CA1166400A - Solution polymerization - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
A composition useful as a catalyst in solution polymeriza-tion comprises (1) a barium, calcium and/or strontium alcoholate, (2) an organoaluminum compound and (3) an organomagnesium com-pound. (2) and (3) may be used as a complex with (1). The com-positions can be used to polymerize ethylenically unsaturated monomers like butadiene, butadiene and styrene, and isoprene and heterocyclic monomers like oxiranes, thiiranes, siloxanes, thia-tanes and lactams. The catalyst composition can produce poly-butadienes and butadiene-styrene copolymers having a trans-1,4 content as high as 90%. The non-terminating features of the polymerization of this invention permit the preparation of functionally terminated butadiene based polymers and block polymers containing sufficient amounts of trans-1,4 butadiene units to crystallize.

Description

SOLUTION POLYMERIZATION
This invention relates to compositions of (1) barium, cal-cium andior strontium alcoho]ates, (2) organoaluminum compounds and (3) organomagnesium compounds and their use as catalysts for the solution polymerization of ethylenically unsaturated monomers like butadiene, butadiene,/styrene and isoprene and for the poly-merization of heterocyclic monomers like oxiranes, thiiranes, siloxanes, thiatanes and lactams.

Background of the Invention The use of dialkylmagnesium or alkylmagnesium iodide in combination with barium ethoxide particularly additionally with l,l-diphenylethylene as initiators of polymerization of butadiene to give polybutadiene having a trans-1,4 content as high as 78%
and a vinyl content oE 6% has been disclosed by the Physico-Chemical Research Institute, Polymer Science U.S.S.R., 18 (9), 2325 (1976). This paper, also, shows that a catalyst system of magnesium and barium tert-butoxide gave a polybutadiene with only 45% trans-1,4 content (200 hours polymerization time and conver-sion of only 10%).
U. S. Patent No. 3,846,385 (U. S. Patent No. 3,903,019 is a Division of the same) shows the preparation of random butadiene-styrene copolymers haviog a high trans-1,4 content and a vinyl content of 9%. The trans-1,4 content increased as the-mol ratio of Ba(t-BuO)2/(Bu)2Mg decreased with little variation in either the vinyl content or heterogeneity index. A copolymer exhibited a well defined crystalline melting temperature at 32.6C by differential thermal analysis (DTA). The Molecular Weight Distribution (MWD) of these copolymers was characterized by having heterogeneity indices (MW/Mn) raslging from 1.4 to

2.2. Polybutadienes made with these catalysts exhibited a trans-1,4 content as high as 78~. No polymerization or copoly-merization occurred when only one of the catalyst components was used alone.

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Polymerization of butfldiene with some cyc1ization in hexane or toluene at 100C using Bu2Mg-BuMgI is reported in "Chem.
Abstracts," 1963, 4045e.
Polymerization of butadiene using Ba(OEt)2 with Et2Mg, 4 9 3 g2I or (C6H13)2Mg is reported in "Chem.
Abstracts," Vol. 84, 1976, 151067n.
Dialkylmagnesium compounds and their complexes with organo--aluminum or with organolithium compounds are said to be cocata-lysts with Ziegler based catalyst systems (transition metal com-pounds) for the polymerization of dienes and olefins. This hasbeen described by Texas Alkyls (Product Data Sheet MAGALA-6E) and Lithium Corporation of America (Product and Technical Bulletin on "Polymerization Using Magnesium Alkyl Catalysts,l- 1978).
British Patent No. 1,531,085 discloses in the working examples the preparation of polybutadienes and butadiene-styrene copolymers having inherent viscosities of 0.8 to 5, trans-1,4 contents of 34 to 90% and vinyl contents of 2 to 38~. A two component catalyst is used. As shown by the working examples the first component can comprise a BalAl(C2H5)412, Ba[Al(C2H5)3OR]2 where R is a nonyl phenate radical, LiAl-(C2H5)4. NaAl(C2H5)4~ KAl(C2H5)4' ( 2H5)3OCH(CH3)2, LiOAl(C2H5)2 compound andso forth. The second component is a polar compound or the like such as tetrahydrofuran, methanol, water, tetramethylethylene diamine, acetone, barium nonyl phenate, lithium isopropylate, Na-tert-amylate, acetonitrile and so forth. The molar ratio between the polar compound and the organic compound of metal of Group IIIA such as Al is from 0.01 to 100.
U. S. Patent No. 4,079,176 discloses a process for polymer-izing dienes and for copolymerizing dienes and vinyl aromaticcompounds with a catalyst composition comprising (A) an organo-lithium and (B) a compound having the formula Ma(MbRlR2R3R4) or MalMc(Rl) where Ma is Ba, CA, Sr or Mg; Mb is B or Al; MC is Zn or Cd; Rl, R2 and R3 are alkyl or aralkyl radicals; R4 is an alkyl, aralkyl radical or oR5 where R5 is an alkyl or aralkyl radical. The working examples show the polymerization of BD and copolymerization of BD with STY to provide polymers exhibiting intrinsic viscosities of 0.81 to 1.6, trans-1,4 contents of 76 to 85% and vinyl contents of 2 to 6~.
U. S. Patent No. 4,080,492 discloses a method for polymeriz-ing BD or copolymerizing BD and vinyl aromatic compounds using a catalytic composition of (a) an organolithium compound and ~b) a cocatalyst system which comprises a Ba or Sr compound and an organometallic compound from Groups IIB or IIIA like zinc or aluminum. Examples of the Ba or Sr compounds are their hydrides, organic acid salt, alcoholates, thiolates, phenates, alcohol and phenol acid salts, betadiketonates and so forth. Table VIIA
shows the use of barium tertiobutanolate. Examples of the Group IIB and IIIA materials are diethylzinc, diethyl cadmium, triethyl aluminum and so forth. The working examples for the preparation of polymers of BD and copolymers of BD and STY show ~ of .34 to 20 2.15, trans-1,4 of 61 to 90% and vinyl contents of 2.4 to 9%.
U. S. Patent No. 4,092,268 is similar to U. S. Patent No.
4,080,492 but it includes isoprene and shows in Examples 11 and 12 the polymerization of isoprene and the copolymerization of isoprene and styrene.
British Patent No. 1,516,861 has a somewhat similar dis-closure to that of U. S. 4,080,492 and both are based on the same French patent application. The U. S. case apparently deleted reference to the polymerization of isoprene.
British Patent No. 1,525,381 (patent of addition to Br.
30 1,516,861, above) discloses a process for polymerizing butadiene and copolymerizing butadiene and styrene using a catalyst compo-sition of (a~ an organolithium, (b) a compound of barium, stron-tium or calcium, (c) an organometallic compound of a metal of Group IIB or IIIA and (d) an amino or ether alcoholate of an alkali metal. An example of (a) is n-butyl lithium; of (b) is l:~Lfi~

Ca, Ba or Sr alcoholate or phenate particularly barium nonyl phenate; of (c) is 2 5)2 n, (C2H5)3 Al or (i-butyl)3 Al;
and of (d) is C2H5(0CH2CH2)2 OLi, 2 5)2NCH2CH20Li or CH2(0CH2CH2)20Na.
The working examples for the polybutadienes and butadiene-styrene copolymers made show inherent viscosities of 0.9 to 2.4, trans-1,4 contents of ôO to 90X and vinyl contents of 2 to 4X.
For Example 2 it is stated that the green strength test on the black loaded uncured copolymers showed a similar resistance to elongation to that of natural rubber.
A class of crystalli~ing elastomers based on butadiene containing sufficient amounts of the trans-1,4 structure to crystallize has been disclosed in U. S. Patent No. 3,992,S61 lS (divisional U. S. patents of the same Nos. 4,020,115; 4,033,900 and 4,048,427 have the same disclosure in the specification).
The catalyst for the preparation of these polymers comprises an alkyl lithium compound such as n-butyl lithium and a barium t-alkoxide salt such as a barium salt of t-butanol and water.
The polymerization temperature, the nature of the solvent and the mole ratio of the catalyst components and its concentration were found to control the polybutadiene microstructure and molecular weight. It is stated that the crystalline melting temperature of the high trans polybutadienes can be depressed near or below room temperature by the copolymerization of styrene, still permitting the rubber to undergo strain induced crystallization. The butadiene polymers and butadiene-styrene copolymers exhibited green strength and tack strength. A high trans polybutadiene exhibited a broad bimodal molecular weight distribution. This patent discloses in the working examples for the invention polybutadiene and butadiene-styrene copolymers exhibiting intrinsic viscosities of 1.43 to 7.39, trans-1,4 contents of 63 to 80.4% and vinyl contents of 6 to 9%.
.

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Copending United States Patent Application Serial No. 077~42S filed September 20, 1979, now United States Patent No. 4,260,712 ~Patent No. 4,260,519 is a div-ision), discloses an improved barium t-alkoxide salt for use with a hydrocarbon lithium compound for the preparation of polybutadiene and butadiene-styrene co-polymers. It shows in the working examples for polybutadiene and butadiene-styrene copolymers intrinsic viscosities of from ~.74 to 7.68, trans-1,4 contents of 73 to 82% and vinyl contents of 6 to 13%.
"Gummi-Asbest-Kunststoffe," pages 832 to 842, 1962 reviews several catalyst systems for polymerizing unsaturated monomers and discusses the properties of several polymers. On page 835, Table 4, it discloses the use of a catalyst sys-tem of R2Mg and RMgHal to polymerize butadiene to make a polybutadiene having 45-49 trans-1,4 units.
Objects An object of the present invention is to provide a new composition useful as a catalyst for the solution polymerization of ethylenically unsaturated monomers and heterocyclic monomers.
Another object of the present invention is to provide a method for solution polymerization of ethylenically unsaturated monomers and heterocyclic monomers using an anionic catalyst complex or composition.
These and other objects and advantages of the present invention will become more apparent from the following detailed description, examples and accompanying drawings in which Figure 1 is a graph showing copolymer composition variation with percent conversion using different catalyst systems;
Figure 2 is a graph showing the polybutadiene microstructure versus the mole ratio of Ba[(t-RO)2 x(OH)x~ to (Bu)2Mg at Mg/Al = 5.4/1 (Example l);
Figure 3 is a graph showing the gel permeation chromatograms of polystyrene and polystyrene-polybutadiene diblock copolymer prepared with the Mg-Al-Ba composition catalyst;

, ~

- 5a -Figure 4 is a graph showing the effect of chain extension on the mo1ecular weight distribution of high trans styrene-butadiene copolymer rubber (15%
styrene);

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Figure 5 is a graph showing the effect of chain extension of high trans styrene-butadiene (copolymer) rubber on variation of viscosity with shear-rate;
Figure 6 shows x-ray diffraction patterns for a high trans styrene-butadiene rubbery copolymer ~about 15% sty; 85% Trans) of this invention;
Figure 7 (which appears on the same sheet as Figure 5) is a graph showing the "green-strength," stress-strain, of uncured but compounded (45 phr of carbon black) of various rubbers and Figure 8 is a graph showing the effect of contact time on tack strength of high trans styrene-butadiene (copolymer) rubber (15% styrene) of this inven-tion and natural rubber (SMR-5), both uncured but compounded with 45 phr carbon black and 13 phr oil.
Summary of the Invention This invention provides a composition of matter useful as an anionic polymerization catalyst comprising (1) an alcoholate selected from the group consisting of barium alcoholate, calcium alcoholate and strontium alcoholate and mixtures thereof, (2) an organoaluminum compound and (3) an organomagnesium compound, where the mol ratio computed as metal of barium, calcium and/or strontium to magnesium is from about 1:10 to 1:2 and where the mol ratio com-puted as metal of magnesium to aluminum is from about 105:1 to 1.5:1.
In a second aspect, this invention provides the method which comprises polymerizing under inert conditions in a hydrocarbon solvent at a temperature of from about 0 to 150C. a monomer selected from the group consisting of a polymerizable heterocyclic monomer and a polymerizable ethylenically unsaturated monomer having an activated double bond with a catalyst in a minor effective amount sufficient to polymerize said monomer to obtain a polymer, said catalyst comprising (1) an alcoholate selected from the group consisting of barium alcoholate, calcium alcoholate and strontium alcoholate and mixtures thereof, (2) (m organoaluminum compound and (3) an organomagnesium compound, where the mol ratio compu~ed as metal of barium, calcium and/or strontium to magnesium is from about 1:10 to 1:2 and where the mol ratio computed as metal of magnesium to aluminum is from about 105:1 to 1.5:1.
In a third aspect, this invention provides for a rubbery copolymer of butadiene-1,3 and up to about 30% by weight total of said copolymer of copolymerized styrene, said copolymer exhibiting:
a. a glass transition temperature of from about -50 to --100C as determined by differential thermal analysis, b. a crystalline melting point ~peak values) in the unstretched state of from about -10 to +40C as determined by differential thermal analysis, c. a trans-1,4 content of from about 81 to 90% and a vinyl content of up to about 4% for the butadiene units, d. a heterogeneity index of from about 2.5 to 5, e. a number average molecular weight of from about 50,000 to 500,000~
f. crystallinity when stretched in the uncompounded and uncured state as shown by x-ray diffraction data and g. quick-grab, green strength and building tack.
Finally, in a fourth aspect, this invention provides for a homopoly-butadiene having a trans content of from abcut 64 to 90%, a vinyl content of from about 2 to 7%, an intrinsic viscosity of from about 0.~0 to 4.29 in deciliters per gram in toluene at 25C and a peak crystalline melting temperaure of from about -16 to 70C.
According to the present invention a composition of a barium alcoholate or alkoxide salt, an organoaluminum compound and an organomagnesium compound has been found useful as an anionic polymerization catalyst for the solution - 6a -polymerization of butadiene as well as butadiene and styrene to make polymers having a high trans content. In place of barium alkoxide, calcium alkoxide or strontium alkoxide can be used. The catalyst may be used for the polymerization of other ethylenically unsaturated monomers as well as heterocyclic monomers like oxiranes, thiiranes, siloxanes, thiatanes and lactams.
The homopolymer of butadiene and copolymer of butadiene with styrene of this invention have a high content of trans-1,4 linkages (~5-90%) and a low vinyl content ~2-3%) which provide sufficient amounts of trans-1,4 polybutadiene placements to permit crystallization. The copolymers of butadiene with styrene of this invention exhibit a glass transition temperature of from about -50 to -100C as determined by differential thermal analysis, and a heterogeneity index of from about 2.5 to 5. The catalyst for these polymerizations comprises an organomagnesium-organoaluminum complex, (1) [(a)alkyl2Mg:(b)alkyl3A1], where the mole ratio of (a) to (b) is from about 105/1 to 1.5/1, in combination with, (2) a barium, calcium and/or strontium (barium being preferred) salt of alcohols, or alcohols and water, the alcohol is preferably a tert-_ 6b -lt~

alcohol, the mole ratio of barium metal to magnesium metal being from about 1/10 to 1/2.
It has been found that the trans-1,4 content of the polybut-adïene segments generally is controlled by the following fac-tors: (1) the mole ratio of barium to magnesium (Ba2 /Mg2 ~present in the Mg alkyl-Al alkyl-Ba salt catalyst composieion, (2) the mol ratio of Mg to Al, (3) the nature of the polymeriza-tion solvent used, (4~ the polymerization temperature, and (5) the catalyst concentration. By the use of appropriate polymeri-zation variables, the trans-1,4 content is sufficiently high (ca 81 to 90%) to provide a crystalline polybutadiene and for certain copolymer compositions (with styrene contents up to about 30%) a strain-crystallizing SBR and Mn about 50,000 to 500,000S linear and branched.
Copolymerization of butadiene and styrene with barium t-alkoxide salts and a complex of an organomagnesium with an organoaluminum (Mg-Al), for example, 5.4 (n-C4H9)2Mg -(C2H5)3Al (MAGALA-6E, Texas Alkyls, Inc.) exhibit 8 a higher initial rate of incorporation of styrene than a n-C4HgLi catalyzed copolymerization as shown by Figure 1.
Proton NMR analysis of these high trans SBR's (15% styrene) shows a distribution of the styrene throughout the polymer from isolated units to styrene sequences longer than tetrads. The amount of block polystyrene placements in the copolymer chain appears to rapidly increase as the extent of conversion increases from 90~ to lOOX. However, it has not been possible to isolate any polystyrene from the products of oxidative degradation with tert-butylhydroperoxide and osmium tetroxide lfollowing the technique of I.M. Kolthoff, T. S. Lee and C. W. Carr, J. Polymer Sci., 1, 429 (1946)] of a high trans SBR polymerized to 92%
conversion and containing 23 weight percent (wt.~) total styrene.
One of the main factors which controls the butadiene microstructure at constant Mg/A1 ratio is the mole ratio of Ba2 /Mg2+. This is shown by Figure 2 for a Mg/Al ratio of 5.4/1. rne trans-1,4 content of polybutadiene, prepared in cyclohexane at 50C, increases and the vinyl content decreases as *Trade Mark Ba jMg2 decreases. Polybutadienes with trans-1,4 contents as high as 90Z with vinyl contents of 2~ have been prepsred with this system at mole ratios of 8a /Mg of 1/5. The optimum Ba /Mg ratio is approximately 1/5.
In particular, complexes of Mg-Al with compounds of barium tert-alkoxide or barium (tert-alkoxide-hydroxide) are highly effective for the preparation of high trans-1,4 polybutadiene (up to about 90X trans). The barium salts useful in the polymeriza-tion are prepared in liquid monomethylamine or liquid ammonia by reacting barium metal with a tert-alcohol or mixture of t-alco-hols, or mixture of tert-alcohol(s) and water (0.01-0~1 equiva-lents of the available barium is reacted with water). Certain barium salts, such as barium (tert-decoxide-tert-butoxide-hydrox-ide), molar ratio of tert-decanol/tert-butanol/H20 (30/59/11), have the advantage that they are soluble to greater ~han 20 wt.%
in toluene and the solutions are stable indefinitely. Thus, they provide a soluble barium compound of invariant solution compo-sition during storage.
Complexes of barium tert-butoxide (which is only sparingly soluble (0.1 wt.%) in toluene at room temperature) with Mg-Al alkyls are, however, also effective catalysts for the preparation of 90% trans-1,4 polybutadienes.
The polymerization activity and the amount of trans-1,4 content are very much dependent on the Mg/Al ratio in these Ba-Mg-A1 catalysts. It has been found that Mg-Al complexes containing (n-C4Hg)2Mg to (C2H5)3Al in mole ratios of about 5.4 and 7.6 (MAGALA-6E and MAGALA-7.5E, Texas Alkyls, Inc.), respectively, are effective for preparing 90X trans-1,4 polybutadiene at constant Ba/Mg = 0.20. In addition, Mg-A1-Ba complexes containing Mg and Al in ratios of 27 and 105 are capa-ble of polymerizing butadiene to polymers having trans-1,4 con-tents of about 81-83Z. However, a complex of (n-C4Hg)2Mg .
2(C2H5)3Al with Ba salts did not polymerize butadiene.
It is possible to prepare polybutadienes with trans-1,4 contents greater than 85Z with Ba-Mg-Al catalysts consisting of a romplex of barium salts with (sec-C4Hg)Mg (n-C4Hg) and _ 9 _ (C2H5)3Al, prepared in situ, in mole ratios of Mg/Al rang-ing from about 2 to 7.6.
Alternatively, soluble catalyst compositions can be prepared by~mixing clear colorless solutions of, e.g., MAGALA-6E in hep-tane with barium (tert-alkoxide-hydroxide) in toluene. Optional-ly, the catalyst can be preformed by heating the solution for 15 minutes at 60C. A yellow colored solution forms upon heating, indicating complex formation (Ba /Mg - 1/5). A small amount of lightly colored precipitate is also formed. Active catalyst components for trans-1,4 addition are present in the solution phase. The insoluble phase in toluene represents only a small fraction of the total metallic compounds.
In addition to the effect of catalyst composition, the nature of the polymerization solvent and temperature influence the microstructure of the butadiene based polymers. Polybuta-dienes prepared in paraffinic and cycloparaffinic hydrocarbon solvents have slightly higher trans-1,4 contents and higher lecular weights than polymers prepared in toluene. The stereo-regularity of butadiene based polymers prepared in cyclohexane with a Mg-Al-Ba catalyst is dependent on polymerization tempera-ture. The decrease in trans-1,4 content with increasing polymer-ization temperature occurred with a corresponding increase in both vinyl and cis-1,4 contents.
The concentration of catalyst affects both the trans-1,4 content and molecular weight of polybutadiene prepared in cyclo-hexane at 50C. The trans-1,4 content increases non-linearly with a decrease in the molar ratio of the initial b~tadiene to (n-C4H9~2Mg concentration, at a constant Ba/Mg ratio. The trans-1,4 content appears to reach a limiting value of about 90X
for polybutadienes prepared with relatively large amounts of catalyst.
Molecular weight increases with an increase in the molar ratio of butadiene to (n-C4Hg)2Mg as well as with an increase in the extent of conversion. In addition, the viscosity of a solution of non-terminated polybutadienyl anion increases with the addition of more monomer. The above results demonstrate - lo that a certain fraction of the poly~er chain ends retain their capacity to add monomer.
The crystalline melting temperatures (45C, 70C) of these poiybutadienes can be decreased to near or below room temperature (about 25C) by adjustments of the trans-1,4 content and the incorporation of a comonomer (styrene). The resultant copolymers are then amorphous at room temperature but will undergo strain-induced crystallization. The rubbers are characteri~ed by both green strength and tack strength equal to or higher than natural rubber. As such, these synthetic rubbers can be expected to be of value in those applications where natural rubber is used. One of these applications is as a tire rubber, especially in radial ply tire construction. In addition, the ability to control the molecular structure of these rubbers makes them useful materials in tire tread compounds.
For styrene-butadiene copolymers, prepared with Mg-Al-Ba catalysts at Ba/Mg of 0.20 to 0.25, the molecular weight appears to be controlled by both the level of Mg and Ba used in the polymerization. The moleculflr weight of higll trans polybutadiene and polystyrene as well as STY-BD copolymers increases with an increase in initial molar concentrations of monomer(s)/Mg at constant Ba/Mg.

Discussion of Details and Preferred Embodiments The barium (preferred), calcium or strontium alcoholate or alkoxide salt or mixture of such salt is made by reacting an alcohol, prefersbly a tertiary alcohol or mixture of tertiary alcohols, optionally additionally including water, with Ba, Ca and/or Sr. It is better to conduct the reaction in liquid NH3 or amine solvent at a temperature of from about -100C up to the boiling point of the solvent or above the boiling point under pressure. After the reaction, the NH3 or amine can be removed from the salt by distillation, vacuum evaporation and solvent extraction. Preferably, the salt is dried in a vacuum at reduced pressure for a period of time sufficient to reduce the nitrogen content of the salt to not greater than about 0.1, preferably not greater than about 0.01~, by wei~ht. Metllods of making the barium alkoxide salts, such as barium t-alkoxide salts, which also will be applicable to the correspond-ing Ca and Sr salts, are shown in United States Patent No. 3,992,561 and copend-ing ~nited States Application Serial No. 077,428~ filed September 20, 1979, Aggarwal et al, now United States Patent No. 4,260,712 ~Patent No. 4,260,519 is a division).
Examples of alcohols to use to make the Ba, Ca and/or Sr salts or alcoholates are methanol, ethanol, propanol, isopropanol, n-butanol, cyclopentanol, cyclo-heptanol, cyclohexanol, s-butanol, t-butanol, pentanol, hexanol, octanol, and decanol and so forth and mixtures of the same. Examples of such alcoholates are calcium diethoxide, di(t-butoxy) strontium, di(isopropoxy) barium, di~cyclohexy-loxy) barium and so forth. If a non-tertiary alcohol or carbinol is used, it is preferred that the mixture contain at least 50 mol % of a tertiary carbinol.
The preferred carbinol to use is a tertiary carbinol, having the general formula HO-C-R where the Rs are selected from the group consisting of alkyl or cycloalkyl radicals of from 1 to 6 carbon atoms which may be the same or different such as a methyl, ethyl, propyl, butyl, isopropyl, amyl, cyclohexyl and the like radicals. Examples of these tertiary carbinols are t-butanol, 3-methyl-3-pentanol, 2-methyl-2-butanol, 2-methyl-2-pentanol, 3-methyl-3-hexanol, 3,7-dimethyl-3-octanol, 2-methyl-2-heptanol, 3-methyl-3-heptanol, 2,4-dimethyl-2-pentanol, 2,4,4,-trimethyl-2-pentanol, 2-methyl-2-octanol, tricyclohexyl carbinol, dicyclohexyl propyl carbinol, cyclohexyl dimethyl carbinol, t-decanol ~4-n-propyl-heptanol-4),

3-ethyl-3-pentanol, 3-ethyl-3-hexanol, 3-ethyl-3-heptanol, 3-ethyl-3-octanol, 5-ethyl-5-nonanol, 5-ethyl-5-decanol, 6-ethyl-6-undecanol, 5-butyl-5-nonanol,

4-isop~opyl-4-heptanol, 2-methyl-4-n-propyl-4-heptanol, 4-n-propyl-4-nonanol, 5-n-propyl-5-nonanol, 2,2-dimethyl-4-n-propyl-4-heptanol, 4-n-propyl-4-B

decanol, 5-n-propyl-5-decanol, 2,6-dimethyl-4-isobutyl-4-heptan-ol, 3,3,6-trimethyl-4-n-propyl-4-heptanol, 6-n-propyl-6-undecan-ol, 5-n-butyl-5-decanol, 6-n-butyl-6-undecanol, 6-n-pentyl-6-un-decanol, 2,8-dimethyl-5-isopentyl-5-nonanol, and 2,8-dimethyl-5-isobutyl-5-nonanol and the like and mixtures of the same.
There, also, may be used a tertiary carbinol having the general formula H0-C-R'' where R' is an alkyl radical of from I to 4 carbon \R' atoms which may be the same or different and where R" is a hydrocarbon radical having a molecular weight of from about 250 to 5,000. These materials may be obtained by polymerizing in solvent media butadiene and/or isoprene with or without a minor amount of styrene and/or alpha methyl styrene using a monolithium hydrocarbon catalyst such as butyllithium to obtain a liquid lithium terminated polymer or oligomer. The preparation of such liquid diene containing polymers is known. See U. S. Patent No.
3,078,254. Appreciable amounts of catalyst are used to obtain liquid polymers, See U. S. Patent No. 3,301,840. The resulting polymer solution is then treated with an epoxide such as isobu-tylene oxide o~C,H3 (H2C-C-CH3, I,1-dimethyl-1, 2-epoxyethane or 1,2-epoxy-2-methyl propane) to obtain a product which may be shown as:

polymer-cH2-7-oLi .

In place of isobutylene oxide there can be used 1,1-diethyl-1,2-epoxyethsne, l,l-dipropyl-1,2-epoxyethane, I,l-diisopro W 1-1,2-epoxyethane, l,l-dibutyl-1,2-epoxyethane, 1,1-diisobutyl-1,2-epoxyethane and the like epoxide and mixture thereof. See U. S.
Patent No. 3,538,043. These epoxide treated lithium terminated f.`~

polymers can then be hydroly~ed with water to form the tertiary carbinol or alcohol:

polymer-CH2-C-OLi + H20 ~ LiOH and ,H3 polymer-CH2-C-OH. See V. S. Patent No. 3,055,952.

The hydrolyzed polymer or liquid tertiary carbinol is then removed from the organic solvent and is ready for reaction with barium to form a barium tertiary alkoxide salt.
Mixtures of the above tertiary carbinols can be used.
Water, if used in preparing the Ba, Ca or Sr alcoholates or salts, is employed in the alcohol or alcohol mixture as follows:
from about 0 to 20, preferably from about 0 to 12, mol~ of water to from about 100 to 80, preferably from about 100 to 88, molX of the alcohol or alcohol mixture.
The resulting preferred alcoholate or alkoxide salt, or lS mixture of said salts, preferably containing not over about 0.1~, and even more preferably not over about 0.01% by weight of nitrogen, have the following general formulae:
/R ~R' Ml(O-C-R)a(OH)b]2 and/or Ml(0-C\R' )a(H)bl2 where the mol ratio of a to b is from about 100:0 to 80:20, preferably from about 100:0 to 88:12, and where R, R' and R " are the same as defined above and where M is barium, calcium and/or strontium, preferably barium, or mixture of said metal salts or alcoholates.
The organoaluminum compounds used in the practice of the present invention are alkyl and cycloalkylaluminum compounds.
These compounds can be prepared by reacting aluminum metal with an olefin in the presence of hydrogen. Another method, for example, comprises the reaction:
- 2Al+3(cH3)2Hg~ 3Hg+2(CH3)3Al.

l~t~t~ 3 Other methods can be used~ See "Aluminum Alkyls," Texas Alkyls, Copyright lg76 by Stauffer Chemical Company, Westport, Connec-ticut, 71 pages including the bibliography shown therein and "Encyclopedia of Polymer Science and Technology," Vol. 1, 1964, Interscience Publishers a division of Jolln Wiley & Sons, Inc., New York, Pages 807 to 822. These organoaluminum compounds have ehe general formula R3IIAl where RIII is an alkyl radical or cycloalkyl radical, which may be the same or different~ of from 1 to 20, preferably of from 1 to 10, carbon atoms. Mixtures of these organoaluminum compounds can be used. Examples of such compounds are trimethyl aluminum, triethyl aluminum, tri-n-propyl aluminum, triisopropyl aluminum, pentyl diethyl aluminum, 2-methylpentyl-diethyl aluminum, tri-n-butyl aluminum, triisobutyl aluminum, dicyclohexylethyl aluminum, tri-n-pentyl aluminum, tri-n-hexyl aluminum, tri-n-octyl aluminum, tri (2-ethylhexyl) aluminum, tricyclopentyl aluminum, tricyclohexyl aluminum, tri (2,2,4-trimethylpentyl) aluminum, tri-n-dodecyl aluminum, and tri (2-methylpentyl) aluminum and the like.
The organomagnesium compounds used in the practice of the present invention are alkyl and cycloalkyl magnesium compounds.
These compounds can be prepared by the action of R2Hg on magnesium, the reaction being facilitated by the presence of ether. They, also, may be prepared by allowing olefins to react under pressure at about 100C with magnesium metal in the presence of hydrogen. Please see "Organometallic Compounds,"
Coates et al, Vol. 1, 1967, 3rd Ed., Methuen & Co. Ltd., London.
These organomagnesium compounds have the general formula RI2VMg where RIV is an alkyl radical or cycloalkyl radical, which may be the same or different, of from 1 to 20, preferably of from 1 to 10, carbon atoms. Mixtures of these organomagnesium compounds can be used. Examples of such compounds are dimethyl magnesium, diethyl magnesium, dipropyl magnesium, di-n-butyl magnesium, di-sec-butyl magnesium, di-n-amyl magnesium, methyl-ethyl magnesium, n-butyl ethyl magnesium (BEM), n-propylethyl magnesium, di-n-hexyl magnesium, dicyclohexyl magnesium, cyclohe~ylethyl magnesium, didecyl magnesium, di-ter-butyl magnesium and didodecyl magnesium and the like.
Organo Mg-Al complexes can be used instead of mixtures of Mg and Al compounds. One method of preparation is to add the organoaluminum compound to a reactor containing the reaction products of organic halides with magnesium in hydrocarbon solvent. After filtraticn of the reaction mixture, there is obtained a solution of the complex containing little soluble halides. Please see Malpass et al, "Journal of Organometallic Chemistry," 93 (1975), Pages 1 to 8. These complexes will have the general formula Rm Aln.Rp Mgq where the mol ratio of Al to MB is as set forth herein, where m, n, p and q are numbers sufficient to satisfy the required valences of the radi-cals and atoms and where RIII and RI are alkyl or cycloalkyl radicals, which may be same or different, as described above.
In the catalyst composition the mol ratio computed as metal of magnesium to aluminum is from about 105:1 to 1.5:1, and the mol ratio computed as metal of barium, calcium and/or strontium to magnesium is from about 1:10 to 1:2.
Just prior to polymerization, the barium salt, the organo-aluminum compound and the organomagnesium compound (or the organoaluminum magnesium complex) each in hydrocarbon solution are mixed together. The time required to form a catalyst complex or composition ranges from a few minutes to an hour or longer depending on the reaction temperature. This should be accomp-lished under an inert atmosphere, and the ingredients may be heated to speed reaction at temperatures of from about 25 to 100C, preferably from about 40 to 60C. After the catalyst composition has formed, the polymerization solvent and monomer(s) may be charged to the catalyst, or the preformed catalyst dis-solved in its solvent may be injected into a reactor containing the monomers dissolved in the hydrocarbon polymerization solvent.
The monomers to be polymerized can be ethylenically unsatur-ated monomers or heterocyclic monomers. The ethylenically unsat-urated polymerizable monomers to be polymerized with the cata-lysts of the present invention are those having an activated 4`3~

unsaturated double bond, for example, those monomers where adjacent to the double bond there is a group more electrophilic than hydrogen and which is not easily removed by a strong base.
Examples of such monomers are nitriles like acrylonitrile and methacrylonitrile; acrylates and alkacrylates like methyl ~acrylate, ethyl acrylate, butyl acrylate, ethyl hexyl acrylate, octyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, methyl ethacrylate, ethyl ethacrylate, butyl ethacrylate and octyl ethacrylate; the dienes such as butadiene-1,3 and isoprene; and the vinyl benzenes like styrene, alphamethyl styrene, p-tertiary butyl styrene, divinyl benzene, methyl vinyl toluene and para vinyl toluene and the like and mixtures of the same. Examples of polymerizable heterocyclic monomers are oxiranes like ethylene oxide, propylene oxide, 1,2-butylene oxide, styrene oxide, isobutylene oxide, allyl glycidyl ether, phenyl glycidyl ether, crotyl glycidyl ether, isoprene monoxide, butadiene monoxide, vinyl cyclohexane monoxide and the like and mixtures thereof. Other heterocyclic monomers which may be polymerized are siloxanes such as octamethyl tetrasiloxane, thiiranes like propylene sulfide, thiatanes like thiacyclobutane and lactams like epsilon-caprolactam. Depending on the monomer employed, the resulting polymers can be rubbery, resinous, or thermoplastic. For example, a homopolybutadiene prepared accord-ing to the present invention having 90~ trans content is thermo-plastic or resinous, while a copolymer of butadiene and styrenecontaining about 15-20X styrene and 90% trans i9 still rubbery.
Preferred monomers for use in the practice of the present invention are mixtures of butadiene-1,3 and up to about 30~ by weight total of the mixtures of styrene to make rubbery co-polymers exhibiting a high trans-1,4 content and a low vinyl content. Moreover, by altering the butadiene-styrene copolymer composition or microstructure a rubber can be prepared which has behavior closely simulating that of natural rubber in building tack and green strength. Thus, it is within the scope of this invention to prepare polymers which can serve as replacements in those applications where natural rubber is employed such as in tires.
The obtained number-average molecular weight in the absence of-chain transfer i9 controlled by the molecular weight calculat-ed from the ratio of grams of monomer polymerized to moles ofcatalyst charged. Conversions of monomer to polymer up to about 100% may be obtained.
Temperstures during solution polymerization can vary from about 0 to 150C. Preferably, polymerization temperatures are from about 30 to 100C. Time for polymerization will be dependent on the temperature, amount of catalyst, type of polymers desired and so forth. Only minor amounts of the cata-lyst composition are necessary to effect polymerization. How-ever, the amount of catalyst employed may vary with the type of polymer desired. For example, in general, when making polymers having a high average molecular weight using a given amount of monomer, only a small amount of the catalyst complex is necessary whereas when making a low average molecular weight polymer, larg-er amounts of the catalyst complex are employed. Moreover, since the polymer is a living polymer, it will continue to grow as long as monomer is fed to the polymerization system. Thus, the molec-ular weight can be as high as a million or even more. ~n the other hand, very high molecular weight polymers require lengthy polymerization times for a given amount of the catalyst complex, and at lower catalyst complex concentrations the polymerization rate will drop. A usef~l range of catalyst complex to obtain readily processable polymers in practicable times is from about 0.00001 to 0.10, preferably from about 0.00033 to 0.005, mol of the catalyst complex or composition computed as magnesium per 100 grams total of monomer(s).
Since the polymer in solution in the polymerization media is a living polymer or since the polymerization is a non-terminating polymerixation (unless positively terminated by failure to add monomer or by adding a terminating agent such as methanol), block polymers can be prepared by sequential addition of monomers or functional groups can be added. Also, since the living polymer contains a terminal metal ion, it as shown above can be treated with an epoxide like ethylene oxide and then with water to provide a polymer with a terminal hydroxyl group for reaction with a polyisocyanate to jump the polymer through formation of polyurethane linkages.
The polymerization is conducted in a liquid hydrocarbon solvent. While bulk polymerization may be used, such presents heat transfer problems which should be avoided. In solvent polymerizations it is preferred to operate on a basis of not over about 15 to 20% polymer solids concentration in the solvent to enable ready heat transfer and processing. Solvents for the monomers and polymers should not have a very labile carbon-hydro-gen bond and should not act at least substantially as chain terminating agents. They preferably should be liquid at room temperature (about 25C). Examples of such solvents are benzene (less desirable), toluene, the xylenes, the trimethyl benzenes, hemimellitene, pseudocumene, mesitylene, prehnitene, isodurene, o, m, and p cymenes, ethylbenzene, n-propylbenzene, cumene, 1,2,4- or 1,3,5-triethylbenzene, n-butyl benzene and other lower alkyl substituted benzenes, hexane, heptane, octane, nonane, cyclohexane, cycloheptane, cyclooctane and the like and mixtures of the same. The saturated aliphatic and cycloaliphatic solvents and mixtures thereof are preferred. Some solvents may give lower trans contents but on the other hand may give higher molecular weights.
Polymerization, of course, should be conducted in a closed reactor, preferably a pressure reactor, fitted with a stirrer, heating and cooling means, with means to flush with or pump in an inert gas such as nitrogen, neon, argon and so forth in order to polymerize under inert or non-reactive conditions, with means to charge monomer, solvent and catalyst, venting means and with means to recover the resulting polymer and so forth.
The rate of polymerization can be increased by the addition of small (catalytic) amounts of ethers, amines or water. For example, the sddition of anisole to the Mg-Al-Ba catalyst system increased the rate of copolymerization of butadiene with styrene _ 19 _ in cyclohexane at 50C without affecting the percent trans-1,4 content and the rate of incorporation of styrene. Anisole appears to be more effective for increasing the rate of polymeri-zation than triethylamine but less effective than tetrahydrofuran (THF). However, a polybutadiene prepared in the presence of THF
had a microstructure of 75% trans and 6% vinyl.
A small amount (catalytic) of free water, oxygen or ammonia, also, seems to be beneficial in the preparation of polymers with the Ba-Al-Mg initiator system. The addition of a small amount of either of these materials increases the polymerization rate and the molecular weight of polymers prepared with this novel initi-ator system. When the free water is added in small amounts, the trans-1,4 content of the polybutadiene or butadiene-1,3/styrene copolymer is not affected if the mole ratio of the Ba salt to the organomagnesium compound is kept at Ba/Mg = 0.20.
The rate of polymerization can also be increased by increasing the initial molar concentrations of monomers like butadiene and the Mg-Al-Ba catalyst composition.
Since the polymers produced by the method of the present invention contain active sites or are living polymers, they can be chain extended or branched at any practical time prior to termination or short stopping the polymerization reaction. This may be obtained by adding to the polymerization reaction media chain extenders such as dibromomethane, 1,2-dibromoethane, silicon tetrachloride and hexachlorosilane. Other chain extenders that may be used include divinyl and trivinyl aromatic compounds like divinyl benzene (1,2; 1,3 or 1,4), 1,3 divinyl naphthalene, 1,2,4-trivinyl benzene, and so forth; diisocyanates and polyisocyanates like l,6-diisocyanate hexane (may be carcinogenic), diphenylmethane diisocyanate and 90 forth (isocyanates like tolylene diisocyanate and tetramethylene diisocyanate may be unsatisfactory); diepoxides like cyclohexane diepoxide, l,4-pentane diepoxide and so forth; diketones like 2,4-hexane-di-one, 2,5-hexane-di-one and so forth and dialdehydes like 1,4-butanedial, 1,5-pentanedial and so forth (see ~. S.
Patent No. 3,985,830). The chain extender should be soluble in the polymerization media such as the solvent. Moreover, the chain extender should not kill the carbanions, or if it does, there should be sufficient carbanions present so that the chain extens;on proceeds in a satisfactory manner before the chain extension reaction ceases.
After polymerization the catalyst may be terminated by adding water, alcohol or other agent to the polymeric solution.
After the polymer has been recovered and dried, a suitable anti-oxidant such as 2,6-di-tert-butyl-p-cresol or other antioxidant may be added to the same. Rowever, the antioxidant may be added to the polymeric solution before it is stripped of solvent.
The polymers produced by the method of the present invention can be compounded and cured in the same manner as other plastic and rubbery polymers. For example, they can be mixed with sulfur lS or sulfur furnishing materials, peroxides, carbon black, SiO2, TiO2, Sb203, red iron oxide, other rubber fillers and pigmen~s, tetramethyl or ethyl thiuram disulfide, benzothiazyl disulfide and rubber extending or processing mineral or petroleum oils and the like. Stabilizers, antioxidants, UV light absorbers and other antidegradants can be added to these polymers. They can also be blended with~other polymers like natural rubber, butyl rubber, butadiene-styrene~acrylonitrile terpolymers, polychloroprenej S~R, polyurethane elastomers and so forth.
The polymers produced by the method of the present invention can be used in making protective coatings for fabrics; body and engine mounts for automobiles; gaskets; sidewalls, treads and carcasses for tires; belts; hose; shoe soles; and electric wire and cable insulation; and as plasticizers and polymeric fillers for other plastics and rubbers. With large amounts of sulfur hard rubber products can be made.
: ~
The following examples will serve to illustrate the present invention with more particularity to those skilled in the art.
Parts are parts by weight unless otherwise stated.
The polymerizations described in the examples were carried out in an argon atmosphere in capped glass bottles fitted with neoprene rubber gasket inner liners. Solvents were purified by ~ ~ .

~ .

' ' passing the liquid through columns of 5A molecular sieves. Buta-diene (99 mol %) was purchased from Phillips Petroleum Company.
Purification was accomplished by passing the BD through columns of-13X molecular sieves. Isoprene was purchased from Phillips Petroleum (99.5 mol Z pure) and was further purified by distil-lation from sodium ribbon. Styrene was purchased from Gulf Oil Chemical and El Paso Products, Texas, and vacuum distilled from a small quantity of (n-butyl) (sec-bueyl) magnesium. Propylene oxide was used a~ received from Oxirane Corporation (contained 75 parts of water per million).
In charging the polymerizations, the order of addition of materials was solvent first, then Mg-Al alkyls, next the barium salt, and finally the monomer(s). The copolymer composition and percent polybutadiene microstructure were obtained from infrared analysis, unless otherwise noted, and from C NMR (Nuclear Magnetic Resonance) for certain polymers. The microstructure values determined from IR and 1 C NMR were essentially identi-cal. The trans-1,4 and vinyl content were determined using the 967 cm 1 and 905 cm 1 infrared absorption bands, respective-ly. Intrinsic viscosities were determined in toluene at 25C.Gel permeation chromatograms (GPC) were obtained using a Waters Gel Permeation Chromatograph. Solutions at 1 wt.~ were injected onto columns at a flow rate of 1 ml/minute. The instrument oven and the differential refractometer were at 50C. The column set configuration used, as designated by Waters Associates, was 1 x 106~ + 1 x 105~ + 1 x 104R + 1 x 103R.
All thermal transitions were obtained by Differen~inl Therm-al Analysis (DTA) using a heating rate of 20C/minute. Crystal-line melting temperatures were determined from the position of 30 the endothermic peak(s) present in the curve, obtained after cooling the sample from 125C to -150C at approximately 20C/minute.
X-ray diffraction patterns were obtained from films cured with 1% dicumyl peroxide in the absence of fillers. All the 35 experiments were carried out at room temperature using CuK~
radiation and a nickel filter.

Example 1 (a) Barium Salt To 82.2 milliequivalents (meq) of barium metal (5.65 g) was ~ added 325 ml of monomethylamine which had been flash dis-tilled from Na-dispersion. The reactor was cooled to -78C
with rapid stirring and fl deep blue colored solution, characteristic of the amine solution of the metal, was obtained. To this solution a mixture of t-decanol (21 milliequivalents), t-butanol (40 milliequivalents) and water (7.3 milliequivalents) in benzene (3.75 mols total t-alco-hols in benzene) was slowly added and the reaction mixture was stirred for 3 hours and then allowed to stand for 2 days at -15C, which resulted in the quantitative conversion of the alcohols and water to barium salts. After flash distil-lation of the amine, the resulting white solid (11.28 g) was dried at 100C under vacuum. Toluene (475 g) was added to the salts and the reactor was heated to 70C for 2 hours;
The total alkalinity of a hydrolyzed aliquot of the clear colorle~s solution, removed from the excess barium metal, measured 0.148 meq of hydroxide per gram or 2.4 wt.~ barium salts, demonstrating total dissolution of the Ralt. The empirical composition of this product can be represented as:

Ba[(t-c4H9o)l 17(t-cloH2lo)o.6l(oH)o~22]

(b) Barium-~-Al Catalyst Complex Composition Solutions of (1) [5.4 (n-C4Hg)2Mg (C2H5)3Al]
complex (MAGALA-6E) and (2) barium salts, prepared according to Example 1 (a) above, were charged to the polymerization solvent under an inert atmosphere. Prior to addition of nomer(s), the catalyst mixture was permitted to react initially at 60C for 15 minutes. The mole ratio of barium to magnesium was based on the moles of total alkalinity of the soluble barium salts (one-half the milliequivalents of titratable base) to the moles of magnesium in MAGALA-6E.

.~

~ti~i~t'O

MAGALA-6E was obtained from Texas Alkyls (25 w~.% in heptane) and diluted with cyclohexane to a concentration of 0.28 meq of magnesium (0.075 meq aluminum) per gram of solution. The magnesium and aluminum contents were deter-mined by atomic absorption spectroscopy, and the molar ratio of Mg/Al was found to be 5.4/1 for a complex designated by Texas Alkyls, Inc., as MAGALA-6E

(5.4 1(n-C4Hg)2Mg] [C2H5)3All).

Example 2 This example demonstrates the usefulness of the catalyst, described in Example 1, for the preparation of crystalline butadiene based polymers. Table I, below, shows that poly-butadienes o~ this invention have a high degree of stereoregu-larity with crystalline melting temperatures of 43C and 70C.
The high trans-1,4 configuration (89%) results in a thermoplastic polymer which is hard and highly crystalline at room temperature.
Isoprene can be polymerized with a Mg-Al-Ba catalyst compo-sition, as described in Table I. A polyisoprene was obtained with an isomer content of 49% trans, 39% cis and 12% 3,4.

Table I
Molecular Structure of Polydiene and Styrene-Butadiene Copolymer Prepared in Cyclohexane at 50C
with Mg-Al-Ba Catalyst Composition (Mg/Al = 5.4/1, Ba/Mg = 1/5, mol ratios of metal) g. Total Monomers %
RunMonomer(s) per mMConversionl~t.% Styrene No.(grams) (BU)2M8 (hours)Charged Found 10 1 Butadiene 38.7 100(91) -- --(27.1) 2Butadiene/Styrene45.5 86 (118) 22 17 (24.4/7.0) 3 Isoprene 34.1 98 (77) -- --(23.9) Peak tol Crystalline Run % Diene Structure [nl25 Melting Temp.
No. Trans-1,4 Vinyl dl/g (C) 1 89 2 2.11 43, 70 20 2 88a 2a 1.60 19 3 49a (12)a~b 0.92 None observed.
a - percent microstructure determined by 13C NMR
b - value in parenthesis represents 3,4 content The rate of polymerization is faster for butadiene polymers than for butadiene-styrene copolymers. For example, complete conversion of butadiene to polymer is readily obtained in 24 hours at 65C. With butadiene-styrene copolymers, it is diffi-cult to obtain a conversion in exceqs of 907~ in 24 hours at 65C. Further, the remaining 10% monomer in the SBR system is primarily styrene, and it requires in excess of 72 hours at 65C
to obtain complete conversion. Viscosities (n) are intrinsic viscosities in deciliters per gram in toluene at 2SC.

V

A polystyrene-polybutadiene diblock copolymer (41~ styrene) was prepared with the Mg-Al-Ba catalyst composition (described in Example 1) by the addition of butadiene to a non-terminated solu-tion of polystyryl carbanions. Styrene was polymerized to 96%conversion, see Table II, below, and the resulting polystyryl carbanion was used in Run 5. All polymerizations were conducted in cyclohexane at 50C.

Table II
Preparation of Polystyrene-Polybutadiene Diblock Copolymer and Hydroxyl Terminated Polybutadiene with Mg-Al-Ba Catalyst g. Total Monomers % Mn tol Run Monomers(s) per mM Conversion Wt.% x (d) ~nl25(d) 15 No. (grams) (Bu)2Mg (hours) Composition 10-3 dl~g 4 Styrenea 15.996a (48)% styrene 20C 0.20 (10.5) = 100

5 Polystyryl 1. 96 (48) (10.5) 20Butadiene 39.1 2. 98 (119) ~ styrene 114C 0.93 (14.8) = 41 6Butadiene 23.5 88 (115) (24.2) Ethylene % hydroxyl 51b 1.31 Oxide = 0.031 (0~09) a - polystyrene precursor used in the preparation of polystyrene-polybutadiene diblock copolymer (Run 5).
b - Mn measured by membrane osmometry.
c - Mn estimated by GPC.
d - final polymer.

o Figure 3 shows two MWD (Molecular Weight Distribution) curves of ehis diblock copolymer (Run 5) and its polystyrene precursor (Run 4). A comparison of the peak positions in the MWD
curves and the shapes of the curves demonstrates the successful preparation of a diblock copolymer. Homopolymers of styrene or butadiene could not be extracted from the reaction products using acetone/cyclohexane (75/25) snd n-pentane as solvents for poly-styrene and polybutadiene, respectively, and as nunsolvents for the diblock copolymer.
A hydroxyl terminated polybutadiene (Run 6) was prepared by the addition of ethylene oxide at the end of a butadiene polymer-ization initiated with Mg-Al-Ba catalyst (see Table II). The terminal alkoxide units were then hydrolyzed to form the carbi-nol. The hydroxyl functionality of this polymer was 0.91 based on hydroxyl equivalent molecular weight and number-average molec-ular weight.
These results demonstrate that polybutadiene or polystyrene chain ends retain their capacity to add monomer and can be deriv-atized to result in useful materials. Thus, block copolymers, functionally terminated polymers and polymers with different molecular architecture and molecular weight distribution can be prepared.

t~7~.`V

Example 4 Polymerizations of butadiene were carried out according to Run 1, Example 2 using various Ba and Ca compounds suhstituted for barium (t-decoxide-t-butoxide-hydroxide), designated as the control. The results are given in Table IIII below. Ba salts of t-butanol and mixtures of t-butanol and water, both prepared according to Example 1, were equally effective as the control for the preparation of about 90% trans-1,4 polybutadiene. Barium ethoxide complexed with Mg-Al alkyls polymerized butadiene to a high molecular weight polymer having a diene structure of 76%
trans-1,4 and 7~ vinyl. Complexes of Mg-Al alkyls with Ca[(t-C4HgO)l 8(0H)o 2] are catalysts for the quantita-tive polymerization of butadiene (see Runs 10-13, Table III).
However, the maximum in trans-1,4 content of 77% occurred for a Ca2 /Mg2 ratio of 0.51 in comparison to a trans-1,4 of up to 90~ for a Ba2~/Mg2 ratio of 0.20. This example demonstrates the usefulness of certain Ba and Ca alkoxide salts in preparing high trans-1,4 crystallizing polybutadiene.

Table Ill Effect of Composition oE Various Ba and Ca Compounds on the Molecular Structure of Polybutadienea Composition of Mole Ratio Conversion Run No. Group IIA SaltM 2+IM 2+ (h rs) 1 Ba[(t-cloH2lo)o~6l 0.20 100 (91) (t-C4H90)l,l7(0H)o~22l (CONTROL) 7 Bsl(t~c4HgO)l~8(oH)o~2l0.20 90 (43) 8 ( 4 9 )2 0.20 96 (71) ( 2 5 )2 0.18 82 (168) Cal(t-C4H9O)1,8(OH)0,2]0.11 99 (47) 11 " 0.25 98 (71) lS 12 " 0.51 97 (24) 13 " 0.90 100 (72) 13-1 Bal(t-cloH2lo)l~8(oH)o~2] 0.20 100 (70) % Crystalline tol Diene StructureMelting [ nl 25 20 Run No. Trans Vinyl Temp., C dllg 1 89 2 43, 70 2.11 7 90 3 29, 59 1.38 8 88 2 41, 68 2.92 9 76 7 9 1.68 64 8 -30 Soft Polymer 11 70 7 -11 Soft Polymer 12 77 6 11, 27 0.90 13 72 6 -2 1.36 13-1 86 3 38,58 Rubber a - polymerization solvent: cyclohexane - polymerization temperature: 50C. Me2+:Ba2~ or Ca2+

`l,`V

Example 5 The effect of the mole ratio of Mg/Al in organometallic complexes of magnesium and aluminum on percent polybutadiene microstructure is shown in Table IV, below. The Mg Al-Ba catalysts were prepared according to Example 1 at constant Ba/Mg mole ratio of about 1/5. A control polymeriæation of butadiene with (sec-C4H9)Mg(n-C4H9) in combination Witll a barium salt prepared according to Example 1 resulted in a trans-1,4 content of 67%, in the absence of Et3Al. A trans-1,4 content of only 81~ was obtained in polymers made with a Ba-MgAl complex at Mg/Al = 105/1 (MAGALA-DNHM, Texas Alkyls, Inc.) catalyst (~un 20). No polymerization of butadiene occurred with a barium salt in combination with MAGALA-0.5E (Mg/Al = 1/2) (Runs 14, 15 and 16 below). The highest degree of stereoregularity was obtained with complexes of barium salts with MAGALA-6E or MAGALA-7.5E (Runs 17 and 18). The trans-1,4 contents in these polybutadienes were 89%
with 2% or 3% vinyl unsaturation.

Table IV
__ Effect of Mg/Al Mole Ratio in Mg-Al Complexes on Microstructure of Polybutadiene % Diene 5 RunOrganometallic Mole Ratios Structure No.Complex of Mg and Al Mg/Al Ba/Mg Al/Ba Trans Vinyl al(n-Bu)2Mg 2(Et)3A1 0.54 0.19 9.70No Poly-merization 15al(n-Bu)2Mg~2(Et~3A1 0.54 0.29 6.40No Poly-merization 16al(n-Bu)2Mg~2(Et)3A1 0.54 0.61 3.00No Poly-merization b5.4(n-Bu)2Mg~l(Et)3Al* 5,4* 0.19 0.97 89 2 18b7.6(n-Bu) Mg~l(Et)3Al# 7.6# 0.16 0.82 89 3 1519b27(n-hexyl)2Mg~l(Et)3A127.0 0.22 0.17 83c4C
20b105(n-hexyl)2Mg.l(Et)3Ald105.0 0.22 0.04 81 4 2lb(sec-Bu)Mg(n-Bu) No Al 0.12 0 67 10 a - polymerizations were carried out in n-hexane at 65C.
b - polymerizations were carried out in cyclohexane at 50C.
c - estimated values from infrared spectrum of polymer film.

d - MAGALA DNHM, Texas Alkyls, Inc. - di-n-hexyl magnesium containing 1-2 mole % Et3Al relative to the Mg compound.
* MAGALA-6E; 5.4 ratio as analyzed.
# MAGALA-7.5E; 7.6 ratio as analyzed.

Example 6 The effect of the mole ratio of barium (t-decoxide-t-butox-ide-hydroxide), prepared according to Example 1, to dibutylmag-ne-sium in MAGALA-6E on polybutadiene microstructure and molecular weight is summarized in Table V, below. The polymerization charge was the same as given in Run 1 of Example 2. Figure 2 shows that the amount of trans-1,4 structure is increased to a maximum of about 90% as the mole ratio of Ba /Mg is decreased from 1.0 to about 0.2. Concurrently, the vinyl content decreased from 7% to 2~. No polymeriza~ion of butadiene was observed in cyclohexane at 50C after 3 days with MAGALA-6E alone or with a mole ratio of Ba2 /Mg2 = 0.05.
Polybutadienes prepared with mole ratios of Ba2 /Mg2 equal to 0.2 are characterized by trans-1,4 contents of about 90~, crystalline melt temperatures of 43C and 70C, intrinsic viscosities of about 2.0 in toluene at 25C, and absence of gel.

Table V
Effect of Mole Ratio of Barium Salts to (Bu)2Mg in Mg-Al-Ba Catalyst on Molecular Structure of Polybutadiene ~ % Diene Crystalline tol Run Mole Ratios Conversion Structure Melting [nl25 2+ 2+ 3+ 2+
No. Ba /Mg Al /Ba (hours) Trans ~ Temp., C dl/g 22 0 0No spparent - - - -pzn. of butadiene with MAGALA-6E, alone 23 0.05 3.91No apparent - - ~ -pzn.
(72 hours) 24 0.11 1.6763 (72) 87 2 36, 60 2.35 1 0.20 0.85100 (91) 89 2 43, 70 2.11 0.30 0.6296 (72) 79 3 -9, 33 2.26 2026 0.52 0.3599 (74) 73 4 -16, 24 1.82 27 1.00 0.1894 (44) 64 7 -15 0.82 Polymerization Conditions: 1. Polymerizations were carried out in cyclohexane at 50C.
2. Molar concentrations of butadiene 25and (Bu)2Mg were approximately:
[Butadiene]O = 2.4;
~(Bu)2Mglo = 2.8 x 10 3 l ~t;~o Example 7 The catalyst complex of MAGALA-6E and barium (t-decoxide-t-butoxide-hydroxide), Example 1, was used to prepare polybutadi-enes according to Example 2, in n-hexane and toluene, as well as cyclohexane. The structural analysis, as shown in Table VI, below, shows that a high trans-1,4 polybutadiene was formed in these solvents. A slightly lower trans-1,4 content and intrinsic viscosity were obtained for the polymer prepared in toluene.

Table VI
Effect of Solvent on the Molecular Structure of Butadiene Based Polymers Prepared with Ba[(t-RO?2_x~OH)x]
5.4 (n-Bu)2Mg 1 (Et)3Al (MAGALA-6E) Catalyst Composition of Example 1.
Polymerization Temp. = 50C
% Diene tol Crystalline Run Polymerization% Structure [~]25 Melting No.SolventStyrene Trans Vinyl dl/g Temp., C
28 n-hexane8 88 2 2.02 23, 34 1Cyclohexane0 89 2 2.11 43, 70 2029 Toluene0 85 3 1.84 24, 36 It, also, is possible to prepare polybutadienes in cyclo-hexane at 50C with trans-1,4 contents of 88% (3% vinyl) with Mg-Al-Ba catalysts obtained by combining barium (t-al~oxide-hy-droxide) with (sec-C4Hg)Mg-(n-C4H9) and (C2H5)3AI, instead of the commercial MAGALA, in mole ratios of M~/AI of 2 to 3 and Ba/Mg of 0.20. An increase in Mg/Al mole ratio (at con-stant Ba/Mg) from 3 to 6 to 15 to 25 results in a decrease in trans-1,4 content from 88% to 86% to 83X to 80X.

~ ~ti~3'1't`0 ex~
Table VII, below, compares the temperature dependence for SBR's prepared with the Mg-Al-Ba catalyst composition of Example 1 in cyclohexane. Trans-1,4 content increased from 83% to 90% as polymerization temperature decreased from 75C to 30C. The increase in trans-1,4 content with decreasing polymerization temperature occurred with corresponding decreases in both vinyl and cis-1,4 contents. It is to be noted that high trans-1,4 SBR's can be prepared over a fairly wide range of polymerization temperatures with this catalyst system.

Table VII
Effect of Polymerization Temperature on Molecular Structure of High Trans SBR
Polymerization ~ % Diene tol Run Wt. ~ Temperature Conversion Structure [nl25 No. Styrene - (C) (hours)Trans Vinyl dl/g 30 6.5 30 55 (172) 90.0 1.6 0.88 31 17.0 50 86 (118) 88.0 2.1 1.60 32 22.0 65 95 (119~ 85.6 3.1 1.54 20 33 23.2 75 92 (23) 82.9 3.7 1.49 Mole Ratio: Ba/Mg = 0.20 Q

Example 9 The concentration of the Mg-Al-Ba catalyst composition of Example 1 with constant Ba /Mg2 ratio (0.20) has a marked effect on the trans-1,4 content of polybutadiene, as shown in Table VIII, below. The trans-1,4 content approaches a limiting value of about 90% as the molar ratio of butadiene to dibutyl-magnesium decreases from 1549 to 795. The intrinsic viscosity increases with an increase in this ratio suggesting that the polymer m~lecular weight is controlled by the ratio of grams of butadiene polymerized to moles of catalyst charged.

Table VIII
-Effect of Catalyst Concentration on Molecular Structure of Polybutadiene Prepared with Mg-Al-Ba Catalyst Initiator Initial 15Charged Bd Molar Ratio % ~ Diene tol Run (mM) Charged IBdlo/ Conv. Structure [~25 No. Ba Salt (BU)2Mg (grams) [(8U)2Mg]o (hrs.) Trans Vinyl dl/g __ 7 0.36 1.76 28.5299 90 90 3 1.38 (M = 8,100)a (43) 20 1 0.14 0.63 27.1_ 795 100 89 2 2.11 (M =21,500)a (91) 34 0.07 0.29 24.3_ 1549 100 80 3 4.29 (M =4l~9oo)a (96) Solvent: cyclohexane. Temperature: 50C. Mole Rat;o: Ba/Mg=0.20.

a: Mn calculated from grams of BD charged to gram-equivalents of Mg charged (carbon-Mg).

`t~``Q

Example lO
Figure 4 shows that the MWD of high trans SBR (15% styrene) can be broadened (changed or controlled) by chain extension with divinylbenzene (DVB). DVB was added at 87~ conversion, and the linking reaction of chain ends with DVB (mole ratio of DVB/Mg =
1.0) was carried out in cyclohexane at 82C for 6 hours.
The shape of the MWD of the linear precursor SBR (Run 35) is fairly narrow with a small fraction of low molecular weight tail-ing. Heterogeneity indices (M /M ) of 2.0 to 3.0 (estimated by GPC) are representative values of these linear SBR's. A com-parison of the shapes of the MWD curves in Figure 4 shows a buildup in the amount of high molecular weight polymer and an increase in molecular weight as a result of linking of chain ends with DVB.
High trans SBR's chain extended with DVB can be oil extend-ed. They have less cold flow (Table IX below) and improved mill processibility behavior relative to linear high trans SBR's.
Figure 5 compares the rheological behavior of a linear high trans SBR of this invention and a corresponding SBR chain extended with DVB. Measurements of complex viscosity (n~-) of these raw poly-mers at various shear rates were obtained with a Rheometric Mechanical Spectrometer at 90C with an eccentric rotating disc (ERD). It can be seen that the chain extended SBR shows higher viscosity at low shear rates and lower viscosity at high shear rates than the linear control polymer. This information corre-lates well with the lower cold flow of high trans SBR chain extended with DVB.

~ ~.ti~i'~`~.`O

Table IX
Effect of Chain Extension of High Trans SBR on Cold Flow Wt.% tol Cold Flow Styrene in ~ n] 25 MW/Mn Oil Content ML-4 at 50Cc Run No. Composition dl/g (by GPC) (phr) (100C) (m&/min.) 35a 15 1.583.7 0 48 20.0 368 20 1.58 - 0 - 11.9 37b 15 1.953.2 14 40 3.4 38b 22 2.20Bimodal 0 - 0 39b 21 2.20Bimodal 37.5 41.5 1.0 a - linear SBR, unextended.
b - SBR's chain extended with divinylbenzene (DVB) after 80-90%
conver~ion.
c - Phillips Chem. Co. Method WATB 5.01.20 of December 1, 1961.

~6~'`f3 Example 11 An SBR, prepared by the process of tl~e present invention and containing 14.8% styrene with 84.5% trans-1,4 placements in the po-lybutadiene portion, was cured in the absence of fillers with 1~ dicumyl peroxide. The crystalline melt temperature of the peroxide cross-linked SBR was 18C, obtained on a Perkin-Elmer DSC-II instrument. The cured rubber film was mounted in the unstretched state on an x-ray unit. The sample was subjected to x-ray analys;s using CuK~ radiation and a nickel filter at room temperature. As shown in Figure 6, this SBR gum vulcaniæate in the unstretched state exhibited a diffuse halo characteristic of a non-crystalline material. At 200% strain, a diffraction pattern of oriented crystalline polymer (equatorial arcs) was observed. Several off-axial reflections appeared in the X-ray scan in addition to the equatorial fiber arc as the sample was elongated to 700%. This result demonstrates the ability of this rubber to undergo strain-induced crystallization. Building tack and green strength are properties often characteristic of a crystalli~able elastomer such as natural rubber. It will be demonstrated in the following examples that this set of proper-ties is also chsracteristic of the SBR's of this invention.
With respect to Figure 6 the following information is given:

Sample % HoursDistance of Polymer Sample 25 PhotographElongationExposureto X-ray Film, Approx.
A 0 4 30 mm.

B 200 ~4- 30 mm.
C 700 6 50 mm.
D 700 17 50 mm.

E~ample 12 Green strength is a quality that is possessed by natural rubber and is essentially absent in emulsion SBR. In fact, very few synthetic rubbers have green strength comparable to natural rubber. Green strength is a measure of the cohesiveness in stretched, uncured rubber. The presence of green strength in a rubber prevents the occurrence of thinning down and breakinB
during fabrication of an uncured tire. It ig ~enerally accepted that the green strength of natural rubber arises from strain-in-duced crystallization.
Green strength has been measured for an uncompounded high trans SBR prepared with the Mg-Al-Ba catalyst of this invention.
The SBR contained 20% styrene with 88~ trans-1,4 polybutadiene placements and exhibited a crystalline melting temperature of 22C, as measured by DTA. Green strength data was obtained from stress-strain measurements on unvulcanized polymers with an Instron tester at room temperature. The crosshead speed was 50.8 cm/minute. Sample specimens were prepared by press molding ten-sile sheets at 121C for 5 minutes with a ram force of 11360 kg.
The data in Table X, below, demonstrate that the green strength (0.95 MPa) of the uncompounded and uncured experimental high trans SBR of this invention was equivalent to natural rubber (MV-5) (peptized No. 3 ribbed smoked sheets; uncured and uncom-pounded).
The stress-strain curves of uncured, compounded (45 phr HAF
carbon black) high trans SBR (15X styrene) with 85X trans content of this invention are compared with natural rubber ~SMR-5) and an emulsion SBR in Figure 7. The green tensile strengths of NR and high trans SBR are nearly equivalent (1.4 MPa). The stress-strain cu N es of NR and the experimental high trans SBR of this invention have positive slopes above 150% elongation relative to a negative slope in the stress-strain cu N e of emulsion SBR
(SBR-1500~. The presence of a positive slope can be taken as evidence for strain-induced crystallization.

Table X
Comparison of Green Tensile Strength of Unfilled, Uncured High Tranc SBR ~ith Natural Rubber Run No.

Natural RubberHigh Trans SBR
(MV-5)(20% Styrene) Mooney Viscosity ML-4 (100C) 72 30 Tensile Strength PSI ` 139 138 MPa 0.96 0.95 Elongation at break, X 633 1395 Example 13 Tack strength is defined as the force required to separate two uncured polymer surfaces after they have been brought into contact. The limiting tack strength of a rubber is necessarily its green strength, or the force required for its cohesive fail-ure. Although high green strength is necessary, it is, by it-self, insufficient to insure good tack. High tack strength is an especially desirable property in the fabrication of articles, es-pecially those having a complex geometry, prior to vulcani~ation.
10Tack strength was measured using the Monsanto Tel-Tak*
machine. The test specimens were raw and compounded polymers pressed between Mylar film at 100C. Two 0.64 cm x 5.08 cm die- , - cut sample strips were placed at right angles to each other and retained in special sample clamps. A fixed load, 0.221 MPa, was then applied for 30 seconds. The samples were pulled apart at a constant separation rate of 2.54 cm/minute. The test was run at room temperature. The true tack values reported in Table XI, be-low, represent the difference between the apparent tack (rubber versus rubber) and the value obtained for rubber versus stainless steel. The results in Table XI for several uncompounded and un-cured rubbers show that the apparent tack strength of high trans SBR (0.28 MPa) of this invention is higher than natural rubber.
The presence of carbon black (45 phr HAF) in formulations of high trans SBR (15% styrene, 85% trans) of this invention and NR
(SMR-5) resulted in an increase in tack strength, as shown by comparing data in Tables XI and XII, below. The compounded tack strength of high trans SBR of this invention is equivalent to NR
within experimental error. The tack strength of a blend of equal amounts of high trans SBR of this invention and NR was slightly higher than the respective unblended polymers.
It is important in construction of tires that tack strength is developed quickly when two strips of rubber are brought into contact. Figure 8 shows that high tack strength is obtained for low contact times (6 seconds) for both high trans SBR of this 3S invention and NR. Both rubbers have what is often referred to as "quick-grab".
*Trade Mark f~

`t.`~

Table XI
Monsanto Tel-Tak*of Uncompounded, Uncured Rubbers Crystalline Tack Strength Melting Apparent True Run No. Polymer Description Temp., C PSI MPa PSI MPa 39bHigh Trans SBR
of this invention (21% styrene, 87% trans) 24 41 0.28 35 0.24 10 40Natural Rubber (MV-5) 28 34 0.23 32 0.22 41Trans-polypentenamer 9 38 0.26 35 0.24 42High Trans SBR
of this invention 15 (23~ styrene, 83% trans) -1 34 0.23 23 0.16 43Cis-1,4 Polybutadiene (99% cis) -6 27 0.19 15 0.10 44SBR-1500 (Emulsion)CNone Observed 22 0.15 4 0.03 a - 30 seconds contact time, 32 oz. load.
b - 37.5 phr Philrich 5*oil added to polymer.
c - BD-STY rubber, about 23.5% bound styrene, cold polymerized.

*Trade Mark ~ .

Table XII
Monsanto Tel-Tak of Compounded, Uncured Rubbers Apparent Contact Time Tack Strength 5 Run No.Polymer Description (minutes) PSI MPa High Trans SBR 0.5 52 0.36 (15% styrene, 85% trans) 3.0 69 0.48

6.0 69 0.48 46 Natural Rubber 0.5 65 0.45 (SMR-5) 3.0 64 0.44 6.0 67 0.46 47 Blend of 50/50 0.5 71 0.49 High Trans SBR/NR 3.0 69 0.48 (SMR-5) 6.0 73 0.50 Formulation for the Above Compounded but Uncured Rubber, Parts by Weight IngredientHigh Trans SBR NR Blend Polymer 100 10050/50, NR/High Trans SBR
HAF Carbon Black 45 45 45 20 Oil 5 Naphthenic 0 7 Naphthenic ZnOlStearic Acid 5/3 5/3 5/3 Antioxidant 2 2 2 Tackifier 775 3 3 3 Sulfur 1.0 1.0 1.0 25 Total Accelerator 1.8 1.8 1.8 ,<~

Example 14 A high trans SBR of this invention was prepared according to Run No. 2 in Example 2. The resulting copolymer contained 20%
styrene with 86% trans-1,4 content in the polybutadiene portion.
The intrinsic viscosity in toluene at 30C was 1.82 dltg. The copolymer showed a crystalline melt temperature of 20C in the DTA thermogram.
A description of the compound recipe and cure conditions for the above SBR along with a commercial butadiene-styrene copolymer (SBR-1500) and natural rubber (SMR-5) is given in Table XIII, be-low. Satisfactory rates of cure in the SBR's were obtained with a sulfur cure accelerated with 2-(morpholino) thiobenzothiazole (NOBS Special) and tetramethylthiuram monosulfide (TMTM). A com-parison of the physical properties for these rubbers is given in Table XIV, below.
It should be noted that high trans SBR has higher tear strength than SBR-1500. This can be related to strain-induced crystallization in the high trans SBR. It is clear that the vulcanizate properties of high trans SBR approach those of natural rubber.

Table XIII

Formulations (PHR) Natural Rubber High Trans SBR
SBR-1500(SMR-5)(20% Styrene) Run No.: 48 49 50 Ingredients Rubber 100 100 100 Antioxidant 2246a 2 2 4e Zinc Oxide 5 5 5 10 Stearic Acid 3 3 3 Atlantic Wax 3 3 Tackifier 775b 3 3 3 HAF Carbon Blsck 45 45 42 PHILRICH 5*0il 15 (Phillips Pet.) 5 5 14f NOBSC 1.6 0.5 1.&
TMTMd 0.2 - 0.2 CRYSTEX*Sulfurg (Stauffer Chem.) 1.3 2.5 1.3 20 Cured, min./C 45/142 35/142 21/142 a - 2,2'-methylenebis (4-methyl-6-tert-butylphenol) b - octylphenol formaltehyde (non-heat reactive) c - 2-(morpholino) thiobenzothiazole (American Cyanamid) d - tetramethylthiuram monosulfide e - 2phr, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylene diamine and 2phr, N,N'-Bis(1,4-dimethylpentyl)-p-phenylene diamine f - Naphthenic Oil (Circosol 42 ~ Sun Oil Co.) g - CRYSTEX*contains 80% sulfur in mineral oil .

*Trade Mark - ~ti -Table XIV
Comparis;on of Properties of High Tran~ SBR of This Invention with S~R-1500 (Emulsion Polymèr) and Natural Rubber Run No.

SBR-1500 Natural Rubber High Trans SBR
_ _ ___~ _ Modulus at 100%, MPa 1.51 1.50 1.38 Modulus at 300~, MPa 6.47 7.34 3.68 Tensile Strength~ MPa 21.94 25.23 20.13 10Elongation, X 700 ti50 770 Hardness, Shore A 66 59 63 Tear Strength, Crescent, kN/m 83 123 112 Goodrich Heat Buildup (100C), ~T C 32 28 28 Perm. Set, Z
(100C) 10.2 18.6 6.4 DeMattia No. of Flexes x 10-3 100 100 100 Crack Growth, ~ 100 41 75 Example 15 To n-butylethyl magnesium (Texas Alkyls, Inc., BEM, a mixture of n~butylethyl magnesium and triethyl aluminum, mole ratio of Mg to Al of 50:1, in heptane) was added cyclohexane and additional triethyl aluminum to give a mole ratio of Mg/Al = 4.8 to 1. To tlle Mg-AI composi~ion was added Ba[(t-cloH2lo)o~96(t-c4~l9o)o~96( )0.08 in toluene to provide a mole ratio of Ba/Mg = 0.26. The result-ing Ba-Al-Mg catalyst complex was then used to polymerize propyl-ene oxide (P0) at 80C to obtain a tacky solid. The polymeriza- .
tion conditions used were as follows:

Grams P0 %
P0 Solvents, grams Per mM Conv.
Grams Cyclohexane Heptane TolueneMg (Hrs.~ -1540.2 8.8 3.8 19.1 10.9 40(64) , .. .... ... . .
, . . .

l~ti~t~O
- 47a -SUPPLEMENTARY DISCLOSURE
The method of this invention, also, can provide homopolybutadienes having trans contents of ~rom about 64 to 90%, vinyl contents of from about 2 to 7%
intrinsic viscosities of from about 0.90 to 4.29 in deciliters per gram in toluene at 25C, and peak crystalline melting temperatures of from about -16 to 70C, preferably rubbery polymers having a trans content of from about 75 to 80% and vinyl content of from about 2 to 4%.

Two batches of polybutadiene were prepared, the batches blended and then vacuum dried. The polymerization recipe, reaction contains and charging pro-cedure are shown below:
Polymerization Recipe Grams Mole Butadiene -1,3 2,000 n-Hexane 8,000 [?-6 tn-c4H9)2Mg (C2H5)3Al] 5.9 Bu2Mg 0.0424 Bu2Mg MAGALA-7.6E 0.6 Et3A1 0.0056 Et3Al Ba[(t-C4HgO)1 g(OH)o l] 3.2 0.0115 Mole Ratios Ba/Mg = 0.27 Mg/Al = 7.6 a: Commercially available (Texas Alkyls) as a 10 wt.% solution in n-Heptane.
b: Prepared in liquid NH3 by reacting Ba with a mixture of t-butanol and H20 Reaction Conditions Temperature - 65C
Time - 24 hours % Conversion - 100%
B

- ~7~ -Charging Procedure 1. Phillips Petroleum Company 99% pure n-hexane was charged to the reactor.
Prior to charging, the hexane was dried by passing through 5 R molecular sieves.
2. Phillips Petroleum Company Rubber Grade ~99%) butadiene -1,3 was charged to the reactor. Prior to charging, the butadiene -1,3 was passed as a liquid through Linde 13 X molecular sieves.
3. A solution of the complex (MAGALA-7.6E) of dibutylmagnesium-triethyl-aluminum in n-heptane was charged to the reactor followed by a solution of the barium salt in toluene.
4. The batch was heated to 65C.
5. Polymerization was carried out for 24 hours and then the batch was cooled to 25C.
6. Just prior to discharging the batch, 1 part per hundred (phr) AØ 2246 (2,2'-methylene bis(4-methyl-6-tert-butyl phenol) and 1 phr lauric acid were mixed with the batch A description of the blended polybutadienes is given in Table XV, below.
For comparison purposes, the corresponding data for a commercially available high cis polybutadieneis included. The experimental polybutadiene rubber or elastomer has a much higher trans/cis ratio, lower cold flow and a different crystalline melt endotherm. Polymer molecular weight, as measured by GPC, is essentially the same.

iB

- 47c ~ V

TABLE XV
Characterization Data of Experimental Poly BD RUBBER and High Cis BD Rubber Commercial Experimental Cis Poly BDa Trans PolyBD
Diene Structure ~%~
Trans 4 77 Cis 92 20 Vinyl 4 3 Brookfield Viscosity ~cps at 23C)b 143 117 Intrinsic Viscosity, tol. at 30C (dl/g)2.46 2.11 Mooney Viscosity ~ML-4 at 100C) 47 55 Cold Flow at 50 (mg/min.)C 3.2 0.5 By GPC:
Mn 149,000 152,000 Mw 401,000 409,000 _ _ 2.69 2.70 ~/Mn By DTA:
Tg, C -100 -92 Tm~ C - 25 26 a -Butadiene solution polymerized using Ziegler/Natta type catalyst system.
b -5% wt.!wt. in toluene ~#3 spindle, 100 rpm) c -Phillips Chem. Co. Method WATB 5.01.20 of December 1, 1961.
The data in Table XVI and Table XVII below, show the formulations and tread vulcanizate properties of the commercially available high cis poly BD and the experimental trans poly BD in blends with emulsion SBR-1714. The experi-B

- 47d -mental rubbcr was cured with one additional part of stearic acid. Laboratory evaluation sho~ed the experimental rubber to be generally equivalent except for high Pico abrasion index ~175 versus 149) and slightly lower dry skid resistance ~120 versus 125). Based on the data presented herein, it is seen that the cxperimental rubber may be useful as a substitute for the commcrcially available high cis poly BD in passenger tire tread compounds. The superior abrasion resistance, although not expected on the basis of the relative Tg values, suggests an advantage in treadwear over the commercially available high cis poly BD containing blends.

TABLE XVI
Compound Recipes ~phr) Run A Run B
SBR-1714a 60 60 Commercially available high CisPoly BD, above 40 --Experimental Trans poly BD, above -- 40 PHILRICH 5*oil, aromatic, ~total) b tPhillips Petroleum Co.) 44 44 HAF-HS Carbon Black 75 75 Santoflex 13C~ 1.4 1.4 Santoflex 77d* 1.4 1.4 Atlantic Wax 3.0 --Zinc Oxide 3.0 3.0 Stearic Acid 2.0 3.0 Santocure NSe* 1.1 1.1 TMTM 0.11 0.11 Sulfur 1.98 1.95 *Trade Mark '~

` v - ~7~ -a - Free radical cold emulsion polymerized butadiene -1,3/styrene copolymer target bound styrene of 23.5%, nominal Mooney viscosity ML 1+4(212F) of 52, contains target 50 phr highly aromatic oil.
b -Total oil in recipe including that in SBR-1714~
c -N-~1,3-Dimethylbutyl)-N'-phenyl-p-phenylene-diamine ~Monsanto, Rubber Chemicals Div.).
d -N,N'-Bis~1,4-dimethyl-pentyl)-p-phenylenediamine ~Monsanto, Rubber Chemicals Div.).
e -N-t-butyl-2-benzothiazolesulfenamide (Monsanto, Rubber Chemicals Div.).
f-Tetramethylthiuram monosulfide.
TABLE XVII
Vulcanizate Properties Run A Run B
Compound Mooney, ML-4~100C) 58 57 T95, minutes/142C 35 28 Modulus at 300%, MPa (PSI) 9.3(1355) 8.6 (1250) Tensile Strength, MPa (PSI) 18.4(2670) 17.8 (2580) Elongation at Break ~%) 520 510 Shore A 66 67 Coodrich HBU, 100C ~TC) 33 31 Permanent Set ~%) 14 13 Pico Abrasion Index 149 175 Skid Resistance (dry) 125 120 Goodyear Rebound (%) 49 47 Goodyear Rebound Decay (tan~) 0.22 0.23 Cure Time/Temp. 35 min/287F28min/287F

~B

- 47f ~ iti~

Even though the above experimental trans polybutadiene, prepared with the Mg-Al-Ba catalyst system, has a significantly higher trans/cis ratio than tha commercially available high cis poly BD, the vinyl contents ~3-4%) are very similar. The mole ratio of catalyst components, monomer/catalyst ratio and polymerization temperature can be used to control the trans polybutadiene microstructure and polymer molecular weight. A trans-1,4 configuration of 77%
results in a material which is rubbery at room temperature. Although the raw experimental trans BD polymer crystallizes as does the commercially available high cis poly BD, the tendency to crystallize can be largely suppressed by cross-linking.
Relative to the preparation of a 90% trans-1,4 polybutadiene, with the barium salt in combination with (Bu)2Mg and Et3Al, the experimental trans poly BD is prepared with the same catalyst system but using a higher Ba/Mg mole ratio. A small increase in Ba content results in a decrease in the amount of trans-1,4 structure from 90% to about 75-80%.

IB

Claims (28)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A composition of matter useful as an anionic polymeriza-tion catalyst comprising (1) an alcoholate selected from the group consisting of barium alcoholate, calcium alcoholate and strontium alcoholate and mixtures thereof, (2) an organoaluminum compound and (3) an organomagnesium compound, where the mol ratio computed as metal of barium, calcium and/or strontium to magnesium is from about 1:10 to 1:2 and where the mol ratio computed as metal of magnesium to aluminum is from about 105:1 to 1.5:1.

2. A composition according to claim 1 where the alcoholate contains an OH moiety in an amount of up to about 20 mol%, the balance being the alcohol moiety of said alcoholate.

3. A composition of matter useful as an anionic polymeriza-tion catalyst comprising (1) at least one of and where the mol ratio of a to b is from about 100:0 to 80:20, and where M is at least one metal selected from the group consisting of Ba, Ca and Sr, where R is selected from the group consisting of alkyl and cycloalkyl radicals of from 1 to 6 carbon atoms which may be the same or different, where R' is an alkyl radical of from 1 to 4 carbon atoms which may be the same or different and where R'' is a hydrocarbon radical having a molecular weight of from about 250 to 5,000, (2) R3IIAl where RIII is selected from the group consisting of alkyl and cycloalkyl radicals of from 1 to 20 carbon atoms which may be the same or different and (3) R?VMg where RIV is selected from the group consisting of alkyl and cycloalkyl radicals of from 1 to 20 carbon atoms which may be the same or different, where the mol ratio of magnesium to aluminum of (2) and (3) computed as metal is from about 105:1 to 1.5:1 and where the mol ratio of M to magnesium of (1) and (3) computed as metal is from about 1:10 to 1:2.

4. A composition according to Claim 3, where (1) is , where the mol ratio of a to b is from about 100:0 to 88:12, where RIII has from 1 to 10 carbon atoms and where RIV has from 1 to 10 carbon atoms.

5. A composition according to Claim 3 where (1) contains less than about 0.1% by weight of nitrogen.

6. A composition according to Claim 3 where (1) contains less than about 0.01% by weight of nitrogen.

7. A composition according to Claim 3 where (2) and (3) are in the form of a complex of R?IIAl?R?VMgq where m, n, p and q are numbers sufficient to satisfy the valences of the radicals and atoms of the complex.

8. The method which comprises polymerizing under inert condi-tions in a hydrocarbon solvent at a temperature of from about 0 to 150°C a monomer selected from the group consisting of a polymeriz-able heterocyclic monomer and a polymerizable ethylenically unsaturated monomer having an activated double bond with a catalyst in a minor effective amount sufficient to polymerize said monomer to obtain a polymer, said catalyst comprising (1) an alcoholate selected from the group consisting of barium alcoholate, calcium alcoholate and strontium alcoholate and mixtures thereof, (2) an organoaluminum compound and (3) an organomagnesium compound, where the mol ratio computed as metal of barium, calcium and/or strontium to magnesium is from about 1:10 to 1:2 and where the mol ratio computed as metal of magnesium to aluminum is from about 105:1 to 1.5:1.

9. The method according to Claim 8 where the alcoholate con-tains an OH moiety in an amount of up to about 20 mol%, the balance being the alcohol moiety of said alcoholate.

10. The method which comprises polymerizing under inert conditions in a hydrocarbon solvent at a temperature of from about 0 to 150°C a monomer selected from the group consisting of a polymerizable heterocyclic monomer and a polymerizable ethyl-enically unsaturated monomer having an activated double bond with a catalyst composition in a minor effective amount sufficient to polymerize said monomer to obtain a polymer, said catalyst compo-sition comprising (1) at least one of where the mol ratio of a to b is from about 100:0 to 80:20, where M is at least one metal selected from the group consisting of Ba, Ca and Sr, where R is selected from the group consisting of alkyl and cycloalkyl radicals of from 1 to 6 carbon atoms which may be the same or different, where R' is an alkyl radical of from 1 to 4 carbon atoms which may be the same or different and where R'' is a hydrocarbon radical having a molecular weight of from about 250 to 5,000, (2) R?IIAl where RIII is selected from the group consisting of alkyl and cycloalkyl radicals of from 1 to 20 carbon atoms which may be the same or different and (3) R?VMg where RIV is selected from the group consisting of alkyl and cycloalkyl radicals of from 1 to 20 carbon atoms which may be the same or different, where the mol ratio of magnesium to aluminum of (2) and (3) computed as metal is from about 105:1 to 1.5:1 and where the mol ratio of M to magnesium of (1) and (3) computed as metal is from about 1:10 to 1:2.

11. The method according to Claim 10 where the temperature is from about 30 to 100°C.

12. The method according to Claim 11 where the monomer is a mixture of butadiene-1,3 and up to about 30% by weight of styrene.

13. The method according to Claim 10 in which the ratio of said catalyst composition to said monomer is from about 0.00001 to 0.10 mole of said catalyst composition computed as magnesium metal per 100 grams total of said monomer(s).

14. The method according to Claim 13 in which the ratio of said catalyst composition to said monomer is from about 0.00033 to 0.005 mole of said catalyst composition computed as magnesium metal per 100 grams total of said monomer(s).

15. The method according to Claim 10, where (1) is , where the mol ratio of a to b is from about 100:0 to 88:12, where RIII has from 1 to 10 carbon atoms and where RIV has from 1 to 10 carbon atoms.

16. The method according to Claim 10 where (1) contains less than about 0.1% by weight of nitrogen.

17. The method according to Claim 10 where (1) contains less than about 0.01%
by weight of nitrogen.

18. The method according to Claim 10 where (2) and (3) are in the form of a complex of R?IIAln?R?VMgq where m, n, p and q are numbers sufficient to satisfy the valences of the radicals and atoms of the complex.

19. The method according to Claim 10 where the solvent is selected from the group consisting of saturated aliphatic and saturated cycloaliphatic hydro-carbon solvents and mixtures thereof.

20. A rubbery copolymer of butadiene-1,3 and up to about 30% by weight total of said copolymer of copolyerized styrene, said copolymer exhibiting:
a. a glass transition temperature of from about -50 to -100°C as determined by differential thermal analysis, b. A crystalline melting point (peak values) in the unstretched state of from about -10 to +40°C as determined by differential thermal analysis, c. A trans-1,4 content of from about 81 to 90% and a vinyl content of up to about 4% from the butadiene units, d. a heterogeneity index of from about 2.5 to 5, e. a number average molecular weight of from about 50,000 to 500,000, f. crystallinity when stretched in the uncompounded and uncured state as shown by x-ray diffraction data and g. quick-grab, green strength and building tack.

21. Homopolybutadiene having a trans content of from about 64 to 90%, a vinyl content of from about 2 to 7%, an intrinsic viscosity of from about 0.90 to 4.29 in deciliters per gram in toluene at 25°C and a peak crystalline melting temperature of from about -16 to 70°C.

22. Homopolybutadiene according to claim 21 having a trans content of from about 75 to 80% and a vinyl content of from about 2 to 4% and being rubbery.

23. A process for preparing an anionic polymerization catalyst as defined in claim 1 which comprises:
(A) preparing the alcoholate salt by reacting the alcohol with Ba, Ca, and/or Sr, and removing excess alcohol; and (B) ether (i) preparing an organoaluminum compound by reacting aluminum metal with an olefin in the presence of hydrogen;
and (ii) preparing an organomagnesium compound either by reacting a compound R2Hg with magnesium, or by reacting magnesium with an olefin in the presence of hydrogen; or (iii) preparing an organomagnesium/aluminum complex by reacting an organoaluminum compound with the reaction product of organic halide with magnesium in a hydrogen solvent; and (C) combining together the products of steps (A) and (B) in a hydrocarbon solvent.

24. A process according to claim 23 wherein in step (A) liquid ammonia or an amine is used as solvent, and is removed after the reaction from the alcoholate salt by vacuum drying to leave a nitrogen content in the alcoholate salt of at most 0.1%
by weight of the alcoholate salt.

25. A process according to claim 24 wherein the nitrogen content is reduced by at most 0.01% by weight.

26. A process according to claim 23 wherein the alcohol used in step (A) additionally contains water, to provide an alcoholate salt including some hydroxide.

27. A composition according to claim 1 where the alcoholate contains an OH moiety in an amount up to about 12 mol %, the balance being the alcohol moiety of said alcoholate.

28. The method according to claim 8 where the alcoholate contains an OH moiety in an amount up to about 12 mol %, the balance being the alcohol moiety of said alcoholate.