Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – Liquid composition
Reexamination Certificate
2000-08-28
2004-06-22
Webb, Gregory (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
Liquid composition
C510S412000, C510S286000, C510S291000, C252S364000
Reexamination Certificate
active
06753304
ABSTRACT:
The invention relates to compositions comprising perfluorobutyl methyl ether (C
4
F
9
—O—CH
3
) and to the use of these compositions, in particular as agent for cleaning or drying solid surfaces.
Completely halogenated chlorofluorohydrocarbons (CFCs), in particular 1,1,2-trichloro-1,2,2-trifluoro-ethane (CFC-113), are widely used as solvents in industry for degreasing and cleaning various surfaces, particularly for solid components of complicated shape which are difficult to clean. In addition to their application in electronics, in the cleaning of soldering flux, to remove the soldering flux which adheres to printed circuits, they are also conventionally used to degrease metal components or to clean metal components of high quality and of high accuracy. In these various applications, CFC-113 is generally used in combination with other organic solvents, preferably in the form of azeotropic compositions or pseudoazeotropic compositions having substantially the same composition in the vapour phase and in the liquid phase, so that they can be easily employed at reflux.
Compositions based on CFC-113 are also conventionally used as drying agent, in order to remove the water adsorbed at the surface of solid components.
However, CFC-113, as well as other completely halogenated chlorofluoroalkanes, it is today suspected of being involved in the destruction of the stratospheric ozone layer.
Consequently, there is currently an urgent need to find novel compositions which do not have a harmful effect on the ozone layer.
Chlorine-free hydrofluorinated compounds are completely inert with respect to the stratospheric ozone layer and these compounds are found to be increasingly widely used in numerous applications, at the expense of the compounds carrying chlorine atoms.
To this end, Patent Application WO 96/36689 provides azeotropic compositions formed of perfluorobutyl methyl ether with one or more organic solvents chosen from linear or branched and cyclic or acyclic alkanes comprising from 6 to 8 carbon atoms, cyclic or acyclic ethers comprising from 4 to 6 carbon atoms, ketones comprising 3 carbon atoms, chlorinated alkanes comprising 1, 3 or 4 carbon atoms, chlorinated alkenes comprising 2 to 3 carbon atoms, alcohols comprising 1 to 4 carbon atoms, partially fluorinated alcohols comprising 2 to 3 carbon atoms, 1-bromopropane, acetonitrile, HCFC-225ea and HCFC-225cb.
One of the objectives of the present invention is to furnish other compositions which optionally form azeotropes or pseudoazeotropes and which have a particularly good performance when they are used as cleaning agent in solvent cleaning processes. A further object of the invention is such compositions possessing properties particularly suited to the cleaning of printed circuit boards. Another objective of the invention is to furnish such compositions devoid of a destructive effect with regard to the ozone layer.
Another object of the invention is compositions possessing particularly suitable properties as agent for fixing a toner to a recording substrate in a device for printing or reproducing documents.
The present invention consequently relates to compositions comprising a perfluorobutyl methyl ether and a cosolvent. It relates more particularly to the compositions comprising a perfluorobutyl methyl ether of general formula C
4
F
9
—O—CH
3
, where C
4
F
9
is a linear or branched perfluorinated chain, and an organic solvent possessing an ester functional group. CF
3
—(CF
2
)
3
—O—CH
3
, (CF
3
)
2
CF—CF
2
—O—CH
3
and their mixtures are the preferred perfluorobutyl methyl ethers. In the continuation of the account, the term “perfluorobutyl methyl ether” is used to denote a mixture of these 2 compounds sold by 3M under the name HFE-7100. Mention may be made, as examples of organic compounds comprising an ester functional group, of methyl formate, ethyl formate, propyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate or propyl propionate.
Methyl formate, ethyl formate, methyl acetate and ethyl acetate are preferred. Methyl formate, ethyl formate and methyl acetate are particularly preferred.
The thermodynamic state of a fluid is fundamentally defined by four interdependent variables: the pressure (P), the temperature (T), the composition of the liquid phase (X) and the composition of the gas phase (Y). A true azeotrope is a specific system comprising 2 or more components for which, at a given temperature and at a given pressure, the composition of the liquid phase X is exactly the same as the composition of the gas phase Y.
A pseudoazeotrope is a system comprising 2 or more components for which, at a given temperature and at a given pressure, X is substantially the same as Y. In practice, this means that the constituents of such azeotropic and pseudoazeotropic systems cannot be easily separated by distillation and consequently their composition remains substantially constant in solvent cleaning operations and in operations for the recovery of waste solvents by distillation.
For the purposes of the present invention, the term “pseudoazeotropic mixture” is understood to mean a mixture of two constituents with a boiling point (at a given pressure) which differs from the boiling point of the true azeotrope by at most 0.5° C. Mixtures with a boiling point which differs from the boiling point of the true azeotrope by at most 0.2° C. are preferred. Mixtures with a boiling point which differs from the boiling point of the true azeotrope by at most 0.1° C. are particularly preferred.
The contents of perfluorobutyl methyl ether and of ester in the compositions according to the invention can vary within wide limits, depending upon the use envisaged.
The compositions according to the invention generally comprise at least 1% by weight of perfluorobutyl methyl ether. They advantageously comprise at least 5% thereof. In a particularly preferred way, they comprise at least 10% thereof. They can comprise up to 99% thereof. They generally comprise at most 95% thereof.
Compositions according to the invention which are very particularly preferred are those which comprise perfluorobutyl methyl ether and an ester in proportions in which they form a minimum boiling point azeotrope or pseudoazeotrope.
The compositions of the azeotropic mixtures according to the; invention were evaluated on the basis of the results of the experimental measurements presented in the examples hereinbelow.
Perfluorobutyl methyl ether and methyl acetate form a binary azeotrope or pseudoazeotrope when their mixture comprises approximately from 21 to 52% by weight of methyl acetate. The binary compositions comprising approximately from 28 to 48% by weight of methyl acetate are preferred. Under a pressure of 102.3 kPa, the binary composition composed essentially of approximately 61% by weight of perfluorobutyl methyl ether and of approximately 39% by weight of methyl acetate constitutes a true azeotrope, the boiling point of which is approximately 52.6° C. This composition is very particularly preferred.
Perfluorobutyl methyl ether and ethyl formate form a binary azeotrope or pseudoazeotrope when their mixture comprises approximately from 22 to 53% by weight of ethyl formate. The binary compositions comprising approximately from 26 to 46% by weight of ethyl formate are preferred. Under a pressure of 102.6 kPa, the binary composition composed essentially of approximately 68% by weight of perfluorobutyl methyl ether and of approximately 32% by weight of ethyl formate constitutes a true azeotrope, the boiling point of which is approximately 50.2° C. This composition is very particularly preferred.
Perfluorobutyl methyl ether and methyl formate form a binary azeotrope or pseudoazeotrope when their mixture comprises approximately from 40 to 92% by weight of methyl formate. The binary compositions comprising approximately from 59 to 80% by weight of methyl formate are preferred. Under a pressure of 102.2 kPa, the binary composition composed essentially of approximately 36% by weight of perfluorobutyl methyl ether and of approximately 64%
Barthelemy Pierre
Dournel Pierre
Connolly Bove & Lodge & Hutz LLP
Solvay ( Societe Anonyme)
Webb Gregory
LandOfFree
Compositions comprising perfluorobutyl methyl ether and use... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Compositions comprising perfluorobutyl methyl ether and use..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Compositions comprising perfluorobutyl methyl ether and use... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3315138