1,1,2-Trichloro-1,2,2-trifluoroethane (known in the trade under the name F113) has been widely used in industry for cleaning and degreasing highly-varied solid surfaces (metal components, glasses, plastics, composites) for which the absence or at least the lowest possible residual content of impurities, in particular of organic nature, is required. F113 was particularly well suited to this use because of its nonaggressive nature with regard to the materials used. This product was used in particular in the field of the manufacture of printed circuits, for removing the residues of the substances used to improve the quality of the soldered joints (denoted by the term solder flux). This removal operation is denoted in the trade by the term "defluxing".
Mention may also be made of the applications of F113 in the degreasing of heavy metal components and in the cleaning of mechanical components of high quality and of great accuracy, such as, for example, gyroscopes and military, aerospace or medical equipment. In its various applications, F113 is generally used in combination with other organic solvents (for example methanol), in order to improve its cleaning power. It is then preferable to use azeotropic or near-azeotropic mixtures. The term "near-azeotropic mixture" is understood to mean, within the sense of the present invention, a mixture of generally miscible chemical compounds which, under certain specific conditions of proportions, temperature and pressure, boils at a substantially constant temperature while retaining substantially the same composition. When it is heated to reflux, such a near-azeotropic mixture is in equilibrium with a vapour phase, the composition of which is substantially the same as that of the liquid phase. Such azeotropic or near-azeotropic behaviour is desirable in ensuring satisfactory operation of the devices in which the abovementioned cleaning operations are carried out and in particular in ensuring the recycling by distillation of the cleaning fluid.
F113 is also used in fields, in particular in optics, where it is required to have available surfaces which are devoid of water, that is to say surfaces where water is only present in the form of traces undetectable by the measurement method (Karl Fischer method). F113 is, for this purpose, employed in drying (or dewetting) operations on the said surfaces, in combination with hydrophobic surface-active agents.
However, the use of compositions based on F113 is now forbidden as F113 is one of the chlorofluorocarbons (CFCs) suspected of attacking or damaging the stratospheric ozone.
In these various applications, F113 can be replaced by 1,1-dichloro-1-fluoroethane (known under the name F141b), but the use of this substitute is already controlled because, although low, it still has a destructive effect with regard to ozone.
Application EP 0,512,885 discloses a composition, comprising from 93 to 99% by weight of 1,1,1,3,3-pentafluorobutane and from 1 to 7% of methanol, which can be used as substitute for F113. 1,1,1,3,3-pentafluorobutane, also known in the trade under the name F365mfc, has no destructive effect with regard to ozone.
Application EP 0,856,578 discloses a composition, comprising from 10 to 90% by weight of 1,1,1,2,3,4,4,5,5,5-decafluoropentane, from 10 to 90% of dichloromethane and from 0 to 10% of methanol, which can also be used as substitute for F113. 1,1,1,2,3,4,4,5,5,5-Decafluoropentane, known in the trade under the name 43-10mee, also has no destructive effect with regard to ozone.