Patent US4017670A successfully refreshed from Google Patents.
US4017670A
Expired / Lapsed
US
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Suspension polymerization process
Assignee: Atlantic Richfield Co
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Filing: 1976-05-24
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Granted: 1977-04-12
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Expires: 1996-05-24
Abstract
Abstract The production of polymer beads by a suspension polymerization 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 treated the aqueous medium containing the phosphate and any extender with ultrasound prior to adding the monomer and polymerizing. The resulting polymer bead size is thereby found to be smaller than would have been obtained without the use of ultrasound.
Inventors
- 👤 John P. Spicuzza, Jr.
- 👤 Frank J. E. Mills
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 22:40
CPC Classifications
C; C08; C08F; C08F12/00; C08F12/02; C08F12/04
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
131 words
In a process for producing polymer beads by adding vinyl aromatic monomer containing from 0.15 to 0.55 percent by weight based on monomer of a monomer-soluble free-radical producing catalyst to an aqueous dispersion of from 0.20 to 1.0 percent by weight based on monomer of a finely divided, difficultly water-soluble phosphate with or without an extender for said phosphate and subjecting the resulting suspension to an elevated temperature to cause said monomer to polymerize, the improvement consisting of treating the aqueous dispersion of phosphate, prior to the addition of monomer, with 40,000 to 60,000 cycles per second ultrasonic waves for at least 10 minutes, whereby the polymer bead size resulting from the polymerization is less than the bead size produced by the same lot of phosphate in the absence of ultrasound.
Claim 2
Dependent Claim
131 words
In a process for producing polymer beads by adding vinyl aromatic monomer containing from 0.15 to 0.55 percent by weight based on monomer of a monomer-soluble free-radical producing catalyst to an aqueous dispersion of from 0.20 to 1.0 percent by weight based on monomer of a finely divided, difficultly water-soluble phosphate with or without an extender for said phosphate and subjecting the resulting suspension to an elevated temperature to cause said monomer to polymerize, the improvement consisting of treating the aqueous dispersion of phosphate, prior to the addition of monomer, with 40,000 to 60,000 cycles per second ultrasonic waves for at least 10 minutes, whereby the polymer bead size resulting from the polymerization is less than the bead size produced by the same lot of phosphate in the absence of ultrasound.
Claim 3
Dependent Claim
12 words
The process of claim 1 wherein the vinyl aromatic monomer is styrene.
Claim 4
Dependent Claim
15 words
The process of claim 1 wherein the finely divided, difficultly water-soluble phosphate is tricalcium phosphate.
Claim 5
Dependent Claim
20 words
The process of claim 1 wherein the ultrasonic treatment is with 55,000 cycles per second ultrasonic waves for 10 minutes.
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) | 1980-04-11 | 1980-10-11 | 1981-04-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-04-11 | 1984-10-11 | 1985-04-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-04-11 | 1988-10-11 | 1989-04-12 | $7700.00 | Window Closed / Lapsed |