Compositions comprising 1,1-dichloro-1-fluoroethane and process for the removal of water from a solid surface

Compositions based on 1,1-dichloro-1-fluoroethane and a surfactant comprising at least one imidazoline, which are usable for removing water from a solid surface.

FIELD OF THE INVENTION 
The present invention relates to compositions based on 
1,1-dichloro-1-fluoroethane and to a process for removal of water from a 
solid surface by means of these compositions. 
TECHNOLOGY REVIEW 
In the field of the electrical, electronic, optical and mechanical 
industries, in particular during the production of high precision parts, 
it can happen that the latter come into contact, intentionally or 
otherwise, with water or moisture. The water can adhere to the surface of 
these parts and then cause certain deleterious effects during subsequent 
steps in which they are involved, or can adversely affect their quality. 
It is accordingly essential, for many precision parts, for the water 
adhering to their surface to be removed completely from them. This 
operation of removal of 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 surfactant. 
Many compositions are known for the removal of water by displacement of the 
latter, in particular compositions based on 1,1-dichloro-1-fluoroethane. 
In particular, in Patent Application JP-A-05/004004, compositions are 
described which are based on 1,1-dichloro-1-fluoroethane to which a 
surfactant, preferably selected from salts derived jointly from aliphatic 
monocarboxylic acids comprising 6 to 10 carbon atoms and primary aliphatic 
monoamines comprising 8 to 12 carbon atoms, is added. 
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. Furthermore, these compositions sometimes form emulsions with 
water, making subsequent separation of the composition and displaced water 
difficult. These compositions become exhausted very quickly. After a few 
cycles of use of these compositions for the removal of water from the 
surface of parts, they lose their efficacy completely. 
SUMMARY OF THE INVENTION 
The subject of the invention is compositions comprising 
1,1-dichloro-1-fluoroethane and a surfactant, which display a good 
capacity for the removal of water from solid surfaces without displaying 
the abovementioned drawbacks of the known compositions. 
DETAILED DESCRIPTION OF THE INVENTION 
Accordingly, the invention relates to compositions comprising 
1,1-dichloro-1-fluoroethane and a surfactant, characterized in that the 
surfactant comprises at least one imidazoline. 
Imidazoline is understood to denote any organic compound comprising a 
structure 
##STR1## 
According to a preferred embodiment of the compositions according to the 
invention, the imidazoline corresponds to the formula 
##STR2## 
in which R represents an alkyl or alkenyl chain, Y represents a hydroxyl 
or amino group and n is an integer equal to at least 1. In this preferred 
embodiment of the compositions according to the invention, the number of 
carbon atoms in the alkyl or alkenyl chain R does not generally exceed 25, 
and preferably 20. Imidazolines in which R is an alkyl or alkenyl chain 
comprising at least 6, and preferably at least 10, carbon atoms are 
especially preferred. Very special preference is given to imidazolines in 
which R comprises 11 or 17 carbon atoms. In this preferred embodiment of 
the compositions according to the invention, the integer n does not 
generally exceed 20, and preferably 12. Imidazolines in which n is equal 
to 2 are especially preferred. Imidazolines in which R comprises 11 or 17 
carbon atoms and n is equal to 2 are especially advantageous, especially 
those in which R comprises 17 carbon atoms, n is equal to 2 and Y is an 
amino group. 
The imidazoline used in the compositions according to the invention can be 
in free base form or in the form of a mono- or dicarboxylate salt. In the 
case where the imidazoline is in the form of a mono- or dicarboxylate 
salt, the carboxylate portion is preferably derived from a saturated or 
unsaturated fatty acid containing 4 to 22 carbon atoms. Good results have 
been obtained with oleates and laurates. According to an advantageous 
embodiment of the compositions according to the invention, the imidazoline 
is in free base form or in the form of a monocarboxylate salt. 
Imidazolines which are usable in this embodiment of the compositions 
according to the invention are well known, and can be synthesized, in 
particular, by reaction at high temperature of saturated or unsaturated 
fatty acids corresponding to the formula RCOOH with substituted 
ethylenediamines of formula NH.sub.2 --CH.sub.2 --CH.sub.2 
--NH--(CH.sub.2).sub.n --Y. They are also to be found on the market, in 
particular under the names SERVAMIN.RTM.KOO 360 and SERVAMIN.RTM.KOO 330 
(sold by the firm SERVO), IMIDAZOLINE 18NH, IMIDAZOLINE 18OH, IMIDAZOLINE 
12NH and IMIDAZOLINE 12OH (sold by the firm LAKELAND) and MIRAMINE.RTM.HDO 
(sold by the firm RHONEPOULENC). 
In the compositions according to the invention, the imidazoline content is 
advantageously equal to at least 0.001%, and preferably 0.01%, by weight 
relative to the weight of 1,1-dichloro-1-fluoroethane. The imidazoline 
content does not generally exceed 5%, and preferably 1%, by weight 
relative to the weight of 1,1-dichloro-1-fluoroethane. 
Compositions according to the invention can contain, in addition to 
1,1-dichloro-1-fluoroethane and the surfactant, other compounds, in 
particular halogenated hydrocarbons, alcohols such as methanol, ethanol 
and decanol, or esters such as methyl acetate. In this case, the content 
of other compounds does not generally exceed 25%, and preferably 10%, by 
weight relative to the weight of 1,1-dichloro-1-fluoroethane. 
The compositions according to the invention can contain, in addition to the 
compounds described above, additives enabling the performances of the 
compositions to be improved when they are used, such as stabilizers, 
de-emulsifying agents and/or antifoams. 
In the compositions of the invention, the surfactant can contain, in 
addition to the imidazoline, one or more other surfactants. 
Compositions consisting essentially of 1,1-dichloro-1-fluoroethane and at 
least one imidazoline are preferred. 
The compositions according to the invention are liquid compositions which 
are especially well suited for displacing water from solid surfaces. They 
satisfy, in effect, the most severe criteria applicable to compositions 
used for removing water from solid surfaces, by displacement of this 
water. Thus, they are especially effective for displacing more than 70%, 
generally at least 95% and even all of the water present on a solid 
surface. The displacement of the water is very rapid. In this application, 
the compositions according to the invention have the advantage that they 
do not form an emulsion with water but, on the contrary, promote the 
formation of two superposed phases, one of which (the lower phase) 
consists essentially of the composition according to the invention in 
which a little water may possibly be dissolved, and the other (the upper 
phase) consists essentially of the displaced water. This permits a simple 
subsequent separation between the displaced water and the composition. The 
compositions according to the invention have the additional advantage that 
they lend themselves to a large number of successive uses without the 
nature and proportion of their constituents undergoing appreciable 
modification. The surfactant is not, in effect, significantly extracted 
from the compositions by the water which is displaced and is subsequently 
separated from them. 
The compositions according to the invention are suitable for the drying of 
a wide variety of different materials. They are suitable, in particular, 
for the drying of parts or materials made of metal, glass, ceramic, 
precious stones or plastic. 
Accordingly, the invention also relates to a process for the removal of 
water from a solid surface, which is characterized in that the surface is 
treated with a composition according to the invention. 
The process according to the invention applies equally well to moist 
surfaces, to surfaces on which droplets of water are present and also to 
surfaces completely covered with a film of water. 
To treat the solid surface with the composition according to the invention, 
it is possible, for example, to subject it to a spraying, a sprinkling, a 
coating with the composition or an immersion in a bath of the composition. 
The optimum amount of composition to be used depends, in particular, on 
the dimensions of the part treated, the amount of water to be removed and 
the treatment method employed. It may be readily determined in each 
particular case by routine work. When the immersion technique is used, the 
composition may be stirred by any suitable means and the action of the 
composition may be enhanced, for example by application of ultrasound. 
The process according to the invention may be carried out at any 
temperature between the solidification point of water and the boiling 
point of the composition. The treatment time is not critical. For 
practical reasons, it is generally advised to place the surface to be 
treated in contact with the composition for a period of approximately one 
minute, although shorter or longer treatment times may be used, depending 
on the characteristics of the surface to be treated. In general, the 
treatment time is at least 5 seconds, usually at least 30 seconds. In 
principle, there is no upper limit to the treatment period. Usually, 
however, the treatment time does not exceed 10 minutes. More often than 
not, it does not exceed 5 minutes. 
According to a preferred embodiment of the process according to the 
invention, the solid surface is treated by immersion in a bath of the 
composition. In this case, as a special preference, the bath is at the 
boiling point. 
At the end of the treatment with the composition, the solid surface is, 
usually, rinsed by means of a non-aqueous solvent, employed in liquid or 
gaseous form. 1,1-Dichloro-1-fluoroethane may be used for this purpose.

EXAMPLES 
The non-limiting examples which follow are given by way of illustration. 
Example 1R (comparative) 
A piece of polyvinylidene fluoride (PVDF) parallelepipedal 
(30.times.20.times.10 mm) in shape and pierced with holes 1 mm in diameter 
was immersed in water so as to fill the holes therein. The piece was then 
dipped into a bath consisting of 1,1-dichloro-1-fluoroethane at the 
boiling point. After 15, 30, 45 and 60 seconds of immersion, the piece was 
removed from the bath and the number of water-free holes was determined by 
visual inspection. The results of these observations are collated in Table 
I, where the proportion of water-free holes is expressed as a percentage 
of the total number of holes. 
In this Example, 1,1-dichloro-1-fluoroethane used alone proved ineffective 
for removing the water; even after one minute of immersion, only a small 
portion of the holes may be considered to be water-free. 
Example 2R (comparative) 
The procedure of Example 1R was repeated with a bath consisting of 99.8% by 
weight of 1,1-dichloro-1-fluoroethane, 0.124% by weight of nonanoic acid 
and 0.076% by weight of nonylamine. The percentages of water-free holes 
are given in Table I. 
This bath, not according to the invention, proved ineffective for removing 
the water; even after one minute of immersion, only a small portion of the 
holes may be considered to be water-free. 
Example 3 (according to the invention) 
The procedure of Example 1R was repeated with a bath according to the 
invention, consisting of 99.8% by weight of 1,1-dichloro-1-fluoroethane 
and 0.2% by weight of a mixture of imidazolines of general formula 
1-(2-hydroxyethyl)-2-(C.sub.11 H.sub.19-23)-2-imidazoline (sold by the 
firm LAKELAND under the name IMIDAZOLINE 12OH). The percentages of 
water-free holes are given in Table I. 
After one minute of immersion, all the holes may be considered to be 
water-free. 
Example 4 (according to the invention) 
The procedure of Example 1R was repeated with a bath according to the 
invention, consisting of 99.8% by weight of 1,1-dichloro-1-fluoroethane 
and 0.2% by weight of a mixture of imidazolines of general formula 
1-(2-aminoethyl)-2-(C.sub.11 H.sub.19-23)-2-imidazoline (sold by the firm 
LAKELAND under the name IMIDAZOLINE 12NH). The percentages of water-free 
holes are given in Table I. 
After one minute of immersion, 72% of the holes may be considered to be 
water-free. 
Example 5 (according to the invention) 
The procedure of Example 1R was repeated with a bath according to the 
invention, consisting of 99.8% by weight of 1,1-dichloro-1-fluoroethane 
and 0.2% by weight of a mixture of imidazolines of general formula 
1-(2-aminoethyl)-2-(C.sub.17 H.sub.31-35)-2-imidazoline (sold by the firm 
SERVO under the name SERVAMIN.RTM.KOO 330). The percentages of water-free 
holes are given in Table I. 
After one minute of immersion, all the holes may be considered to be 
water-free. 
Example 6 (according to the invention) 
The procedure of Example 1R was repeated with a bath according to the 
invention, consisting of 99.8% by weight of 1,1-dichloro-1-fluoroethane 
and 0.2% by weight of a mixture of imidazolines of general formula 
1-(2-hydroxyethyl)-2-(C.sub.17 H.sub.31-35)-2-imidazoline (sold by the 
firm SERVO under the name SERVAMIN.RTM.KOO 360). The percentages of 
water-free holes are given in Table I. 
After one minute of immersion, 98% of the holes may be considered to be 
water-free. 
TABLE I 
______________________________________ 
% of holes water-free after 
Example 15 s 30 s 45 s 60 s 
______________________________________ 
Example 1R 3 4 4 4 
Example 2R 4 4 6 6 
Example 3 82 96 97 100 
Example 4 43 50 62 72 
Example 5 48 87 98 100 
Example 6 37 73 89 98 
______________________________________ 
Example 7 (according to the invention) 
The procedure of Example 1R was repeated with a bath according to the 
invention, consisting of 96% by weight of 1,1-dichloro-1-fluoroethane, 
3.8% by weight of methanol and 0.2% by weight of a mixture of imidazolines 
of the general formula 1-(2-hydroxyethyl)-2-(C.sub.11 
H.sub.19-23)-2-imidazoline (sold by the firm LAKELAND under the name 
IMIDAZOLINE 12OH). The percentages of water-free holes are given in Table 
II. 
After one minute of immersion, 99% of the holes may be considered to be 
water-free. 
Example 8 (according to the invention) 
The procedure of Example 1R was repeated with a bath according to the 
invention, consisting of 98% by weight of 1,1-dichloro-1-fluoroethane, 
1.8% by weight of ethanol and 0.2% by weight of a mixture of imidazolines 
of general formula 1-(2-hydroxyethyl)-2-(C.sub.11 
H.sub.19-23)-2-imidazoline (sold by the firm LAKELAND under the name 
IMIDAZOLINE 12OH). The percentages of water-free holes are given in Table 
II. 
After one minute of immersion, 96% of the holes may be considered to be 
water-free. 
Example 9 (according to the invention) 
The procedure of Example 1R was repeated with a bath according to the 
invention, consisting of 94% by weight of 1,1-dichloro-1-fluoroethane, 
3.7% by weight of methanol, 2.1% by weight of methyl acetate and 0.2% by 
weight of a mixture of imidazolines of general formula 
1-(2-hydroxyethyl)-2-(C.sub.11 H.sub.19-23)-2-imidazoline (sold by the 
firm LAKELAND under the name IMIDAZOLINE 12OH). The percentages of 
water-free holes are given in Table II. 
After one minute of immersion, 86% of the holes may be considered to be 
water-free. 
TABLE II 
______________________________________ 
% of holes water-free after 
Example 15 s 30 s 45 s 60 s 
______________________________________ 
Example 7 64 87 96 99 
Example 8 53 83 91 96 
Example 9 44 69 79 86 
______________________________________ 
Example 10 (according to the invention) 
The procedure of Example 1R was repeated with a bath according to the 
invention, consisting of 99.8% by weight of 1,1-dichloro-1-fluoroethane 
and 0.2% by weight of the salt of general formula 
1-(2-hydroxyethyl)-2-(C.sub.17 H.sub.31-35)-2-imidazoline oleate (sold by 
the firm RHONE POULENC under the name MIRAMINE.RTM.HDO). The percentages 
of water-free holes are given in Table III. 
After 45 s of immersion, all the holes may be considered to be water-free. 
Example 11 (according to the invention) 
The procedure of Example 1R was repeated with a bath according to the 
invention, consisting of 96% by weight of 1,1-dichloro-1-fluoroethane, 
3.8% by weight of methanol and 0.2% by weight of the salt of general 
formula 1-(2-hydroxyethyl)-2-(C.sub.17 H.sub.31-35)-2-imidazoline oleate 
(sold by the firm RHONE POULENC under the name MIRAMINE.RTM.HDO). The 
percentages of water-free holes are given in Table III. 
After 30 s of immersion, all the holes may be considered to be water-free. 
TABLE III 
______________________________________ 
% of holes water-free after 
Example 15 s 30 s 45 s 60 s 
______________________________________ 
Example 10 89 99 100 
Example 11 97 100 
______________________________________ 
Example 12R (comparative) 
A metal-coated plastic tube of shiny and smooth appearance was immersed in 
water so as to cover it with a film of water. The tube was then dipped 
into a bath consisting of 99.8% by weight of 1,1-dichloro-1-fluoroethane, 
0.124% by weight of nonanoic acid and 0.076% by weight of nonylamine, at 
the boiling point. After 60 seconds of immersion, the tube was removed 
from the bath and subjected to rinsing by means of pure 
1,1-dichloro-1-fluoroethane (comprising two immersions in a liquid bath at 
the boiling point, followed by a treatment in the vapour phase). It was 
determined by visual inspection whether droplets of water were present on 
its surface. 
This procedure (immersion in water, dipping into the bath, rinsing by means 
of pure 1,1-dichloro-1-fluoroethane) was repeated using the same bath 
until the point where the latter lost its activity (which was detected by 
the presence of droplets of water on the surface of the tube). 
After barely 5 cycles (immersion in water, dipping into the bath, rinsing), 
droplets of water remained present on the surface of the tube. 
Example 13 (according to the invention) 
The procedure of Example 12R was repeated with a bath according to the 
invention, consisting of 99.8% by weight of 1,1-dichloro-1-fluoroethane 
and 0.2% by weight of a mixture of imidazolines of general formula 
1-(2-aminoethyl)-2-(C.sub.17 H.sub.31-35)-2-imidazoline (sold by the firm 
SERVO under the name SERVAMIN.RTM.KOO 330). 
After 25 cycles (immersion in water, dipping into the bath according to the 
invention, rinsing), the surface of the tube proved to be water-free. 
The results of the observations made in Examples 12R and 13 show that the 
compositions according to the invention have the advantage that they lend 
themselves to a large number of successive uses without losing their 
efficacy.