Patent US4289685A successfully refreshed from Google Patents.
US4289685A
Expired / Lapsed
US
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Process for the preparation of flame-resistant polycarbonates
Assignee: Bayer AG
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Filing: 1980-08-04
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Granted: 1981-09-15
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Expires: 2000-08-04
Abstract
Abstract The invention relates to a process for rendering flame-resistant the thermoplastic aromatic polycarbonates prepared by a solution process, characterized by dispersing an aqueous solution of salt-like flameproofing agent in a washed and neutral polycarbonate/organic solvent system.
Inventors
- 👤 Frank Druschke
- 👤 Dieter Margotte
- 👤 Erhard Tresper
- 👤 Ludwig Bottenbruch
- 👤 Wolfgang Cohnen
- 👤 Uwe Hucks
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 13:20
CPC Classifications
C; C08; C08K; C08K5/00; C08K5/36; C08K5/41; C08K5/42; C08K3/00; C08K3/01; C08K3/016; C08K5/0008; C08K5/0066
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
90 words
In the process of rendering flame-resistant the thermoplastic aromatic polycarbonates prepared by a solution process, the improvement comprising steps (i) washing the polycarbonate/organic solvent system until neutral and free of electrolytes and (ii) adding to the neutral and electrolyte free system an effective amount of an aqueous solution of a salt-like flameproofing agent and (iii) dispersing said aqueous solution, in the form of particulates of less than 2 μm in diameter, in said system and (iv) isolating the polycarbonate/salt-like flameproofing agent composition by evaporating the water and the organic solvent.
Claim 2
Dependent Claim
90 words
In the process of rendering flame-resistant the thermoplastic aromatic polycarbonates prepared by a solution process, the improvement comprising steps (i) washing the polycarbonate/organic solvent system until neutral and free of electrolytes and (ii) adding to the neutral and electrolyte free system an effective amount of an aqueous solution of a salt-like flameproofing agent and (iii) dispersing said aqueous solution, in the form of particulates of less than 2 μm in diameter, in said system and (iv) isolating the polycarbonate/salt-like flameproofing agent composition by evaporating the water and the organic solvent.
Claim 3
Dependent Claim
25 words
The process of claim 1 wherein said salt-like flameproofing agent is selected from the group consisting of alkali metal salts and alkaline earth metal salts.
Claim 4
Dependent Claim
22 words
The process of claim 1 wherein said salt-like flameproofing agents comprise between 0.001 and 5%, relative to the weight of said composition.
Claim 5
Dependent Claim
14 words
The process of claim 1 wherein emulsifying agents are added in said step (ii).
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-09-14 | 1985-03-16 | 1985-09-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-09-14 | 1989-03-16 | 1989-09-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-09-14 | 1993-03-16 | 1993-09-15 | $7700.00 | Window Closed / Lapsed |