Process for manufacturing impact resistant monovinylaromatic polymers
AssigneeFina Technology, Inc.
InventorsJose M. Sosa, Billy Ellis
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Abstract
The present invention discloses a process for manufacturing monovinylaromatic compounds containing an elastomer to provide increased toughness and strength. One particular embodiment of the invention discloses a process for manufacturing high impact polystyrene wherein styrene monomer containing a dissolved polybutadiene rubber is flowed into an elongated upflow stirred reactor containing three reaction zones, wherein the styrene and rubber are polymerized past the inversion point, then discharged to at least one additional reactor to continue their conversion to polymer.
Claims14
In a process for the continuous production of high impact polystyrene wherein styrene monomer is polymerized in the presence of an elastomer dissolved therein, said process having at least one continuous-stirred tank reactor, the improvement comprising utilizing as an initial reactor, an elongated stirred tank reactor having plugflow characteristics, and wherein said elongated stirred tank reactor has a reaction zone having a length to diameter ratio exceeding about 2.
A process for the continuous production of elastomer-modified polystyrene, said process comprising the steps of:
- A. Introducing an initial, non-preheated, feedstock solution of elastomer and styrene monomer into an elongated upflow reactor after first warming said reactor to operating temperature;
- B. Adding a polymerization initiator to said feedstock solution while introducing the feedstock into said reactor;
- C. Flowing said solution upward in said reactor and reacting said styrene monomer, elastomer, and initiator to form a partially polymerized solution having styrene-elastomer particles therein, and wherein said reacting step moves said solution past the inversion point;
- D. Controlling the size of particles being formed in said reactor by stirring said solution with rotating stirring paddles having a tip speed of about 60 to about 150 feet per minute;
- E. Continuing to react said solution in said reactor as it moves upwardly therethrough, thereby carrying said reaction considerably past said inversion point;
- and,
- F. Flowing said solution into a second stirred reactor vessel to achieve further conversion of the solution into elastomer-modified polystyrene.
Dependencies are inferred from the claim text.