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Patent US4435450A successfully refreshed from Google Patents.
US4435450A
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US
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Method for applying abrasion resistant thin polyurethane coatings
Assignee: PPG Industries Ohio Inc
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Filing: 1982-07-02
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Granted: 1984-03-06
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Expires: 2002-07-02
Abstract
Abstract A method for applying a thin abrasion resistant polyurethane coating while minimizing exposure to volatile free isocyanate is disclosed. The method involves forming a hydroxy-terminated prepolymer which is subsequently crosslinked using a relatively non-volatile triisocyanate, and applying the material by flow coating or dip coating techniques, rather than spraying, in order to minimize volatilization.
Inventors
- 👤 Charles R. Coleman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 01:49
CPC Classifications
B; B32; B32B; B32B17/00; B32B17/06; B32B17/10; B32B17/10005; B32B17/1055; B32B17/1077; C; C08; C08G; C08G18/00; C08G18/06; C08G18/08; C08G18/10; C08G18/28; C08G18/30; C08G18/32; C08G18/3203; C08G18/3206; C08G18/40; C08G18/42; C08G18/44; C08G18/70; C08G18/72; C08G18/74; C08G18/75; C08J; C08J7/00; C08J7/04; C08J7/0427; C08J7/046; C08J2475/00
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
101 words
A method for applying an abrasion resistant polyurethane coating onto a surface of a substrate while minimizing volatilization of free isocyanate comprising the steps of: a. reacting an aliphatic diisocyanate with excess hydroxy-terminated diol to form a linear hydroxy-terminated prepolymer; b. adding to said prepolymer a triisocyanate crosslinking agent having a molecular weight greater than 500; c. applying said prepolymer and triisocyanate mixture in a solvent to the surface of the substrate by contacting said surface with said solution in a continuous liquid phase; d. evaporating said solvent; and e. reacting said prepolymer and triisocyanate to form a crosslinked polyurethane coating.
Claim 2
Independent Claim
101 words
A method for applying an abrasion resistant polyurethane coating onto a surface of a substrate while minimizing volatilization of free isocyanate comprising the steps of: a. reacting an aliphatic diisocyanate with excess hydroxy-terminated diol to form a linear hydroxy-terminated prepolymer; b. adding to said prepolymer a triisocyanate crosslinking agent having a molecular weight greater than 500; c. applying said prepolymer and triisocyanate mixture in a solvent to the surface of the substrate by contacting said surface with said solution in a continuous liquid phase; d. evaporating said solvent; and e. reacting said prepolymer and triisocyanate to form a crosslinked polyurethane coating.
Claim 3
Dependent Claim
20 words
The method according to claim 1, wherein a continuous stream of solution is flowed onto the surface of the substrate.
Claim 4
Dependent Claim
14 words
The method according to claim 1, wherein the substrate is dipped into the solution.
Claim 5
Dependent Claim
24 words
The method according to claim 2 or claim 3, wherein the aliphatic diisocyanate is a cycloaliphatic diisocyanate and the polyol is a polyester polyol.
Claim 6
Dependent Claim
29 words
The method according to claim 4, wherein the cycloaliphatic diisocyanate is 4,4'-methylene-bis-(cyclohexyl isocyanate), the polyol is a polycarbonate diol, and the triisocyanate has a molecular weight greater than 560.
Claim 7
Dependent Claim
31 words
The method according to claim 5, wherein the prepolymer and triisocyanate are dissolved in a solvent selected from the group consisting of methyl ethyl ketone, propylacetate, toluene, cyclohexanone and mixtures thereof.
Claim 8
Dependent Claim
33 words
The method according to claim 6, wherein the prepolymer and triisocyanate are dissolved at a concentration of about 20 to 30 weight percent in a solvent comprising a mixture of toluene and cyclohexanone.
Claim 9
Dependent Claim
14 words
The method according to claim 6, wherein said solution further comprises a wetting agent.
Claim 10
Dependent Claim
14 words
The method according to claim 8, wherein said wetting agent is a fluorocarbon surfactant.
Claim 11
Dependent Claim
22 words
The method according to claim 9, wherein the crosslinked polyurethane coating has a thickness less than about 0.005 inch (about 0.13 millimeter).
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-03-06 | 1987-09-05 | 1988-03-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-03-06 | 1991-09-05 | 1992-03-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-03-06 | 1995-09-05 | 1996-03-06 | $7700.00 | Window Closed / Lapsed |