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Patent US4086211A successfully refreshed from Google Patents.
US4086211A
Expired / Lapsed
US
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Method of producing polyurethane products having an improved flex crack resistance
Assignee: Bridgestone Corp
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Filing: 1976-03-15
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Granted: 1978-04-25
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Expires: 1996-03-15
Abstract
Abstract Polyurethane products having improved flex crack resistance can be obtained by curing a mixture of (a) a polyurethane prepolymer having terminal isocyanate group and (b) at least one curative selected from polyamine and polyol to prepare a polyurethane product, and heat treating the polyurethane product at a temperature of 60°-180° C for 1-30,000 minutes under an atmosphere having an absolute humidity of at least 2%.
Inventors
- 👤 Hideo Nakauchi
- 👤 Toshiyuki Osaki
- 👤 Kazuo Naito
- 👤 Sakae Inoue
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 20:50
CPC Classifications
C; C08; C08G; C08G18/00; C08G18/06; C08G18/08; C08G18/10
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
85 words
A method of producing a polyurethane product having improved flex-crack resistance, which comprises the steps of: (1) curing a mixture of: (a) an isocyanate terminated polyether type polyurethane prepolymer having a molecular weight 800-20,000 and (b) a polyamine curative in an amount of 0.6-0.9 equivalent per isocyanate equivalent of said prepolymer, (2) post-curing the reaction product from step (1), and (3) subsequently heat treating the resultant article for 60-18,000 minutes under an atmosphere of a temperature of 80°-140° C and an absolute humidity of 5-80%.
Claim 2
Independent Claim
85 words
A method of producing a polyurethane product having improved flex-crack resistance, which comprises the steps of: (1) curing a mixture of: (a) an isocyanate terminated polyether type polyurethane prepolymer having a molecular weight 800-20,000 and (b) a polyamine curative in an amount of 0.6-0.9 equivalent per isocyanate equivalent of said prepolymer, (2) post-curing the reaction product from step (1), and (3) subsequently heat treating the resultant article for 60-18,000 minutes under an atmosphere of a temperature of 80°-140° C and an absolute humidity of 5-80%.
Claim 3
Dependent Claim
28 words
The method according to claim 1, wherein said polyurethane prepolymer is a reaction product of polyethers having terminal active hydrogen with a molar excess of an organic polyisocyanate.
Claim 4
Dependent Claim
25 words
The method according to claim 1, wherein said polyurethane prepolymer is a reaction product of polyoxyalkylene polyols with a molar excess of an organic polyisocyanate.
Claim 5
Dependent Claim
24 words
The method according to claim 2, wherein said organic polyisocyanate is at least one compound selected from the group consisting of tolylene-2,4-diisocyanate and tolylene-2,6-diisocyanate.
Claim 6
Dependent Claim
17 words
The method according to claim 1, wherein the treating time of the polyurethane product is 60-3,000 minutes.
Claim 7
Dependent Claim
18 words
The method according to claim 1, wherein said post-cure is conducted at about 100° C for 3-24 hours.
Claim 8
Dependent Claim
12 words
The method according to claim 1, wherein said polyamine curative is 4,4'-methylene-bis(2-chloroaniline).
References Cited (Backward Citations)
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Cited
US2850467A
Cited
US3190857A
Cited
US3403721A
Cited
US3789032A
Cited
US3980606A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-04-24 | 1981-10-24 | 1982-04-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-04-24 | 1985-10-24 | 1986-04-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-04-24 | 1989-10-24 | 1990-04-25 | $7700.00 | Window Closed / Lapsed |