Synthesis of high vinyl rubber

Details Synthesis of high vinyl rubber Synthesis of high vinyl rubber

1999-01-08

2000-10-31

Teskin, Fred

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

Polymers from only ethylenic monomers or processes of...

526175, 526180, 526181, 526335, 502154, 502155, 502156, 502157, C08F 448, C08F13604

Patent

active

061404349

ABSTRACT:
Metal salts of saturated aliphatic alcohols can be used as modifiers in lithium initiated solution polymerizations of diene monomers into rubbery polymers. Sodium t-amylate is a preferred modifiers because of its exceptional solubility in non-polar aliphatic hydrocarbon solvents that are employed as the medium for such solution polymerizations. However, using sodium t-amylate as the polymerization modifier in commercial operations where recycle is required can lead to certain problems. These problems arise due to the fact that sodium t-amylate reacts with water to form t-amyl alcohol during steam stripping in the polymer finishing step. Since t-amyl alcohol forms an azeotrope with hexane, it co-distills with hexane and thus contaminates the feed stream. The present invention solves the problem of recycle stream contamination. This invention is based upon the discovery of highly effective modifiers that do not co-distill with hexane or-form-compounds during steam stripping which co-distill with hexane. The modifiers of this invention are metal salts of cyclic alcohols. Since the boiling points of these metal salts of cyclic alcohols are very high, they do not co-distill with hexane and contaminate recycle streams. Additionally, metal salts of cyclic alcohols are considered to be environmentally safe. The, subject invention more specifically discloses an initiator system which is comprised of (a) a lithium initiator, (b) a metal salt of a cyclic alcohol, and (c) a polar modifier.

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