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Description  |
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BACKGROUND OF THE INVENTION
The present invention relates to a composition for cleaning a surface of a
substrate, more particularly relates to a composition containing as main
components a halogenated hydrocarbon solvent, a fluorine-containing
alcohol and an organic acid.
Stains such as paints, printing inks, abrasives, resin films of sintered
fluxes and other resinous materials formed on a surface of a substrate are
removed from the substrate, in general, by wiping the surface of the
substrate with a cloth which is soaked with solvent or by immersing the
substrate into an inorganic strong acid or alkali to dissolve or peel off
the stains. The both treatments, however, have the following defects. In
the physically wiping treatment much labor and time is required, and in
the immersing treatment the inorganic strong acid or alkali injures the
substrate and is dangerous to handle.
In the electronic industry, a resist film is removed from a substrate by
using a cleaning composition containing an aromatic sulfonic acid, a
halogenated hydrocarbon and, if necessary, a phenol. Although the
composition can peel off the film, the rate of peeling off is low, and
also when the composition is adapted to a substrate having a fine resist
pattern thereon the resist film cannot be completely peeled off at very
fine portions.
An object of the present invention is to provide a composition for cleaning
a surface of a substrate which has a resin film thereon or is stained with
a resinous material.
Another object of the present invention is to provide a composition for
completely removing a resist film having a fine resist pattern from a
surface of a substrate in a short time.
SUMMARY OF THE INVENTION
The present invention relates to a composition for cleaning a surface of a
substrate, which contains as main components (a) a halogenated hydrocarbon
solvent, (b) a fluorine-containing alcohol and (c) an organic acid.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1 to 3 show sketchy views of the substrates from which the resist
films are removed by using the compositions prepared in Examples 3 to 5,
respectively.
FIGS. 4 to 5 show sketchy views of the substrates from which the resist
films are removed by using the compositions prepared in Comparative
Examples 4 to 5, respectively.
DETAILED DESCRIPTION
As the halogenated hydrocarbon solvent (component (a)) in the invention, an
aliphatic or aromatic hydrocarbon substituted by at least one chlorine
atom, fluorine atom or bromine atom can be employed. The halogenated
aliphatic hydrocarbon preferably has 1 to 4 carbon atoms. Examples of the
halogenated hydrocarbon are, for instance, halogenated aliphatic
hydrocarbons such as methylene chloride, chloroform, 1,1-dichloroethane,
1,2-dichloroethane, 1,1,1-trichloroethane, trichloroethylene,
perchloroethylene, trichloromonofluoromethane, tetrachlorodifluoroethane,
trichlorotrifluoroethane, dibromotetrafluoroethane, 1,3-dichloropropane,
2,2-dichloropropane, 1,3-dichlorobutane and 1,4-dichlorobutane;
halogenated aromatic hydrocarbons such as o-dichlorobenzene,
m-dichlorobenzene, trichlorobenzene, chlorotoluene, benzotrifluoride and
o-chlorobenzotrifluoride. These compounds may be employed alone or in
admixture thereof.
The fluorine-containing alcohol (component (b)) in the present invention is
a saturated or unsaturated fluorine-containing alcohol which may have a
side chain and/or an other bond. Examples of the fluorine-containing
alcohol are, for instance, compounds represented by the formulas:
##STR1##
wherein each of a, c, e, g and i is an interger of 1 to 5 and each of b,
d, f, h and j to t is an integer of 1 to 3. These compounds may be
employed alone or in admixture thereof.
The organic acid (component (C)) employed in the present invention is an
aliphatic or aromatic sulfonic acid, an aliphatic or aromatic ester, an
aliphatic or aromatic carboxylic acid or the like. Examples of the organic
acid are, for instance, aliphatic sulfonic acids such as decanesufonic
acid, dodecanesulfonic acid and di-2-ethylhexylsulfosuccinic acid;
aromatic sulfonic acids such as benzenesulfonic acid,
heptylbenzenesulfonic acid, octylbenzenesulfonic acid,
decylbenzenesulfonic acid, dodecylbenzenesulfonic acid, cumenesulfonic
acid, toluenesulfonic acid, naphthalenesulfonic acid, xylenesulfonic acid,
methylbenzenesulfonic acid, naphtholsulfonic acid, phenolsulfonic acid,
cresolsulfonic acid, chloronaphtholsulfonic acid, chlorophenolsulfonc
acid, chlorobenzenesulfonic acid, phenol-2,4-disulfonic acid,
p-aminobenzenesulfonic acid and biphenylsulfonic acid; aliphatic
sulfonates such as a dodecylsulfonate and a dodecanesulfonate; aromatic
sulfonates such as a toluenesulfonate and a dodecylbenzenesulfonate;
aliphatic carboxylic acids such as acetic acid, propionic acid, lauric
acid, oleic acid, linoleic acid, adipic acid, maleic acid, hydroxyacetic
acid, acetoacetic acid, aminoacetic acid, hydroxyphenylacetic acid,
monochloroacetic acid, trichloroacetic acid, H(CF.sub.2 CF.sub.2)COOH,
H(CF.sub.2 CF.sub.2).sub.3 COOH, H(CF.sub.2 CF.sub.2).sub.4 COOH,
F(CF.sub.2 CF.sub.2).sub.3 COOH and CF.sub.3 CF.sub.2 OCF.sub.2
CF(CF.sub.3)COOH; aromatic carboxylic acids such as benzoic acid, phtahlic
acid, hydroxybenzoic acid, sulfobenzoic acid, 2 -hydroxy-5-sulfobenzoic
acid, naphthalenecarboxylic acid and chlorophthalic acid. These compounds
may be employed alone or in admixture thereof.
The components (a), (b) and (c) can be admixed in various range, in general
in a range within which the components (a), (b) and (c) are compatible
with each other. When a weight ratio of the components (a)/(b)/(c) is
within a range of 20 to 70/5 to 40/5 to 80, the effect of removing stains
by peeling off or dissolution particularly increases regardless of the
kinds of applied or deposited resinous materials, and thus an excellent
surface cleaning effect can be obtained. When the weight ratio of the
components (a)/(b)/(c) is outside 20 to 70/5 to 40/5 to 80, the stains to
be removed might be limited in relation to kinds of resinous materials of
the stains and their depositing conditions. When the components (a) and
(b) or (a), (b) and (c) form an azeotropic mixture, the composition of the
present invention can be desirably empolyed because such composition can
be easily recovered and used again.
The stained surface off the substrate to be treated can be easily cleaned
by immersing the substrate into the composition of the invention or by
wiping the surface of the substrate after spraying, applying or spreading
the composition to the substrates. Preferably the substrate is treated by
immersing or ultrasonic cleaning. The treatments can be carried out at a
temperature from room temperature to an elevated temperature, in general
up to a boiling point of the composition.
With the composition of the present invention, if necessary, other
solvents, surfactants, stabilizers and the like may be admixed. Examples
of the solvent are, for instance, benzene, toluene, xylene,
trimethylbenzene, ethylbenzene, diethylbenzene, triethylbenzene,
octylbenzene, decylbenzene, dodecylbenzene, tridecylbenzene, cumene,
tridecyltoluene, phenol, cresol, resorcinol, pentane, hexane, acetone,
methyl ethyl ketone, methyl isobutyl ketone, etoxyethanol, ethylene glycol
monoalkyl ether, tetrahydrofuran, nitromethane, formamide,
dimethylformamide, dimethylacetamide, N-methylpyrrolidone, acetonitrile,
propionitrile, malonitrile, succinonitrile, glutaronitrile, adiponitrile
tetramethylenesulfone, and an admixture thereof.
As the surfactant, a cationic surfactant, an anionic surfactant and the
like can be optionally employed. Examples of the surfactant are, for
instance, alkylbenzenesulfonic acid salts, dialkylsulfosuccinic acid
salts, alkylsulfuric acid salts, alkyltrimethyl quaternary ammonium salts,
organoic acid salts of di or monoalkylamine, alkylbentaines,
alkylimidazolines, polyoxyethylene alkyl ethers, polyoxyethylenesorbitan
esters, polyoxyethylenealiphatic acid esters and the like.
The solvent, surfactant and stabilizer may be usually admixed,
respectively, in an amount of not more than 40 parts by weight on the
basis of 100 parts by weight of the mixture of the components (a), (b) and
(c).
The composition of the present invention can rapidly and completely clean
the surface of substrate by peeling off or dissolving stains which are
mainly formed of resin films or resinous materials. The cleaning effect of
the composition can be particularly obtained in case of electronic parts
having a fine resist pattern. Furthermore the composition of the invention
can peel off or dissolve stains such as solid, oily and tarry carbon which
can hardly be removed by using usual cleaning agents.
The present invention is more specifically described and explained by means
of the following Examples. These Examples are intended to illustrate the
present invention and are not to be constructed to limit the scope of the
invention.
EXAMPLE 1
1,1,2-Trichloro-1,2,2-trifluoroethan (flon-113), methylene chloride,
H(CF.sub.2 CF.sub.2)CH.sub.2 OH and dodecylbenzenesulfonic acid (DBS) were
admixed in a weight ratio of 35:35:10:20 to obtain the composition of the
present invention.
The removing effect of the composition was examined by immersing an iron
plate (2 mm.times.5 mm) coated with an alkyl resin paint available from
Shinto Paints Co., Ltd. under the trade designation "Alkys #200" into 100
ml of the composition at room temperature and measuring a time required in
completely peeling off (hereinafter referred to as "peeling off time").
The result is shown in Table 1.
EXAMPLE 2 AND COMPARATIVE EXAMPLES 1 TO 3
After preparing the compositions shown in Table 1, with respect to each
composition a peeling off time was measured in the same manner as in
Example 1. The results are shown in Table 1.
TABLE 1
__________________________________________________________________________
Components of composition (weight ratio)
Peeling off time
__________________________________________________________________________
Example 1
Flon-113/methylene chloride/H(CF.sub.2 CF.sub.2)CH.sub.2 OH/
50 seconds
DBS (35/35/10/20)
Example 2
Methylene chloride/H(CF.sub.2 CF.sub.2)CH.sub.2 OH/DBS
65 seconds
(75/5/20)
Comparative
Methylene chloride/DBS 115 seconds
Example 1
(80/20)
Comparative
Methylene chloride/H(CF.sub.2 CF.sub.2)CH.sub.2 OH
120 seconds
Example 2
(94/6)
Comparative
Perchloroethylene/trichloroethylene/
130 seconds
Example 3
H(CF.sub.2 CF.sub.2)CH.sub.2 OH (43.5/43.5/13)
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EXAMPLE 3
A photosensitive solution (for negative resist) containing polyisobutylene
was applied to a silicate substrate and dried to form a resist film, and
then the substrate was baked for 40 minites at 220.degree. C.
The baked substrate was immersed into the composition of the invention
which was prepared by admixing perchloroethylene, H(CF.sub.2
CF.sub.2)CH.sub.2 OH and DBS in a weight ratio of 60:10:30 for 5 minutes
at 100.degree. C., washed with isopropanol, and then washed with
trichlorotrifluoroethane.
FIG. 1 shows the sketchy view of the surface of the washed substrate
observed by means of a microscope (1000 magnifications).
EXAMPLES 4 TO 5 AND COMPARATIVE EXAMPLES 4 TO 5
After preparing the compositions shown in Table 2, the procedures in
Example 3 were repeated to peel off the resist film. FIGS. 2 to 5 show the
sketchy views of the surfaces of the substrates after being peeled off by
using the composition prepared in Examples 4 to 5 and Comparative Examples
4 to 5, respectively, which were observed by means of a microscope (1000
magnifications).
TABLE 2
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Components of composition (weight ratio)
______________________________________
Example 4 o-Dichlorobenzene/perchloroethylene/
H(CF.sub.2 CF.sub.2)CH.sub.2 OH/DBS/phenol
(27/32/10/18/13)
Example 5 o-Dichlorobenzene/perchloroethylene/
H(CF.sub.2 CF.sub.2).sub.2 CH.sub.2 OH/DBS
(32/37/10/21)
Comparative Perchloroethylene/H(CF.sub.2 CF.sub.2)CH.sub.2 OH
Example 4 (85/15)
Comparative o-Dichlorobenzene/perchloroethylene/
Example 5 DBS/phenol
(30/35/20/15)
______________________________________
As is clear from FIGS. 1 to 3, the resist films were completely peeled off
by using the compositions of the present invention, but as is clear form
FIGS. 4 to 5, the resist films were not satisfactorily peeled off at very
fine portions.
EXAMPLE 6
A resist pattern was formed on a flexible board by using a dry film resist
of a copolymer mainly containing an acrylate to prepare a flexible printed
circuit board. A peeling off time of the resist was measured by immersing
the board into the composition prepared in Example 1 at room temperature
(25.degree. C.). The result was shown in Table 3.
EXAMPLE 7 AND COMPARATIVE EXAMPLES 6 TO 8
After preparing the compositions shown in Table 3, with respect to each
composition a peeling off time was measured by repeating the procedure in
Example 6. The results are shown in Table 3.
TABLE 3
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Components of composition (weight ratio)
Peeling off time
__________________________________________________________________________
Example 6
Flon-113/methylene chloride/H(CF.sub.2 CF.sub.2)CH.sub.2 OH/
130 seconds
DBS (35/35/10/20)
Example 7
Methylene chloride/H(CF.sub.2 CF.sub.2).sub.2 CH.sub.2 OH/DBS
150 seconds
(75/5/20)
Comparative
Methylene chloride/DBS 380 seconds
Example 6
(80/20)
Comparative
Methylene chloride/H(CF.sub.2 CF.sub.2).sub.2 CH.sub.2 OH
390 seconds
Example 7
(94/6)
Comparative
Perchloroethylene/trichloroethylene/
405 seconds
Example 8
H(CF.sub.2 CF.sub.2)CH.sub.2 OH (43.5/43.5/13)
__________________________________________________________________________
As is clear from Table 3, the composition of the present invention can
rapidly peel off the resist from the printed circuit board.
As a result of observing the surfaces of the boards by means of a
microscope, when the compositions of the present invention were used the
resists were completely removed even at very fine portions, but when the
compositions prepared in Comparative Examples 6 to 8 were used there still
remained non-peeled portions.
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