US3755282A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Suspension polymerization of vinyl aromatic monomers in the presence of unsaturated carboxylic acid
Assignee: Atlantic Richfield Co
•
Filing: 1971-06-29
•
Granted: 1973-08-28
•
Expires: 1991-06-29
Abstract
Abstract The production of polymer beads by a suspension polymerization process in which a vinyl aromatic monomer having a free-radical generating catalyst dissolved therein is suspended in an aqueous medium with the aid of from 0.2 to 1.0 per cent by weight, based on monomer, of a finely divided phosphate suspending agent and heated to cause the monomer to polymerize into polymer beads is improved by the addition to the suspension of at least about 0.0001 per cent by weight based on monomer of an Alpha , Beta ethylenically unsaturated carboxylic acid as sole extender. The process of the invention is especially applicable in the preparation of large polymer beads.
Inventors
- 👤 H Wright
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 18:46
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/16; C08J9/20; C08F; C08F2/00; C08F2/12; C08F2/16; C08J2325/00; C08J2325/02; C08J2325/04; C08J2325/08; Y; Y10; Y10S; Y10S526/00; Y10S526/909
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
20 words
The process of claim 1 wherein said polymerization produces polymer beads having an average particle size greater than 1,200 microns.
Claim 2
Dependent Claim
19 words
The process of claim 1 wherein said monomer is styrene and said catalyst comprises benzoyl peroxide and t-butyl perbenzoate.
Claim 3
Dependent Claim
11 words
The process of claim 1 wherein said phosphate is tricalcium phosphate.
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) | 1976-08-27 | 1977-02-26 | 1977-08-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-08-27 | 1981-02-26 | 1981-08-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-08-27 | 1985-02-26 | 1985-08-28 | $7700.00 | Window Closed / Lapsed |