US4083901A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for curing polyurethanes
Assignee: Bridgestone Firestone Inc
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Filing: 1975-08-29
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Granted: 1978-04-11
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Expires: 1995-08-29
Abstract
Abstract Disclosed is a process for the uniform cure of polyurethane elastomers including the steps of mixing polyurethane prepolymers, having free isocyanate groups, with a stable curing agent complex to form a blend, thereafter transferring it to a suitable mold and subjecting it to a predetermined amount of microwave energy until it is substantially cured.
Inventors
- 👤 Steven Edward Schonfeld
- 👤 Georg Gustav Anton Bohm
- 👤 Michael William Hayes
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 17:22
CPC Classifications
H; H05; H05B; H05B6/00; H05B6/64; B; B29; B29C; B29C35/00; B29C35/02; B29C35/08; C; C08; C08G; C08G18/00; C08G18/06; C08G18/08; C08G18/10; B29C35/0805; B29C2035/0855; B29K; B29K2075/00; Y; Y10; Y10S; Y10S264/00; Y10S264/46; Y10S264/77
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
89 words
A method for the uniform cure of solid polyurethane elastomers comprising the steps of: mixing a polyurethane prepolymer, containing free isocyanate groups, with a stable curing agent complex, containing a releasable curative to form a heterogenous blend wherein said complex consists of methylene dianaline and a halide salt; transferring the blend to a suitable mold; exposing said blend in said mold to a predetermined amount of microwave energy sufficient to cause release of said curative; and, thereafter maintaining said predetermined amount of energy until said blend is substantially cured.
Claim 2
Independent Claim
89 words
A method for the uniform cure of solid polyurethane elastomers comprising the steps of: mixing a polyurethane prepolymer, containing free isocyanate groups, with a stable curing agent complex, containing a releasable curative to form a heterogenous blend wherein said complex consists of methylene dianaline and a halide salt; transferring the blend to a suitable mold; exposing said blend in said mold to a predetermined amount of microwave energy sufficient to cause release of said curative; and, thereafter maintaining said predetermined amount of energy until said blend is substantially cured.
Claim 3
Dependent Claim
48 words
A method for the uniform cure of solid polyurethane elastomers, as set forth in claim 1, including the additional step of: applying heat to said blend during said mixing step to raise the temperature thereof to a desired degree below the temperature at which said curative is released.
Claim 4
Dependent Claim
30 words
A method for the uniform cure of solid polyurethane elastomers, as set forth in claim 1, including the additional step of: applying heat to the exterior surfaces of said mold.
Claim 5
Dependent Claim
79 words
A method for the uniform cure of solid polyurethane elastomers, as set forth in claim 1, wherein said predetermined amount of microwave energy is selected by varying the frequency and power of the microwave unit and the period of time for which said blend is subjected thereto and is variable depending upon the polar nature of the various components within said blend, the thickness of the desired polyurethane elastomer and the orientation of the blend within the microwave field.
Claim 6
Dependent Claim
37 words
A method for the uniform cure of solid polyurethane elastomers, as set forth in claim 1, wherein said polyurethane prepolymers containing free isocyanate groups are selected from the group consisting essentially of: polyesters, polyethers and polymeric diols.
Claim 7
Dependent Claim
21 words
A method for the uniform cure of solid polyurethane elastomers, as set forth in claim 5, wherein said prepolymer is polytetrahydrofuran.
Claim 8
Dependent Claim
64 words
A method for the uniform cure of solid polyurethane elastomers, as set forth in claim 1, wherein said mold is formed from components at least one of which is non-transparent to microwave energy, whereby the temperature of said mold will increase at a rate comparable to that of said blend contained therein while said mold and said blend are subjected to said microwave energy.
References Cited (Backward Citations)
US3294879A
Cited
US3420923A
Cited
US3482004A
Cited
US3737488A
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US3662043A
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US3755261A
Cited
US3917792A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-04-10 | 1981-10-10 | 1982-04-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-04-10 | 1985-10-10 | 1986-04-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-04-10 | 1989-10-10 | 1990-04-11 | $7700.00 | Window Closed / Lapsed |