CA1052948A - Polymerization process - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE:
Homopolymers of conjugated dienes and copolymers of conjugated dienes with other conjugated dienes or with vinyl aromatic compounds having an elastomeric character are prepared by use of a catalytic system formed of the reaction product of (a) an organometallic compounds of a metal of Group IIIA of the Mendeleev periodic table of elements with (b) at least one electron-donor compound containing at least one hereto-atom.

Description

1~5'~94~
~ he pre~ent invention relates to a process of producing homopolymers of conjugated dienes or copolymer~ of conjugated dienes with other conjugated dienes or wlth vinyl aromatic compounds.
From Britiæh patent No. 1,246,914, it i~ already known to prepare in solution homopolymers of conjugated dienes - or ¢opolymers of conjugated dienes with other conjugated dienes or with vinyl aromatic compounds by means of organometallic compounds of an alkaline earth metal of the formula M1 M2 R R2 R3 R4 in which M1 represents caloium, barium, or strontium, M2 represents zinc or cadmium, and R1, R2, R3, R4 represent a hydrocarbon radical. ~he polymers obtained have a very low intrin~ic viscosity of between 0.24 and 0.62.
It is known (Chemical Abstracts, Vol. 78; 85 514 ~ (1973) and RAPRA No. 23 738 L (1974) to prepare in a hydrocarbon i reaction medium homopolymers of conjugated dienes or copolymers ; of conjugated dienes with other conjugated dienes or with vinyl '~ aromatic compounds by means of organometallic compounds of an ~ alkaline earth metal and aluminum. However, the polymers ~ 20 obtained by this process, like the polymers mentioned above, have a very low intrinsic viscosity and, therefore, do not have elastomeric properties which are sufficient to permit their use ~; as the principal component of mixtures serving for the manufacture of tires. ~urthermore, such a process of manufacture cannot be applied industrially due to the very low homopolymerization or copolymerization reaction velocity.
Finally, it is widely known that the organometallic compounds of aluminum have an extremely low or even zero intrinsic catalytic activity and that they are not considered initiators for the homopolymerization of copolymerization of conjugated dienes.
~ he applicant has discovered a new process which makes - lOSZ948 it possible industrially to obtain within relatively short times and with good yield ho~opolymers of conjugated dienes or copoly-mers of conjugated dienes with other conjugated dienes or with vinyl aromatic compounds having an elasticity similar to rubber and which can be used in the manufacture of pneumatic tires.
Therefore, the object of the present invention is a process for the homopolymerizat~on of conjugated dienes or the copolymerization of conjugated dienes with other conjugated dienes or with vinyl aromatic compounds whioh comprises reactingthe monomers at a temperature between 50C. and 120C. in the presence of a catalyti¢ system formed of the reaction product of a) an organometallic compound of a metal of Group ~ IIIA of the Mendeleev periodic table of elements having one of .~ the following formulas:
Me1 Me3 R1 R2 R3 R4 Me2(Me3R1R2 R3 R4 Me3R1 R2 R3 ~' Me1 o Me3R1 R2 ~ ~, in which Me1 represent~ an alkali metal, Me2 represents an :
. alkaline earth metal, Me3 represents a metal of Group IIIA, Rl, R2 and R3 represent an alkyl or aralkyl radical and R4 represents an alkyl or aralkyl radical or a radical XB in which .. X represent~ an oxygen, 2ulfur or nitrogen atom and B represents an alkyl or aralkyl radical, or a radical Me3(R5R6) in which R5 and R6 represent an alkyl or aralkyl radical; with b) at least one electron-donor compound containing at least one hetero-atom selected from the group consisting of aprotic polar compounds, protic polar compounds and compounds formed of the reaction product of protic polar compounds with an alkali metal or with an alkaline earth metal.
~he applicant has surprisingly found that the reaction 105'~948 product of compounds which, taken alone, are not initiators of : the homopolymerization or of the copolymerization of conjugated dienes with other conjugated dienes or with vinyl aromatic com-pounds or which have only an e~tremely low intrin~ic initiating activity constitutes an initiating catalytic system for the homopolymerization of conjugated dienes or the copolymerization of coniugated dienes with other oonjugated dienes or with vinyl aromatic compounds which can be used industrially as elastomers.
.~ ~he organometallic compounds o~ a metal of Group IIIA
10 which are particularly suitable as a component of the catalytic s~stem are those in which the alkali metal i~ lithium, sodium, or potassium, those in which the alkaline earth metal is - -magnesium, calcium, strontium or barium, and those in which the metal of Group IIIA is boron, aluminum, gallium, indium or thallium. By way of example, the following compounds can be mentioned: Al(CH3)3, Al(C2H5)3, Al(i-C4Hg)3, ~ (C2H5)4_7, a~ l (C2H5)4_7J K~ l(C2H5)4_7~ ~i ~ l(C2Hs)3 C2H5-7~
(C2H5)30 Al(C2H5)2_7~ Mg ~ l(C2H5)4-72' C2 5 g 2 5 4 a ~ l(C2H5)4_72~ Sr ~ l(C2H5)4_72, Ba ~ l(C2H5)4 72' Ba r l(C2H5~30 C2H5_72- Ba ~ l-(iso C4Hg)4_72~ ~i 0 Al (C2H5)2, (C2H5)2' ~ (CH3)3~ ~ (C2H5)3, ~i B(C2H5) ~i B (C2H5)3C4~9, Ga(C~Hs?3, In(C2H5)3~ ( 2 5 3 By way of.examples of aprotic polar compounds, there : are especially suitable the ethers ænd particularly the cyclic ~ ethers, such as tetrahydro~uran and dioxane, as well as the .
corresponding thioethers, such as thiodiisobutyl; the tertiary amines, such as N,N,N',N'-tetramethylethylenediamine (~MED); the ~ aromatic amines and in particular the pyridine derivatives, `. such as 4-methylpyridine, and the corresponding oxide~; phospho- rou~ compounds, such as the phosphines and their oxides, the phosphites, the phosphoramides and in particular hexamethyl-phosphorotriamide (HMP~); the ketones and particularly acetone;

r 105~948 the nitriles and particularly acetonitrile; the aldehgde~; the esters; the amides; the nitro-aliphatic or aromatic compounds;
the sulfoxides and particularly dimethyl sulfoxide; the sulfones;
and the sulfites.
As protic polar compounds there are suitable in particular water; the alcohols and particularly methanol; the primary or ~econdary amines; the phenol~; and the thiols.
As compounds formed of the reaction proauct of protic polar compounds with an alkali metal or with an alkaline earth metal there are particularly suited the alcoholates and phenates of alkali metals or alkaline earth metals, such as lithium isopropylate, barium nonylphenate ands~ium orp~assium t~
amy~ t~e~1~1i me~l or alkaline earth metal mercapto and thio-phenates; as well as the ether-alcoholate~ and amine-alcoholates of alkali metals or aIka~ne e~h meta~s, such a~the~ithium alooholate of ethyl d~ycoland lithium N,N-diethylamino-2-ethanolate.
~he organometallic compound of a metal of Group IIIA
and the electron-donor compound or compounds can be introduced -~
into the reaction medium either individually in any order or preformed. In accordance with the second variant, the catalytic system i8 "preformed" by mixing the variou~ components and then - bringing the mixture to a temperature of between 20C. and 100C.
for 5 to 60 minutes. ~-~
The two components of the catalytic system can be used in variable proportions but it is preferable to use them in proportions such that the molar ratio of the ele¢tron donor compound or compounds to the organometallic compound of a metal of Group IIIA i~ between 0.01:1 and 100:1. For a given concentra-~`~ tion of organometallic compound of a metal of Group IIIA, a modi-fi¢ation of the value of the molar ratio may modify both the in-trin~ic viscosity and the micro-structure of the polymer formed as well as the polymerization and copolymerization reaction .

~05'~948 velocity. Among the organometallic compounds of a metal of Group IIIA organo-aluminum compounds are preferred due both to their advantageous method of manufacture and to their extensive availability on the market.
In the case of catalytic systems formed of an organometallic compound of aluminum having the formula Me2~ 1 R1R2R3R4 72 ~ such as defined above, and one or more polar compound~ of the class of aprotic polar compounds, for a given concentration of an aluminum organometallic compound when the value of the molar ratio of the aprotic polar sompound or compounds to the organo-aluminum compound increase~, the reaction velocity and the intrinsic vis¢oæity of the polymer formed increa~e without the micro-structure of the polymer being changed. Thi~ i9 all the more surpri~ing, since the addition of polar compounds to organo-lithium initiators leads to a system which does not change the intrinsi¢ ~iscosity of the polymer but changes the mi¢ro-structure thereof.
In the case of catalytic systems formed of an organometallic compound of aluminum having the formula Me2(Me3R1 R2 R3 R4)2, as defined previously, and a polar compound selected from among those having one of the formulas R (0 CH2CH2)n 0 Me1, or (R) ~ CH2CH20 Me1 in which Me1 represents an alkali metal, R represents an alkyl radical and n is a whole number, copolymers having a very high content of trans-1,4 linkages (up to 92%)and a very low content of 1,2 or 3,4 linkages, that is to say less than 4~, and which retain an elastomeric character can be obtained. The copoly~ers of butadiene and styrene (SBR) thu~ obtained have a resistance to elongation similar to that of natural rubber when in crude state (nonvulcanized) and when filled in accordance with the customary formulations used for the manufacture of automobile tires.
The homopolymerization or copolymerization reaction is lQ5'~948 - carried out either in an inert hydrocarbon solvent wh1ch may, for instance, be an aliphatic or alicyclic hydrocarbon, such a3 pentane, hexane, heptane, iso-octane, cyclohexane, or an aromatic hydrocarbon, such as benzene, toluene, xylene, or in bulk polymerization.
~he reaction is generally carried out at a temperature of between 50C. and 120C. and preferably between 80C. and 100~C., under a pressure which corresponds to the vapor pressure of the reagents. The process of the invention can be carried out batch-wi~e or continuously.
~he process not only makes it possible to obtain high yields of macromolecular compounds per unit of weight of the catalytic system but it al~o makes it possible to regulate to the desired extent the molecular weight of the homopolymers or copolymers prepared.
The process furthermore makes it possible to obtain homopolymers or copolymers which during the reactio~ can give rise to grafting reactions with all reagents capable of reacting ;t ~,~
with living polymers.
As representative examples of conjugated dienes which are suitable for the homopolymerization and copolymerization mention may be made of 1,3-butadiene, isoprene, 2,3-dimethyl-1, 3-butadiene, 1,3-pentadiene and 2-ethyl butadiene.
As representative examples of suitable vinyl aromatic compounds mention may be made of styrene; ortho-, meta-, and para-methyl styrene; di- and polymethylstyrene; para-tert-butylstyrene, the vinyl naphthalenes; the methoxystyrenes;
the halostyrenes; and divinylbenzene.
~he products obtained by the process of preparation employing the catalytio system in accordance with the invention furthermore have a broad molecular weight distribution and a high intrinsic viscosity, that is to say sufficient 90 that the 105'~948 product~ can be used as the principal component of mixes 9¢rving for the manufacture of pneumatic tires, and a micro-structure which may vary extremely. As a matter of fact, the content of trans-1,4 linkages may be between 20~ and 90% and the content of 1,2-linkages may be between 1% and 60%. Furthermore, the~e products are very well suited for mechanical working on tools.
The invention will be fully underatood from the following examples which, by way of illustration, describe ~pecial manners for carrying it out. In all the examples the intrinsic viscosities were determined at 25C. in solution of 1 g. per liter in toluene, the concentrations of catalysts are expressed in micromols per 100 g. of monomers and the homo-polymerization or copolymerization reactions were stopped when the rate of conversion reached 80~ (except in Examples 19, 23 and 27), by addition of methanol in suitable quantities (1%).
The percentages of trans-1,4 linkaees and 1,2 linXages are expressed with reference to the polybutadiene portion while the percentage of styrene is expre~sed with reference to the total amount of polymer obtained.
Example 1 Two liters of heptane were introduced as sol~ent into a reactor under the pressure of rectified nitrogen whereupon 205 g. of butadiene and 69 g of styrene were introduced and - the temperature was increased to 80C. ~he catalytic system formed of Ba ~ l(C2H5)4_72 and of tetrahydrofuran (~HF) in variable ~uantities was then introduced in succession in four tests. ~en the rate of conversion wa~ reached, the reaction was stopped and the copolymer recovered.
The results of the four tests are set forth in the following table:

~o5~948 TABLE I

Catalytic System Reaction SBR Copolymers Time .
~est Ba~ l(C2Hs)4_72 THF Intrinsic Steric No. . Vi8c osity Conf gur~ ~tion % tr. % % Sty.
1,4 1,2 Incorp.
T 1820 0 40 hr. 0.8 85 3 15 1 1100 1100 8 hr. 1,6 81 3 15 30 min.

2 1100 2200 6 hr. 2.1 80 3 16

3 1100 4400 4 hr. 2.45 30 4 16 It was found that the reaotion time is 5 to 10 times less (lest ~ versus Tests 1-3) and that when the value of the molar ratio 6f ~HF to Ba~ l(C2~5)4 72 increases, the reaction velocity and the intrinsic viscosity of the SBR copolymer increase while the microstructure of the SBR copolymer remains unchanged.
Example 2 -Four tests were carried out repeating the procedure of Example 1 with different catalytic systems. ~he results J
ere aet forth in ~able II below:

~05'~948 ' _ ~ O O N ~O U~
O O ~ .

h~

6q C~ _ .

h ~r-- ~-- 0 ~
rPI~ _ _ _ Pl o,~ . _ . _ .

U~ .
, H U~ h o ~ N

` ~1 a .~, ., . .. ~ , .
O X ~ X
t ~ N N "~ t~ N . -O CO~ :-. ~_ ~ ~ N
. . ~
~ O O O O
~ ~ O O 0 O N ~J N ~
~1 1~
0 U~
. $ ~ N N P
~ O C~ 1 Cg h ~ .`
~ o c~ v~ m m a o _ o 2 _ N t~ ~ .

_ 9 _ ~05'~948 ExamPle 3 Three te~tq were carried out. Into a 250 ml. Steinie bottle under pressure of rectified nitrogen there were introduced 100 ml. of heptane as solvent and 13.6 g. butadiene. The catalytic system formed of Ba~ l(C2H5)4 72 and methanol was then introduced. The bottle was placed in a thermostatically controlled - tank at 80C. in which it was agitated.
At the end of the reaction, the polybutadiene was recovered in ordinary manner. The results are set forth in Table III below.
TABLE III
, ~ ~ .
~ Catalytic System Time Polybutadiene `. i Test Ba~ l(C H ) 72 Methanol IntrinsicSteric ~` ~o.2 ~ ~- _ _ v~ I ~ tr. ¦ %

i 11100 74 7 hr. 1.64 86 3 21100 222 6 nr. 1.59 84 3 31100 444 5 hr. 1.50 81 ¦ 3 Example 4 A test was carried out repeating the procedure of Example 3 and using similar conditions except that a catalytic system formed of ~a~ l(C2H5)4_72 and water was employed. ~he results are set forth in Table IV below.
TAB~E IV

Catalytic System Reaction Polybutadiene Time .
Test Ba~ l(C2Hs)4_72 H20 Intrinsic Steric No. Viscosity Configuration r _ ~,4r 1 1~2 L _ 1100 440 17 hr. 1.55 87 ¦ 2 _ 10 --- 105'~948 ExamPle 5 ~ hree tests were conducted, the reaction being carried out in a reactor under pressure of rectified nitrogen. ~wo liters of heptane were introduced as solvent followed by 191 g.
of butadiene a~d 82 g. of styrene. lhe temperature was increased to 80C. and the catalytic system formed of Ba/~l(C2H5)4_72 and of lithium isopropylate was added. At the end of the reaction, the copolymer was recovered in a customary manner. ~he results are set forth in ~able V below.
~AB~E V
'~
_ ~ , ~ Catalytic System Reaction SBR Copolymers _ ~e~t Ba~Al(c2Hs)~ 2 ~ithium Intrinsic Steric No. Isopro- Viscosity Configuration pylate % tr. % % Sty.
1,4 1,2 I~orp.
1 340 2400 4 hr. 3 83 4 21 2 380 2600 4 hr. 2.6 83 3 20 3 1 550 1380 4 hr. 1.7 at 4 23 ., ExamPle 6 ~wo tests were carried out. Two liters of solvent (heptane) followed by 205 g. of butadiene and 69 g. of styrene were introduced into a reactor under the pressure of rectified nitrogen. Ihe temperature was brought to 80~C. and then the components of the catalytic system, i.e., N,N,N',N'-tetramethyl-ethylenediamine (~MED) and ~a~ l(C2H5)4 72' were introduced one } after the other. The results are set forth in ~able VI below.

.: ' ' .

105~ 948 TABLE VI

Catalytic System Reaction SBR Copolymers ~ime Iest Ba ~Al(C2Hs)4~ 2 ~MED Intrinsic Steric No. Viscosity Configuration % tr. ~ ~ Sty 1,4 1,2 Incorp.
1 2440 1220 45 mhirn. 0.8 84 4 15 2 2440 l2440 ~ hr. 1.5 81 4 16 Example 7 ~ wo liter~ of heptane, 205 g. of butadiene and 69 g.
of styrene were introduced into a reactor under pressure of rectified nitrogen whereupon the temperature was increased to -- 80C. and 4-methylpyridine or r-picoline and Ba~l(C2H5)4 72 were added one after the other. ~he results are set forth in Table VII below.
~A~E VII

Catalytic System Reaction SBR Copolylaers _ _ Iime Ba [Al(C2Hs)4~ 2 r-picoline Intrinsic Steric Viscosity Configuration tr. % % Sty.
1,4 1,2 Incorp.
1100 1100 1 hr.1.30 607 18 40 min.
ii Example 8 ~wo tests were carried out repeating the procedure of `~ Example 3 using the catalytic system of 13a~1(C2H5)4 72 and acetonitrile. ~he results are set forth in Table VIII below.

j .

~5'~94~3 TAB~E VIII
`
.
Catalytic Sy3tem Reaction Polybutadiene Time Test Ba[Al(C2Hs)4~2 Acetonitrile Intrinsic Steric No. Viscosity Configuration ; lF-F~- ~,2 1 1100 74 3 hr. 1.6 77 3 45 min.
2 1100 222 3 hr. 1.7 75 5 15 min.
, Example 9 Three tests were carried out repeating the procedure of Example 3 and using similar conditions except that acetone and Ba~ l(C2H5)4_72 were used as the catalytic ~y~tem. The results are set forth in Table IX below.
;~ ~AB~E IX

Catalytlc System Reaction Polybutadiene , .
i Test BatAl(C2H5)J 2 AcetoneIntrin~ic Steric No. Viscosity Configuration 1 1100 74 7 hr. ~ % tr.
2 1100 222 30 mhirn. 1.8 78 3 3 1100 444 5 hr. 2.0 75 4 30 min.
i~ . I . l .
" .
~ ExamPle 10 :~
The procedure of Example 3 was repeated using similar conditions except that thiodii~obutyl and Ba~ l(C2H5)4_72 were used as the catalytic system. ~he results are set forth in ~able X below.

.. .. . . : ~ : -- . ~ . ~. . . .
. . ~ , .
.. . . . . .
.

~,o5~ 948 ~ABLE X

Catalytic System Reaction Polybutadiene Time , Ba~Al(c2H ) ~ Thiodi- Intrinsic Steric S 4 2 ¦i~obutyl l l ¦ 1,4 1100 222 22 hr. 1.50 85 2 Example 11 Three tests were carried out repeating the procedure of Example 3 and using similar conditions except that hexamethyl-pho9phorotriamide (HMP~) and Ba~ l(C2H5)4_72 were used a~ the catalytic system. ~he reYults are set forth in ~able XI below.
~ABIæ XI

., .
,~ Catalytic System Reaction Polybutadiene Test BaCAl(c2Hs)4~2 HMP~ Intrinsic Steric No. VisGosity Configuration . % tr. 1,2 1 1100 2223 hr. 1.55 82 2 2 1100 444152 hirn. 1.68 80 3 3 1100 8882 hr. 2.48 78 3 Example 12 s ~wo tests were carried out repeating the procedure of Example 3 and using similar conditions except that a catalytic system formed of BarAl(C2H5)30R 72~ OR being the nonylphenate radical, and lithium isopropylate were used. The results are set forth in ~able XII below.

~(~5~948 TABLE XII

Catalytic System Reaotlon Polybutadiene ~est Ba~Al(c2Hs)30R~2 ~ithium Intrinsic Steric No. Isopropylate Viscosity Configuration ~ tr. 1,2 1 1450 2900 18 hr.1 15 76 4 2 1450 5800 17 hr.1.33 78 4 Under the same conditions the use of Ba~ l(C2H5)30R 72 by itself did not lead to any trace of polymer, even after 48 hours of reaction.
Example 13 ~` Two tests were carried out repeating the procedure of Example 3 and using similar conditions exoept that ~i Al(C2H5)4 and lithium isopropylate were used as the catalytic system. ~he results are set forth in ~able XIII below. -_ B~E XIII

Catalytic System Reaction Polybutadiene Time .
Test ~i Al(C2X ) ~ithium ~so- Intrinsic Steric No. 5 4 propylate Viscosity Configuration tr. 1,2 1 1450 750 3 hr. 1 22 60 8 30 m~n.
2 1450 1450 3 hr. 1.24 60 8 30 min.
s . I ., Under the same conditions, the use either of ~i Al(C2H5)4 alone or of lithium isopropylate alone did not lead to any trace of polymer even after 48 hours of reaction.

.

~o52948 Example 14 A test was carried out repeating the procedure of Example 3 and using ~i Al(C2H5)4, lithium isopropylate and barium nonylphenate as components of the catalytic system. The reæults are set forth in ~able XIV below.
TABLE XIV

Catalytic System naction Polybutadiene , . . . .
~i Al(C2H5)4 ~arium ~ithium Intrinsic Steric Nonyl- Iso- Viscoæity Configuration phenate propylate ; ~,4r' ¦ 1~2 1450 725 2900 1 hr.
30 =i~. 2,3 79 4 ~; :
As compared with the preceding example 13, the addition of the barium nonylphenate had the effect of orienting the micro~tructure. ~-Example t5 -A test was carried out repeating the procedure of Example 3 using a catalytic sy~tem conæisting of ~i Al(C2H5)4, - and sodium tert-amylate. The reæults are set forth in ~able XV
below.
TA~E XV

Catalytic System Reaction Polybutadiene ~i Al(C2H5)4 Sodium Tert- Intrinsic Steric _ amylate Viscosity Configu ration ~L ¦ 2900 ~ 4 ¦ 1~2 ¦

~o5~,2948 Example 16 - Two tests were carried out repeating the procedure of Example 3 except that a catalytic system formed of Na Al(C2H5)4 and potassium tert-amylate (ROK) wa~ used. ~he re3ults are set forth in Table XVI below.
TABLE XVI

Catalye~c ~y~t~- - R ~ e~n Polybutadiene ~est Na Al(C2H ) ROE Intrinsic Steric No. 5 4 Viscosity Configuration .
%,4r' 1,2 1 1450 725 5 hr. 3.12 37 38 2 1450 1450 5 hr. 2.55 40 36 ~ - .
Under the same conditions the use of Na Al(C2H5)4 by itself did not lead to any trace of polymer, e~en after 48 hours of reaction.

I Example 17 -~, Two te~ts were carried out repeating the procedure of Example 3 except that a catalytic system formed of K AltC2H5) and potassium tert-~mylate (ROE) was used. ~he results are set , forth in ~able XVII below.
~AB~E X~
, . ~- "
Catalytic System Reaction Polybutadiene . . , ,:
~ ~est Intrinsic Steric ~ ~0 ~ ~
1 1450 360 4 hr. 1.37 50 26 30 min.

.
' ' ' '' ' ' ~ ' .

`'''` 105~'Z948 Under the same conditlons the use of KAl(C2H5)4 by itself did not lead to any trace of polymer, e~en after 48 hours of reaction.
Example 18 A test was carried out repeating the procedure of Example 3 using a catalytic ~ystem consisting of CH
; ~i Al(C2H5)3 0 C ~CH3 and barium nonylphenate.

~he results are set forth in ~able XVIII below.
~AB~E XVIII
~, . 10 Catalytic System Reaction Polybutadiene Time ~i Al(C2H5)3 - CH ~ 3 Barium Intrinæic Steric \CH3 Nonyl- Viscosity Configuration phenate 725 ~ '4 Under the same condltion~, the use of Li Al(C2H5)30-CH ~ 3 by itself did not -lead to any trace of polymer, even after ~8 hours of reaction.
Example 19 A test was carried out repeating the procedure of Example 3 employing a catalytic ~ystem consisting of ~iOAl(C2H5)2 and barium nonylphenate. The polymerization reaction was stopped when the conversion rate reached 60%
instead oi~ 80%. ~he re~ults sro ~et i'orth in ~able XIX below.

, .

, .

:lOSZ948 TAB~E XIX
.

Catalytic System Reactlon Polybutadiene Time lil O Al(C H )z Barium Nonyl- IntrinRic I Steric 2 5 phenate Viscosity Configuration ~, 4r~ 2 2960 740 5 hr. 1 . 9 63 ¦ 6 , .
Under the same conditions the use of LiOAl(C2H5)2 by itself did not lead to any trace of polymer, even after 48 - hours of reaction.
, Example 20 Two tests were carried out repeating the procedure `~ ~ -of Example 3 using a catalytic system consisting of (C2H5)3 Al(C2H5)2_7 and lithium isopropylate. The results are set forth in Table XX below. - - -TABI E XX
., . ...... _ . . . . ~ - -Catalytic System Reac ti on Time Polybutadlene . ., :, Test Li[Al(C2H5)30 Al(C2H5)21 ~ithium Intrinsic Steric No. ~ Iso- Viscosity Configuraki on propylate ~y _ . _ . ~ ~

. 1 1100 370 30 mhirn. 1.78 58 9 2 1100 1 I 00 30 mlll. 1, 95 59 9 Under the same oonditions the use of 30 ~i~l(C2H5)30 Al(C2H5)2_7 by itself did not lead to any trace of polymer, even after 48 hours of reaction.

.

.. . . . .
.

~5"~94~

ExamPle 21 Two tests were carried out repeating the procedure of Example 3 using a catalytic system consistine of Al(C2H5)3, lithium isopropylate, and barium nonylphenate. The results are set forth in Table XXI below.
TAB~E XXI
. . _ Catalytic System Reaction Polybutadiene Time Test Al(C H ) Lithium Barium Intrinsic Steric No. 2 5 3 Iso- Nonyl- V1scosity Can~guration propylate phenate .
tr 1,2 1 2900 3600 360 5 hr. 1.7 88 3 1 2900 3600 720 5 hr. 1.35 85 3 ., ;~ Under the same conditions the use of Al(C2H5)3 by itself did not lead to any trace of polymer, even after 48 hours of reaction. ~-Example 22 A test was carried out repeating the procedure of Example 3 except that a catalytic system consisting of ~i B(C2H5)3C4Hg and barium nonylphenate was used. The results are ~et forth in Table XXII below.
?AB~E XXII
., .. .
Catalytic System Reaction Polybutadiene Test ~i B(C2Hs)3C4Hg Barium Intrinsic Steric No. phenate Viscosity Configuration . ..
%,4r 1,2 S900 100 4 hr. 1.6 83 3 ' ~

5,~2948 Under the same conditions the u~e of ~i ~(C2H5)3C4Hg by itself did not lead to any trace of polymer even after 48 hours of reaction.
Example 23 A mi~ture of heptane, butadiene and styrene having a weight ratio of monomers to solvent of 1:5 and of butadiene to styrene of 3:1 was introduced continously into a reactor.
Ba~ l(C2H5)4 72 and lithium isopropylate were also introduced continuously in a molar ratio of 1:10 with such a speed that there was 960 ~ mols of Ba~ l(C2H5)4 72 in the reactor for 100 g. of monomers and that there was an average time of ~tay in the reactor of 1 1/2 hours. ~he copolymerization was ~ -effected at sooa. and the reaction wai~ stopped when the percentage conversion reached was 60% rather than 80%. The copolymer was recovered at the outlet of the reactor. It contained 16%
styrene and had an intrinsic viscosity of 1.64, a trans-1,4 linkage content of 81% and a 1,2 linkage content of 3%.
Example 24 Two liters of heptane, 191 g. of butadiene ar~d 82 g.
of styrene were introduced into a reactor under the pressure of rectified nitrogen and the temperature was increased to 80C.
~here was then added in succession the catalytic system formed of 460 tu mols of Ba~ l(C2H5)4 72 per 100 g. of monomers and 1380 ~ mols per 100 g. of monomers of lithium isopropylate.
When the rate of conversion reaohed 80~o (2 hours), 50 cc. of copolymer were recovered in customary manner and the reaction ~topped by the addit-ion of methanol. An amount of diphenyl i carbonate (CDP) was then added to the reactor such that the ratio i 7 of CDP Ba~ l(C2H5)4_72 wa~ equal to 0.5:1.
< 30 ~he copolymer obtained was recovered by a conventional method. ~he microstructure of the copolymer obtained before - grafting and of the grafted copolymer was: 81% trans-1,4 linkages, ~5~948

4~ of 1,2 linkages and 24% incorporated styrene.
The intrinsic viscosity of the ungrafted copolymer was 1.7 and that of the grafted copolymer was 2.6.
Example 25 1) PreParation of the CoPolymer: Two liter~ of heptane, 191 g. of butadiene and 82 g. of styrene were introduced into a reactor under the pressure of rectified nitrogen whereupon the temperature was increased to 80C. The catalytic system formed of Ba~ l(C2H5)4_72 and lithium isopropylate waq then gradually added. When a rate of conversion of 80~ had been reached, the reaction was stopped and the copolymer recovered in customary manner. ~he elastomer obtained was then diluted with 37,5 parts of aromatic oil (Exarol MX 140, marketed by Compagnie Française de Raffinage) per 100 parts of dry elastomer.
lhe results are set forth in Table XXV A
lAB~E XXV A
_ Catalytic System Reaction SBR Steric Configuration Time ~ ~-BatAl(C2H ~d 2 ~ithium Intrinsic ~ tr % ~ Styr.
Iso- Viscosity 1,4 1,2 Incorp.
Propylate Before After Dilution With the Oil 1000 7100 5 hr. 2.67 ¦ 1.96 84 4 22 30 min. l _ _ 2) Rubber Making Mix:
~he elastomer described abo~e was used to form a mixture ha~ing the following formula in parts by weight:
100 - Elastomer diluted with 37.5 parts of aromatic oil 2 - Stearic acid 3 - ZnO
1 -Antioxidant (Santoflex 13: N-(dimethyl 1,3-butyl N'-phenyl-p-phenylene diamine) ,~ ~o5~948 - HAF Black (Philblack O) - Aromatic oil (Sundex 8125, PM 380, density 0.995 marketed by Sun Oil) - Santocure (~-cyclohexyl-mercaptobenzothiazole ; sulfenamide) ~; 1.8 - Sulfur ~ he same mixture was prepared with a butadiene/styrene copolymer (SBR 1712) available on the market as a control. The two mixtures were then vulcanized for 60 minutes at 144C.
The mechanical propertie~ obtained are set forth in ~able XXV B below.
TAB~E XXV 13 Control Pro~erties (SBR 1712) Test SBR
Modulus at 100% elongation 16 14.9 ( kg/cm2 ) Modulus at 300% elongation 67.5 58 (kg/cm2) ~ , steresis loss at 60C. 29 24.6 Index of coefficient of friction at 20C. (SRT) 100 84 20Scott rupture index - elongation at rupture (%) 570 540 - rupture force (kg/cm2) 231 222 - Shore A hardness 62 60 SBR 1712 is a butadiene/styrene copolymer ¢omprising 23.5% styrene, 15-16% of 1,2 linkage~, 60% of tra~s-1,4 linkages and 37.5 parts of aromatic oil.
It was found that the elastomer in accordance with the in~ention ha~ properties substantially equal to those of the above conventional copolymer. It can be u~ed as the principal 30 component of a mlx for the manufacture of pneumatic tires.
.~

,;
~., .
.... . . .
-........ ~ , ''"` ' ' ~ : :

105,'~948 Example 26 This example relate~ to the preparation of butadiene/styrene copolymers; six tests were carried out.
The copolymerization was effected in a reactor in an inert atmosphere (rectified nitrogen) at 80C. in the presence of heptane as solvent. The weight ratio of monomers to sol~ent was 1:5. The reaction was stopped when the rate of conversion reached 80%. The conditions of the tests and the results obtained are set forth in Table XXVI.
TABLE XXVI
Catalytic System Ba ~ l(C2H5)4_72 and Te~t Nos.
2H5(CH2CH2)2~i 1 2 3 4 5 , -Molar ratio Li/Ba 1 1 1.5 1 5 2 2 Initial Styrene content 24 32 24 32 24 32 (% by weight) ~ Quantity of 730 600 910 750 400 1300 -~ Ba~ l(C2Hs) 4_72 Reaction time (in140 ` 200 190 270 270 33 minutes) -Copolymers -- .
Intrinsic Viscosity2~17 2.08 1 86 2.09 2.1 1.90 Content of trans-1,4(~) 85 85 87 87 90 90 1 Content of 1,2(~o) 3 3 3 3 3 3 i Content of incorporated 15 23 15 23 15 23 styrene (~ by weight) On test pieces of the copolymer of Test 5 and of natural rubber (~) filled in accordance with the formulation Of Example 25 but not vulcanized, force-elongation measurements (measurement of the green strength) were carried out at 25C.
The force elongation measurement were carried out on "dumb-bell" test specimen~ of a thickness of 2. 5 mm. and effected with the u~e of an "In~tron" electronic dynamometer 24 hours after ~05Z948 molding and with a rate of traction of 10 cm./minute. The result~ obtained are set forth in the graph Or the drawing, the ~ . .
'~ ordinate of which represents the force exerted in g,/m~' and -' the abscissa represents the elongation (in %). It wa~ found - , that the copolymer prepared by the improved method of the invention had a resistance to elongation similar to that of - natural rubber.
.~
Exam~le 27 A mixture of toluene, butadiene and styrene in ` 1Q proportion~ such that the weight ratio of monomers to solvent was equal to 1:5 and the ratio of butadiene to styrene was equal to 3:1 was introduced continuously into a reactor.
Ba~ l(C2H5)4_72 and C2H5(0CH2CH2)20~i were also introduced ~ continuously in quantities such that their moltar ratio was ,~s 1:2. The rate of flow was such that there were 1000 micromols of Ba~ l(C2H5)4~ 2 in the reactor per 100 g. of monomers and '' that an average time of stay in the reactor of 1 hour was ~ obtained. ~he copolymerization was effected at 90C. and the ,1 reaction was stopped when,the percentage conversion reached was ~,- ,~ 20 65% rather than 80~. ~he copolymer formed was recovered ' , ;l continuouæly at the outlet of the reactor. It contained 15~ by ! ' weight of styrene and had an intrinsic viscosity of 1.6. ~he content of 1,2 linkages was 3% and that of tranæ-1,4 linkages was 83%. ~ ' ExamPle 28 ~he catalytic system of Ba~ l(C2H5)4 72 and (C2H5)2NCH2CH20~i was used. 100 ml. of heptane as solvent and 13.6 g. of butadiene were introduced into a 250 ml. Steinie bottle under the pressure of recti~ied nitrogen. The catalytic system was then added whereupon the bottle wa~ placed in a tank which was thermostatically controlled at 80C., in which it was agitated.

,, , ' ' . , 105;~948 At the end of the reaction, when the percent of conversion reached 80%, the polybutadiene formed was recovered by an ordinary method. ~he results are set forth in Table XXVIII.
TAB~E XXVIII

Catalytic System Reaction Polybutadiene _ (in min.) ¦~9t~ ~Al( ~ )4]21' 2~S)2NC~2Cn2~ ¦ ¦ V~cooity ¦ 1~4 ¦l,Z ¦

~ 100 ¦ 200 60 1 . 75 85 4 Example 29 A test was carried out repeating the procedure of -Example 28 and using similar conditions except that a catalytic ' ~ l(C2H5)4_72 and C2Hs(0CH2CH2)20Na was u~ed $ ~he re3ults are ~et forth in Table XXIX below.
~, TAB~E XXIX
.
., .
Catalytic System Reaction Polybutadiene ~, 20 ~ !2~ ~2¦C2~(CC~2C~2)2C~a¦ ¦Intrin~ c ¦ % tr.¦

1 ¦ 100 ¦ 100 3 hr. 5 ¦ 88 ¦ 3 -..
Example 30 ~:
A test was carried out repeating the procedure of Example 29 and using similar conditions except that a catalytic system formed of Ba~ l(C2H5)4_72 and C2H5~0CH2CH2)3Li was employed. The results are set forth in Table XXX below.

~:

-' r`~

~ABLE XXX

.~ Catalyti~ Sy~tem Reaction Polybutadiene .~, (in mi~) .
.), . .

Na Ba ~(C2H5)~2 C2H5(oCH2CH2)3cai Viscosity ~,4tr. 1,2 . 1 100 100 60 2.8 80 4 .~ .
, , 1~ ..

. ., :

Claims (14)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1 A process of producing homopolymers of conjugated dienes or copolymers of conjugated dienes with other conjugated dienes or with vinyl aromatic compounds, which comprises reacting the monomers at a temperature between 50°C.
and 120°C. in the presence of a catalytic system formed of the reaction product of a) an organometallic compound of a metal of Group IIIA of the Mendeleev periodic table of elements having one of the following formulas:
Me1Me3R1R2R3R4 Me2(Me3R1R2R3R4)2 Me3R1R2R3 Me1O Me3R1R2 in which Me1 represents an alkali metal, Me2 represents an alkaline earth metal, Me3 represents a metal of Group IIIA, R1, R2 and R3 represent and alkyl or aralkyl radical and R4 represents an alkyl or aralkyl radical or a radical XB in which X represents an oxygen, sulfur or nitrogen atom and B represents an alkyl or aralkyl radical, or a radical Me3(R5R6) in which R5 and R6 represent an alkyl or aralkyl radical; with b) at least one electron-donor compound containing at least one hetero-atom selected from the group consisting of aprotic polar compounds, protic polar compounds and compounds formed of the reaction product of protic polar compounds with an alkali metal or with an alkaline earth metal.

2. The process according to claim 1 wherein the reaction is conducted in an inert hydrocarbon solvent reaction medium.

3. The process according to claim 1 wherein the electron-donor compound is selected from the group consisting of ethers; thioethers; tertiary amines; aromatic amines; phosphorus compounds; ketones; nitriles; aldehydes; esters; amides; sulfo-xides; alcohols; thiols; phenols; water; primary or secondary amines; compounds formed of the reaction product of alcohols, thiols, phenols, primary or secondary amines with an alkali metal or with an alkaline earth metal; and compounds having one of the following formulas:
R(OCH2CH2)n O Me1 or (R)2NCH2CH2O Me1 in which Me1 represents an alkali metal, R represents an alkyl radical and n is a whole number.

4. The process according to claim 1 wherein the electron-donor compound is selected from the group consisting of tetrahydrofuran, lithium isopropylate, water, methanol, acetone, acetonitrile, hexamethylphosphortriamide, N,N,N',N'-tetramethylethylenediamine, barium nonylphenate, the lithium alcoholate of ethyl diglycol, and lithium N,N-diethylamino-2-ethanolate.

5. The process according to claim 1 wherein the molar ratio of the electron-donor compound to the organo-metallic compound of a metal of Group IIIA is between 0.01:1 and 100:1.

6. The process according to claim 1 wherein the organometallic compound of a metal of Group IIIA is a compound of aluminum or boron selected from the group consisting of:
Ba[AL(C2H5)4]2, Li Al(C2H5)3O Al(C2H5)2, Al(C2H5)3, Ba[AL(i-C4H9)4]2, Sr[AL(C2H5)4]2, Ca[AL(C2H5)4]2, Li[AL(C2H5)4], Na[AL(C2H5)4], K[AL(C2H5)4], Li O Al(C2H5)2, NaO Al(C2H5)2, B(C2H5)3 and Li B (C2H5)3C4H9.

7. The process according to claim 1 wherein the catalytic system is formed of the reaction product of (a) Ba[AL(C2H5)4]2 with (b) an electron-donor compound containing at least one hetero-atom selected from the group consisting of tetrahydrofuran, lithium isopropylate, N,N,N',N'-tetramethylethylenediamine, hexamethylphosphoro-triamide, the lithium alcoholate of ethyl diglycol and lithium N,N-diethylamino-2-ethanolate.

8. The process according to claim 1 wherein the catalytic system is formed of the reaction product of (a) Li[Al(C2H5)4] with (b) barium nonylphenate and lithium isopropylate.

9. The process according to claim 1 wherein the catalytic system is formed of the reaction product of (a) Al(C2H5)3 with (b) barium nonylphenate and lithium isopropylate.

10. The process according to claim 1 wherein the catalytic system is formed of the reaction product of (a) LiOAl(C2H5)2 with (b) barium nonylphenate.

11. The process according to claim 1 wherein the catalytic system is formed of the reaction product of (a) LiB(C2H5)3C4H9 with (b) barium nonylphenate.

12. The process according to claim 1 wherein the conjugated diene is butadiene and the vinyl aromatic compound is styrene.

13. Homopolymers and copolymers prepared by the process according to claim 1.

14. Articles of rubber manufactured by means of the homopolymers or copolymers according to claim 13.