrigerant such as‘ liquid ethylene,
temperatures in the reaction liquid may go no
liquid methane, liquid ethane, ‘liquid propane or 50 higher'than ——70° C. Nevertheless, the particles
agglomerate into large, solid masses’; yet if the
admixtures of “these ‘several substances; or the
ole?nicv or ole?nic-poly'ole?nic mixture may be
solid carbon dioxide is added to the reaction‘mix
cooled to a temperature'er —'T8'° “C. by the addi
ture for internal cooling, it appears that a sub
tion'tliereto of an ‘excess of'solid c‘arbon'dioxide,
stantial portion of the solid carbon dioxide dis
solves in the reaction mixture to decrease the
either with‘or‘with'out a diluent such as the low
freezing alkyl' halides, ‘liquid propane'er other
solubility of the polymer in the medium, and
while theereaction temperature may be close to
similar inert 'd‘ilu‘ent's', or ‘external cooling may be
éiriployécl' With ‘or Without a duuent.
'
—’?O° C., the particles do not cohere or lagglome
"To the "cooled ole?nic mixture,‘ there is then
added a FriedelzCrafts type active halide catalyst, 60 Fourthly, maximum rapidity’ of stirring ishelp
ful in securing and maintaining ?ne-particle size,
which may be boron trifluor'ide, or‘with the iso
ole?niclpolyole?nic mixture is preferably a solu
in part because of the rapid incorporationof the
catalyst solution in ?ne particle form, and in part
tibn of aluminum‘ chloride ‘in an alkyl halide such
as ethyl or methyl chloride or in carbon'disul?'de,
by the'mechanical prevention of agglomeration
or in other low freezing, inert solvent. The alu 65 of particles when the cohesive tendency is small.
minum chloride is ‘desirably ‘present in the solu
Fifthly, it is desirable that the‘ catalyst solution
crate.
,
>
V
,
tion in‘th'e proportion ernom 0.5% to 5 or 6%}
be added by distributionfrom a spray nozzle onto
and'is preferably's‘prayedes ?ne droplets on to
the rapidly stirred surface of thepolymerization
the surface 'of‘the rapidly stirred ole?nic mixture ,
mixture, or that‘the catalyst be introduced in a
or introduced in'a suitably dilute concentration 70 small stream intothe reaction mixture under
below‘ the ‘liquid level of the "reaction mixture
conditions of maximum turbulence ofstirring.
with intense agitation,
" ‘
Sixthly, the maintenance of the ?ne particle
condition is’facilitated by addition-agents, such
' The polymerization reaction proceeds rapidly
to yield a- high ‘molecular‘weig'ht polymer‘of ‘iso;
as stearic acid and zinc stearate. The exact
butylene or‘ interpolymer'of the‘isoeole?n'with a method of operation of these addition agents is
2,408,007;
5
6
unknown, but their presence is found to be help
mately 155° C. for a time interval of 30 minutes;
at the end of which time it was found to be fully
cured and to have a tensile strength of about 4400
pounds per square inch, 2. value substantially
ml in the maintenance of the ?ne particle size
in the slurry,
‘
‘
i
‘
Example 1
above that obtainable by the prior processing
An ole?nic mixture was prepared and polymer
methods.
‘
Example 3
ized as indicated above, and when the desired
polymerization stage was reached, the polymer
A quantity of the interpolymer solution as ob
ization' mixture at the low polymerization tem
tained in Example 1 was placed in a closed bomb
perature was discharged quickly into about one 10 and brought up to a temperature of approxi
and one-half volumes of 54-solvent naphtha at
mately 175° C. and then discharged through a
a temperature of about 70° C. (although carbon
nozzle valve into a closed receptacle having an
tetrachloride or propyl chloride or other conven
outlet for the recovery of the volatilized solvent.
ient solvents could have been used). The solvent
The solid interpolymer fell to the bottom of the
contained about 1% of isopropyl alcohol. The 15 receptacle and was collected therefrom, small
polymerization mixture contained residual ethyl
residual quantities of the volatile solvent being
ene, contained residual quantities of the isobutyl
removed by heating the interpolymer in a current
ene and of the diole?n and substantial quantities
of warm air.
‘
of the catalyst. Immediately upon discharge of
This interpolymer was compounded in a for
the polymerization mixture into the solvent, the 20 mula similar to that shown in Example 2, and
solid polymer, present in the polymerization mix
gave a, similarly highly, cured material of similar
ture as ?ne particles, obtained as above described,
tensile strength.
dissolved. Simultaneously, the catalyst, both
Example 4
that remaining in the liquid portion of the mix
The puri?ed interpolymer solution of Example
ture and that occluded in the solid particles, was 25
1 is particularly advantageous for the prepara
quenched and converted into non-catalytic com
tion of emulsions which are particularly easily1
pounds , by the alcohol. Simultaneously, the
prepared and particularly stable, because of the‘
diluent~refrigerant was volatilized by the sensible ‘
absence of the tendency toward precipitation
heat of the naphtha and was recovered in the
gaseous form. The solution having been cooled 30 produced by residual traces of catalyst which
remain in the interpolymer when other methods
by the refrigerant was then warmed to room tem
of puri?cation are applied.
perature.
In preparing the emulsion of this example, ap
The interpolymer solution was then washed
proximately two parts of an emulsifying agent in
the form of triethanol amine oleate per 100 parts
of solid polymer were added to the polymer solu
with water. . This washing step removed the cata
lyst quenching agent and with it, the catalyst».
breakdown products, thereby freeing the sohd in
terpolymer from catalyst, both the catalyst in the
tion and the polymer solution with the emulsify
ing agent was added to approximately one volume
reaction mixture which upon warming would have
of water while stirring vigorously. The polymer
yielded undesirably low molecular weight inter
polymers, and the catalyst occluded in the solid 40 solution formed a highly dispersed emulsion in
which the particles of polymer solution ‘were of
interpolymer which, while it would not cause un
very small size. The emulsion was then warmed
desirable polymerization reactions, would have
injured the interpolymer by causing molecular ‘
with vigorous stirring and the vvolatile solvent
weight breakdown during storage and would have
volatilized out of the emulsion, leaving an emule
interfered with the curing operation.
Example 2
. sion of the solid particles of polymer in a condi
tion of extremely ?ne dispersion.
Example 5
The solution of interpolymer obtained from
Example 1, substantially free from catalyst and
catalyst breakdown products, was treated with an
excess of a precipitant in the form of isopropyl
alcohol, approximately 1 volume of isopropyl al
cohol being added to 4 volumes of the interpoly
mer solution. Nearly all of the solid interpoly
A quantity of the emulsion of interpolymer
solution in Water as prepared in Example 4 was
placed in a closed bomb and brought up to an
elevated temperature well above the boiling point
of the volatile hydrocarbon solvent. The heated
emulsion was then discharged through a nozzle
mer was thereby precipitated from the solution 55 valve into a receptacle, equipped with an outlet
for the recovery of the volatile solvent. Substan
in a highly advantageous form for further come,
tially all of the volatile solvent and a portion of
pounding; and also substantially free from low
water were volatilized by this procedure, leaving
molecular weight interpolymers which would in
in the receptacle an emulsion of exceedingly ?ne
terfere with the compounding, and free from in
terfering catalyst or catalyst breakdown products.
' This material was compounded according to a 60
grained particles of the interpolymer in water.
Example 6
formula requiring:
-
Interpolymer
Carbon .blar'k
Parts
__________________________ __ 100
_
50
Zinc oxide ___________ _‘____ ______________ __
_
5
Stearic acid, ___________________________ __
5
Tuads ,(tetramethyl thiuram disul?de) _____
‘ 1
This procedure is applicable to the simple
polymers of an iso-ole?n as well as to ‘the ‘inter
65 polymers, of iso-ole?n-diole?n and iso-ole?n
polyole?n.
A mixture of isobutylene with ethyl chloride
as a diluent; and solid powdered carbon dioxide
snow (dry ice) was prepared, and treated with
This compound was prepared by working the in
terpolymer on the roll mill and adding the vari 70 boron trifluoride catalyst with attention to the
above described details for obtaining a ?ne
ous additional components to the material on the
mill, cutting‘ the sheet of- compound back and
forth across the mill.
‘
The compounded material was then placed in
particle slurry. The resulting polymer had a
molecular weight of approximately 150,000; had
an iodine number too low to measure, and had
a‘moldand cured at atemperature of approxi~v 75 the characteristics of a rubbery, elastic, b‘odyf.
o
2,408,007‘
7
This material was-discharged from the reaction
vessel ‘into petroleum naphtha, the petroleum
naphtha containing approximately 21% of iso
pr‘coyl alcohol. The particles of polymer dis
solvedreadily, and the isopropylalcohol quenched
8
pension
perature,into aform
residual
a‘solid‘polymer
portion of product
‘polymerization
in
mixture, then bringing the suspension ‘of solid
product, without substantialrise in temperature
into contact with a volatile hydrocarbon solvent,
the boron trifluoride catalyst, both that in the
unpolymerized isobutylene and that occluded in
the solid polymer. The solution was then
thereby dissolving the said polymer insaid solvent
and thereafter washing the polymer solution ‘to
remove the aluminum compounds present therein.
brought up to room temperature and washed to
4. The process for preparing irnprbvedpolye
remove the catalyst breakdown products and 10 merization products comprising the steps of ‘poly;
other interfering materials, as in Example 1, and
merizing at a temperature between ->-50° C. and
the unpolymerized isobutylene volatilized out.
—v1-50‘° C.-, a mixture containing from ‘70170 99'
I This polymer likewise is readily recovered by
parts of isobutylene with from 30 to 1 partsof
precipitation, as in Example 2, or by ?ashing off
isoprene by the application thereto'of a catalyst»
the solvent as in Example 3.
It likewise is a 15 solution of aluminum chloride dissolved in-an
highly desirable material for the preparation of
emulsions as in Examples 4 and 5.
Thus the invention consists of the steps, in
combination, of polymerizing olefinic or ole?nic
polyole?nic material at low temperature, dissolv
ing the polymer or interpolymer at low tempera
ture in a hydrocarbon solvent containing a cata
lyst quenching agent, washing the solution and
inert solvent which is liquid at the reaction tem
perature, to form a solid polymer product in sus
pension in a residual portion of polymerization
mixture, then bringing the suspension or solid
product, without substantial rise in temperature
into contact with a volatile hydrocarbon solvent,‘
thereby dissolving the said polymer in said solvent' and thereafter washing the polymer solu
recovering the polymer or interpolymer in solid
tion to remove the aluminum compounds present
form therefrom, either as a solid polymer or inter 25 therein.
polymer or as a polymer or interpolymer emul
5. The process for preparing improved poly
sion.
In ‘the above examples and throughout this
speci?cation" and the appended claims, wherever
merization products comprising the steps of poly;
inerizing at a temperature between ~50? C. and
-=-150° C., a mixture containing fror'nj70 to 99
the term "'ole?nic material” is used, it refers to 30 parts of isobutylene with from 30 to 1 parts of
iso-eol‘e?ns such as isobutylene or to polyole?ns
dimethyl butadi'ene by the application thereto of
such as butadiene, isoprene, pentadione-LB; 2
a catalyst solution of aluminum chloride dissolved
methyl heXa'diene-LS; *rn’yrcene, hexatriene or
in an inert solvent which is liquid at the reaction
any other ~‘monocle?'ns or 'polyole?ns or homologs
. temperature, to form a solid polymer product in
thereof capable of interpoly'merization with an 35 suspension in a residual portion of polymeriza
isoeole?n.
'While there are above disclosed but a limited
number of embodiments of the invention, it is
possible to produce still other embodiments with—
out departing from the inventive concept herein
disclosed, and it is, therefore, desired that only
such limitations be imposed upon the appended
claims as'are stated therein or required by the
prior art.
The invention claimed is:
1. Process for‘pr'ep‘aring improved 'p'o-ly'meri‘z‘ae
r tion products comprising polymerizing at a tem
perature between -—50° C. and -150° C. a mix
tion‘ mixture, then bringing the suspension of
solid product, without substantial rise in te‘m
peratur'e'into contact with a volatilehydrocarbon
solvent, thereby dissolving the said polymer, in
said solvent and thereafter washing the polymer '
solution to remove the aluminum compounds
present therein.
1
,
6. The process for preparingv improved poly
m'er‘izati'o‘n products comprising the steps 'of poly-1
merizing at a temperature between —50° 'C. and
—150° C., a mixture containing from 70 to 99
parts of isobutylene with from 30 to 1 parts of
butadiene by the application thereto of a catalyst,
ture containing from '70 to 99 parts 'of isobutylene
solution of aluminum chloride dissolved in ethyl
and from 30 to 1 parts of a conjugated diole?n 50 chloride, to form a solid polymer product in sus-_
of 4 to 8 carbon atoms per molecule in the pres
pension in ‘a residual portion of polymerization
ence of a catalyst solution of aluminum chloride
dissolved in an inert solvent which is liquid at
product, 'Without‘ substantial ‘rise in ‘ temperature
the reaction temperature to form a solid polymer
into contact with a volatile hydrocarbon ‘solvent,
mixture, then bringing the suspension of'solid
product containing occluded catalyst therein, 55 thereby dissolving‘ the said polymer in said sol-'
then bringing this solid. polymer product without
vent and 'th‘ereafter'washing the polymer‘ solution‘ 1
substantial rise in temperature into contact with.
to remove the aluminum compounds present
therein.
a volatile hydrocarbon solvent containing an alco~
holic catalyst quenching agent, thereby dissolving
'7. The process for preparing‘ imprcved'ipolyl
the said polymer in said solvent and destroying
merization products comprising the‘ steps of poly’
the activity of the said occluded catalyst, then
washing the polymer solution to remove the
aluminum compounds present therein.
'
merizing at a temperature between ‘450° C.
and —150° C., a mixture containing from 70 to 99‘
parts. of isobutylene with from‘ 30 to 1 parts of
butadi'ene by the application thereto of a-catalys't
2'. ‘Process according to claim 1» in which the‘
said solid'polymer product is in the form; ‘of a 65 solution of’ aluminum "chloride dissolved infan"
inert ‘solvent which is liquid at the reaction
slurry of separate particles dispersed in'the re
temperature, ‘to form} a solid polymerprcductin
action mixture.
suspension in a residuai‘portion of polymerizae
3'. The process for preparing improved poly
merization products comprising the steps of poly
tion mixture, I then briiig'ingthe suspension of
meriz‘ing at a temperature between _—50° C. and 70 solid product, without substantial rise in; tome‘
-150° C., a mixture containing from 70 to 99
peratu-re- in-to' con-tact? with a volatile hydrocarbon
parts of iso-butylene’ with from 30 to 1 parts of
solvent, thereby dissolving the said polymer in
butadiene by the application thereto‘ of a catalyst
said solvent, washing the polymer solution to re
solution of aluminum chloride dissolved in an
inert solvent which is liquid at- the reaction tom-
move the aluminum compounds presenttherein,
and thereafter precipitating a-solid? polymer from“
2,408,007
9
10
the solution by the addition to the solution of a
substantial portion of an alcohol.
8. The process of preparing improved poly
merization products comprising the steps of poly
merizing at a temperature between -50° C.
and —150° C., a mixture containing from 70 to 99
parts of isobutylene with from 30 to 1 parts of
butadiene by the application thereto of a catalyst
solution of aluminum chloride dissolved in an
inert solvent which is liquid at the reaction tem
perature, to form a solid polymer product in sus
pension in a residual portion of polymerization
merizing at a temperature between --50° C.
and ~l50° C., a mixture containing from '70 to 99
parts of isobutylene with from 30 to 1 parts of
butadiene by the application thereto of a catalyst
solution of aluminum chloride dissolved in an
mixture, then bringing the suspension of solid
inert solvent which is liquid at the reaction tem 10 product, without substantial rise 'in temperature
perature, to form a solid polymer product in sus
into contact with a volatile hydrocarbon solvent,
pension in a residual portion of polymerization
thereby dissolving the said polymer in said sol
mixture, then bringing the suspension of solid
vent, washing the polymer solution to remove the
product, without substantial rise in temperature
aluminum compounds present therein, and there
into contact with a volatile hydrocarbon solvent,
after precipitating a solid polymer from the solu
thereby dissolving the said polymer in said sol
tion by the addition to the solution of a sub
vent, washing the polymer solution to remove the
stantial portion of an alcohol, the said alcohol
aluminum compounds present therein and there
} being added in steps to obtain a fractional pre~
cipitation.
after volatilizing out the solvent from the poly
mer.
20,
ROBERT M. THOMAS.
9. The process for preparing improved poly
DONALD C. FIELD.
merization products comprising the steps of poly
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