Cleaning and liquid contact with solids – Processes – Miscellaneous
Patent
1997-12-29
1999-09-07
Hardee, John R.
Cleaning and liquid contact with solids
Processes
Miscellaneous
510409, 510412, C11D 158, C11D 324
Patent
active
059481749
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to compositions based on a hydrofluorocarbon and to a process for removing water from a solid surface by means of these compositions.
TECHNOLOGY REVIEW
In the electrical, electronic, optical and mechanical industries in particular, especially during the production of high precision components, it can happen that these, intentionally or otherwise, come into contact with water or moisture. There is a risk of the water adhering to the surface of these components and then causing certain harmful effects during subsequent stages of their use or detrimentally affecting their quality. It is consequently essential, for numerous precision components, to be completely free from water adhering to the surface. This operation for removing water from the surface can be carried out in particular by displacement of the water by means of a dense water-immiscible organic liquid optionally containing a surface-active agent.
Numerous hydrofluorocarbon-based compositions for the removal of water by displacement of the latter have already been provided, in particular compositions based on 1,1,1,3,3-pentafluorobutane. In particular, in Patent Application JP-A-05/168805, a description is given of compositions composed of 1,1,1,3,3-pentafluorobutane, of a solvent soluble in 1,1,1,3,3-pentafluorobutane and of a surface-active agent selected from salts derived from aliphatic fatty monocarboxylic acids and from aliphatic fatty monoamines.
When these known compositions are used to remove water from a solid surface, very small droplets of water are nevertheless often retained at the surface. Moreover, such compositions sometimes form emulsions with the water, which makes the subsequent separation of the composition from the displaced water difficult. These compositions are sometimes exhausted very quickly, so that, after a few cycles of use in removing water from the surface of components, they lose all their effectiveness.
Compositions which avoid this disadvantage comprise 1,1-dichloro-1-fluoroethane and an imidazoline (French Patent Application 94.06237). However, 1,1-dichloro-1-fluoroethane has a non-zero ozone destruction potential (ODP).
However, the substitution of 1,1,1,3,3-pentafluorobutane, such as for 1,1-dichloro-1-fluoroethane, is ruled out because imidazolines are generally insoluble in 1,1,1,3,3-pentafluorobutane.
SUMMARY OF THE INVENTION
A means has now been found for dissolving imidazolines in 1,1,1,3,3-pentafluorobutane and generally in hydrofluorocarbons which exhibit a zero ozone destruction potential, thus making it possible to obtain compositions exhibiting a good ability to remove water from solid surfaces without exhibiting the abovementioned disadvantages of the known compositions.
The invention consequently relates to compositions comprising a C.sub.3 -C.sub.10 hydrofluorocarbon, a cosolvent and a surface-active agent, the latter comprising at least one imidazoline.
DETAILED DESCRIPTION OF THE INVENTION
C.sub.3 -C.sub.10 hydrofluorocarbon is understood to denote saturated aliphatic or alicyclic hydrocarbons comprising from 3 to 10 carbon atoms, at least one fluorine atom and at least one hydrogen atom. In particular, hydrofluorocarbons which can be used in the compositions according to the invention are hydrofluoroalkanes of general formula C.sub.a H.sub.b F.sub.c, in which a is an integer from 3 to 8, b is an integer from 1 to (a+2) and c is an integer from a to (2a+1). Hydrofluoroalkanes as defined above containing from 4 to 6 carbon atoms are preferred. By way of example, the hydrofluoroalkane of the compositions according to the invention can be selected from compounds of empirical formula C.sub.4 H.sub.5 F.sub.5, C.sub.4 H.sub.4 F.sub.6 and C.sub.5 H.sub.2 F.sub.10, such as 1,1,1,3,3-pentafluorobutane (HFC-365mfc), 1,1,1,2,2,4-hexafluorobutane (HFC-356mcf) and 1,1,1,2,2,3,4,5,5,5-decafluoropentane (HFC-4310mee). 1,1,1,3,3-Pentafluorobutane is very well suited. The compositions according to the invention can also contain mixtures of hydrofluoro
REFERENCES:
patent: 3903012 (1975-09-01), Brandreth
patent: 4763423 (1988-08-01), Kemp, Jr.
patent: 5478492 (1995-12-01), Barthelemy et al.
patent: 5578138 (1996-11-01), Paulus et al.
Barthelemy Pierre
Paulus Mireille
Putteman Robert
Hardee John R.
Schneller John W.
Solvay ( Societe Anonyme)
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