3,528,957 United States Patent Office Patented Sept. 15, 1970 2 ing and forming machinery. In spite of its relatively high 3,528,957 cis-1,4 content, the polybutadiene produced by this proc METHOD OF PRODUCING POLYBUTADENE ess is, on the average, no better or no worse in processing MorfordAkron, C.Ohio, Throckmorton, assignors to Theand GoodyearWilliam M.Tire Saltman, & Rub. properties than polybutadiene made with the alkyl-lithium ber Company, Akron, Ohio, a corporation of Ohio catalyst System which produces a polybutadiene with No Drawing. Filed July 10, 1967, Ser. No. 651,991 about a 40% cis-1,4 structure. Polybutadiene made with Int, C. C08d, 3/06 the two component catalyst system comprising alkyl U.S. CI. 260-94.3 10 Cains aluminum halides and cobalt salts results in molecular Structures very high in cis-1,4 configuration (in the neigh borhood of 98%), yet these polymers do not show ap ABSTRACT OF THE DESCLOSURE 10 preciable processing advantage over the polybutadiene A method and a catalyst system for the solution po type polymers made by either of the other two processes lymerization of butadiene or butadiene in mixture with previously mentioned. other diolefins to form polymers containing a high con Based on the most practical test of what indicates good tent of cis-1,4 addition is described. The solution polym 5 polymer processability, that is, manifestations during ac erization is carried out under conventional polymeriza tual factory processing, polybutadiene produced by a tion conditions. The catalyst employed is a mixture of ternary catalyst System comprising (1) triethylaluminum, (1) organometallic compounds of metals of Groups I, (2) an organonickel salt, and (3) boron trifluoride di II and III; (2) at least one compound selected from the ethyl ether complex, which possesses a very high cis-14 class consisting of organonickel and organocobalt com 20 molecular structure of about 98%, shows an appreciable pounds, and (3) at least one boron trifluoride complex gain in processability over the polybutadienes prepared prepared by complexing boron trifluoride with a member in the aforementioned process. of the class consisting of monohydric alcohols, phenols, The present invention also employs a ternary catalyst Water and mineral acids containing oxygen. System similar to the just mentioned except that one 25 catalyst component comprises borontrifluoride complexed with at least one member from the group comprising This invention is directed to methods of polymerizing a monohydric alcohol, a phenol, water and an oxygen butadiene and butadiene in mixture with other diolefins containing mineral acid, the result of which, produces to form polymers having a high content of cis-14 ad an unexpected increase in the polymerization reaction dition. It is also directed to catalyst systems useful for 30 rate of 2 to 3 times greater than that achieved by the this purpose. just-mentioned catalyst system. The processability of the Polymers of butadiene or butadiene in mixture with polymer produced by the system of the present invention other diolefins containing a high proportion of the is equivalent to that produced by the system using boron butadiene units in the cis-1,4 configuration possess proper trifluoride diethyl ether complex. ties which make them useful as synthetic rubbers. 35 In addition to promoting unexpected reaction rates, It is an object of this invention to provide a method the catalyst system of the present invention has also shown whereby butadiene can be polymerized to a high content an unexpected versatility in performance. of cis-1,4 polybutadiene. Another object is to provide a For example, the catalyst System just mentioned using catalyst System by which these polymerizations may be the boron trifluoride" diethyl ether complex appears to be accomplished. Another object is to form copolymers of 40 quite limited with respect to the selection of the trialkyl isoprene or other diolefins and butadiene in which the aluminum component if optimum reaction rates for this polybutadiene segment has a high content of cis-1,4 struc system are to be attained. To maintain the optimum re ture. Another object is to produce high cis-1,4 poly action rate with this catalyst system, the choice of trialkyl butadiene with excellent processing properties. Other ob aluminum compound appears o be limited to triethyl jects will become apparent as the description proceeds. aluminum. When the ethyl group in the trialkylaluminum The term "good processability” describes a polymer compounds is replaced with longer chain alkyl groups, which before and after compounding manifests properties for example, n-propyl or isobutyl, not only is the polym ideal for use on rubber processing equipment. These de erization reaction rate of this system appreciably reduced, sirable porperties lead to ready banding on mix mills, but the molecular weight of the resulting polymer de good tack, and ease of extrudability. 50 creases below desirable values. The decline in reaction It is still obscure which chemical and physical param rate and polymer properties is particularly sharp when the eters of a polymer contribute to the properties associated triethylaluminum is replaced with diisobutyl aluminum with good processability. It is hypothesized that a given hydride, triisobutylaluminum and/or organoaluminum molecular weight distribution of the polymer influences compounds containing even longer chain alkyl group than the processing properties of the polymer to a greater 55 the butyl group. degree than a high cis-1,4 molecular orientation. In contrast, the catalyst system of the present inven For example, polybutadiene made by a process, using tion, using as one catalyst component, boron trifluoride a two component catalyst system consisting of trialkyl complexed with at least one member from the group aluminum and titanium tetraiodide, has a cis-1,4 molec comprising a monohydric alcohol, a phenol, water and ular configuration in the neighborhood of 90 to 94% of 60 an oxygen-containing mineral acid, is much more versa the polymer structure formed. However, as a general rule, tile than the aforementioned system with respect to the the polybutadiene produced by this process does not pos selection of the trialkylaluminum compound. Various tri sess the ultimate in processability properties, and often alkylaluminum or dialkylaluminum hydrides (as indi requires blending with other elastomers to attain the cated by the specific embodiments herein) can be used in desired degree of processability with standard rubber mix 65 the catalyst system of this invention without affecting the 3,528,957 3. 4. rapid polymerization, the high yield, or the desirable poly Also “organomagnesium compounds' means any or mer viscosities characteristic of the system. ganomagnesium compound or any organomagnesium Thus, according to the invention, butadiene or buta halide of the Grignard type corresponding to the for diene in combination with other diolefins is polymerized mulas RMg or RMgY where R may be alkyl, aryl, by contact under solution polymerization conditions with arylalkyl or alkaryl and Y is fluorine, or R'R''Mg where a catalyst comprising (1) at least one organometallic R’ may be alkyl, aryl, or alkaryl and R' may be either compound in which the metal is selected from Groups I, alkyl, aryl, arylalkyl or alkaryl. Representative among the II and III of the Periodic System, (2) at least one organo compounds responding to these formulea are diethylmag metallic compound selected from the class consisting of nesium, dipropylmagnesium, ethylmagnesium fluoride and organonickel and organocobalt compounds, and (3) at phenylmagnesium fluoride. least one boron trifluoride complex prepared by complex O By the term “organozinc compound is meant any or ing boron trifluoride with a member of the class consist ganozinc compound responding to the formula R27n ing of monohydric alcohols, phenols, water and mineral where R may be alkyl, aryl, alkary or arylalkyl. Repre acids containing oxygen. sentative among such compounds are diethylzinc, dibu The organometallic compounds wherein the metals are tylzinc or diphenylzinc. selected from Groups I, II and III of the Periodic System By the term “organolithium compounds' is any organo are organocompounds of such metals as lithium, Sodium, lithium compound responding to the formula R-Li where potassium, rubidium, cesium, magnesium, calcium, stron R is an alkyl, alkaryl, arylalkyl or aryl group. Represent tium, beryllium, barium, zinc, cadmium, aluminum, gal ative among the compounds responding to the formula lium, and indium. The term “organometallic,' as used 20 set forth above are ehtyllithium, propyllithium, n-, sec here to refer to compounds, indicates that metals of or t-butyllithium, hexyllithium, styryllithium or phenyl Groups I, II and III of the Periodic System are attached lithium. Also, the organolithiumaluminum compounds directly to a carbon atom of alkyl, cycloalkyl, aryl, aryl may be used. These compounds respond to the formula alkyl and alkaryl radicals. All of the above compounds R'R''LiAl where R and R' may be alkyl, alkaryl or may be used in the practice of this invention. arylalkyl groups and R and R' may or may not be the When considering the organometallic compounds con same group. Representative of these compounds are taining metals from Groups I, II and III, it is preferred n-butyltriisobutyllithium aluminum, tetrabutyllithium for this invention to use organoaluminum compounds, aluminum, butyltriethyllithium aluminum and tetraiso