Brominated styrenic polymers and their preparation
AssigneeAlbemarle Corporation
InventorsCharles H. Kolich, Jeffrey Todd Aplin, John F. Balhoff
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Abstract
Preparing brominated styrenic polymer by maintaining a mixture formed from (i) brominating agent, (ii) a solvent solution of styrenic polymer, and (iii) aluminum halide catalyst, at −20 to +20° C., and terminating bromination in 20 minutes or less. New brominated anionic styrenic polymers have better melt flow and/or lower initial ΔE values than the best previously-known brominated anionic styrenic polymers. Other features of such new polymers include high thermal stabilities at 320° C. and/or very low initial color values. Brominated styrenic polymers, especially brominated anionic styrenic polymers, are useful as flame retardants for thermoplastic polymers.
Claims28
A process of preparing brominated anionic styrenic polymer, which process is conducted as a continuous process and which process comprises maintaining in a reaction zone, reaction mixture continuously formed from (i) a brominating agent, (ii) a solution of anionic styrenic polymer in a solvent, and (iii) aluminum halide catalyst in which the halogen atoms are bromine or chlorine with at least one such halogen atom being a bromine atom, in which (i), (ii), and (iii) are fed as at least two separate feeds in which (i) and (ii) are not fed as a mixture, at one or more temperatures in the range of −20 to +20° C., said mixture being continuously proportioned so that bromination of polymer occurs to form a brominated anionic styrenic polymer having a bromine content of at least about 60 wt %, and terminating the bromination of polymer in reaction mixture continuously exiting from the reaction zone in a bromination time of 20 minutes or less, and wherein the brominated anionic styrenic polymer formed in the process has an initial Hunter solution ΔE Color Value of 3 or less.
A process of preparing brominated anionic styrenic polymer, which process comprises:
- A) causing reaction mixture continuously formed from (i) a brominating agent, (ii) a solution of anionic styrenic polymer in a solvent, and (iii) aluminum halide catalyst in which the halogen atoms are bromine or chlorine with at least one such halogen atom being a bromine atom, in which (i), (ii), and (iii) are fed as at least two separate feeds in which (i) and (ii) are not fed as a mixture, to continuously travel through and exit from a reaction zone maintained at one or more temperatures in the range of −20 to +20EC so that bromination of polymer occurs during at least a portion of such travel, said reaction mixture being continuously proportioned to form a brominated anionic styrenic polymer having a bromine content of at least about 60 wt %;
- B) terminating bromination of polymer in the reaction mixture as or after reaction mixture exits from the reaction zone;
- and
- C) continuously having the time between formation of reaction mixture in A) and termination in B) in the range of 20 minutes or less,
- wherein the brominated anionic styrenic polymer formed in the process has an initial Hunter solution ΔE Color Value of 3 or less.
Dependencies are inferred from the claim text.