Tin containing elastomers and products having reduced hysteresis properties
AssigneeBridgestone/Firestone, Inc.
InventorsWilliam L. Hergenrother, Tristram W. Bethea, John M. Doshak
Life of this patent
Estimating the term…
Abstract
An anionic polymerization initiator comprising the reaction product of a an organatin halide and lithium in a suitable solvent. Elastomeric polymers prepared with these initiators have tin containing functional groups on substantially every polymer chain and provide vulcanizable rubber compounds exhibiting reduced hysteresis. Articles such as tires, produced with low hysteresis elastomeric polymers have lower rolling resistance. Methods are also provided for preparing the initiators and the elastomers having reduced hysteresis properties.
Claims26
An elastomer having reduced hysteresis properties comprising:
- a plurality of polymer molecules wherein substantially each said polymer molecule contains at least one tin atom and a lithium atom prior to quenching;
- wherein substantially each of said polymer molecules before termination has the general formula R.sub.3 SnYLi where R is an organo group and Y is a polymer selected from the group consisting of diene homopolymers, monovinyl aromatic polymers, diene/monovinyl aromatic random copolymers and block copolymers.
An elastomer having reduced hysteresis properties made by anionically polymerizing a monomer solution containing at least one monomer selected from the group consisted of conjugated diene monomers having from about 4 to 12 carbon atoms, vinyl aromatic monomers having from about 8 to 18 carbon atoms and mixtures thereof, in the presence of an organic initiator containing tin;
- wherein substantially each polymer molecule of the elastomer contains a tin atom derived from said organic initiator;
- and,
- wherein substantially each of said polymer molecules before termination has the general formula R.sub.3 SnYLi where R is an organo group and Y is a polymer selected from the group consisting of diene homopolymers, monovinyl aromatic polymers, diene/monovinyl aromatic random copolymers and block copolymers.
A method of preparing an elastomer comprising the steps of:
- forming a solution of one or more anionically polymerizable monomers in a solvent, wherein said anionically polymerizable monomers are selected from the group consisting of conjugated dienes having from about 4 to about 12 carbon atoms, monovinyl aromatic monomers having 8 to 18 carbon atoms and trienes;
- and
- polymerizing said monomers in the presence of an organotin lithium initiator;
- wherein said elastomer comprises a plurality of polymer molecules, substantially each said molecule having a tin atom on one end and a lithium atom on the other end, prior to termination.
An elastomer having reduced hysteresis properties made by anionically polymerizing a monomer solution containing at least one monomer selected from the group consisted of conjugated diene monomers having from about 4 to 12 carbon atoms, vinyl aromatic monomers having from about 8 to 18 carbon atoms and mixtures thereof, in the presence of an organic initiator containing tin;
- wherein substantially each polymer molecule of the elastomer contains a tin atom derived from said organic initiator;
- and,
- wherein said organic initiator comprises the reaction product of an organotin compound selected from the group consisting of triorgano substituted-tin halide compounds and hexaorgano substituted di-tin compounds having a tin-tin bond, and lithium in the presence of a suitable solvent.
A vulcanizable elastomeric compound having reduced hysteresis properties comprising:
- an elastomer comprising a plurality of polymer molecules wherein substantially each said polymer molecule contains at least one tin atom and a lithium atom prior to quenching, wherein substantially each of said polymer molecules before termination has the general formula R.sub.3 SnYLi where R is an organo group and Y is a polymer selected from the group consisting of diene homopolymers, monovinyl aromatic polymers, diene/monovinyl aromatic random copolymers and block copolymers;
- and,
- from about 20 to about 100 parts by weight of carbon black, per 100 parts of said elastomer.
An improved tire having decreased rolling resistance resulting from a treadstock containing a vulcanizable elastomeric compound comprising:
- an elastomer comprising a plurality of polymer molecules wherein substantially each said polymer molecule contains at least one tin atom and a lithium atom prior to quenching, wherein substantially each of said polymer molecules before termination has the general formula R.sub.3 SnYLi where R is an organo group and Y is a polymer selected from the group consisting of diene homopolymers, monovinyl aromatic polymers, diene/monovinyl aromatic random copolymers and block copolymers;
- and,
- from about 20 to about 100 parts by weight of carbon black, per 100 parts of said elastomer.
Dependencies are inferred from the claim text.