US3917792A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Elastomeric polyurethane parts produced by liquid injection molding
Assignee: Uniroyal Chemical Co Inc
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Filing: 1974-01-28
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Granted: 1975-11-04
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Expires: 1994-01-28
Abstract
Abstract The instant invention relates to a method for producing a molded article by injecting, under elevated pressure, a fluid dispersion of 4,4''-methylene dianiline and a designated alkali metal salt complex in an isocyanatoterminated prepolymer or polymer, into a closed preheated mold which is maintained at a temperature of about 100*-195*C. The dispersion is injected at a rate sufficient that the mold filling is effected before gelation of the fluid dispersion and a thermoset polyurethane molding is removed in less than about 3 minutes after completion of the mold filling. The instant invention eliminates the need for a degassing step. It is also intended to include a one-shot curing system in the instant invention. Briefly, the one-shot method involves simultaneously mixing and reacting one or more polyols, one or more polyisocyanates and the complex of 4,4''-methylene dianiline and salt.
Inventors
- 👤 Jr Philip Conacher
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 08:55
CPC Classifications
B; B29; B29C; B29C45/00; B29C45/0001; C; C08; C08G; C08G18/00; C08G18/06; C08G18/08; C08G18/10
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
120 words
IN A PROCESS WHEREIN AN NCO- TERMINATED POLYURETHANE PREPOLYMER IS CURED BY CONTACT WITH A COMPLEX OF 4,4''-METHYLENE DIANILINE AND A SALT SELECTED FROM THE GROUP CONSISTING OF SODIUM CHLORIDE, SODIUM BROMIDE, SODIUM IODIDE, SODIUM NITRITE, LITHIUM CHLORIDE, LITHIUM BROMIDE, LITHIUM IODIDE, LITHIUM NITRITE, AND SODIUM CYANIDE, THE RATIO OF THE DIANILINE TO THE SALT IN THE COMPLEX BEING 3 MOLES TO 1 MOLE, SAID CURING BEING CONDUCTED AT A TEMPERATURE OF APPROXIMATELY 100* TO 195*C., THE IMPROVEMENT COMPRISING INJECTING A FLOWABLE DISPERSION OF SAID PREPOLYMER INTO A CLOSED, PREHEATED MOLD, SAID DISPERSION CONTAINING ENTRAPPED AIR, APPLYING A PRESSURE TO THE MOLD CONTENTS SUFFICIENT TO PREVENT THE ENTRAINED GASES FROM ESCAPING FROM THE MOLD, AND RECOVERING A BUBBLE-FREE POLYURETHANE CASTING.
Claim 2
Dependent Claim
120 words
IN A PROCESS WHEREIN AN NCO- TERMINATED POLYURETHANE PREPOLYMER IS CURED BY CONTACT WITH A COMPLEX OF 4,4''-METHYLENE DIANILINE AND A SALT SELECTED FROM THE GROUP CONSISTING OF SODIUM CHLORIDE, SODIUM BROMIDE, SODIUM IODIDE, SODIUM NITRITE, LITHIUM CHLORIDE, LITHIUM BROMIDE, LITHIUM IODIDE, LITHIUM NITRITE, AND SODIUM CYANIDE, THE RATIO OF THE DIANILINE TO THE SALT IN THE COMPLEX BEING 3 MOLES TO 1 MOLE, SAID CURING BEING CONDUCTED AT A TEMPERATURE OF APPROXIMATELY 100* TO 195*C., THE IMPROVEMENT COMPRISING INJECTING A FLOWABLE DISPERSION OF SAID PREPOLYMER INTO A CLOSED, PREHEATED MOLD, SAID DISPERSION CONTAINING ENTRAPPED AIR, APPLYING A PRESSURE TO THE MOLD CONTENTS SUFFICIENT TO PREVENT THE ENTRAINED GASES FROM ESCAPING FROM THE MOLD, AND RECOVERING A BUBBLE-FREE POLYURETHANE CASTING.
Claim 3
Dependent Claim
13 words
The process of claim 1 wherein said pressure is between about 100-800 psi.
Claim 4
Dependent Claim
16 words
The process of claim 1 wherein said curing takes place in less than about 2 minutes.
Claim 5
Dependent Claim
16 words
The process of claim 1 wherein said complex is derived from 4,4''-methylene dianiline and sodium chloride.
Claim 6
Dependent Claim
16 words
The process of claim 1 wherein said complex is derived from 4,4''-methylene dianiline and lithium chloride.
Claim 7
Dependent Claim
18 words
The process of claim 5 wherein said curing takes place for a maximum period of about 100 seconds.
Claim 8
Dependent Claim
18 words
The process of claim 6 wherein said prepolymer is formed by reacting polytetramethylene ether glycol and tolylene diisocyanate.
Claim 9
Dependent Claim
99 words
A process for curing an NCO- terminated polyurethane prepolymer consisting essentially of injecting under pressure a fluid air-containing dispersion of the prepolymer and curing complex into a closed preheated mold, said complex being a complex of 4,4''-methylene dianiline and sodium chloride, the ratio of the dianiline to the sodium chloride in the complex being 3 moles to 1 mole, applying a pressure of about 100 to 800 psi to the mold contents, heating the mold contents to a temperature of about 100*-195*C. for a time sufficient to complete the reaction, and recovering a bubble-free polyurethane molding from the mold.
Claim 10
Dependent Claim
99 words
A process for curing an NCO- terminated polyurethane prepolymer consisting essentially of injecting under pressure a fluid air-containing dispersion of the prepolymer and curing complex into a closed preheated mold, said complex being a complex of 4,4''-methylene dianiline and sodium chloride, the ratio of the dianiline to the sodium chloride in the complex being 3 moles to 1 mole, applying a pressure of about 100 to 800 psi to the mold contents, heating the mold contents to a temperature of about 100*-195*C. for a time sufficient to complete the reaction, and recovering a bubble-free polyurethane molding from the mold.
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) | 1978-11-03 | 1979-05-05 | 1979-11-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-11-03 | 1983-05-05 | 1983-11-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-11-03 | 1987-05-05 | 1987-11-04 | $7700.00 | Window Closed / Lapsed |