Compositions – Solvents
Reissue Patent
1999-05-26
2002-12-17
Wu, Shean C. (Department: 1756)
Compositions
Solvents
C252S067000, C510S108000, C510S177000, C510S408000, C510S411000, C510S415000
Reissue Patent
active
RE037938
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to compositions that include pentafluoropropane. These compositions are useful as cleaning agents, expansion agents for polyolefins and polyurethanes, aerosol propellants, refrigerants, heat transfer media, gaseous dielectrics, fire extinguishing agents, power cycle working fluids, polymerization media, particulate removal fluids, carrier fluids, buffing abrasive agents, and displacement drying agents.
BACKGROUND OF THE INVENTION
Fluorinated hydrocarbons have many uses, one of which is as a refrigerant. Such refrigerants include dichlorodifluoromethane (CFC-12) and chiorodifluoromethane (HCFC-22).
In recent years it has been pointed out that certain kinds of fluorinated hydrocarbon refrigerants released into the atmosphere may adversely affect the stratospheric ozone layer. Although this proposition has not yet been completely established, there is a movement toward the control of the use and the production of certain chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) under an international agreement.
Accordingly, there is a demand for the development of refrigerants that have a lower ozone depletion potential than existing refrigerants while still achieving an acceptable performance in refrigeration application. Hydrofluorocarbons (HFCs) have been suggested as replacements for CFCs and HCFCs since HFCs have no chlorine and therefore have zero ozone depletion potential.
In refrigeration applications, a refrigerant is often lost during operation through leaks in shaft seals, hose connections, soldered joints and broken lines. In addition, the refrigerant may be released to the atmosphere during maintenance procedures on refrigeration equipment. If the refrigerant is not a pure component or an azeotropic or azeotrope-like composition, the refrigerant composition may change when leaked or discharged to the atmosphere from the refrigeration equipment, which may cause the refrigerant to become flammable or to have poor refrigeration performance.
Accordingly, it is desirable to use as a refrigerant a single fluorinated hydrocarbon or an azeotropic or azeotrope-like composition that includes one or more fluorinated hydrocarbons.
Fluorinated hydrocarbons may also be used as a cleaning agent or solvent to clean, for example, electronic circuit boards. It is desirable that the cleaning agents be azeotropic or azeotrope-like because in vapor degreasing operations the cleaning agent is generally redistilled and reused for final rinse cleaning.
Azeotropic or azeotrope-like compositions that include a fluorinated hydrocarbon are also useful as blowing agents in the manufacture of closed-cell polyurethane, phenolic and thermoplastic foams, as propellants in aerosols, as heat transfer media, gaseous dielectrics, fire extinguishing agents, power cycle working fluids such as for heat pumps, inert media for polymerization reactions, fluids for removing particulates from metal surfaces, as carrier fluids that may be used, for example, to place a fine film of lubricant on metal parts, as buffing abrasive agents to remove buffing abrasive compounds from polished surfaces such as metal, as displacement drying agents for removing water, such as from jewelry or metal parts, as resist developers in conventional circuit manufacturing techniques including chlorine-type developing agents, or a strippers for photoresists when used with, for example, a chlorohydrocarbon such as 1,1,1-trichloroethane or trichloroethylene.
SUMMARY OF THE INVENTION
The present invention relates to the discovery of compositions of pentafluoropropane and a fluoropropane such as tetrafluoropropane, trifluoropropane, difluoropropane or fluoropropane; 1,1,1,4,4,4-hexafluorobutane; (CF
3
)
2
CHCH
3
; 1,1,1,2,3,4,4,5,5,5-decafluoropentane; a hydrocarbon such as butane, cyclopropane, isobutane, propane, pentane; or propylene; or dimethyl ether. These compositions are useful as refrigerants, cleaning agents, expansion agents for polyolefins and polyurethanes, aerosol propellants, heat transfer media, gaseous dielectrics, fire extinguishing agents, power cycle working fluids, polymerization media, particulate removal fluids, carrier fluids, buffing abrasive agents, and displacement drying agents. Further, the invention relates to the discovery of binary azeotropic or azeotrope-like compositions comprising effective amounts of pentafluoropropane and a fluoropropane such as tetrafluoropropane, trifluoropropane, difluoropropane or fluoropropane; 1,1,1,4,4,4-hexafluorobutane; (CF
3
)
2
CHCH
2
; 1,1,1,2,3,4,4,5,5,5-decafluoropentane; a hydrocarbon such as butane, cyclopropane, isobutane, propane, pentane, or propylene; or dimethyl ether to form an azeotropic or azeotrope-like composition.
REFERENCES:
patent: 5538659 (1996-07-01), Chisolm et al.
patent: 5558810 (1996-09-01), Minor et al.
patent: 5562857 (1996-10-01), Werner et al.
patent: 5605882 (1997-02-01), Klug et al.
patent: 5650089 (1997-07-01), Gage et al.
patent: 5672294 (1997-09-01), Lund et al.
patent: 5677358 (1997-10-01), Lund et al.
patent: 5866029 (1999-02-01), Lund et al.
Chisolm Tuneen E. C.
Minor Barbara Haviland
E. I. du Pont de Nemours and Company
Edwards Mark A.
Wu Shean C.
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