Abstract: The present invention is directed to a catalyst system for synthesizing rubbery polymers, such as styrene-butadiene rubber, that can be utilized in tire tread rubbers. The catalyst system, in one embodiment, includes an organolithium compound and a potassium alkyl borohydride or potassium alkyl aluminum hydride defined by: (R)3A?(H)K+, wherein A is boron or aluminum, H is hydrogen, K is potassium, and R, which is the same or different, is either H, a C1-C10 alkyl, a C3-C10 cycloalkyl, phenyl, or phenyl substituted C1-C10 alkyl, or a C3-C10 cycloalkyl, with the proviso that at least one R is a C1-C10 alkyl, and further wherein any two R's may optionally be part of a carbocyclic ring. The rubbery polymers can have low to medium vinyl microstructure content, i.e., from about 10% to about 40%, and are useful in tire tread rubber compounds which can exhibit improved wear and tear characteristics.

Abstract: The present invention is directed to a catalyst system for synthesizing rubbery polymers, such as styrene-butadiene rubber, that can be utilized in tire tread rubbers. The catalyst system, in one embodiment, includes an organolithium compound and a potassium alkyl borohydride or potassium alkyl aluminum hydride defined by: (R)3A?(H)K+, wherein A is boron or aluminum, H is hydrogen, K is potassium, and R, which is the same or different, is either H, a C1-C10 alkyl, a C3-C10 cycloalkyl, phenyl, or phenyl substituted C1-C10 alkyl, or a C3-C10 cycloalkyl, with the proviso that at least one R is a C1-C10 alkyl, and further wherein any two R's may optionally be part of a carbocyclic ring. The rubbery polymers can have low to medium vinyl microstructure content, i.e., from about 10% to about 40%, and are useful in tire tread rubber compounds which can exhibit improved wear and tear characteristics.

Abstract: The present invention is directed to rubbery block polymers containing a polylactone, such as polycaprolactone, methods of making the same, and to rubber compounds containing those block polymers. The rubbery block polymer is an anionically polymerized block polymer defined by A-B, wherein A includes at least one type of polymerized conjugated diene monomer, a polymerized vinyl aromatic monomer, or a mixture thereof and wherein B is a polylactone, such as polycaprolactone, which is hydroxy terminated. The rubbery block polymer may be compounded so to provide, for example, a tire tread with desirable properties for use in an automobile tire. Such rubber compound, for example, can include the rubbery block polymer, an organosilane coupling agent, such as a bis(trialkoxysilyl) alkane, bis(trialkoxysilylalkyl) polysulfide, or mixtures thereof, and silica filler in specified amounts.

Abstract: The present invention is directed to an amine containing catalyst system for synthesizing rubbery polymers, such as polybutadiene rubber and styrene-butadiene rubber, having a high trans microstructure. The catalyst system, in one embodiment, includes (a) an organolithium compound, (b) a group IIa metal salt, (c) an organoaluminum compound, and (d) an amine compound which can be selected from (1) a heterocyclic aromatic compound which includes a ring structure with one or more nitrogen atoms as part of the ring; (2) a heterocyclic non-aromatic compound which includes a ring structure with two or more nitrogen atoms as part of the ring; (3) an aromatic compound including a ring structure substituted with at least one amine and at least one polar functionality containing group selected from a carboxyl group or a hydroxyl group; (4) a bicyclic chelating diamine compound; or (5) an aliphatic amine which includes a C5-C20 alkyl group.

Abstract: This invention reveals a catalyst system for use in isothermal polymerizations which consists essentially of (a) an organolithium compound, (b) a calcium alkoxide and (c) a lithium alkoxide. The subject invention further discloses a process for synthesizing a random styrene-butadiene rubber having a low vinyl content by a process which comprises copolymerizing styrene and 1,3-butadiene under isothermal conditions in an organic solvent in the presence of a catalyst system which consists essentially of (a) an organolithium compound, (b) a calcium alkoxide and (c) a lithium alkoxide. An amine can also be added to the catalyst system to increase the molecular weight (Mooney viscosity) of the rubber.

Abstract: The invention is directed to a pneumatic tire having at least one component comprising a vulcanizable rubber composition, wherein the vulcanizable rubber composition comprises, based on 100 parts by weight of elastomer (phr), from about 30 to 100 phr of high trans random SIBR, and from about zero to about 70 phr of at least one additional elastomer, wherein the high trans random SIBR comprises from about 3 to about 30 percent by weight of styrene.

Abstract: The group IIa metal containing catalyst system of this invention can be utilized to synthesize rubbery polymers having a high trans microstructure by solution polymerization. Such rubbery polymers having a high trans microstructure content, such as polybutadiene rubber, styrene-isoprene-butadiene rubber, styrene-butadiene rubber, can be utilized in tire tread rubbers that exhibit improved wear and tear characteristics. This invention more specifically reveals a catalyst system which is comprised of (a) an organolithium compound, including organolithium functionalized compounds, (b) a group IIa metal salt selected from the group consisting of group IIa metal salts of di(alkylene glycol)alkylethers and group IIa metal salts of tri(alkylene glycol) alkylethers, and (c) an organoaluminum compound, and optionally an organomagnesium compound.

Abstract: Metal salts of cyclic alcohols can be used as modifiers in lithium initiated solution polymerizations of diene monomers into rubbery polymers having a low vinyl content. For instance, such initiator systems can be used in the copolymerization of styrene and isoprene to produce low vinyl styrene-isoprene rubber having a random distribution of repeat units that are derived from styrene. It is important for such polymerizations to be conducted in the absence of polar modifiers, such as Lewis bases. The subject invention more specifically discloses an initiator system which is comprised of (a) a lithium initiator and (b) a metal salt of a cyclic alcohol, wherein said initiator system is void of polar modifiers. The present invention also discloses a process for preparing a rubbery polymer having a low vinyl content which comprises: polymerizing at least one diene monomer with a lithium initiator at a temperature which is within the range of about 5° C. to about 100° C.

Abstract: This invention is based upon the discovery of certain anionic initiator systems can be used to initiate the solution polymerization of conjugated diolefin monomers into rubbery polymers having a low vinyl content. For instance, such initiator systems can be used in the copolymerization of styrene and isoprene to produce low vinyl styrene-isoprene rubber having a random distribution of repeat units that are derived from styrene. These initiator systems are comprised of (a) a lithium initiator and (b) a member selected from the group consisting of (1) a sodium alkoxide, (2) a sodium salt of a sulfonic acid, and (3) a sodium salt of a glycol ether. It is important for the initiator system to be free of polar modifiers, such as Lewis bases.

Abstract: The process and catalyst system of this invention can be utilized to synthesize a highly random styrene-butadiene rubber having a high trans content by solution polymerization. The styrene-butadiene rubber made by the process of this invention can be utilized in tire tread rubbers that exhibit improved wear characteristics. This invention more specifically reveals a catalyst system for use in isothermal polymerizations which consists essentially of (a) an organolithium compound, (b) a calcium alkoxide and (c) a lithium alkoxide. The subject invention further discloses a process for synthesizing a random styrene-butadiene rubber having a low vinyl content by a process which comprises copolymerizing styrene and 1,3-butadiene under isothermal conditions in an organic solvent in the presence of a catalyst system which consists essentially of (a) an organolithium compound, (b) a calcium alkoxide and (c) a lithium alkoxide.