Claims
- 1. A brominated polystyrene product made by the process comprising:
- pretreating a solution of a polystyrene reactant comprising from about five to about 20 percent by weight of said polystyrene reactant, in a halogenated hydrocarbon solvent with at least about 0.1 percent by weight of an additive to suppress halogenation of the polystyrene backbone, prior to brominating the polystyrene in the presence of a catalyst;
- subsequently adding a metal halide bromination catalyst to said solution, capable of effecting bromination of the ring without causing crosslinking of the polystyrene;
- adding to said solution from about 1 to about 3.4 moles of a brominating agent, per mole of polystyrene repeating units;
- reacting said polystyrene with said brominating agent at a temperature of from about -20.degree. C. to about 50.degree. C., and
- isolating the brominated polystyrene.
- 2. A brominated polystyrene having a backbone halogen content of less than about 750 ppm and, a .DELTA.E color as low as about 5.
- 3. A brominated polystyrene, as in claim 2, having a bromine content of at least about 66 percent by weight.
- 4. A brominated polystyrene, as in claim 2, wherein said brominated polystyrene reactant is produced from a polystyrene having a weight average molecular weight of from about 500 to about 1,500,000.
- 5. A brominated polystyrene, as in claim 4, wherein said polystyrene reactant is selected from the group consisting of homopolystyrene, polystyrene oligomers, halogenated polystyrenes and alkylated polystyrenes.
- 6. A brominated polystyrene process as in claim 2, wherein said a backbone halogen content is 580 ppm.
- 7. A brominated polystyrene process as in claim 2, wherein said .DELTA.E color is 8.5.
- 8. A flame retardant additive comprising the brominated polystyrene, as in claim 2.
Parent Case Info
This application is a division of application Ser. No. 08/661,350, filed Jun. 14,1996 now U.S. Pat. No. 5,637,650.
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Divisions (1)
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Number |
Date |
Country |
Parent |
661350 |
Jun 1996 |
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