Note: Descriptions are shown in the official language in which they were submitted.
CASE 769
1046196
The present invention relates to a process for the
polymerization of ethylene, propylene and 1,3-butadiene to
amorphous or substantially amorphous terpolymers, which may
be vulcanized with high yields of cross-linking by means
of conventional recipes hased on sulphur, characterized in
that the polymerization yields~ referred to the used cata-
lyst, are high so as to make superfluous a phase of purifi-
cation or of washing.
Ethylene-propylene-butadiene terpolymers are described
in the previous art. However, only exceptionally it is
possibIe to obtain said polymers having a statistical distri-
bution, either intermolecularly or intramolecularly of the
monomeric unities, the only one able to ensure homogeneous
vulcanization with sulphur.
The di~ferent polymerization behaviour of the mono-
olefins as to the conjugated olefins, already widely pointed
out in the literature, justifies the objective difficulty of
obtaining unsaturated gums of practical interest beginning
from ethylene, propylene and butadiene. Furthermore the
polymerization yields are not satisfactory and anyhow always
noticeably lower than the ones which may be obtained by re-
placing the butadiene with non conju~ated diolefins.
The Applicant has now surprisingly found that it is
possible to obtain terpolymers ethylene-propylene-butadiene,
amorphous or substantially amorphous and homogeneously vulca-
nizable by means of conventional recipes for unsaturated
rubbers by means of a process characterized in that mixtures
ethylene, propylene and butadiene are let to react, in the
conditions hereinafter specified, in presence of aromatic
solvents and of a catalyst prepared beginning from :
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a) one or more compounds of vanadium soluble in said
solvents ;
b) one or more compounds of aluminium having the gene-
ral formula RlR2AlX, wherein Rl and R2 ~ the same or
different, may be hydrogen, alkyl, cycloalkyl~ alkyl-aryl or
aryl with 1-18 carbon atoms and X = chlorine or bromine;
c) one or more and compounds according to Lewis or accord-
ing to Br~nsted;
d) one or more compounds chosen in the group formed by ~
1. organic compounds containing the group CX3 with ~ ;
X = halogen~ -
2. thionyl-chloride,
3. hexachlorocyclopentadiene.
The vanadium compounds mentioned in point a) comprise
tetravalent and pentavalent, and complex trivalent vanadium
halides~ the alcoholates~ the chelates and generally the
complex compounds either of vanadium or of vanadyl.
For complexes we mean all the compounds characterized
by bonds among the vanadium and unidentate and bidentate
organic binders~ where the term "bond" is defined as an ion
or a molecule bound to the metal or considered bound to the
metal and the terms "unidentate and bidentate" mean a molecule
which has one or~ respectively, two positions with which may
form covalent bonds or coordination bonds with the metal.
Characteristic examples of compounds of the vanadium
which may be used are formed by vanadium tetrachloride (pre-
ferably stabilized in SiC14 solution)~ vanadyl-trichloride~
vanadium trichloride complexed with three molecules of tetra-
hydrofurane, vanadium triacetylacetonate, vanadyl diacetyla-
cetonate, vanadyl triisopropylate~ vanadium tetra(dimethyl-
amide)~ and so on.
The components b) of the catalyst system are the alu-
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minium dihydrocarbylhalides~ among which the preferred
ones, for cost and availability reasons, are the diethyl-
monochloride and the diisobutylmonochloride of aluminium.
Similar results are obtained by making use of the
corresponding bromides. Also the hydrides of aluminium
hydrocarbyl-halides may be advantageously used.
The components c) of the catalyst object of the
present invent on are all the acid compounds according
Lewis and according Bronsted~ and comprise either the pluri-
halogenated compounds of the metals of the III and IV Group
of the periodic system~ or the compounds able to free H~
ions~ i.e the organic acids~ the inorganic acids and the
water. A condition to be respected is that they are suffi-
ciently soluble in the reaction hydrocarbon means or that are
solubilized by reaction with other catalytlc compounds.
Examples of said compounds are the boron trichloride,
the aluminium trichloride~ the aluminium monoethylchloride,
the aluminium mono-isobutyldichloride~ the aluminium tri-
bromide, the tin tetrachloride, the acetic acid~ the benzoic
acid~ the water and so on.
The components d) of the catalytic system are~ as
already specified, those organic compounds which present in
their molecular one or more groups CX3 being X the halogen.
In particular, the esters of the trichloroacetic acid and the
free acid trichloroacetic besides the thionyl chloride and the
hexachlorocyclopentadiene are active.
A certain activity but a minor one, is shown by the
trichlorotoluene~ the para-chlorotrichlorotoluene~ the chloride
of the trichloroacetic acidg the carbon tetrachloride.
The molar ratio between the components b) and a) is normal-
ly high as the vanadium compound is used in a very little
amount. Said ratio is higher than 10 : 1 and normally comprised
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between 50 : 1 to 100 : 1. HoweYer, when the concentration
of the vanadium ls lower than 5 0 10 5 mole/liter~ the
ratio Al/V is preferably comprised between 100 : 1 and
500 : 1~ While the optimum amount nf the used vanadium com-
pound varies between 1 . 10-4 and 1 10 5 mole/liter~ the
amount of the compound of aluminium varies between 1 and
8. 10-3 mole/liter. --
The molar ratio between the components c) and b) is
critical. This ratio, in the case in which c) is an inorganic
or organo-metallic plurihalogenated compound~ may be expressed
with the global ratio between the gram atoms of halogen and the
ones of aluminium contained in the reactants b~ and c).
This ratio X/Al must be comprised between l and 1.25
or~ preferably, between 1.05 and 1.15.
~5 In the case in which c) ii a protonic acid or the water~
the ratio between b) and c) i~ chosen in the range between
10 : 1 and 1 : 1 or~ preferably~ between 4 : 1 and 2 : 1.
The molar ratio between the components d) and b) of
the catalyst may vary widely, also in relation to the parti-
cular Gompound d) and to the modalities of reaction. It is
generally lower than l and is preferably chosen in the range
comprised between 1 : 4 and 1 : 1.
All the above-mentioned reactions are effected in pre-
sence of a hydrocarbon which~ according to a characteristic
of the present invention, is of aromatic type. Howe~er, also
mixtures of aromatic hydrocarbons with aliphatic~ cyclo-
aliphatic hydrocarbons or halogenated hydrocarbons and mixtu-
res with the above-mentioned ones may be used.
Therefore~ even if solvents as the benzene and the
toluene are preferred~ it is possible to use the chlorobenzene
or mixtures benzene/cyclohexane; toluene/n-heptane, chloro-
benzene/tetrachloroethylene and so on.
104~;~96
The polymerization temperature is chosen in a wide
range. Generally operation is made at temperatures higher
than the room temperature in order to avoid the use of
expensive refrigerator-cycles. Therefore the more suit-
able range i~ comprised between 20 and 800C~ even if it iB
not excluded the possibility of operation at lower or higher
temperatures~ for example between 0 and 120C.
The polymerizations are effected under moderate
pressures of ethylene (2 - 20 kg/cm2). The pressure of
propylene varies from 1 to 20 atmospheres and over~ in
function of the temperature and of the quantity of used
solvent.
For the regulation of the molecular weights is added,
if necessary~ hydrogen to the system even if a sufficient
regulation is obtained~ while the temperature of polymeri-
zation is let to vary.
EXAMPLE
In a steel autoclave with enameled inner walls~ having
the capacity of 5 liters~ equipped with mechanical stirrer
~0 and with jacket for the thermoregulation with circulating
liquid, equipped with valves~ one of which with dipping pipe,
for the introduction of the reagents~ has been introduced a
solution obtained by
- anhydrous toluene cc 670
- butadiene g 12.5
( 2 5)2 cc 1.5
- Al(C2H5)C12 g o.l65
By means of a little cylinder g 750 of propylene have
been introduced. At this point the autoclave has been thermosta
tated at 50C. -The internal pressure has rised to 13.5 kg/cm .
Ethylene has been added up to the total pressure of 18 5 kg/cm
at 50C.
:.,
`: :
1046196 ~:
By means o~ a pump it has been introduced in 20l a
solution containing 33.5 mg of vanadium-triacetylacetonate ,,,~ ~
and 0.42 cc (3.5 mM) of methyl-trichloroacetate in 50 cc of ~ -
toluene, ' ,'
Afte~ o~her 30 minutes it has been introduced slowly
(in about 40~) a second solution of toluene (50 cc) contain- ' '
ing 0.66 cc of CCl3COOCH3.
In the course of the test it has been fed the ethy~
lene consumed little by little by keeping the total pressure
at 18.5 kg/~m . The polymerization is finished after 130 ~'
minutes from the beginning.
The polymer has been coagulated wi,th methanol and
dried under vacuum at 50C: g 135 (28~500 g per gram of
metal vanadium) have been weighed.
The infs~ared analysis revealed the presence of l.2% by
weight of butadienic unities l~4 trans- and the 33 ~0 of pro-
pylenic unities. The examination with X rays shows absence
of crystallinity. The intrinsic viscosity / ~ 7 measured in
toluene at 30C is of l.5 dl/g.
The polymer has been subjected to vulcanization for 60
minutes at 150C in admixture with the following compounds , '
(parts for 100 parts of polymer): '
- stearic acid
- zinc oxide 5
- carbon black HAF So
- mercaptobenzothiazole 0.75
- tetramethylthiuramemonosulfide 1.5
- sulphur 2
The v1llca,nized product, subjected to traction~ has
given 1,he following results : tensile stress 250 kg/cm
ultimate elongation 500 %, 200 % modulus 6l kg/cm ; 300 %
modu,lus l25 kg/cm , "tension set" l5 %.
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EXAMPLE 2
ln the autoclave described in Example 1 has been
charged a solution prepared with :
- anhydrous toluene cc 700
( 2 5)2 cc ~.5
- AlBr3 g 0.21
- butadiene g 18
Then propylene has been added (g 780) and, after having
thermostatated at 50C~ethylene up to reach the total pressu-
re of 19 kg/cm2.
In the course of 20 minutes has been introduced a
solution of toluene (50 cc) wherein had been dissolved
33.5 mg of vanadium triacetylacetonate and 0.80 g (7 mM) of
thionyl chloride. Starting from the 30t minute from the
beginning~ has been introduced gradually further SOC12
(o.83 g) in toluene solution (50 cc) in a time of about 20
whereas the internal pressure of the autoclave was kept at
19 kg/cm2 (50G) by introduction of further ethylene.
The reaction product was discharged after one hour and
coagulated with methanol : g 102 of gummy polymer were obtain-
ed. This gummy polymer is formed by 1.4 % of butadiene unities
1.4 trans (Infrared examination) and by 36 % of propylenic
unities: Mooney viscosity ML 100 ( 1 + 4) = 78; the crystalli-
nity X rays was absent.
The polymer, vulcanized as described in Example 1~ has
given the following results :
- tensile stress 235 kg/cm
- ultimate elongation 480 %
- 300 % modulus 118 kg/cm
3 - "tension set" 14 %
EXAMPLE 3
In the autoclave described in the Example 1 has been
104~
effected a test at the temperature of the melting ice~ used
for the thermostatation
The ~ollowing reagents have been introduced :
- anhydrous toluene cc 720
( 2 5)2 cc 1.5
- Al(C2H5)C12 g 0.15
- butadiene g 18
- CCl 3-COOH g 0.48
- propylene g 810
After having reached the equilibrium temperature~ which
inside the autoclave is of 7C~ ethylene has been added in
such a way that the pressure of 4 kg/cm2 has brought firmly
to 6 kg/cm .
The polymerization has begun by addition of vanadium
~5 triacetylacetonate (mg 17.5) dissolved in toluene (cc 50)~
introduced in 20~ by means of a pump.
During the test~ which lasted 45 minutes~ has been -
fed further ethylene by keeping the pressure at 6 kg/cm
(at 7C).
G 52 were obtained of coagulated polymer containing
1.5 ~ of butadienic unities 1.4 trans- (weight of propylenic
unities : 32 ~ (by weight) - [~ toluene 30C: 2.3. The `
polymer results amorphous at the rays X examination.
EXAMPLE 4
In the autoclave described in Example 1~ has been intro-
duced a solution containing :
- toluene cc 720
( 2 5)2 cc 2.2
- - Al(C2H5)C12 g 0.18
- butadiene g 18
Also 770 g of propylene have been introduced by means
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104~ 6
of a little cylinder. The autoclave has been thermostatated
at 50C. The observed internal pressure was of 13.5 kg/cm
and has been elevated at 18.5 kg/cm by addition of ethylene
(whose partial pressure at 50C was therefore of 5 kg/cm ).
In the course of 10 minutes we introduced in the auto-
clave a solution prepared with
- toluene cc ~0
- V¦acac)3; acac = acetyl-acetonate mg 17.5
- CCl -COOCH cc 0.6
By keeping the autoclave under stirring~ starting from
the 20th minute from the beginning of the polymerization has
been introduced gradually (in about 20' a toluenic solution
~100 cc) containing dissolved 1.2 cc of methyl trichloro-
acetate.
The autoclave has been opened after one hour of poly-
merization. The polymer has been isolated in the usual way :
g 155~ equal to 60~000 g for gram of metal vanadium have
been obtained. The product has resulted amorphous at the
rays X examination and contains 1.8 % of butadienic unities
and 33 % of propylenic unities (by weight)~ The / ~ 7 in
toluene at 30 was of 1.5 dl/g~
10 .
