Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
~o~43
The present invention relates to a process for the
high yield polymerization of ethylene and 1,3-butadiene
to give copolymers characterized by :
i) high chain linearity
ii) narrow molecular weight range,
iii) substantially complete 1~4-trans configuration
-~ of the butadiene units,
iv) statistical inter- and intramolecular distribu-
tion of the monomer units,
v) low content of residual vanadium~ even without
any purification stage,
such copolymers being vulcanizable by means of usual sulphur
base recipes in order to produce cross-linked products
similar to high density polyethylenes which~ however~ have
improved mechanical~ thermal and chemical properties.
Ethylene-butadiene copolymers are known from the art,
' however no known product has contemporaneously the above-
said characteristics.
They all are to be deemed indispensable when a product
is desired having substantial advantages with respect to
polyethylenes.
In fact the chain linearity, e.g. the substantial
absence of intermolecular cyclizations, cross-linkings and
transversal bonds, warrants a low flowing of the melted
polymer and enhances the workability and the extrudibility
thereof.
- The narrow molecular weight range~ combined with the
chain linearity, ensures the copolymer to have better me-
chanical properties, such as the impact resistance, under
the same molecular weight, and other characteristics.
~,~ , .
. - . ' ~ ~ -
iO~3'~
The low polydispersity polymers are the most suitable
to be used in the transformation techniques based on the
centrifugal moulding, the injection moulding of large manu-
factured articles~ fiber spinning and others.
The 1,4-trans addition of butadiene units into a poly-
ethlene chain is the only one which does not disturb nota-
bly the crystalline structure of this last polymer~ at least
at not high contents of copolymerized butadiene. As a
consequence the physical properties (melting point~ density~
etc ) of the copolymers, which are indeed able to vulcanize
at high rates, are not sensitively different from the ones
of high density polyethylene.
The statistical distribution of the monomeric units,
both inside the single macromolecule and between a macro-
molecule and the other one~ is a necessary feature for the
whole polymer undergoing a homogeneous cross-linking.
Only such copolymers n~ay be high yield vulcanized to give
products having physical-mechanical, thermal and chemical
properties better than the ones of the best polyethylenes.
At last the low vanadium content is also an important
characteristic of ethylene-butadiene copolymers since9 -
because of the presence of double bonds, oxidation react- -
ions have to be avoided in which vanadium acts as a catalyst. ~ ~`
Moreover vanadium salt rests, if present in appreciable
; 25 amounts~ give the copolymers unwished colourings. The use
of catalysts producing high yields of copolymerization,
besides removing the cited drawbacks, allows to run simple - `
processes from which the washing phase of the obtained poly-
mer is lacking.
All abovesaid is necessary in order to let the prepara-
tion of ethylene-butadiene copolymers be interesting from an
industrial point of view.
~ . . . . .
.:.. .. .. - ::. ,: . ,. . . .: . : :
... .. ..
The different behaviour under polymerization of the
monomers, e.g. ethylene and butacliene, explains the difficulty
of obtaining, directly from the polymerization of mixtures thereof
copolymers having the abovesaid properties.
Characteristics and properties of the ethylene-butadiene
copolymers are strictly dependinq on the preparation process and,
therefore, on the particularly used catalyst. The known catalyst
systems, employing titanium, vanadium or chromium compounds as the
transition metal compound, besides not warranting the formation
~ 10 of copolymers having all the abovesaid characteristics, do not
; give sufficiently high polymerization yields.
In Canadian applications Nos. 094,055, 155,084 and 188,555,
Applicant has described the preparation of ethylene-butadiene
copolymers which may be homogeneously cross-linked`by means of
sulphur base recipes, however the catalysts therein described are
not very active when relatively low molecular weight products are
desired.
It has now been surprisingly found that it is possible
to obtain high polymerization yields of ethylene-butadiene
copolymers characterized by high chain linearity, narrow molecular
weight range, almost complete 1,4-trans configuration of the
butadiene units, inter- and intra-molecular statistical
distribution of the monomeric units, low vanadium content, the
process consiting in polymerizing, under the conditions herein-
after reported, ethylene and butadiene mixtures in the presence
of one or more aromatic solvents and a catalyst system consisting
of:
a) one or more vanadium compounds soluble in the
abovesaid solvents;
b) one or more aluminium compounds having the general for-
mula R1R2AlX in which R1 ancl R2~ the same or different~
are alkyl, cycloalkyl~ alk~laryl ~r aryl radicals con-
taining from l to 18 carbon atoms or hydrogell and X is
chlorine or bromine;
c) one or more acid compounds according to Le~is or
Br~nsted;
d) one or more organic compounds containing in the mole-
cule at least C~3 group, X being a halogen.
Tle vanadium compounds referred to in point (a) include
.10 tetra- and pentavalent and complexed trivalent vanadium
halides, vanadium and vanadyl alcoholates, chelates compounds
and complexes. The term "complexes" refers to all compounds
containing bonds between vanadium and mono- or biclentate
organic ligands, wherein "ligand" means an ion or a molecule
bound to metal or deemed to be bouncl to metal and the terms
~ mono- and bidentate~ mean a molecule having one or, .. :
respectively~ two positions therewith it can form covalent
or coordination bonds with the metal. ~.`
Examples of vanadium compounds which may be employed ;`
are : vanadium tetrachloride (preferably stabilized in
~iC14 solution), vanadyl trichloride, vanadium trichloride
complexed with three molecules of tetrahydrofuran, vanadium
triacetylacetonate, vanadyl diacetylacetonate, vanadyl tri -
isopropylate, tetra(dimethylamide) vanadium, etc.
The components (b) of the catalyst system are aluminium
dihydrocarbylhalides~ among which a preferred use is made
of diethylmonochloride and diisobutylmonochloride owing --
to cost and availability reasons~ Similar results are obtain-
. ed by employing the corresponding bromine derivatives. Also
aluminium hydrocarbyl halide hydrides may be advantageously
employed.
The components (c) of the inventive catalyst are all
.,
.
.
.
_............. .. .
1~;1 L~
acid compounds according to Lewis or Br~nsted and include
both polyhalogenated compounds of metals belonging to the
III or IV group oE the periodic system~ and the compounds
- able to free H+ ions~ that is organic acids~ inorganic
acids and water~ provided that they are sufficiently soluble
in the hydrocarbon reaction medium or are solubilized when
reacting with the other components of the catalyst system.
Examples of such compounds are boron trichloride, aluminium
trichloride, aluminium monoethylchloride, aluminium mono-
isobutyldichloride, aluminium tribriomide~ tin tetrachloride~
acetic acid, benzoic acid, water, etc.
The components (d) of the catalyst system are~ as
already said, those organic compounds containing in their
molecule one or more groups CX3~ X being halogen Parti-
cularly active are trichloroacetic acid esters besides the
free acid itself. Also active~ even if with lower capacities~
are p.chloro-trichlorotoluene~ trichloroacetic acid chloride~
carbon tetrachloride.
The molar ratio between the components (b) and (a) is
usually high since the vanadium compound is used in very
little amounts. Said ratio is high than 10 : 1 and usually
ranging from 50 : 1 to 100 : 1. However, when the vanadium
concentration is lower than 5 . lO-5 mole/litre, the Al/V
ratio is preferably ranging from 100 : 1 to 500 : 1 . The
best amoun-t of the vanadium compound is comprised between
1 . 10-4 and 1.10-5 mole/litre, whereas the aluminium
compound is comprised between 1 and 8.10-3 mole/litre.
The molar ratio between the components (c) and (b) is
critic. It, when (c) is a multihalogenated inorganic or
organometal compound, may be defined as the global ratio
between the gramatoms of halogen and the aluminium ones
contained in the reagents (b) and (c). The ratio X/Al must
6.
: .
1.1)~3~4;~
be comprised between 1 and 1.25 or~ preferably~ between
1.05 and 1.15.
When (c) is a protonic acid or water, the ratio between
(b) and (c) is selected from the range of from 10 : 1 to
1 : 1 or~ preferably~ from ,4 : 1 to 2 : 1. ;
The molar ratio between the components ld) and (b)
of the catalyst may widely vary, also in function of the
particular compound (d) and the reaction formalities, It
is generally lower than 1 and is preferably selected from
the range of from 1 : 4 to 1 : 1 . -
All aforesaid reactions are carried out in the presence
of a-hydrocarbon that, according to a peculiar feature of :
the present invention, is of the aromatic type However
use may be made also of mixtures constituted by aromatic
hydrocarbons with aliphatic and cycloaliphatic hydrocarbons~
halogenated aromatic hydrocarbons or mixtures thereof with
the abovesaid ones or with other hydrocarbons containing
halo~ens.
Therefore, even if a preferred use is made of benzene
- 20 or toluene, it is possible to use chlorobenzene or mixtures - .
constituted by benzene-cyclohexane~, toluene-n-heptane,
chlorobenzena-tetrachloroethylene, etcO
The polymerization temperature widely ranges. The
operations are gener:a~y carried out at temperatures higher
than the room one in order to prevent from using expensive
. freezing cycles.
Therefore the most suitable range is comprised from.
50 to 100C, also if a wider range must be employed so that
.. the range would be from 0 to 120C.
; 30 The polymerizations are carried out under high ethylene
,
- pressures (2 - 20 kg~cm ).
If necessary~ hydrogen too is added in order to regulate
7.
., .
3~
the molecular weights.
Ethylene-butadiene copolymers, obtainable according
to the aforedescribed proce~s, are free from gel, branchings
and internal cyclization as it is possible to check from
infrared and nuclear magnetic resonance spectra and from
the hot complete solubility thereof in hydrocarbon and
chlorohydrocarbon solvents
The narrow molecular weight range, together with a high
chain linearity, is emphasized by the flowing measurements
; 10 in the melted stated~ according to ASTM 1236-65T rule. The
ratio between the flow indexes measured by applying weights
of 21.6 kg (MFI21 6) and 2-16 kg (MFI2 16)~ respectively~
is said "shear sensitivity" and is, on the abovesaid copo-
lymers~ comprised between 10 and 50.
Lower the average molecular weight~ lower this ratio
and~ at the same molecular weight~value, that ratio is lower
i~ the polymer is more mo~odispersed and free from branch- `
ings ( R. Martinovitch~ P. J. Boche~ R.A. McCord~ SPE J. 16,
1335 (~971) ).
The molecular weight of the inventive copolymers,
expressed as M~ M and determined by a gel-permeation chro-
matography (Polymer Fractionation, M~J~Ro Cantow~ Academic
Press N.Y.~ 1967) ranges from 2 to 3.
The butadiene unit amounts (butadiene moles per 100
moles of both monomers) can widely range, e. g. from 0.1
to more than 10~ and is regulated in view of the foreseen
employment~ The products, having a higher interest for the
following transformation in cross-linked manufactured
articles, contains 0.5 to 5 % by mole copolymerized butadiene.
Copolymers having less than 0.~ % butadiene undergo a
"regradation" in the presence of vulcanizing agents: co-
polymers having more than 5% unities are interesting,
8.
. . . :
1~3~4;~
besides their low cost~ because of their compatibility with
other high unsaturation polymers.
The 1,4-trans-butadiene units consti-tute, as from the
infrared spectrography, at least 98% of all copolymerized
butadiene. In fact bands awardable to unities of the cis
or 1,2 type are not relevant. The quantitative determina- `~
tion of butadiene contained in copolymer is therefore per-
formed based on the band a-t 965 cm 1 according to known
techniques.
The in~er- and intramolecular statistic distribution
; of the inventive copolymer monomer unities is confirmed by
the fact that the polymerization raw product may cross-
link~ whatsoever fraction is consitlered, when subjecting to
curing by means of conventional sulphur or sulphur clonors
or quinone compounds base recipes~ h or witllout acce~era-
tors or inert charges. The cross-linking rate is moa~ured
by the value of the maximum couple achievecl at Zwick curing
device or by the insoluble portion~ after 24 hours~ in boil-
ing xylene, and is expressed as gel percentageO It is a
;~ 20 function of the average molecular weight~ molecular weight
distribution, unsaturation content of copolymer~ besides the
employed vulcanizing mix, and generally ranges from 30 to 90
` with respect the final product.
According to the inventive process, ethylene-butadiene
copolymer is obtained with such high yields that it is
` possible to eliminate the washing phase of the polymerization
raw product, since the few catalytic residuals may remain
in the polymer itself. In fact residual vanadium is general-
` , ly lower than 50 ppm.
Ethylene-butadiene copolymers are highly crystalline at
X-ray examen. Their crystallinity is, in the interesting range
the typical one of high density polyethylene~ The lack of the ~;
crystallinity typical of 1,4-trans-polybutadiene~ also for
. .
- 9.
1~ `
1~3~4;~' :
contents higher than 10 % of these structural unities9 is
a further evidence of the statistic c~stribution of ethylene
and but~diene unities.
~ t last the copolymers density is not very different
from the linear polyethylene one and ranges from 0~950 to
0.960 g/m ( rule ASTM D 150';-68).
The cross-linked products obtainable from the inven-tive
ethylene-butadiene copolymers are interesting because of
several practical applications.
Inter alia we emphasize the preparation of stiff foamed
materials (very good insulating) and sound proofing materials
burning without any black smoke emission), stiff containers~
piper, pipe coating jackets, etc.
When practically used~ the cross-linked copolymers
have, with respect to polyethylenes~ higher mechanical cha-
racteristics, such as ultimate tensile strength and the impact
resistance (rule ASTM D 256~56)~ improved stress-cracking
resistance (rule ASTM D 1693), low decreasing of the flexibi-
lity modulus (rule ASTM D 747) and a substantial inertia
towards oils and solvents.
Ethylene-butadiene copolymers~ which are not cross-linked,
may be utilized as intermediates in the preparation of di-
functional olefin monomers following a suitable demolition of
the unsaturated chain.
Some data of the properties till now listed~ as also
vulcanizing recipes and conditions, are reported in the
- Examples hereinafter reported, supplied for the mere purpose
of better illustrating the invention without limiting the sameO
EXAMPLE
Use was made of a steel autoclave having 5 l capacity~
provided with a mechanical stirrer~ a thermoregulating appa-
10.
:' ~ . . -
r~
-
lU~3~3
ratus~ electrical detector~ a manometer and inlet valves:
therein was introduced a solution obtained from : 1800 ml
of anhydrous toluene
_ - 1.35 ml of Al(C2}15)2Cl
- 0.12 g of Al(C2H5)Cl2
- 40 g of butadiene
The Cl/Al ratio of the mi~Yture was 1.1 .
The autoclave was thermostated at 80C~ then were
introduced
- ethylene 14 atm.
- hydrogen 6 atm.
Through a piston pump~ was injected a toluene solution
(200 ml) containing 17 5 mg of vanadium-triacetylacetonate
and g 1.06 of methyl trichloroacetate over about 20 minutes.
The Polymerization started as soon as the solution
was introduced, it prosecuted over 90 minutes~ during which
consumed ethylene was continuously replaced by keeping the
pressure constant at 20 atmospheresO
The test was stopped by introducing 25 ml of methyl
alcohol. The polymer, collected by filtering the suspension
and vacuum oven dried at 50C, was under the shape of a
white powder and weighed g 165 in the dry state. The yield ~
was 66,ooo g for gram of metallic vanadium. Contained 1,4- `;
- -trans-butadiene units (IR analysis) = 2.8 % by mole.
The other characteristics of the polymer as such are the
following ones
- MFI2 16 = -7 g/10l
~ MFI21 6 = 23 g/10' (shear sensitivity = 40)
- density = 0.9547 g/ml
- M /M = 2.25
- me~ting point (at the polarizer microscope) = 131C~
:
11 . -
~ .::: ' '` ~ ' ' '
The raw copolymer was prcss -treatetl for 30' at 180~
after having been mixed with the Eollot~in~ ingreclients
(parts referre(l to 100 part,s o~ polymer) -
- ~.inc oxide 5
- stearic acid
- 2~2~-dimethyl-bis(4 methyl-terbutylphenil)
- N-oxidiethylbenzothiazole-2-sulphenamide
(NOBS Special) l.5
cnzothiazyl-disulphicle (Vulcacit D~l; trademark) 0,5
_ sulphur 3
The product~ thus obtained~ had a gel content (insoluble
in boiling xylene) c~E 80 % and showed the characterist.ic re-
ported in the ~ollo~ing table (next to the values oE the
polymer as such ) :
Polymer cross~linked
` as sucll pol~mer
Impact resistance (kg.cm/cm ) 7.2 62.5
Yield stress (kglcm2) ' . .248 198
Ultimate tensile stress (kg/cm ) 267 275
Elongation at break (%) . 1600 578
,` Stress cracking (h) O 500
- Flexion modulus (kg/cm ) 7800 ~6700 -~
EXA~-SPLE 2
- By employing the apparatus and according to the condi-
tions of Example 1~ a test was carried out by using the follow-`
- ing reactants O
- anhydrous toluene ml 1800
( ~ 5)2 ml. 1035 ~ :
' - ~l(C~115)Cl2 0,12
- buta~iene g 40
and~ af-ter thermostating at 800C~ ethylene up to 10 kg/cm
and hydrogen up to 20 kg/cm , in this sequence. The ratio
1~4;~
; between the two partial pressures was about 1
Over 30 minutes~ the autoclave was gradually charged
with a toluene solution (200 ml) containing 35 mg of V tri-
- acetylacetonate and 1.06 g of methyl trichloroacetate. During
the test ethylene was fed so that to keep constant the start-
ing pressure of 20 kg/cm2.
The polymerization was stopped after 90 minutes by
introducing 25 ml of methyl alcohol. The polymer was
isolated from the suspension through a filtration and a
vacuum drying at 50C. 148 g of a product were obtained
(29.000 g for gram of metallic vanadium)~ it being a -finely
subdivided white product that, at infrared analysisg showed
. a 3.3 % content of 1~4-trans-butadiene units~ had a MFI2 16
equal to 12.5~ a MEI21 6= 295 (shear sensity = 23~5)o
The raw copolymer was subjected to cross~linking by
using the mix and the conditions already disclosed in
Example 1. The cross-linked product had a gel content of
53 % and showed an impact resistance of 16.3 kg,cm/cm
` (versus 2.6 kg.cm/cm2 of the polymer as such) The flexion
modulus was 7,200 kg/cm (versus 9,900 kg/cm of the start-
ing polymer).
EXAMPLE 3
: By using the autoclave of Example 1, a polymerization
was carried out starting from following reactants : ~-
:; 25 - anhydrous toluene ml 1800
-~ - butadiene g 40
_ Al(c2Hs)2cl ml 1 (802 mM)
- Al(C2H5)C12 g 0.096(0.8 mM)
The autoclave was thermostated at 800C and pressured by
ethylene (partial pressure 14 kg/cm2) and hydrogen (partial
pressure 6 kg/cm ).
The temperature being constant, a toluene solution was
130
.. - ` ~
3~
gradually added over 30 minutes (200 cm3) it being consti-
tuted by 35 mg of vanadium triacethylacetonate and 0.53 g of
methyl trich]oroacetate. Consumed ethylene was reinstated
- by letting the total pressurle be constant at 20 kg/cm2 .
The test was interrupted after 45 minutes by adding 25 cm3
of methyl alcohol.
Obtained polymer, after drying, weighed 147 g, contained
(IR analysis) 2.3 % of 1.4-trans-butadiene units, MFI2 16
equal to ~.8 g/lO~ and MFI21 6 equal to 88 3 g/lOt ( shear
sensivity = 18).
The M /M ratio, determined through gel permeation~ was
2.12. After a cross-linking in the presence of sulphur accord-
ing to the recipe described in Example 1, a product was obtain-
ed having 75 ~ gel, and having an impact resistance of 36.2
kg.cm/cm2 (against 3.9 kg.cm/cm2 of not cross-linked poly-
mer)
EXAMPLE 4
.
In the autoclave of Example l was introduced a solution
consisting of
- anhydrous toluene ml 1800
- butadiene g 20
~ Al(C2HS)2Cl ml 2
- CC13COOH g o.654
The autoclave was thermostated at 80oC~ then ethylene was
fed till to a pressure of 9 kg/cm2 and hydrogen at a partial
pressure of 4 kg/cm2 (total pressure equal to 13 kg/cm2).
Over 20~ were fed 70 mg/vanadium triacetylacetonat~,
~ dissolved in 200 ml of toluene, while temperature and pressu-
re were kept constant (the latter by adding ethylene again).
The polymerization was stopped after 60~. The polymer~
treated as abovesaid (see Example 1) weighed~ in the dry state
137 g (13,700 g for gram of metallic vanadium). It contained
14.
1C~43~
2.1 % o~ 4-trans-butadiene units and had the following
fluidity indexes : MFI2 16 = 7.o6 g/10'; M~I21 6 = 184~8
g/10' (shear sensitiv,ity = 26. 2 ),
~- Under cross-linking according E~ample l~ copolymer cross-
linked in an amount equal to 58 %.
EXAMPLE S
By using the same abovesaid apparata ( E~ample l)~ a
'` copolymerization test was carried out with the following
reactants :
10 - anhydrous toluene ml 1800
- butadiene g 20
- Al(C2H5 )2Cl ml 1.25
~ Al(C2H5)Cl2 0.12
- ` CC13COOH g 0 49
The solution, thus obtained~ was put in an autoclave
and thermostated at lO5~C. Then ethylene and hydrogen were
added at partial pressure of 19 and 1 atm., respectively.
The polymerization started after the introduction of
a toluene solution of vanadium triacetylacetonate (52 mg
20 in 200 ml) carried out over 12 minutes. The polymerization
was stopped after 75 ' by adding 25 ml of methyl alcoholc
150 g of dry polymer were isolated having the following
characteristics :
- trans 1,4-butadiene units 1.2 % (by mole)
,~ 25 ~ 2.16 0.21
' - MFI21 6 10.4
~ (shear sensitivity = 49 )
; - density 0. 955 6
- melting temperature ( at pola-
rizer microscope) 15 3C
The yield with respect to V was 19~700 grams for gram
15 .
.
.: .
43~4~
of metal.
The copolymer was 78 % cross-linked, a~ter a treatment
at 180C for 30' in the pres~nce o~ the same ingre~ients
described in Example 1.
The impact resistance o~ the cross-linked product was
71.2 kg.cm/cm2 (against 11.3 of the copolymer as such).
EXAMPLE 6
In the autoclave of Example 1 was introduced a solution
prepared starting from
10 - anhydrous toluene ml 1800
- H20 mg 72
- butadiene g 40
( 2 5)2 ml 1.5
The solution was thermostated at 800C and saturated by
ethylene up to a pressure of 1~ kg/cm . H~vdrogen was then
introduced at a partial pressure of 6 kg/cm (20 kg/cm in
all),
By keeping the temperature at 800C, firstly was intro- ~ `
duced~ over 5~ a solution of vanadyl diacetylacetonate
(26.5 mg in 100 ml of toluene) and then~ over 20~ about~ a
toluene solution of trichloroacetic acid (g 0.98 in 100 ml).
During the test, over 90~, ethylene was fed so that to
maintain the total pressure at 20 kg/cm . 190 g of dry poly-
mer were obtained that at IR analyses, contained 2.7 % of
1.4-trans-butadiene unitsJ MFI2 16 = o-38 g/10l~ MFI21 6 =
= 11.8 g/10' ( shear sensitivity = 31). The yield, as to
vanadium, was 37~700 grams for metal gram .
After a sulphur base cross-linking, the polymer had a
gel content of 82 %. The impact resistance of the cross-
~ 30 linked product was 78.5 kg.cm/cm2 ( against 1402 kg/cm2 of
-- the copolym~er as such) .
EXAMPLE 7
16.
. .-.- ~ . , .
10~3~
According to the formalities of Example 1~ in th~ auto-
clave at 105C were reacted :
- anhydrous toluene ml 1800
`~ - Al~C2H5)2Cl ml 1.35
~ Al(C2HS)C12 g 0.12
- butadiene g 20
- CCl3COC1 g 0.546
Ethylene and hydrogen were fed (at 105C) up to partial
pressures of 19 and 1 atm, respectively.
The polymerization was started by the gradual addition
of a toluene solution (200 ml) containing 35 mg of vanadium
triacetylacetonate.
The test dured 45', during which temperature and total
pressure were kept constant by an ethylene feeding.
_ obtained polymer g 48
Characteristics :
- 1.4-trans units 1.2 %
- MFI2 16 0.52 g/lO
_ 21.6 20.9 g/10'
(shear sensitivity)
~ - density 0.9562
- - ~ /M 2.18
w n
The product obtained after a sulphur cross-linking
(see Example 1) had 68 % gel, xylene insoluble at 140C,
showed an impact resistance of 65.2 kg.cm/cm2 ( against 9.5
of the copolymer as such).
EXAMPLE 8
In the autoclave of Example l were introduced
- anhydrous toluene ml 1800
- Al(C2H5) Cl ml 1.4
- Al(C2HS)Cl2 Ool
- butadiene ~ 40
17.
,~
:: '-, , ' . , , ~ ,
1~4~
After having thermostated at 80C were introduced
ethylene and then hydrogen till to pressures of 18 and 20
kg/cm2
~ Then, over 5'~ was added a toluene solution of vanadium
5triacetylacetonate (52 mg ir. 100 ml)~ and over 30~ 42 ml of
CC14 diluted by 100 cm3 of toluene.
The polymerization was stopped after 45C~ thus
obtaining 48 g of dry polymer. The characteristics of the
product were the following ones :
~ butadiene (% by mole) 1.8
2.16 12~58 g/10'
21.6 226.5
(shear sensitivity = 18.1).
The cross-linking product~ obtained according to
Example l, had a gel content equal to 62 %. :
18.
