Note: Descriptions are shown in the official language in which they were submitted.
- 1 - 2 ~ ~?~3 7
AZEOTROPIC SOLVENT COMPOSITION
BACKGROtJND OF THE INVENTION
The present invention relates to an azeotropic
solvent composition comprising a dichloropentafluoro-
propane (hereinafter referred to as "HCFC-225") and a
fluorine alcohol.
Trichlorotrifluoroethane (hereinafter referred
to as "CFC-113"), one of chlorofluoroethane compounds, i5
incombustible, low in toxity to living bodies and
excellent in selective solvent power that it can dissolve
fats and oils, greases, waxes, and the like without
erosion of polymer substances such as plastics and
rubbers. Accordingly, CFC-113 has hitherto been widely
used alone or in the state of a mixture or azeotropic
composition with another 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 by chlorine atoms and
fluorine atoms (hereinafter referred to as
"perhaloethanes") such as CFC-113 destroy the ozone layer
surrounding the earth has been raised on a global
scale. Therefore, it is urgently required to decrease
the used amount of such perhaloethanes or to omit the use
of the perhaloethane.
~s one of methods decreasing the used amount of
the perhaloethane, for example, a method using a mixed
solvent of CFC-113 with an organic solvent other than the
perhaloethanes has been studied. According to the
method, however, the used amount of CFC-113 can be
decreased no more than a certain extent, because the
` performances of the mixed solvent are lowered. Also,
when usin~ CFC 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 mixed solvent can be applied to steam
cleaning. E'or satisfying the requirements as mentioned
`.:
.,;
.
.
~ - 2 - ~3~
above, it is necessary that the mixed solvents are
azeotropic mixtures. It is not easy to find such a
mixture. Thus, no useful substitute has been found.
On the other hand, though as to solvents
containing no perhaloethane at all, various studies have
been made, no useful substitute has been found, too.
Although mixed solvents of a halogenated
organic solvent and a fluorine alcohol have been also
known in Japanese Examined Patent Publication No.
12864/1971, azeotropic compositions of HCEC-225 and a
fluorine alcohol have not been found out. Also, mixed
: solvents of a halogenated organic solvent, particularly
fluorocarbon solvents, and a hydrocarbon alcohol have
hitherto been well ~nown. The mixted solvents have,
however, a defect that an acid such as hydrochloric acid
generates in the presence of moisture to corrode
metals. Thus, when the mixed solvent is used, it is
required to remove moisture, or use conditions or kinds
of materials to be washed are limited.
An object of the present invention is to
provide an azeotropic solvent composition containing no
CFC-113, which has the improved rogin-flux cleaning
power, which destroys scarcely the ozone layer, and which
is incombustible.
This and other objects of the present invention
will become apparent from the description hereinafter.
- SUMMARY OF THE INVENTION
In accordance with the present invention, there
is provided an azeotropic solvent composition comprising
a dichloropentafluoropropane and a fluorine alcohol. The
composition of the present invention, surprisingly, does
not corrode metals even in the presence of moisture and
is stable.
_TAILED DESCRIPTION
HCFC-225 used in the present invention has
isomers such as 1,1-dichloro-2,2,3,3,3-pentafluoropropane
.,
-
2 ~
-- 3
[boiling point (bp) : 51C], 1,2-dichloro-1,2,3,3,3-
pentafluoropropane (bp : 56C), 1,3-dichloro-1,2,2,3,3-
pentafluoropropane tbp : 56.1C), 2,2-dichloro-1,1,3,3,3-
pentafluoropropane (bp : 54C), 2,3-dichloro-1,1-2,3,3-
5pentafluoropropane (bp : 56C), 3,3-dichloro-1,1,2,2,3-
pentafluoropropane (bp : 58C), 1,1-dichloro-1,2,3,3,3-
pentafluoropropane (bp : 49C), 1,3-dichloro-1,1,2,3,3-
pentafluoropropane (bp : 48C) and 1,2-dichloro-
1,1,3,3,3-pentafluoropropane (bp : 50C).
10HCFC-225 is incombustible, low in toxity to
living bodies and chemically stable, and has the
selective solvent power that it can wash and remove
stains such as f~ts and oils, exerting scarcely influence
on plastics, rubbers, metals, and the like. Moreover,
15HCFC-225 less destroys the ozone layer than CFC-113.
In the present invention, as the fluorine
alcohol, there are exemplified alcohols having at least
two fluorine atoms and not less than two carbon atoms in
one molecule. More concretely, fluorine alcohols having
the following formulas as mentioned below are cited;
CF3CH20H
.~,
H(CF2CF2t~-CH2H
H(CF2CF ~ CH2OH
~- CF3
': H(cF2cF2~cHoH
30 CH3
H(CE'2CF ~ CHOH
CF3 CH3
35F(CF2CF2-~ CH2OH
,::
F(CF2CF ~ CH2OH
CF3
:'
.
.~
~3~8~7
-- 4
( 2 2 ~ 2 2
F(CF2CF~h--CH2CH2H
CF3
F(CF2CF2 ~-CH2CH2CH20H
F(CF2CF ~ CH2CH2CH20H
CF3
wherein each a, c, e, g and i is an integer of l to 5 and
each b, d, f, h and j is an integer of l to 3.
Among them, trifluoroethanol (bp : 77C),
tetrafluoropropanol (bp : 107C) and pentafluoropropanol
(hereinafter referred to as "5FP", bp : 81C) are more
preferable. Furthermore, 5FP is more preferable because
it is incombustible. The fluorine alcohols may be used
alone or as an admixture thereof.
The composition of the present invention
comprises HCFC-225 having the above-mentioned properties
and the fluorine alcohol. Moreover, since the
composition is azeotropic, it is easy to control the
liquid composition of the solvent and to recover and
reuse the solvent, so the composition can be applied to
steam cleaning. Furthermore, the composition is very
effective in electric and electronic industries as a
cleaning solvent for removing rogin-flux used in
soldering of printed-circuit board. The composition is
also chemically stable, particularly is remarkably stable
even in the presence of moisture and the metal, and has
the selective solvent power that it can wash and remove
only the stains, exerting no bad influence on plastics,
rubbers, metals, and the like. Moreover, the composition
less destroys the ozone layer than CFC-113 and is
incombustible.
The mixture of HCFC-225 and the fluorine
alcohol forms an azeotropic composition or an azeotropic
; like composition within the range of a weight ratio of
2 ~
HC~C-225 to the fluorine alcohol of 99.5 to 88.0/0.5 to
12.0, pre~erably 99.5 to 31.0/0.5 to 9Ø The azotropic
composition has an azeotropic temperature of 47.5 to
57.5C. Examples of the azeotropic mixture and the
azeotropic like composition are, for instance, an
a2eotropic mixture (azeotropic point : 49.8C) of 93.5 %
by weight of 1,1-dichloro-2,2,3,3,3-pentafluoropropane
(bp : 51C) and 6.5 % by weight of pentafluoropropanol
(5~P) (bp : 81C), an azeotropic mixture (azeotropic
point: 54.5 C) of 92.2 % by weight of 1,3-dichloro-
1,2,2,3,3-pentafluoropropane (bp: 56.1C) and 7.8 ~ by
weight of 5FP (bp: 81~C), an azeotropic like composition
of 93.5 to 92.2 % by weight of a mixture of l,l-dichloro-
2,2,3,3,3-pentafluoropropane and 1,3-dichloro-1,2,2,3,3-
pentafluoropropane, the weight ratio of l,l-dichloro-
2,2,3,3,3-pentafluoropropane to 1,3-dichloro-1,2,2,3,3-
pentafluoropropane being 0.5 to 99.5/99.5 to 0.5,
- preferably 5 to 60/95 to 40, more preferably 20 to 50/80
to S0, and 6.5 to 7.8 % by weight of 5FP, and the llke.
The composition containing mainly HCFC-225 of the present
invention is suitable for use not only as a cleaning
solvent for removing the rogin-flux which is used in
- printed-circuit boards and which is difficult to be
removed by a single component alone, but also in various
.': 25 uses in which CFC-113 has been generally used, for
.
instance, as a degreasing solvent for removing paraffins,
~- animal and vegetable oils, processing oils; as a cleaning
solvent for removing mold release agents used in molding
and processing of plastics; as a cleaning solvent for
removing waxes used for temporarily fixing silicon wafers
used in semiconductors, quartz and ceramics in their
.~ processing such as cutting or polishing, pressure
sensitive adhesive tapes, paints, inks, and th~ like; as
a disperse medium for ceramics or metal powder; as a
drying dehydration desiccant; as a dry-cleaning solvent;
and the like.
Although the composition of the present
invention is chemically stable compared to solvents
.
:
i
~3~7
.
containing an aliphatic alcohol, a stabilizer can be
included.
It is preferred that the stabilizers can be
distilled together with the azeotropic composition of the
invention or the mixture of the azeotropic composition
and the stabilizer can form an azeotropic composition, in
addition that the stabili~ers have a large effect for
stabilizing the composition.
Examples of the stabilizers as mentioned above
are, for instance, aliphatic nitro compounds such as
nitromethane, nitroethane and nitropropane; acetylene
alcohols such as 3-methyl-1-butyne-3-ol and 3-methyl-1-
pentyne-3-ol; epoxides such as ~lycidol, methyl glycidyl
ether, allyl glycidyl ether, phenyl glycidyl ether, 1,2-
butylene oxide, cyclohexene oxide and epichlorohydrin;ethers such as dimethoxymethane, 1,2-dimethoxyethane,
1,4-dioxane and 1,3,5-trioxane; unsaturated hydrocarbons
such as hexene, heptene, octene, 2,4,4-trimethyl-1-
pentene, pentadiene, octadiene, cyclohexene and
cyclopentene; olefinic alcohols such as allyl alcohol, 1-
butene-3-ol and 3-methyl-1-butene-3-ol; acrylates such as
methyl acrylate, ethyl acrylate and butyl acrylate; and
the like. The stabilizers may be used alone or as an
admixture thereof. Among them, nitromethane is
pre~erable. In addition thereto, other compounds may be
used. In such a case as the stabilizer is used with the
other compounds, synergic stabilizing effect can be
obtained. Examples of the other compounds are, for
instance, phenols such as p~lenol, trimethylphenol,
cyclohexylphenol, thymol, 2,6-di-t-butyl-4-methylphenol,
- butylhydroxyanisole and isoeugenol; amines such as
hexylamine, pentylamine, dipropylamine, diisopropylamine,
diisobutylamine, triethylamine, tributylamine, pyridine,
N-methylmorpholine, cyclohexylamine, 2,2,6,6
tetramethylpiperidine and N,N'-diallyl-p-phenylene-
diamine; toriazoles such as benzotriazole, 2-(2'-hydroxy~
5'-methylphenyl)benzotriazole and chlorobenzotriazole;
and the like.
2 ~ 7
An amount of the stabilizer depends cn the kind
of the stabilizer, so it is suitably determined according
to the kind of the used stabilizer. Generally, the
amount is from 0.1 to 10 % by weight, preferably from 0.5
to 5 ~ by weight, based on the azeotropic composition. In
such a case as nitromethzne is used, an amount of
nitromethane is from about 0.1 to 1.0 ~ by weight of the
a2eotropic composition.
The stabilizer is used in an amount such that
the azeotropic composition is not impaired. Usually,
since the stabilizer is used in a small amount such as
not more than 1 % by weight, the addition of the
stabilizer does not influence much the azeotropic
composition.
lSThe composition of the present invention is the
same as or superior to CFC-113 in the flux cleaning
power, incombustibillty, chemical stability, and the
like. The composition has the selective solvent power
` while it exerts scarcely influence on the plastics,
rubbers, particularly metals. Also, the azeotropic
solvent composition of the invention contains HCFC-225
destroying less the ozone layer than CFC-113 as the main
component, is excellent in rogin-flux cleaning power,
that is, it can remove the rogin-flux which cannot be
removed sufficiently by using the single component alone
with maintaining the excellent various properties of
HC~C-225. Moreover, the composition is excellent in
properties to be required as the azeotropic solvent
composition, that is, it is low in boiling point, high in
solubility, easy to control the li~uid composition of
solvent and easy to recover or reuse the solvent.
Especially, when the composition of the present
invention is used, the metal cannot be corroded even in
the presence of water, though the metal corrosion in the
presence of water could not be avoided by the combination
with the alcohol as conventionally used. Accordingly,
the composition of the invention can be used in various
use conditions and various kinds of materials to be
2 ~ 3 ~
washed.
The present invention i5 more specifically
described and explained by means of the following
Examples, in which all % and parts are by weight
otherwise noted. It is to be understood that the present
invention is not limited to the Examples and various
changes and modifications may be made in the invention
without departing from the spirit and scope thereof.
Example 1
A distillation flask was charged with 200 9 of
a mixture of 1,1-dichloro-2,2,3,3,3-pentafluoropropane
(225ca, bp : 51C) and pentafluoropropanol (5FP, bp :
81C) in a weight ratio of 225ca to 5FP of 50/50. The
mixture was distilled under normal pressure in a
rectification towar having a theoritical plate number of
30 to give a distillate having an azeotropic point of
49.8C which was lower than the boiling point of each
solvent.
As a result of gas chromatography analysis, it
; was confirmed that the distillate consisted of 93.5 ~ of
1,1-dichloro-2,2,3,3,3-pentafluoropropane and 6.5 ~ of
pentafluoropropanol.
Using the obtained azeotropic mixture as a
solvent, the flux cleaning power, effects on plastics,
and stability were estimated according to the following
tests, respectively.
[Flux cleaning power]
A rogin-flux commercially available under the
trademark "MH-320V" from Kabushiki Kaisha Tamura
Seisakusho is applied to a printed-circuit board (10 cm x
cm), and it is pre-heated at 110C. Then, the
printed~circuit board is subjected to soldering (63Sn) at
250C for 5 seconds. Then, using 1 Q of a solvent shown
in Table 1, dip cleaning is conducted for 1 minute and
vapor cleaning is conducted for 1 minute.
The surface state of the printed-circuit board
is observed with the naked eye. Also, an ionic residue
2 ~ 3 7
g
remaining on the board is measured by using Omegameter~
500 commercially available from KENCO INDUSTRIES INC.
The results are shown in Table 1 as the results
of the flux cleaning power test.
; 5 [Effects on plascics]
: In 100 g of the solvent shown in Table 1 is
dipped a plastic test piece shown in Table 1 (5 mm x 50
mm x 2 mm), and it is allowed to stand in a thermostat
having a temperature of 50C for 5 minutes. Then, the
test piece is taken out from the solvent, and immediately
the weight and volume of the test piece are measured.
The change of the weight and volume of the plastic test
pieces are calculated, and the effects on plastics are
; estimated according to the following criteria:
. 15 ~ : A percentage of the increase of the weight or
volume is from zero and less to than 2 %
O : A percentage of the increase of the weight or
volume is not less than 2 ~ and less than 5 %
A percentage of the increase of the weight or
volume is not less than 5 %
X : The plastic test piece is dissolved in the
solvent.
The results are shown in Table 1 as the effects
on plastics.
- [Chemical stability]
A 100 mQ glass bottle with a sealing stopper is
charged with 100 g of the solvent shown in Table 1, 0.1 %
of the solvent of water [in Comparative Examples 1 or 4
as mentioned below, 0.01 % of the solvent (225ca or 225cb
alone) of water] and a metal, A~ or Zn, and the glass
bottle was sealed. The glass bottle was placed in a
thermostat having a temperature of 50C for 30 days.
In the meantime that the bottle was placed in
the thermostat and after 30 days, whether the metal is
corroded or not is estimated by observing the metal with
the naked eye.
The results are sho~n in Table 1 as the
-- 10
chemical stabilicy.
Com~arative Examples 1, 2 and 3
The flux cleaning power, effects on plastics
and chemical stability were examined in the same manner
as in Example 1 except that as a solvent, 225ca alone
(Comparative Example 1), 5FP alone (Comparative Example
2) or a mixture of 225ca and ethanol (225ca/ethanol = 97
% / 3 %) (Comparative Example 3) was used instead of the
azeotropic mixtuce of 225ca/5FP.
The results are shown in Table 1.
Example 2
A mixture of 1,3-dichloro-1,2,2,3,3-
15 pentafluoropropane (225cb, bp: 56.1C) and 5FP (bp: 81C)
in a weight ratio of 50/50 was distilled in the same
manner as in Example 1 to give a distillate having an
azeotropic point of 54.7C which was lower than the
boiling point of each solvent.
~s a result of gas chromatography analysis, it
was confirmed that the distillate consisted of 92.2 % of
1,3-dichloro-1,2,2,3,3-pentafluoropropane and 7.8 % of
5FP.
As to the obtained azeotropic mixture, the flux
cleaning power, effects on plastics and stability were
measured in the same manner as in Example 1.
The results are shown in Table 1.
A composition of a mixture of 55 % of 1,1-
dichloro-2,2,3,3,3-pentafluoropropane (bp: 51C) and 45 %
of 1,3-dichloro-1,2,2,3,3-pentafluoropropane ~bp:
56.1C), and 5FP in a weight ratio of the mixture to 5FP
being 50/50 was distilled in the same manner as in
Example 1 to give a distillate. The distillate showed a
stable boiling point within a narrow temperature range of
50 to 54.9C.
As a result of gas chromatorgraphy analysis, it
.
~13~3r7
was confirmed that the distillate consisted of 93.4 to
92.4 % of the mixture of 1,1-dichloro-2,2,3,3,3-
pentafluoropropane/1,3-dichloro-1,2,2,3,3-
pentafluoropropane (60 to 4 % /40 to 96 %) and 6.6 to 7.6
% of SFP.
As to the obtained azeotropic like mixtures,
the flux cleaning power, effects on plastics and
.,. stability were measured in the same manner as in Example
.,: 1,
~`. 10 The results are shown in Table 1.
.
Comparative Example 4
; The flux cleaning power, effects on plastics
and chemical stability were examined in the same manner
lS as in Example 1 except that as a solvent, 225cb alone was
used instead of the azeotropic mixture of 225ca/5FP.
The results are shown ln Table 1.
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