Synthesis of polydiene rubber by high solids solution polymerization

摘要

Synthetic elastomers are typically made commercially by employing emulsion polymerization or solution polymerization techniques. In such solution polymerization techniques, it is desirable to operate at the highest solids content which is practical. As a general rule, it is not practical to prepare such rubbers by solution polymerization at solids contents of higher than about 20 percent. However, the subject invention reveals a technique for preparing such rubbers by high solids solution polymerization at extremely high solids contents. This technique offers substantial advantages associated with eliminating large quantities of organic solvents. The subject invention more specifically relates to a process for the synthesis of polyidene rubber by continuous high solids polymerization which comprises: (1) continuously charging at least one diene monomer, at least one organolithium compound, and from about 4 to about 50 phm of at least one organic solvent into a reaction zone; (2) allowing the monomers to polymerize to a conversion of at least about 90% while utilizing conditions under which there is sufficient evaporative cooling in said reaction zone to maintain a temperature within the range of about 10° C. to about 150° C.; and (3) continuously withdrawing said polydiene rubber from the reaction zone.