The present invention relates to an azeotropic solvent composition comprising an azeotropic mixture of 1,1,2-trichloro-1,2,2-trifluoroethane (hereinafter referred to as "Flon-113") and cyclopentane.
Flon-113, one of the chlorofluoroethane compounds, has various advantages such as good incombustibility, low toxity to living bodies and excellent selective solvent power that it can dissolve fats and oils, greases, waxes, and the like without erosion of high molecular compounds such as plastics and rubbers. Accordingly, Flon-113 is widely used alone or as a mixture or azeotropic composition thereof with an other organic solvent, as a solvent, a cleaning solvent, or the like.
Recently, a problem of environmental pollution-that chlorofluoroethane compounds in which all hydrogen atoms of ethane are substituted with chlorine atoms and fluorine atoms (hereinafter referred to as "perhaloethanes") such as Flon-113 destroy the ozone layer surrounding the earth-has been raised on a global scale. Therefore, it is immediately required to decrease the used amount of such perhaloethanes.
Then, substances substitutive for Flon-113 have been variously studied, but no suitable substitute has been found.
On the other hand, mixed solvents of Flon-113 with an other organic solvent have been practically used. However, for using Flon-113 as the mixed solvent, it is required to easily control the liquid composition of the solvent and to easily recover and reuse the solvent. Moreover, it is desired that the solvent can be applied to steam cleaning.
Mixed solvents satisfying the above requirements cannot be obtained by only mixing Flon-113 with one or more kinds of the other solvents. That is, it is necessary that the mixture made is a mixture having an azeotropic point, in other words, the mixture is made azeotropic.
As such an azeotropic mixture of Flon-113, an azeotropic mixture of Flon-113 with methanol or ethanol is known. However, both the azeotropic mixtures have a low alcohol content, only less than 10 % by weight (methanol content: 6 % by weight, ethanol content: 4 % by weight). Accordingly, the azeotropic mixtures of Flon113 with the alcohol are very unsatisfactory from the viewpoint of decrease of the used amount of Flon-113.
An azeotropic mixture of Flon-113 and methylene chloride having a mixing ratio of Flon-113 to methylene chloride of 1 : 1 by weight is also practically used, but it is not desirable, since methylene chloride has high toxity to living bodies.
An object of the present invention is to provide an azeotropic composition capable of further improving cleaning power, in other words power for removing wax, of Flon-113 and capable of decreasing the amount of Flon-113 used.
This and other objects of the present invention will become apparent from the description hereinafter.