US4408005A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Flame retardant polycarbonates
Assignee: Dow Chemical Co
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Filing: 1982-03-22
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Granted: 1983-10-04
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Expires: 2002-03-22
Abstract
Abstract Flame retardant polycarbonate compositions are prepared from dihydric aromatic compounds and alkali metal hydrogen sulfite. These compositions are more effective than similar compositions containing alkali metal sulfites.
Inventors
- 👤 Joseph B. Byrne
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 16:10
CPC Classifications
C; C08; C08K; C08K3/00; C08K3/30
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
22 words
A flame retardant thermoplastic composition comprising an aromatic polycarbonate and an amount of an alkali metal hydrogen sulfite effective to retard flaming.
Claim 2
Dependent Claim
22 words
A flame retardant thermoplastic composition comprising an aromatic polycarbonate and an amount of an alkali metal hydrogen sulfite effective to retard flaming.
Claim 3
Dependent Claim
26 words
The composition of claim 1 wherein the amount of said sulfite used is 0.03 to 0.10 percent by weight based on the weight of said polycarbonate.
Claim 4
Dependent Claim
82 words
The composition of claim 1 wherein the aromatic polycarbonate is prepared from a dihydric aromatic compound having the formula ##STR3## wherein A is a divalent hydrocarbon radical containing 1-15 carbon atoms, ##STR4## X is independently hydrogen, chlorine, bromine, fluorine, or a monovalent hydrocarbon radical such as an alkyl group of 1-4 carbons, an aryl group of 6-8 carbons such as phenyl, tolyl, xylyl, an oxyalkyl group of 1-4 carbons or an oxyaryl group of 6-8 carbons and n is 0 or 1.
Claim 5
Dependent Claim
19 words
The composition of claim 1 wherein the aromatic polycarbonate is prepared from a mixture of 2,2-bis(4-hydroxyphenyl) propane and phenolphthalein.
Claim 6
Dependent Claim
26 words
The composition of claim 3 wherein the amount of said sulfite used is 0.03 to 0.10 percent by weight based on the weight of said polycarbonate.
Claim 7
Dependent Claim
26 words
The composition of claim 4 wherein the amount of said sulfite used is 0.03 to 0.10 percent by weight based on the weight of said polycarbonate.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-10-03 | 1987-04-04 | 1987-10-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-10-03 | 1991-04-04 | 1991-10-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-10-03 | 1995-04-04 | 1995-10-04 | $7700.00 | Window Closed / Lapsed |