Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – Liquid composition
Patent
1996-10-11
1998-06-30
Ivy, C. Warren
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
Liquid composition
570123, 521137, C11D 1700, C07C 2306
Patent
active
057734046
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to an azeotropic composition comprising cis-1,1,2,2,3,4-hexafluorocyclobutane (hereinafter referred to as "HFC-C336ee") and a specific alcohol and/or a specific hydrocarbon compound.
BACKGROUND ART
Trichlorotrifluoroethane (hereinafter referred to as "CFC-113") which is a chlorofluoroethane compound has been used widely as a solvent, detergent and the like solely or in the form of mixture or azeotropic composition with other organic solvent(s), because it is non-flammable and biologically less toxic and in addition, is excellent in selective solvency to oil and fat, grease, wax and the like without attacking high molecular substances such as plastics and rubbers.
In recent years, there has been raised a problem of environmental pollution on world-wide scale, that is, depletion of the ozone layer surrounding the earth due to chlorofluoroethane compounds (hereinafter referred to as "perhaloethane") such as CFC-113 in which all of hydrogen are replaced by chlorine and fluorine, and the chlorofluoroethane compounds cannot be used wholly in 1995. Also there is the same problem with respect to hydrochlorofluorocarbons (HCFC) used as alternatives for the perhaloethane, and prohibition of use thereof is slated in 2020.
It has been proposed to use hydrofluorocarbon (HFC) instead of CFC and HCFC. For example, there are 1,1,2,2,3,3,4,4,-octafluorobutane (HFC-338pcc), 1,1,1,2,3,4,4,5,5,5-decafluoropentane (HFC43-10mee), HFC-C336 and the like. JP-A-213397/1992 describes an azeotropic composition comprising HFC-C338pcc and methanol used as a detergent. Also U.S. Pat. No. 5,064,559 describes an azeotropic composition comprising HFC43-10mee and an alcohol used as a detergent. With respect to HFC-C336, there have been proposed single use thereof as a foaming agent or a detergent (JP-A-295157/1993 and JP-A-331489/1993).
However, HFC-338pcc and HFC43-10mee are not sufficient in solvency against contaminants such as metal processing oil, oil and fat, grease, wax and rosin flux, and are expensive because their syntheses are very difficult. Furthermore, with respect to HFC-C336, there are many isomers having different characteristics, and it is difficult to find out, from them, a compound having excellent properties. Similarly to the above-mentioned compounds, HFC-C336 itself has no sufficient solvency against oil and fat, flux and the like.
Solvency and flammability of a solvent can be adjusted by adding a co-solvent, that is to say, by preparing a mixed solvent. However, even if a mixed solvent is simply prepared, one component is condensed due to vaporization, which causes inconveniences such as change of the solvency and exhibition of flammability.
It is known that an azeotropic mixture is useful since it is vaporized/condensed at a specified temperature and composition. If a solvent mixture is not azeotropic, it is not preferred in practical use because its volatile component having a low boiling point is first vaporized to change its composition, thereby lowering solvency and increasing flammability.
Also the azeotropic composition is preferred in vapor-cleaning process including re-distilling step, final rinsing step and drying step. If the composition is not azeotropic, one component thereof is condensed in the re-distillation step, and thus safety and efficiency in the vapor-cleaning process are impaired.
Heretofore, there have been found many azeotropic compositions of fluorocarbons, and some of them have been used as a vapor-cleaning agent, a degreasing agent or a flux removing agent. However, it is difficult to expect whether or not an azeotropic composition can be formed, and therefore, an effort to find a novel azeotropic system applicable to this field has been continued.
An object of the present invention is to provide an azeotropic composition having increased solvency and nonflammability without using CFC and HCFC and being less detrimental to the ozone layer.
DISCLOSURE OF THE INVENTION
The present invention relates to an azeotropic composition comprising H
REFERENCES:
patent: 3850759 (1974-11-01), Hutchinson
patent: 5599783 (1997-02-01), Ide et al.
Michael Van Der Puy, Journal of Fluorine Chemistry, Estimation of Hydrocarbon Solubilities in Hydrofluorocarbons 67 (1994), pp. 215-224.
Aoyama Hirokazu
Ide Satoshi
Yamamoto Akinori
Daikin Industries Ltd.
Ivy C. Warren
Smith Lymon H.
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