US4763715A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for preparing polycarbonate terpolymer foam suitable for lost foam casting
Assignee: PAC POLYMER Inc A CORP OF
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Filing: 1987-12-14
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Granted: 1988-08-16
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Expires: 2007-12-14
Abstract
Abstract The evaporative casting of molten metals has been shown to produce castings having smooth surfaces without any sign of carbon deposits thereon by using a terpolymer polycarbonate prepared from cyclopentene oxide or cyclohexene oxide, ethylene oxide, propylene oxide, or butylene oxide, and carbon dioxide in making patterns for the lost foam casting process.
Inventors
- 👤 Michael J. Cannarsa
- 👤 Haven S. Kesling, Jr.
- 👤 Hsiang-ning Sun
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 17:05
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/16; C08J9/18; B; B22; B22C; B22C7/00; B22C7/02; B22C7/023; C08G; C08G64/00; C08G64/02; C08G64/0208; C08J9/04; C08J9/12; C08J9/122; C08J9/14; C08J9/142; C08J9/143; C08J9/144; C08J9/146; C08J9/36; C08L; C08L69/00; C08J2369/00
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
185 words
A process for preparing a pattern for use in making metal castings which have no residual carbon on the surface comprising (a) selecting a terpolymer polycarbonate of general formula ##STR2## where the ratio of x to y is between 1:9 and 2:1, z is 3 or 4, n is an integer between 50 and 400, the number average molecular weight is in the range 15,000 to 100,000, and the polycarbonate has only a single glass transition temperature in the range 80°-120° C., (b) forming said terpolymer into particles having a bead size between 100 and 1000 microns in diameter, (c) suspending said particles in water using a suitable suspending agent system, (d) adding a suitable blowing agent to the suspension and heating to impregnate the particles, (e) separating the impregnated beads from the aqueous suspension, washing and drying the beads, (f) pre-expanding the beads by subjecting to atmospheric steam to obtain a density of about 1 to about 4 pounds per cubic foot, (g) aging the beads. and (h) molding the beads into the desired pattern having a density of about 3.0 pcf or less.
Claim 2
Dependent Claim
185 words
A process for preparing a pattern for use in making metal castings which have no residual carbon on the surface comprising (a) selecting a terpolymer polycarbonate of general formula ##STR2## where the ratio of x to y is between 1:9 and 2:1, z is 3 or 4, n is an integer between 50 and 400, the number average molecular weight is in the range 15,000 to 100,000, and the polycarbonate has only a single glass transition temperature in the range 80°-120° C., (b) forming said terpolymer into particles having a bead size between 100 and 1000 microns in diameter, (c) suspending said particles in water using a suitable suspending agent system, (d) adding a suitable blowing agent to the suspension and heating to impregnate the particles, (e) separating the impregnated beads from the aqueous suspension, washing and drying the beads, (f) pre-expanding the beads by subjecting to atmospheric steam to obtain a density of about 1 to about 4 pounds per cubic foot, (g) aging the beads. and (h) molding the beads into the desired pattern having a density of about 3.0 pcf or less.
Claim 3
Dependent Claim
20 words
The process of claim 1 wherein said terpolymer polycarbonate is a terpolymer of cyclopentene oxide, ethylene oxide, and carbon dioxide.
Claim 4
Dependent Claim
20 words
The process of claim 1 wherein said terpolymer polycarbonate is a terpolymer of cyclopentene oxide, propylene oxide, and carbon dioxide.
Claim 5
Dependent Claim
20 words
The process of claim 1 wherein said terpolymer polycarbonate is a terpolymer of cyclopentene oxide, butylene oxide, and carbon dioxide.
Claim 6
Dependent Claim
20 words
The process of claim 1 wherein said terpolymer polycarbonate is a terpolymer of cyclohexene oxide, ethylene oxide, and carbon dioxide.
Claim 7
Dependent Claim
20 words
The process of claim 1 wherein said terpolymer polycarbonate is a terpolymer of cyclohexene oxide, propylene oxide, and carbon dioxide.
Claim 8
Dependent Claim
20 words
The process of claim 1 wherein said terpolymer polycarbonate is a terpolymer of cyclohexene oxide, butylene oxide, and carbon dioxide.
Claim 9
Dependent Claim
21 words
The process of claim 1 wherein said suitable suspending agent system is a finely divided calcium phosphate and an anionic surfactant.
Claim 10
Dependent Claim
31 words
The process of claim 1 wherein said suitable blowing agent is selected from the group consisting of butane, n-pentane, isopentane, hexane, carbon dioxide, and the fluorinated hydrocarbons and mixtures of these.
References Cited (Backward Citations)
US4416926A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-08-16 | 1992-02-15 | 1992-08-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-08-16 | 1996-02-15 | 1996-08-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-08-16 | 2000-02-15 | 2000-08-16 | $7700.00 | Window Closed / Lapsed |