Claims
- 1. A process for free radical mass polymerization of a mixture of vinyl aromatic monomer containing 0 to about 20 wt.% polybutadiene or styrene/butadiene rubber comprising polymerizing such mixture in successive stages with increasing temperature and agitation and incorporating a polymerization inhibiting agent into the resulting polymerizing mixture at a point where 60 to about 95% of monomer is converted to polymer, such inhibiting agent incorporated at a level at which polymerization continues, whereby the molecular weight distribution of the resulting polymer is reduced.
- 2. The process of claim 1 wherein the vinyl aromatic monomer is styrene monomer.
- 3. The process of claim 1 wherein the inhibiting agent is injected into the polymerizing mass as a solution in a suitable solvent.
- 4. The process of claim 1 wherein the inhibiting agent is injected into the polymerizing mass at a point where about 80 to about 90% of monomer is converted to polymer.
- 5. The process of claim 1 wherein the inhibiting agent is incorporated in a point before a final heating stage.
- 6. The process of claim 1 wherein the inhibiting agent is selected from the group consisting of tetraphenyloctatraene, hydrazobenzene, dinitrobenzene, sulfur, aniline, diphenylvinylbromide, hydroquinone, tetranitromethane and p-tert-butyl catechol.
- 7. The process of claim 6 wherein the inhibiting agent is p-tert-butyl catechol.
- 8. The process of claim 6 wherein the inhibiting agent is injected into a polymerizing mass of styrene at a point where about 80 to about 90% of monomer is converted polymer.
- 9. The process of claim 1 wherein the inhibiting agent is added in an amount of about 0.1 to about 1.5 wt.% of the polymerizing mass.
- 10. The process of claim 1 wherein the polymerizing mixture contains 2 to about 20 wt.% rubber.
Parent Case Info
This is a continuation of application Ser. No. 373,118, filed Apr. 29, 1982, now abandoned, which is in turn a continuation of Ser. No. 186,897, filed Sept. 15, 1980, now abandoned.
US Referenced Citations (5)
Foreign Referenced Citations (1)
Number |
Date |
Country |
2660230 |
Apr 1979 |
DEX |
Continuations (2)
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Number |
Date |
Country |
Parent |
373118 |
Apr 1982 |
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Parent |
186897 |
Sep 1980 |
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