US4383099A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Encapsulant material suitable for use under conditions of prolonged vacuum
Assignee: EMI Ltd
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Filing: 1981-07-27
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Granted: 1983-05-10
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Expires: 2001-07-27
Abstract
Abstract An encapsulant material suitable for use in space applications a polyurethane having according to the ESTEC specification a total mass loss of not greater than 1% and condensible volatiles content of not greater than 0.1% combined with a vibration performance characterised by a Q of from 4 to 15 and a peak frequency of 200 to 400 Hz when vibrated at 1g.
Inventors
- 👤 Agathangelos Hajimichael
- 👤 Sidney Hopper
- 👤 Peter K. Smith
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 16:30
CPC Classifications
C; C08; C08G; C08G18/00; C08G18/06; C08G18/28; C08G18/40; C08G18/48; C08G18/4825; C08G18/08; C08G18/10; C08G2350/00
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
159 words
An encapsulant material suitable for use in space applications which comprises a polyurethane formed from the reaction of a polyoxypropylene glycol of molecular weight between 3500 and 5000 and a chemical structure such that the ratio of molecular weight to hydroxyl number is at least 90 with a molar excess of a diisocyanate selected from the group consisting of toluene diisocyanate and isophorone diisocyanate under conditions that will give a prepolymer containing from 3.5% to 5.0% of free isocyanate groups, with an equivalent amount of a triol or diol having a molecular weight of from 90 to 190, said polyurethane when cured having according to the European Space Research and Technology Centre (ESTEC) specification a total mass loss not greater than 1% and condensible volatiles content of not greater than 0.1% combined with a vibration performance characterised by a Q of from 4 to 15 and a peak frequency of 200 to 400 Hz when vibrated at 1 g.
Claim 2
Dependent Claim
159 words
An encapsulant material suitable for use in space applications which comprises a polyurethane formed from the reaction of a polyoxypropylene glycol of molecular weight between 3500 and 5000 and a chemical structure such that the ratio of molecular weight to hydroxyl number is at least 90 with a molar excess of a diisocyanate selected from the group consisting of toluene diisocyanate and isophorone diisocyanate under conditions that will give a prepolymer containing from 3.5% to 5.0% of free isocyanate groups, with an equivalent amount of a triol or diol having a molecular weight of from 90 to 190, said polyurethane when cured having according to the European Space Research and Technology Centre (ESTEC) specification a total mass loss not greater than 1% and condensible volatiles content of not greater than 0.1% combined with a vibration performance characterised by a Q of from 4 to 15 and a peak frequency of 200 to 400 Hz when vibrated at 1 g.
Claim 3
Dependent Claim
34 words
A material according to claim 1 with a vibration performance characterised by a Q of from 5.6 to 12 and a peak frequency of from 240 to 350 Hz when vibrated at 1 g.
Claim 4
Dependent Claim
18 words
A material according to claim 1 which possesses a glass transition temperature of from -70° to -35° C.
Claim 5
Dependent Claim
18 words
A material according to claim 3 which possesses a glass transition temperature of from -60° to -50° C.
Claim 6
Dependent Claim
29 words
A material according to claim 1 which possesses a coefficient of expansion of from 50 to 250 p.p.m./°C. over a range of temperature of from -30° to -50° C.
Claim 7
Dependent Claim
19 words
A material according to claim 1 which has a hardness of from 40 to 70 International Rubber Hardness Degrees.
Claim 8
Dependent Claim
19 words
A material according to claim 6 which has a hardness of from 50 to 60 International Rubber Hardness Degrees.
Claim 9
Dependent Claim
20 words
A material according to claim 1 which has a volume resistivity of from 5.10 9 to 10 11 ohm meters.
Claim 10
Dependent Claim
20 words
A material according to claim 8 which has a volume resistivity of from 2.10 10 to 7.10 10 ohm meters.
Claim 11
Dependent Claim
112 words
A process for the preparation of a polyurethane encapsulant material suitable for use in space applications which process comprises reacting a polyoxypropylene glycol of molecular weight between 3500 and 5000 and a chemical structure such that the ratio of molecular weight to hydroxyl number is at least 90 with a molar excess of a diisocyanate selected from the group consisting of toluene diisocyanate and isophorone diisocyanate under conditions that will give a prepolymer containing from 3.5% to 5.0% of free isocyanate groups and then reacting said prepolymer with an equivalent amount of a triol or diol having a molecular weight of from 90 to 190, and thereafter curing the resultant reaction product.
Claim 12
Dependent Claim
112 words
A process for the preparation of a polyurethane encapsulant material suitable for use in space applications which process comprises reacting a polyoxypropylene glycol of molecular weight between 3500 and 5000 and a chemical structure such that the ratio of molecular weight to hydroxyl number is at least 90 with a molar excess of a diisocyanate selected from the group consisting of toluene diisocyanate and isophorone diisocyanate under conditions that will give a prepolymer containing from 3.5% to 5.0% of free isocyanate groups and then reacting said prepolymer with an equivalent amount of a triol or diol having a molecular weight of from 90 to 190, and thereafter curing the resultant reaction product.
Claim 13
Dependent Claim
12 words
A process according to claim 10 wherein said diisocyanate is isophorone diisocyanate.
Claim 14
Dependent Claim
15 words
A process according to claim 10 wherein said prepolymer is reacted with 1, 2, 6-hexanetriol.
Claim 15
Dependent Claim
22 words
A process according to claim 10 wherein said prepolymer is reacted with said triol or diol in the presence of a catalyst.
Claim 16
Dependent Claim
12 words
A process according to claim 13 wherein said catalyst is dibutyltin dilaurate.
Claim 17
Independent Claim
173 words
A method of encapsulating an object or apparatus in a polyurethane material which material has a total mass loss of not greater than 1% and a condensible volatiles content of not greater than 0.1% combined with a vibration performance characterised by a Q of from 4 to 15 and a peak frequency of 200 to 400 Hz when vibrated at 1 g which method comprises reacting in situ while in contact with said object or apparatus to be encapsulated a prepolymer, formed from the reaction of a polyoxypropylene glycol of molecular weight between 3500 and 5000 and a chemical structure such that the ratio of molecular weight to hydroxyl number is at least 90 with a molar excess of a diisocyanate selected from the group consisting of toluene diisocyanate and isophorone diisocyanate under conditions that will give a prepolymer containing from 3.5% to 5.0% of free isocyanate groups, with an equivalent amount of a triol or diol having a molecular weight of from 90 to 190, and thereafter curing the resultant reaction product.
Claim 18
Independent Claim
173 words
A method of encapsulating an object or apparatus in a polyurethane material which material has a total mass loss of not greater than 1% and a condensible volatiles content of not greater than 0.1% combined with a vibration performance characterised by a Q of from 4 to 15 and a peak frequency of 200 to 400 Hz when vibrated at 1 g which method comprises reacting in situ while in contact with said object or apparatus to be encapsulated a prepolymer, formed from the reaction of a polyoxypropylene glycol of molecular weight between 3500 and 5000 and a chemical structure such that the ratio of molecular weight to hydroxyl number is at least 90 with a molar excess of a diisocyanate selected from the group consisting of toluene diisocyanate and isophorone diisocyanate under conditions that will give a prepolymer containing from 3.5% to 5.0% of free isocyanate groups, with an equivalent amount of a triol or diol having a molecular weight of from 90 to 190, and thereafter curing the resultant reaction product.
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) | 1986-05-09 | 1986-11-08 | 1987-05-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-05-09 | 1990-11-08 | 1991-05-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-05-09 | 1994-11-08 | 1995-05-10 | $7700.00 | Window Closed / Lapsed |