Dispersion polymerization of cycloolefins

At least one cycloolefin monomer containing the norbornene group is polymerized by ring opening polymerization in a hydrocarbon diluent selected from C.sub.4 to C.sub.6 alkanes and isooctane that is a solvent for the monomer(s) but a nonsolvent for the resulting polymer, in the presence of a dispersant selected from terpolymers of ethylene, propylene, and dicyclopentadiene, copolymers of styrene and butadiene, and homopolymers of butadiene, whereby a dispersion of polymer particles in the diluent is produced having a particle size that is substantially smaller than polymer particles prepared in absence of the dispersant, which polymer particles, in the preferred embodiment, do not settle out almost immediately after stopping agitation and result in a much cleaner reactor than in slurry polymerization systems where dispersants are not used.

BACKGROUND OF THE INVENTION 
When polymers are prepared by normal slurry polymerization technique, the 
system consists of two phases: the diluent phase and the solid polymer 
particle phase. The diluent phase may consist of monomers only or monomers 
dissolved in a hydrocarbon medium. The diluent, therefore, is a solvent 
for the monomers and catalysts but a nonsolvent for the polymer formed. 
In slurry polymerization, the particles are generally not stabilized and 
tend to agglomerate to form a polymer paste or slurry that comprises a 
mass of sticky polymer particles that are swollen by the monomer. A common 
problem created by this type of product is the adherence of the polymer 
particles to the reactor walls and the agitation equipment in the reactor 
as well as the plugging of transfer lines, valves, and pumps. Needless to 
say, this causes severe maintenance problems. Since control of reaction 
temperature is of a major concern in a polymerization process, the swollen 
mass of polymer particles can also create additional heat transfer 
problems since a build-up thereof on reactor walls would lower the overall 
heat transfer coefficient for the reaction system. 
It is, therefore, desirable to conduct two-phase slurry polymerization 
whereby polymer build-up on reactor walls and agitation equipment within 
the reactor is reduced to lessen maintenance problems and reactor 
clean-up. It is also desirable to conduct slurry polymerization in a 
manner whereby a dispersion is produced of fine polymer particles 
suspended in the diluent whereby, in a preferred embodiment, the 
dispersion is stable, i.e., where the polymer particles do not settle out 
immediately following the cessation of agitation. It is also desirable to 
produce a dispersion product prepared in the presence of a dispersant 
wherein the polymer particles are much smaller than in a dispersion 
product prepared in absence of a dispersant. The term "dispersion" 
polymerization will be used hereinafter to denote polymerization reactions 
wherein a dispersant is used to attain a dispersion of slurry polymer 
particles. 
SUMMARY OF THE INVENTION 
Dispersion polymerization of at least one cycloolefin is conducted in the 
presence of a hydrocarbon diluent selected from alkanes of 4 to 6 carbon 
atoms and isooctane, an unsaturated elastomer that functions as a 
dispersant and particle size controlling agent, a molecular weight 
modifier, and a catalyst, whereby a dispersion of fine polymer particles 
is formed that are subsequently separated and dried. 
DETAILED DESCRIPTION OF THE INVENTION 
By the implementation of the present invention, it is desired to overcome 
or reduce the problems of equipment maintenance due to plugging of pipes, 
valves, and pumps by agglomerating polymer particles, as well as to reduce 
polymer build-up on inner reactor walls which substantially lowers the 
overall heat transfer coefficient of the reaction system and thus renders 
more difficult the control of the polymerization reaction temperature. As 
is well known, controlling of the polymerization reaction is a 
prerequisite to forming polymers of uniform quailty with minimum particle 
agglomeration and polymer build-up on reactor walls in heterogeneous 
polymerization systems. It is also desired to reduce the average particle 
size of the polymer particles in the dispersion by the utilization of a 
dispersant in the dispersion polymerization of cycloolefins, as is 
described hereinafter. 
The objects of this invention are realized by conducting the dispersion 
polymerization reaction of at least one cycloolefin in a diluent in the 
presence of an unsaturated elastomer that is soluble in the diluent. The 
monomer and the catalysts are also soluble in the diluent whereas the 
polymer particles that precipitate out are insoluble in the diluent. This 
polymerization reaction produces fine polymer particles dispersed in a 
diluent that, in a preferred embodiment, do not quickly settle out upon 
removal of agitation and leave interior reactor walls clean. 
The cycloolefins that can be polymerized in accordance with the process 
described herein are norbornene-type monomers characterized by the 
presence of the norbornene group, defined structurally by the following 
formula I: 
##STR1## 
Pursuant to this definition, suitable norbornene-type monomers include 
substituted and unsubstituted norbornenes, dicyclopentadienes, 
dihydrodicyclopentadienes, trimers of cyclopentadiene, and 
tetracyclododecenes. Preferred monomers of the norbornene-type are those 
defined by the following formulae II and III: 
##STR2## 
where R and R.sup.1 are independently selected from hydrogen, alkyl groups 
of 1 to 20 carbon atoms, and saturated and unsaturated hydrocarbon cyclic 
groups formed by R and R.sup.1 together with the two ring carbon atoms 
connected thereto containing 4 to 7 carbon atoms. In a preferred 
embodiment, R and R.sup.1 are independently selected from hydrogen, alkyl 
groups of 1 to 3 carbon atoms, and monounsaturated hydrocarbon cyclic 
groups containing 5 carbon atoms, the cyclic group being formed by R and 
R.sup.1 as well as by the two carbon atoms connected to R and R.sup.1. In 
reference to formula III, R.sup.2 and R.sup.3 are independently selected 
from hydrogen and alkyl groups containing 1 to 20 carbon atoms, preferably 
1 to 3 carbon atoms. Examples of monomers referred to herein include 
dicyclopentadiene, methyltetracyclododecane, 2-norbornene and other 
norbornene monomers such as 5-methyl-2-norbornene, 
5,6-dimethyl-2-norbornene, 5-isopropyl-2-norbornene, 5-ethyl-2-norbornene, 
5 -butyl-2-norbornene, 5-hexyl-2-no 5,6-dimethyl-2-norbornene, 
5-isopropyl-2-norbornene, 5-ethyl-2-norbornene, 5-butyl-2-norbornene, 
5-hexyl-2-norbornene, 5-octyl-2-norbornene, and 5-dodecyl-2-norbornene. 
Especially contemplated herein are homopolymers, copolymers, and 
terpolymers of methylnorbornene, methyltetracyclododecene and 
dicyclopentadiene, and preferably homopolymers of methyltetracyclododecene 
and copolymers of methyltetracyclododecene and methylnorbornene. The 
copolymers contain 1 to 75% by weight, preferably 10 to 30%, of 
polymerized methylnorbornene with remainder being methyltetracyclododecene 
whereas the terpolymers contain 1 to 75% by weight, preferably 1 to 45%, 
of polymerized methylnorbornene and 25 to 98% by weight, preferably 50 to 
98%, of polymerized methyltetracyclododecene with remainder being 
polymerized dicyclopentadiene. The norbornene-type monomers, or a mixture 
thereof, can contain up to about 20% by weight of at least one other 
copolymerizable monomer. 
The preferred catalyst employed in the dispersion of cycloolefins is a 
combination of an aluminum halide with elemental halide or an 
alkylaluminum halide cocatalyst and a tungsten or a molybdenum compound 
catalyst. The tungsten and molybdenum in the metal compound catalyst can 
be the cation, such as in a tungsten or a molybdenum halide, or the anion, 
as in a tungstate or a molybdate. 
The tungsten or molybdenum compound catalyst, or a mixture thereof, is 
employed at a level of about 0.01 to 50 millimoles per mol of monomer 
charge, preferably 0.1 to 10 millimoles. The molar ratio of the cocatalyst 
to the catalyst is not critical and can be in the range of about 200:1 or 
more, to 1:10, preferably from 10:1 to 2:1. 
The useful molybdenum and tungsten compound catalysts include molybdenum 
and tungsten halides such as molybdenum petachloride, molybdenum 
hexachloride, molybdenum pentabromide, molybdenum hexafluoride, molybdenum 
pentaiodide, tungsten hexachloride, tungsten hexafluoride, and the like. 
Preferred catalysts are the molybdenum halides, especially molybdenum 
pentachloride. 
The alkylaluminum halide cocatalysts are selected from monoalkylaluminum 
dihalides RAlX.sub.2, dialkylaluminum monohalides R.sub.2 AlX, aluminum 
sesquihalides R.sub.3 Al.sub.2 X.sub.3, trialkylaluminum R.sub.3 Al, 
aluminum trihalide AlX.sub.3, and mixtures thereof. In the formulas for 
the alkylaluminum halide catalysts, R is an alkyl radical containing 1 to 
12 carbon atoms, preferably about 2 to 4 carbon atoms, and X is a halogen 
selected from chlorine, iodine, bromine and fluorine. Specific examples of 
such alkylaluminum halides include ethylaluminum dichloride, 
diethylaluminum monochloride, ethaylaluminum sesquichloride, 
diethylaluminum iodide, ethylaluminum diiodide, trialkylaluminum compound 
with elemental iodine, propylaluminum dichloride, propylaluminum diiodide, 
isobutylaluminum dichloride, ethylaluminum dibromide, methylaluminum 
sesquichloride, and methylaluminum sesquibromide. 
Although aluminum is the preferred reducing agent in the alkylaluminum 
halide cocatalysts, other organometallic halide reducing agents can 
function as well. Metals that form suitable organometallic cocatalysts 
include lithium, magnenium, boron, lead, zinc, tin, silicon and germanium. 
Also, the metallic hydrides can be substituted in whole or in part for the 
organometallic cocatalysts. 
The diluent used in the dispersion polymerization reaction is a solvent for 
the monomers and catalysts that are employed, however, it is a nonsolvent 
for the polymer. Generally, one-half to two liters of diluent is used per 
100 grams of monomer charge with about 0.1 to 10% of the diluent being 
used to predissolve the catalysts. The diluents are selected from alkanes 
containing 4 to 6 carbon atoms per molecule, and isooctane. Preferred 
diluents are pentane, hexane, and isooctane. To facilitate solubilization 
of catalysts in the diluent, a small amount of toluene, up to about 5% by 
volume of diluent, can be admixed with the diluent. 
In a preferred embodiment, the molybdenum or tungsten compound catalyst is 
dissolved in a solvent prior to incorporation into the polymerization 
mixture. In the absence of a solvent for the molybdenum of tungsten 
compound catalyst, the polymerization proceeds with some difficulty due to 
the presence of insoluble salt, the catalyst portions of salt. A preferred 
solvent for the molybdenum or tungsten compound catalyst comprises at 
least one alkyl ester of a saturated carboxylic or dicarboxylic acid. Use 
of an ester solvent at lower temperatures has been found to produce a 
brief induction period of about 1 to about 5 minutes after addition of the 
molybdenum or tungsten compound catalyst to the monomer mixture. Such an 
induction period allows mixing of all components of the reaction mixture 
before substantial polymerization begins. The result is more uniform 
process control and, ultimately, substantially gel-free polymers that are 
more readily recovered from the reaction vessel and are more easily 
processable than gelled polymers. 
Suitable alkyl esters of saturated carboxylic or dicarboxylic acids 
typically contain from 2 to 20, preferably 2 to 10 carbon atoms and may be 
substituted by 0 to 3, preferably 0 to 1, halogen atoms. The ester solvent 
should be liquid under a given set of reaction conditions in order to 
maintain the molybdenum or tungsten compound catalyst in solution during 
the reaction. The concentration of the molybdenum or tungsten compound 
catalyst in the ester solvent typically is from about 0.1 molar to about 1 
molar. Examples of suitable alkyl esters include methyl formate, ethyl 
formate, methyl chloroformate, butyl chloroformate, methyl acetate, ethyl 
acetate, isopropyl acetate, t-butyl acetate, n-amyl acetate, methyl 
bromoacetate, ethyl chloroacetate, ethyl propionate, ethyl 
2-bromopropionate, methyl 2-chloropropionate, ethyl butyrate, ethyl 
2-bromobutyrate, ethyl isovalerate, methyl 5-bromovalerate, ethyl laurate, 
diethyl oxalate, dimethyl malonate, diethyl dimethylmalonate, diethyl 
chloromalonate, diethyl succinate, diethyl glutarate, diethyl suberate, 
adipic acid monomethyl ester, and the like. 
A polymerization activator can be used but is generally not needed. 
Excellent activation is obtained using a peroxide or a hydroperoxide, 
especially the organic peroxides such as benzoyl peroxide. The activator 
can be employed in the range of up to 3 moles, preferably up to 1 mole, 
per mole of the alkylaluminum halide cocatalyst. The activator can be 
added at any point in the charging procedure but is preferably added last 
or with the tungsten or molybdenum compound catalyst. 
At least one nonconjugated acyclic olefin can be used as a molecular weight 
modifier having at least one hydrogen on each double-bonded carbon atom 
and containing 2 to 12 carbon atoms, more preferably 3 to 8 carbon atoms. 
Inert substituents on the remaining carbon atoms can be hydrogens and/or 
alkyl groups containing 1 to 8 carbon atoms. Examples of suitable acyclic 
olefins include 1-olefins, 2-olefins, 3-olefins, nonconjugated diolefins, 
and nonconjugated triolefins. More preferably, the nonconjugated acyclic 
olefins are selected from the group consisting of 1-olefins and 2-olefins 
containing 3 to 8 carbon atoms such as 1-butene, 1-pentene, 1-hexene, 
3-methyl-1-butene, 2-pentene, 4-methyl-2-pentene, and the like. Compounds 
not having hydrogen atoms on double-bonded carbons are unreactive in this 
invention. Even conjugated olefins such as butadiene, isoprene and the 
like are active modifiers. 
The nonconjugated acyclic olefin can be used at a level of about 0.0001 to 
1, preferably 0.01 to 0.1 mole per mole of the monomer charge. The 
nonconjugated acyclic olefin can be charged directly or in solution at any 
point in the charging procedure, but it is preferably charged along with 
the monomers. When charged last, the nonconjugated acyclic olefin is 
preferably charged before the reaction begins. 
The dispersant or elastomer that is added to the dispersion polymerization 
system is soluble in the hydrocarbon diluent and is selected from 
unsaturated elastomers that have a double bond along the backbone chain or 
in any pendant group. It is hypothesized that one segment of the elastomer 
is anchored in the interior of the polymer particle and another segment of 
the elastomer is coupled to the diluent phase, thus providing a steric 
barrier that stabilizes the dispersion. In general, the effect of steric 
barrier in a dispersion system is to lower the interfacial tension, 
reducing the energy required for phase separation and in turn, reducing 
the threshold molecular weight for particulation. It has been observed 
that when polymerization is conducted in the presence of a dispersant, the 
polymer particles are much smaller than the ordinary slurry products and 
they usually remain dispersed after agitation is stopped. 
More specifically, suitable dispersants are selected from polymers of a 
lower aliphatic olefin of 2 to 10, preferably of 2 to 4 carbon atoms and a 
small amount of a cyclic diene monomer that contains a norbornene group 
and unsaturation outside of said norbornene group and unsaturation in the 
polymerized state; polymers of a vinyl aromatic compound containing 8 to 
12, preferably 8 to 10 carbon atoms, and an aliphatic diene containing 4 
to 12, preferably 4 to 6 carbon atoms; and polymers of at least one 
monomer selected from aliphatic dienes containing 4 to 12, preferably 4 to 
6 carbon atoms. 
Examples of suitable lower aliphatic olefins include ethylene and 
propylene, and examples of suitable cyclic dienes are dicyclopentadiene 
and ethylidene norbornene, that contain the norbornene group. The cyclic 
dienes that are useful herein contain unsaturation outside of the 
norbornene group, as in the double bond in ethylidene norbornene or as in 
cyclopentene attached to the norbornene group in dicyclopentadiene. An 
example of such a dispersant is a polymer of ethylene, propylene and 
dicyclopentadiene containing a major proportion of ethylene and propylene 
and a small proportion of dicyclopentadiene. Ethylene content of such 
elastomeric polymers should be at least about 40 mole percent, preferably 
at least about 50 mole percent, a minor amount of about 5 to 50, 
preferably 10 to 40 mole percent of propylene, and a small amount of 
diene. Amount of the cyclic diene is on the order of less than about 10 
mole percent but preferably at least about 1 mole percent, and usually on 
the order of about 5 mole percent. Minor amounts of other copolymerizable 
monomers can be used as long as they do not adversely affect the 
dispersing properties of the elastomeric polymers. The 
ethylene/propylene/dicyclopentadiene elastomer having respective 
composition of 61/33.5/5.5 on weight basis, was found to perform admirably 
in terms of providing dispersing function as well as improving impact 
strength of the resulting polymer to an unexpected degree and reducing 
polymer particle size. 
Another class of suitable dispersants is based on polymeric alipatic 
dienes, containing 4 to 12, preferably 4 to 6 carbon atoms per molecule. 
This class of dispersants includes conjugated and non-conjugated, 
preferably conjugated dienes, or a mixture thereof, defined as follows: 
##STR3## 
where each X is individually selected from hydrogen, halogens, alkyl 
radicals of 1 to 5 carbon atoms, and aryl radicals. In a preferred 
embodiment, each X is individually selected from hydrogen, chlorine, and 
alkyl radicals of 1 to 3 carbon atoms. Particularly preferred dienes are 
butadiene, chloroprene, isoprene, and mixtures thereof, especially the 
nonconjugated dienes such as 1,3-butadiene and 1,4-hexadiene. These dienes 
can be copolymerized with up to about 50% by weight of other polymerizable 
monomers such as vinyl aromatic compounds, specifically, styrene and 
alpha-methyl styrene. Specific examples of this class of dispersants 
include polystyrene-polybutadiene diblock copolymer with a composition of 
25/75% by weight respectively, 48/52% by weight diblock copolymer of 
polystyrene/polybutadiene, 23/77% by weight random block copolymer of 
polystyrene/polybutadiene, and cis-polybutadiene homopolymer. 
Amount of the dispersant added to the dispersion polymerization system 
should be sufficient to form a dispersion containing smaller polymer 
particles than without the dispersant, and in a preferred embodiment, the 
polymer particles dispersed in the diluent do not immediately settle out 
after stopping agitation. It should be understood that as long as the 
polymer particles remain in the dispersion or can be easily re-dispersed, 
the plugging of pipes, valves and pumping equipment can be reduced 
substantially due to the enhanced facility to move the polymer particles 
through conduits without settling where some agitation is always present 
and its magnitude is sufficient to maintain the particles in suspension. 
More specifically, amount of the dispersant should be at least 1 part, 
preferably 1 to 20 parts, and more preferably 2 to 10 parts per 100 parts 
of monomer charge. 
To achieve the desired results, dispersion polymerization process described 
herein should be carried out pursuant to a defined procedure. The first 
step of the process comprises the addition of a diluent and a molecular 
weight modifier to a reactor equipped with an agitator. Normal pentane is 
the preferred diluent and 1-pentene is the preferred molecular weight 
modifier. Generally, one-half to two liters of a diluent is used per 100 
grams of the monomer charge, although a small portion is used to pre-blend 
certain ingredients. Up to one mole of the modifier can be used per mole 
of the monomer charge. Next step is to dissolve the dispersant in 
n-pentane and add the solution to the reactor. A small amount of toluene 
is added to the diluent to facilitate solubility of the dispersant in the 
diluent, amount of toluene being about 100 to 300 ml per 10 liters of 
diluent. This step is followed by addition to the reactor of the monomer 
charge dissolved in the diluent and then the catalyst and cocatalyst also 
dissolved in a diluent or another solvent. In a preferred embodiment, the 
catalyst is predissolvent in an alkyl ester of a saturated carboxylic 
acid, such as ethyl acetate, to a concentration of 1 to 10% solids and the 
cocatalyst is predissolved in a diluent to about 20 to 30% solids. Upon 
addition of the catalysts, initiation is instantaneous and the 
polymerization is conducted at about 10.degree. C. to 80.degree. C., 
preferably at 25.degree. to 60.degree. C. with agitation at a pressure of 
atmospheric to 15 psig and higher, preferably 5 psig. The reaction is 
complete in about 0.2 to 1.5 hours, completion being indicated by total 
solids content. Total solids content is indicative of the degree of 
conversion and the reaction is deemed to be complete when all of the 
monomer is converted, as indicated by the weight of polymer obtained. The 
reaction product is a dispersion of discrete polymer particles suspended 
in a diluent. The particle size is generally on the order of about 0.1 
millimeter, more specifically, about 0.3.times.0.2 millimeter compared to 
about 1.times.3 millimeter for conventional slurry polymerization product 
prepared in absence of a dispersant. In a preferred embodiment, the 
dispersion is stable and the particles remain in suspension after stopping 
agitation. The dispersion is refined and dried to a free-flowing 
particulate product. 
The sequence of steps described above should be followed in order to obtain 
the desired results. For instance, dispersant must be in the 
polymerization system prior to addition of the monomer charge since. Since 
initiation of the reaction is instantaneous upon addition of the 
catalysts, as was already described, it follows reason that the catalysts, 
especially the molybdenum or tungsten compound catalyst, should be added 
last. 
In order to illustrate the invention disclosed herein, the following 
examples are presented that demonstrate different materials and different 
reaction conditions used in preparing polymeric cycloolefins by the 
dispersion polymerization technique.

EXAMPLE 1 
This experiment demonstrates the use of a polymer of ethylene, propylene, 
and dicyclopentadiene, hereinafter referred to as EPDM, in the respective 
monomer weight ratio of 61/33.5/5.5, as a dispersant in the dispersion 
polymerization of dicyclopentadiene (DCPD), methylnorbornene (MNB), and 
methyltetracyclododecene (MTD) in the monomer weight ratio of 50/25/25. 
The ingredients used in the dispersion polymerization system were as 
follows: 
______________________________________ 
Volume Basis 
Weight Basis 
______________________________________ 
Pentane 5000 ml 3.1 kg 
DCPD, MNB & MTD 
Monomers 481.6 ml 461.4 g 
Pentene-1 300 ml 192 g 
Toluene 100 ml 86 g 
EASC Solution 4.34 ml 3.19 g 
MoCl.sub.3 Solution 
4.37 ml 4.11 g 
EPDM Dispersant -- 46 g 
______________________________________ 
The EASC solution was ethylaluminum sesquichloride cocatalyst, (C.sub.2 
H.sub.5).sub.3 Al.sub.2 Cl.sub.3, dissolved in hexane at a concentration 
of 24.8% and the MoCl.sub.5 solution was molybdenum pentachloride 
dissolved in ethyl acetate at a concentration of 5%. 
The EPDM dispersant was dissolved in a portion of the pentane and toluene 
mixture and held separately. Pursuant to the dispersion polymerization 
procedure, the ingredients listed above were added to a stainless steel 
stirred tank reactor in the following order, with agitation in progress: 
pentane, the EPDM dispersant solution, monomers with the alkylaluminum 
halide cocatalyst solution, pentene-1 molecular weight modifier, and 
lastly, the molybdenum halide catalyst solution. The polymerization 
reaction commenced immediately after addition of the catalyst as evidenced 
by the temperature rise. The reaction was initiated at about 25.degree. C. 
at atmospheric pressure, and was completed in about one-half hour. The 
reaction was conducted adiabatically, i.e., without adding or removing 
heat, with temperature rising due to the exothermic reactions from about 
25.degree. C. to about 55.degree. C. The final temperature was about 
55.degree. C. The reaction product comprised polymer particles suspended 
in the diluent that remained in suspension after agitation was stopped. 
The particle size was very much smaller than the polymer particles 
obtained by slurry polymerization in absence of a dispersant. 
The polymer dispersion was mixed with about 2500 ml of Fotocol, a 90% 
ethanol mixture with about 10% impurities, in a glass flask and filtered 
through filter paper using an excess amount of Fotocol. The filtered 
polymer was reslurried in about 2500 ml Fotocol that contained 3 parts by 
weight of CAO-5 hindered phenol antioxidant, 1 part of methyl zimate 
thermal stabilizer, and 1 part of Goodrite 3125 antioxidant, based on 100 
parts by weight of the polymer. Following agitation, the Fotocol was 
evaporated and then the polymer was dried in a vacuum oven under high 
vacuum for 4 hours at 40.degree. C. The product was granular and 
free-flowing, with an average particle size of about 0.05 millimeter. 
Other DCPD/MNB/MTD terpolymers at 50/25/25 weight ratio were prepared by 
dispersion polymerization technique, as described above, using different 
dispersants and at different levels. Results of these experiments are 
tabulated in Table I, below, where ratio of the monomers in the dispersant 
is in parts by weight: 
TABLE I 
______________________________________ 
Mol. Parts of 
Wt. of Dispersant Product Type 
Dispersant Dis- Per 100 Parts 
And Max. 
Composition 
persant Monomers Particle Size 
______________________________________ 
Ethylene/ 
Propylene/ 
DCPD Stable Latex 
(61/33.5/5.5) 
190,000 10 &lt;&lt; 0.1 mm 
Ethylene/ 
Propylene/ 
DCPD Stable Suspension 
(61/33.5/5.5) 
" 5 0.1-0.2 mm 
Styrene/ 
Butadiene Stable Suspension 
Diblock (25/75) 
83,000 10 0.1-0.2 mm 
Styrene/ Less stable 
Butadiene Suspension 
Diblock (25/75) 
" 5 0.2-0.5 mm 
Styrene/ Less stable 
Butadiene Suspension 
Diblock (48/52) 
85,000 5 0.2-0.5 mm 
Styrene/ 
Butadiene Less stable 
Random Block Suspension 
(23/77) 300,000 7.5 &lt;&lt; 0.1 mm 
Cis-Polybutadiene Less stable 
Suspension 
140,000 5 &lt;&lt; 0.1 mm 
Ethylene/ Slurry and Paste 
Propylene (no dispersion) 
(55.5/45.5) 
130,000 10 0.1-2 mm 
Polystyrene 
Un- Slurry 
known (no dispersion) 
7.5 about 2 mm 
______________________________________ 
In the above table, stable latex defines a latex containing superfine 
polymer particles which do not precipitate or settle out over an extended 
period of time of about one-half year; stable suspension is characterized 
by the presence of polymer particles that precipitate or settle out over a 
12-hour period after stopping agitation; and less stable suspension is 
characterized by polymer particles that begin to precipitate upon stopping 
agitation and settle out over a one-hour period. These particles do not 
tend to agglomerate whereas in case of a slurry polymer, the particles 
settle out almost immediately after stopping agitation and the particles 
tend to agglomerate. The particle size given in Table I, above, is the 
maximum particle size, with an average particle size being roughly about 
one-half of the maximum. 
The monomers that were polymerized in the presence of the above-identified 
dispersants at 5 to 10 parts per 100 parts of the monomers, produced 
polymer particles of this invention that were much smaller than the slurry 
products produced without any dispersant and the particles remained 
dispersed over a period of time, although in some instances, the particles 
settled out in a period of about one hour. A general trend was observed in 
that the dispersion became more stable and the particle size became 
smaller as the rubber or the dispersant concentration increased. The most 
stable dispersion was obtained with the 
ethylene/propylene/dicyclopentadiene or EPDM dispersant. At 10 parts of 
the EPDM dispersant, the dispersion was extremely stable, with the 
particles remaining in suspension for over one-half year. At 5 parts of 
the EPDM dispersant, however, the dispersion was less stable and some 
particles settled out slowly over a 12-hour period in absence or 
agitation, although some fine particles remained suspended for months. 
The polystyrene-polybutadiene (25/75) diblock copolymer, at 10 parts level, 
also gave a reasonably good dispersion in that only a minor fraction of 
the particles settled out over a 12-hour period. The 
polystyrene-polybutadiene (48/52) diblock copolymer, however, did not give 
as stable a dispersion as the 25/75 polystyrene-polybutadiene diblock 
copolymer. At 10 parts and at 5 parts level of the 48/52 SB copolymer, the 
dispersions were less stable and the bulk of the particles began to settle 
out upon stopping agitation. 
The polystyrene-polybutadiene random block copolymer and cis-polybutadiene 
did not give stable dispersion although these dispersants also produced 
fine polymer particles and a suspension of some super fine particles that 
lasted over a period of one week. 
In addition to yielding dispersions of polymer particles, the EPDM and 
polystyrene-polybutadiene random block dispersants also caused a 
substantial reduction in the build-up of polymer on the interior of the 
stainless steel reactor, and results were similar with a glass reactor. 
This property appears to be consonant with the dispersing properties of 
the dispersants. The build-up of polymer on reactor walls for the 
dispersion polymerization was much less than for slurry polymerization. In 
the dispersion polymerization systems, the polymer build-up on reactor 
walls diminished as the dispersion became more stable. Where stable latex 
was produced, the polymer build-up was nearly nonexistent and the interior 
of the reactor was clean. 
Of all of the dispersants tested, the EPDM dispersant appears to be the 
most active in bonding chemically to the cycloolefin terpolymers and in 
forming steric barriers. In general, the effect of steric barrier in a 
dispersion system is to lower the interfacial tension thus reducing the 
energy required for phase separation and also reducing the threshold 
molecular weight for precipitation. This is believed to be due to the 
carbon to carbon double bond (C.dbd.C) in the pendant 5-carbon ring of 
dicyclopentadiene in the EPDM dispersant which appears to be more 
functional than the C.dbd.C in the backbone chains in the other 
dispersants that were tested. This conclusion is supported by the results 
for the ethylene/propylene copolymer and polystyrene dispersants, both 
being saturated polymers. These experiments did not result in a dispersion 
but a slurry containing particles of about 0.5 mm in diameter and the 
particles were as clearly separated from the diluent as in a slurry system 
prepared without any dispersant. Therefore, the C.dbd.C bonds, especially 
the ones in the pendant group and less significantly the ones in the 
backbone chains, appear to be responsible for the presumed coupling 
reactions which bring about the formation of a dispersion. 
EXAMPLE II 
This example demonstrates improved impact strength of cycloolefinic 
terpolymers prepared by dispersion polymerization in the presence and 
absence of a dispersant. 
The terpolymer was 
dicyclopentadiene/methylnorbornene/methyltetracyclododecene (DCPD/MNB/MTD) 
at 50/25/25 weight ratio prepared as described in Example 1 in absence and 
in presence of 10 parts of ethylene/propylene/dicyclopentadiene (EPDM) 
dispersant having weight ratio of 61/33.5/5.5 per 100 parts of the monomer 
charge. The terpolymer samples also contained 1 part by weight of CAO-5 
antioxidant, 1.5 part of methyl zimate thermal stabilizer, 1 part of zinc 
oxide costabilizer, and 1.5 part of Goodrite.RTM. 3125 antioxidant, but no 
other additives. The heat distortion temperature (HDT) was determined by 
the ASTM D-648 test and the Izod impact resistance at room temperature and 
at -40.degree. C. was determined pursuant to ASTM D-256 test. The results 
are given in Table II, below: 
TABLE II 
______________________________________ 
R.T.Izod -40.degree. C. Izod 
Polymer HDT ft-lb/in ft-lb/in 
______________________________________ 
A. DCPD/MNB/MTD 
(50/25/25) 
Slurry 98.degree. C. 
1.2 0.8 
Without Dispersant 
B. DCPD/MNB/MTD 
(50/25/25) 
Dispersion 87.degree. C. 
14.3 11.8 
With 10 parts EPDM 
Dispersant 
______________________________________ 
As is shown in the above table, 10 parts of the EPDM dispersant used in the 
preparation of the terpolymer incredibly increased its room temperature 
and -40.degree. C. Izod impact strength from 1.2 to 14.3 ft-lbs/in and 
from 0.8 to 11.8 ft-lbs/in, respectively. Although the EPDM-containing 
polymer had a lower heat distortion temperature of 87.degree. C. v. 
98.degree. C. for the blank slurry polymer, this value is still more than 
high enough to qualify the polymer for various engineering plastic 
applications. Plastic applications for the dispersion polymer of this 
example, and other dispersion polymers disclosed herein, include plastic 
prototype parts, solar panels, potting compounds for electronic 
components, and parabolic dishes for microwave receivers.