US4773466A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for preparing polycarbonate copolymer 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: 1988-09-27
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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 copolymer polycarbonate prepared from cyclohexene oxide, cyclopentene oxide, cycloheptene oxide, or isobutylene oxide and carbon dioxide.
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 03:41
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/16; C08J9/18; B; B22; B22C; B22C7/00; B22C7/02; B22C7/023; C08J9/04; C08J9/12; C08J9/14; C08J9/141; C08J9/22; C08J9/228; C08J9/232; C08J2201/00; C08J2201/02; C08J2201/034; C08J2203/00; C08J2203/14; C08J2369/00
Claims Analysis
Total Claims: 8
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 copolymer polycarbonate of general formula which is selected from the group consists of ##STR3## and ##STR4## where n is 3, 4, or 5, x is in the range of 100 to 500, the number average molecular weight is in the range 15,000 to 100,000, said polymer has only a single glass transition temperature in the range 85-130° C., (b) forming said copolymer 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 copolymer polycarbonate of general formula which is selected from the group consists of ##STR3## and ##STR4## where n is 3, 4, or 5, x is in the range of 100 to 500, the number average molecular weight is in the range 15,000 to 100,000, said polymer has only a single glass transition temperature in the range 85-130° C., (b) forming said copolymer 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
18 words
The process of claim 1 wherein the copolymer polycarbonate is a copolymer of cyclopentene oxide and carbon dioxide.
Claim 4
Dependent Claim
18 words
The process of claim 1 wherein the copolymer polycarbonate is a copolymer of cyclohexene oxide and carbon dioxide.
Claim 5
Dependent Claim
18 words
The process of claim 1 wherein the copolymer polycarbonate is a copolymer of cycloheptene oxide and carbon dioxide.
Claim 6
Dependent Claim
18 words
The process of claim 1 wherein the copolymer polycarbonate is a copolymer of isobutylene oxide and carbon dioxide.
Claim 7
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 8
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)
US4633929A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-09-27 | 1992-03-28 | 1992-09-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-09-27 | 1996-03-28 | 1996-09-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-09-27 | 2000-03-28 | 2000-09-27 | $7700.00 | Window Closed / Lapsed |