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Claims  |
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We claim:
1. A liquid, phosphate-free, single phase degreasing composition for
aluminum surfaces, comprising:
(A) alkali metal or ammonium carbonate;
(B) alkali metal hydrogen or ammonium hydrogen carbonate, present jointly
with component (A) in a builder effective amount;
(C) complexing agent present in a complexing effective amount;
(D) anionic or nonionic surfactant, present in a surfactant effective
amount;
(F) water.
2. The composition of claim 1 wherein (A) comprises a compound of the
formula
MM'CO.sub.3 (I)
wherein M and M' individually are lithium, sodium, potassium or NHR.sup.1
R.sup.2 R.sup.3 wherein R.sup.1, R.sup.2 and R.sup.3 individually are H,
C.sub.1-6 alkyl, or hydroxy-C.sub.1-6 -alkylene.
3. The composition of claim 1 wherein (B) comprises a compound of the
formula
MHCO.sub.3 (II)
wherein M is lithium, sodium, potassium, or NHR.sup.1 R.sup.2 R.sup.3
wherein R.sup.1, R.sup.2, and R.sup.3 individually are H, C.sub.1-6 alkyl,
or hydroxy --C.sub.1-6 -alkylene.
4. The composition of claim 2 wherein (B) comprises a compound of the
formula
MHCO.sub.3 (II)
wherein M is lithium, sodium, potassium, or NHR.sup.1 R.sup.2 R.sup.3
wherein R.sup.1, R.sup.2, and R.sup.3 individually are H, C.sub.1-6 alkyl,
or hydroxy --C.sub.1-6 -alkylene.
5. The composition of claim 1 wherein (A) comprises at least one of sodium
carbonate, potassium carbonate, or triethylammonium carbonate and (B) is
at least one of sodium hydrogen carbonate, potassium hydrogen carbonate,
or triethylammonium carbonate.
6. The composition of claim 5 wherein (A) and (B) are present in a ratio of
about 0.1-3:1.
7. The composition of claim 5 wherein (A) and (B) are present in a ratio of
about 0.5:1.0.
8. The composition of claim 1 wherein (C) comprises at least an acrylic
polymer.
9. The composition of claim 1 wherein (C) comprises at least one polymer
of: acrylic acid; methacrylic acid; or copolymers of acrylic acid and/or
methacrylic acid with another monomer containing olefinic double bonds; or
a water soluble salt thereof.
10. The composition of claim 4 wherein (C) comprises at least one polymer
of: acrylic acid; methacrylic acid; or copolymers of acrylic acid and/or
methacrylic acid with another monomer containing olefinic double bonds; or
a water soluble salt thereof.
11. The composition of claim 1 wherein (C) comprises at least one polymer
of: acrylic acid; methacrylic acid; sodium acrylate; sodium methacrylate;
triethanolammonium acrylate; triethanolammonium methacrylate; or
copolymers of acrylic and/or methacrylic acid and maleic acid or their
sodium, potassium, or triethanolammonium salts.
12. The composition of claim 5 wherein (C) comprises at least one polymer
of: acrylic acid; methacrylic acid; sodium acrylate; sodium methacrylate;
triethanolammonium acrylate; triethanolammonium methacrylate; or
copolymers of acrylic and/or methacrylic acid and maleic acid or their
sodium, potassium, or triethanolammonium salts.
13. The composition of claim 1 wherein (C) comprises at least one of:
citric acid; gluconic acid; acetaldehyde glyoxylic acid polyacetal;
ethylenediamine tetraacetic acid; nitrilotriacetate; or the alkali metal
or ammonium salts thereof.
14. The composition of claim 9 wherein (C) further comprises at least one
of: citric acid; gluconic acid; acetaldehyde glyoxylic acid polyacetal;
ethylenediamine tetraacetic acid; nitrilotriacetate; or the alkali metal
or ammonium salts thereof.
15. The composition of claim 10 wherein (C) further comprises at least one
of: citric acid; gluconic acid; acetaldehyde glyoxylic acid polyacetal;
ethylenediamine tetraacetic acid; nitrilotriacetate; or the alkali metal
or ammonium salts thereof.
16. The composition of claim 11 wherein (C) further comprises at least one
of: citric acid; gluconic acid; acetaldehyde glyoxylic acid polyacetal;
ethylenediamine tetraacetic acid; nitrilotriacetate; or the alkali metal
or ammonium salts thereof.
17. The composition of claim 12 wherein (C) further comprises at least one
of: citric acid; gluconic acid; acetaldehyde glyoxylic acid polyacetal;
ethylenediamine tetraacetic acid; nitrilotriacetate; or the alkali metal
or ammonium salts thereof.
18. The composition of claim 1 wherein (D) comprises (1) at least one of:
adducts of 1 to 20 mols of ethylene oxide and/or propylene oxide with:
fatty alcohols; C.sub.6-22 alkylphenols; fatty amines; fatty
alcohol-derived ether amines; epoxidized unsaturated C.sub.6-22 carboxylic
acids; epoxidized C.sub.6-22 carboxylic acids ring-opened with monohydric
alcohols; saturated or unsaturated C.sub.6-22 carboxylic acids; and/or (2)
at least one of: C.sub.6-22 alkyl benzenesulfonic acids, C.sub.6-22 alkane
sulfonic acids, C.sub.6-22 alkyl sulfates, C.sub.6-22 alkyl ether
sulfates, or the alkali metal or ammonium salts thereof.
19. The composition of claim 1 wherein (D) was an HLB value of 10 to 20.
20. The composition of claim 1 wherein (D) has an HLB value of 13 to 17.
21. The composition of claim 18 wherein (D) has an HLB value of 13 to 17.
22. The composition of claim 1 wherein (D) comprises: one or more nonionic
fatty alcohol ethoxylates.
23. The composition of claim 1 wherein (D) comprises the adduct of 12 E.O.
with coconut amine or the adduct of 10 E.O. with a C.sub.12-24 fatty acid
epoxide ring-opened with ethylene glycol or a mixture thereof in about a
1:1 ratio.
24. The composition of claim 10 wherein (D) comprises (1) at least one of:
adducts of 1 to 20 mols of ethylene oxide and/or propylene oxide with:
fatty alcohols; C.sub.6-22 alkylphenols; fatty amines; fatty
alcohol-derived ether amines; epoxidized unsaturated C.sub.6-22 carboxylic
acids; epoxidized C.sub.6-22 carboxylic acids ring-opened with monohydric
alcohols; saturated or unsaturated C.sub.6-22 carboxylic acids; and/or (2)
at least one of: C.sub.6-22 alkyl benzenesulfonic acids, C.sub.6-22 alkane
sulfonic acids, C.sub.6-22 alkyl sulfates, .C.sub.6-22 alkyl ether
sulfates, or the alkali metal or ammonium salts thereof.
25. The composition of claim 12 wherein (D) comprises (1) at least one of:
adducts of 1 to 20 mols of ethylene oxide and/or propylene oxide with:
fatty alcohols; C.sub.6-22 alkylphenols; fatty amines; fatty
alcohol-derived ether amines; epoxidized unsaturated C.sub.6-22 carboxylic
acids; epoxidized C.sub.6-22 carboxylic acids ring-opened with monohydric
alcohols; saturated or unsaturated C.sub.6-22 carboxylic acids; and/or (2)
at least one of: C.sub.6-22 alkyl benzenesulfonic acids, C.sub.6-22 alkane
sulfonic acids, C.sub.6-22 alkyl sulfates, C.sub.6-22 alkyl ether
sulfates, or the alkali metal or ammonium salts thereof.
26. The composition of claim 13 wherein (D) comprises: one or more nonionic
fatty alcohol ethoxylates.
27. The composition of claim 18 wherein (D) comprises the adduct of 12 E.O.
with coconut amine or the adduct of 10 E.O. with a C.sub.12-14 fatty acid
epoxide ring-opened with ethylene glycol or a mixture thereof in about a
1:1 ratio.
28. The composition of claim 1 wherein:
(A) and (B) are together present in about 1 to 20% by weight;
(C) is present in about 1-20% by weight;
(D) is present in about 0.1-10% by weight;
(D) may be present in 0 to about 18% by weight; and
(F) water is present q.s. to 100%;
all based upon the total weight of the compostiion.
29. The composition of claim 24 wherein:
(A) and (B) are together present in about 1 to 20% weight;
(C) is present in about 1-10% by weight;
(D) is present in about 0.1-10% by weight;
(E) may be present in 0 to about 18% by weight; and
(F) water is present q.s. to 100%;
all based upon the total weight of the composition.
30. The composition of claim 1 wherein
(A) and (B) are together present in about 5-13% by weight,
(C) is present in 5-8% by weight;
(D) is present in 1-3% by weight;
(E) is present in 1-10% by weight; and
(F) is present q.s. to 100%;
all based upon the total weight of the composition.
31. The composition of claim 26 wherein
(A) and (B) are together present in about 5-13% by weight,
(C) is present in 5-8% by weight;
(D) is present in 1-3% by weight;
(E) is present in 1-10% by weight; and
(F) is present q.s. to 100%;
all based upon the total weight of the composition.
32. The composition of claim 1 having a pH of about 8.5-12.5.
33. A method for degreasing aluminum surfaces comprising applying the
composition of claim 1 in a diluted form in a degreasing effective
concentration, for a degreasing effective time, and at a degreasing
effective temperature, and then removing said composition from said
surface. |
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Claims |
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Description |
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to liquid, phosphate-free single phase degreasing
compositions which may be used for cleaning aluminum surfaces.
2. Statement of Related Art
The application of inorganic or organic coatings to metal surfaces, which
has recently acquired increasing significance in efforts to improve
corrosion prevention or to obtain decorative effects, requires careful
cleaning of the metal surfaces beforehand in preparation for the
application of the coatings. Metal surfaces are normally treated with
highly alkaline cleaning solutions with more or less complete removal of
soil, particularly grease.
Cleaning with strongly alkaline cleaning solutions has always been
problematical in the case of aluminum surfaces or metal surfaces
containing aluminum in addition to other metals, because aluminum is known
to be extremely sensitive to strongly alkaline aqueous solutions. At
extremely high pH values, undesirably large quantities of aluminum are
dissolved from the metal surfaces in the form of alkaline aluminate
complex salts. Accordingly, where aluminum surfaces are cleaned with
alkaline cleaning preparations, it has always been necessary to strike a
compromise between the degreasing performance of the cleaning composition
on the one hand and the undesirable erosion of metal from the aluminum
surfaces on the other hand. Aqueous systems in which builders suitable as
buffers are used are normally employed for cleaning aluminum surfaces. In
the present context and in the context of the following description and in
the claims, "builders" are understood to be compounds which are active as
buffers and which enhance the cleaning effect of surfactants. Builders
which have been successfully used in the prior art for the cleaning of
aluminum surfaces include, in particular, borate salts such as borax,
which are used in combination with alkali metal orthophosphates or alkali
metal salts of condensed phosphates and which developed an adequate
degreasing effect without excessive quantities of metal being eroded from
the aluminum surface.
The principal disadvantage of known formulations of this type is that the
corresponding borate salts are poorly soluble in water. The effect of this
is that problems are repeatedly encountered in the preparation of the
known solutions because multiphase systems are formed during dosing of the
(generally powder) compositions in process water. In addition, the
condensed phosphates normally used as sequestering (complexing) agents are
gradually hydrolyzed in aqueous solution, losing their complexing
properties in the process. In addition, the phosphates formed in the known
solution and in the wastewater are also ecologically undesirable and have
to be gradually replaced by other compounds to be able to prevent the
eutrophication of surface waters.
The cleaning preparations previously proposed in the prior art are
unsuitable for solving the problems involved in the cleaning of aluminum
surfaces for a number of reasons. For example, U.S. Pat. No. 4,521,332
describes aqueous compositions for the cleaning of metal surfaces which
are strongly alkaline and which contain large quantities of sodium
hydroxide as well as an alkali metal carbonate dispersed in polyacrylic
acid. Cleaning dispersions such as these are unsuitable for the degreasing
of aluminum surfaces simple because of their high alkalinity.
U.S. Pat. No. 4,528,039 describes compositions intended for the degreasing
of aluminum surfaces which, in addition to sodium carbonate, contain
sodium silicate as a builder. Surface active agents and other additives
known from the prior art are also present in the compositions. However,
compositions such as these cannot be used in dissolved form for the
degreasing of aluminum surfaces because, as powders, they have to be
introduced into the aqueous phase in a certain quantity before
application. Complete dissolution or rather homogeneous dispersion of the
compositions in the aqueous phase is not guaranteed, at least on an
industrial scale. In addition, compositions of the type in question are
attended by the disadvantage that automatic dosing of powders is not
readily possible. Because of this, liquid formulations are preferred for
industrial application.
According to H. -G. Germscheid "Untersuchungsmethoden bei der Entfettung"
in "Gavanotechnik" 67, 215 (1976), surfactants play an important part in
the degreasing and cleaning of metal surfaces insofar as they displace the
film of grease adhering to the metal surfaces and thus enable the metal
surfaces to be more or less completely degreased. Degreasing in the
adsence of surfactants is not regarded as possible in this publication. In
particular, it is shown by the results of experiments that the effect of
the surfactants can be enhanced by the effect of other constituents,
particularly builders, in cleaning preparations. The test results
described in the above article also provide quantitative proof of the
synergistic effect of builders and surfactants.
BRIEF DESCRIPTION OF THE INVENTION
Other than in the operating examples, or where otherwise indicated, all
numbers expressing quantities of ingredients or reaction conditions used
herein are to be understood as modified in all instances by the term
"about".
The present invention provides new degreasing compositions for aluminum
surfaces which can be made up in liquid form and which are at least
comparable with, if not better than, known degreasing compositions, that
is they enable an aluminum surface to be completely degreased in a single
operation. In this connection, it had to be borne in mind that, to
increase their stability in storage, liquid degreasing compositions of the
type in question should not be present in two-phase form, for example in
the form of suspensions or dispersions. This means that all the components
involved have to be completely soluble. In addition, degreasing
compositions of this type have to be substantially free from phosphate,
i.e. free both from (a) condensed phosphates as active components, which
in state-of-the-art compositions are hydrolyzed in aqueous phase and thus
lose their activity, particularly their sequestering activity, and (b)
from orthophosphate, to avoid adverse ecological effects, primarily the
eutrophication of surface waters, from the outset. In addition, the
inventive degreasing compositions lend themselves to automatic dosing and,
subsequently, to ready dispersion in the working solution, which is best
guaranteed by a liquid composition.
The present invention therefore affords liquid, phosphatefree single phase
degreasing compositions for aluminum surfaces containing one or more
builders, sequestrants and surfactants in aqueous alkaline solution, which
also comprise: (A) alkali metal carbonate and/or ammonium carbonate; (B)
alkali metal hydrogen carbonate and/or ammonium hydrogen carbonate; (C)
one or more complexing agents which are (1) acrylic polymers, (2)
complexing agents other than acrylic polymers, or (3) a mixture thereof;
(D) one or more anionic or nonionic surfactants; (E) optionally one or
more active substances and/or auxiliaries of the type normally used in
degreasing compositions other than the foregoing; and (F) water.
Both here and in the following description and in the claims, "single phase
degreasing compositions" for aluminum surfaces are understood to be
degreasing compositions which are present in the form of solutions in
which all the components are clearly, i.e. isotropically, dissolved,
rather than in the form of suspensions or dispersions. Single phase
degreasing compositions such as these have a major advantage over
compositions known from the prior art in that they show much greater
stability in storage. This is because no sedimentation of essential
components or any phase separation is observed during storage,
particularly under extreme conditions, so that a substantially uniform
concentration of all the active substances in the concentrates can be
guaranteed, even over relatively long periods. This make the inventive
concentrates easier to handle by the user in the preparation of the
working solutions and leads to rapid dispersion of the active ingredients
in the working solutions, even on an industrial scale.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a graph comparing the quantities of residual grease remaining
after cleaning processes according to the prior art (Comparison Example
1).
FIG. 2 is a graph comparing the quantities of residual grease as a function
of immersion time (Comparison Example 2).
FIG. 3 is a graph comparing the degreasing results of Examples 1 to 4
according to this invention with Comparison Example 3.
FIG. 4 is a graph comparing the degreasing results of Examples 5 to 8
according to this invention with Comparison Example 3.
DETAILED DESCRIPTION OF THE INVENTION
The inventive compositions contain ingredients (A) and (B) as essential
builders, i.e. buffers. Suitable representatives of the groups of
compounds included in these categories are carbonates and hydrogen
carbonates corresponding to general formulae (I) and (II) below
MM'CO.sub.3 (I)
MHCO.sub.3 (II)
in which M and M' may be the same or different and are lithium, sodium,
potassium or ammonium of the formula NHR.sup.1 R.sup.2 R.sup.3, where
R.sup.1, R.sup.2, and R.sup.2 may be the same or different and are
hydrogen, C.sub.1-6 alkyl or hydroxy-C.sub.1-6 -alkylene.
Suitable carbonates (A) include: lithium carbonate; sodium carbonate;
potassium carbonate; ammonium carbonate (R.sup.1 =R.sup.2 =R.sup.3 =H);
mono-, di or tri-alkyl ammonium carbonates in which the alkyl radicals are
methyl, ethyl, propyl, butyl, pentyl or hexyl; and mono-, di-, or
tri-alkanolammonium carbonates, in which the alkanol radicals are
methanol, ethanol, propanol, butanol, pentanol or hexanol.
Suitable hydrogen carbonates (B) include: lithium hydrogen carbonate;
sodium hydrogen carbonate; potassium hydrogen carbonate; ammonium hydrogen
carbonate (R.sup.1 =R.sup.2 =R.sup.3 =H); mono-, di-, or tri-alkyl
ammonium hydrogen carbonates in which the alkyl radicals are methyl,
ethyl, propyl, butyl, pentyl, or hexyl; and mono-, di-, and tri-
alkanolammonium carbonates, in which the alkanol radicals are methanol,
ethanol, propanol, butanol, pentanol or hexanol. Both in (A) the ammonium
carbonates and (B) the ammonium hydrogen carbonates, any alkyl radicals
and/or alkanol radicals present may be linear or branched, linear radicals
being preferred.
Within the entire group of compounds (A) and (B) mentioned, sodium
carbonate and sodium hydrogen carbonate, potassium carbonate and potassium
hydrogen carbonate and triethanolammonium carbonate and triethanolammonium
hydrogen carbonate are preferred. It is possible in each inventive
composition to use one or more of (A) and one or more of (B).
The two classes of compounds comprising ingredients (A) and (B) are known
to have a high buffer capacity and, in this property, may replace the
borate (borax) used as builder in state-of-the-art compositions. In this
regard, ingredients (A) and (B) afford the advantage that they show
extremely good solubility in water and hence contribute to rapid,
effective and uniform dispersion in the concentrates. In addition, they
establish the alkaline pH value required for cleaning compositions of this
type without the addition of alkali metal hydroxides being necessary to
establish an alkaline pH. Such addition gave rise to the disadvantage
known in the prior art that, in view of the large excess of hydroxyl ions,
alkali metal hydroxoaluminates were formed on the aluminum surfaces and
part of the aluminum surfaces was eroded in this complex form during the
cleaning process. Where alkali metal and/or ammonium carbonate and alkali
metal and/or ammonium hydrogen carbonate are used in combination with one
another, there is no sign of increased erosion of the aluminum surfaces,
notwithstanding that an excellent degreasing effect on the aluminum
surfaces is obtained at moderately alkaline pH.
According to the invention, the degreasing compositions preferably contain
sodium and/or potassium and/or triethanolammonium carbonate and sodium
and/or potassium and/or triethanolammonium hydrogen carbonate. Ingredients
(A) and (B) should be present minimally in a combined builder/buffer
effective amount, preferably in a quantitative ratio of 0.1-3:1, a
quantitative ratio of 0.5:1 being preferred. In the preparation of the
single phase degreasing compositions, the compounds are normally used in
the form of their hydrates which, even after brief contact with water,
dissolve completely in the aqueous phase without any need for prolonged
stirring.
According to the invention, the liquid single-phase degreasing compositions
for aluminum surfaces contain (C) one or more complexing agents which are
acrylic polymers or non-acrylic polymer complexing agents in addition to
the carbonate salts mentioned. In the inventive compositions "acrylic
polymers" are understood to be polymers of acrylic acid and/or methacrylic
acid or copolymers of acrylic acid and/or methacrylic acid with another
monomer containing olefinic double bonds, as well as the watersoluble
salts of such polymers or copolymers. Particularly advantageous water
soluble salts are the alkali metal and/or ammonium salts of the polymers
or copolymers mentioned, in which the salt forming cation is one from the
group defined above for M in general formula (I). Among these water
soluble salts, the sodium, potassium and/or triethanolammonium salts may
be used with particular advantage by virtue of their ready availability.
"Other (non-acrylic polymer) complexing agents" are understood to be
complexing agents known from the prior art, as exemplified subsequently.
Compounds which are polymers of acrylic acid, methacrylic acid, sodium
acrylate, sodium methacrylate, copolymers of acrylic acid and/or
methacrylic acid and maleic acid and the sodium salt of acrylic acid-
and/or methacrylic acid-maleic acid copolymers may be used with particular
advantage as acrylic polymers in the degreasing compositions according to
the invention. The polymers mentioned are known to have sequestering
properties, i.e. they are capable of acting as complexing agents for metal
ions. Within the group mentioned, those polymers which have an average
molecular weight of 30,000 to 150,000 or the sodium and/or
triethanolammonium salts thereof are active with particular advantage in
this regard. These compounds have the advantage over the phosphates and
polyphosphates used in the prior art in that not only are they stable to
hydrolysis in aqueous solution, but they also do not lead to the
eutrophication of surface waters and hence cause no ecological damage
while achieving a comparable sequestering effect.
Instead of or together with the acrylic polymers mentioned, one or more
other complexing agents may optionally be used in the inventive degreasing
composition. Although the decreasing compositions according to the
invention containing only acrylic polymers as ingredient (C), (i.e. with
no additions of other identified complexing agents), may be diluted to
working solutions with tapwater of standard hardness without any deposits
being precipitated, it may nevertheless be desirable under certain
conditions, (for example where it is intended to use particularly hard
water for dilution), to add other such complexing agents to the inventive
degreasing compositions, or to replace the acrylics entirely. Useful other
complexing agents include: citric acid, gluconic acid, acetaldehyde
glyoxylic acid polyacetal, ethylenediamine tetraacetic acid (EDTA),
nitrilotriacetate (MTA), and the alkali metal and/or ammonium salts
thereof. The sodium, potassium and/or triethanolammonium salts are
preferably used as complexing agents together with or instead of the
acrylic polymers by virtue of their excellent solubility in water.
Accordingly, sodium citrate, sodium gluconate or the sodium salt of
acetaldehyde glyoxylic acid polyacetal and/or the corresponding potassium
or triethanolammonium salts are suitable for complementing or replacing
the acrylic polymer(s) in the inventive compositions. The compounds
mentioned themselves contribute to a sequestering, i.e. complexing, effect
in conjunction with the acrylic polymers. Although, in principle, one or
more acrylic polymers and other complexing agents from the groups
mentioned may be used in admixture in any ratios by weight, it is
preferred according to the invention to use the acrylic polymers and the
other complexing agents (when the other complexing agents are present), in
a weight ratio of 1: up to 1, preferably 1: up to 0.25.
As ingredient (D) the inventive compositions contain one or more anionic or
nonionic surfactants as further essential components. The surfactants
present are preferably adducts of ethylene oxide and/or propylene oxide
with fatty alcohols, C.sub.6-22 -alkylphenols, fatty amines,
fatty-alkyl-derivatized ether amines, unsaturated, epoxidized and,
optionally, ring-opened (with monohydric alcohols) and saturated fatty
acids containing 6 to 22 carbon atoms in the linear or branched alkyl
radicals, and from the group of alkyl benzenesulfonic acids, alkane
sulfonic acids, alkyl sulfates and alkyl ether sulfates and water-soluble
salts thereof, preferably alkali metal and/or ammonium salts, containing 6
to 22 carbon atoms in the alkyl radical. In adducts such as these, an
average of 1 to 20 mol of the particular alkylene oxide is added onto 1
mol of the particular fatty derivative, i.e. fatty alcohol, alkylphenol,
fatty amine, ether amine or fatty acid or fatty acid derivatives.
Accordingly, suitable surfactants include adducts of ethylene oxide and/or
propylene oxide with fatty alcohols from the group comprising octanol,
nonanol, decanol, undecanol, dodecanol, tridecanol, tetradecanol,
pentadecanol, hexadecanol, heptadecanol, octadecanol, nonadecanol,
eicosanol, uneicosanol, or docosanol, preference normally being attributed
to the linear fatty alcohols and also to mixtures of such alcohols which
are inexpensively obtainable on an industrial scale from natural fats or
oils and mixtures thereof. For example, adducts of ethylene oxide and/or
propylene oxide with tallow fatty alcohols, coconut fatty alcohols and/or
comparable fatty alcohol mixtures of native origin may be used with
particular advantage.
Adducts of alkylphenols containing 6 to 22 carbon atoms in the alkyl
radical may also be used as the surfactant component in accordance with
the invention. Accordingly, ethylene oxide and/or propylene oxide may be
added to the above-mentioned quantitative ratios onto alkylphenols
containing the following groups as the alkyl chain: hexyl, heptyl, octyl,
nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl,
hexadecyl, heptadecyl, octdecyl, nonadecyl, eicosyl, uneicosyl or docosyl.
Both the linear and the branched alkyl radicals are suitable, although the
linear alkylphenols are particularly preferred for forming the adducts
because they are more readily obtainable from natural fats and oils.
Mixtures of such adducts of ethylene oxide and/or propylene oxide with
alkylphenols may also be used as surfactants.
Adducts of ethylene oxide and/or propylene oxide with fatty amines from the
group comprising octylamine, nonylamine, decylamine, undecylamine,
dodecylamine, tridecylamine, tetradecylamine, pentadecylamine,
hexadecylamine, heptadecylamine, octadecylamine, nonadecylamine,
eicosylamine, uneicosylamine and docosylamine or even mixtures of such
fatty amines may also be used in the singlephase degreasing compositions
according to the invention. As with the fatty alcohols, the linear fatty
amines from the group mentioned and mixtures of such fatty amines are
particularly suitable for the formation of suitable adducts because they
may be inexpensively obtained in large quantities from natural fats and
oils.
Other surfactants components suitable for use in accordance with the
invention are adducts of ethylene oxide and/or propylene oxide with
fatty-alkyl-derived ether amines. These ether amines are tertiary amines
containing ether groups with at least one alkyl polyglycol ether group at
the aminonitrogen atom. Suitable fatty alkyl radicals are the C.sub.6-22
alkyl radicals which were mentioned above in connection with the
alkylphenols. The number of E.O. or P.O. groups is between 2 and 20.
Corresponding compounds are described in German patent document No. 35 04
242. In addition to individual compounds, mixtures of the adducts
mentioned may also be used. Thus, both the length of the fatty alkyl
groups and also the number of recurring alkoxy units in the adduct formed
may vary over a more or less wide range.
The same applies to the adducts of ethylene oxide and/or propylene oxide
with fatty acids which may also be used as surfactant component in
accordance with the invention. Fatty acids such as these may be both
unsaturated fatty acids containing 8 to 22 carbon atoms in the linear or
branched alkyl radicals.
Accordingly, the surfactant component which may be used includes adducts of
ethylene oxide and/or propylene oxide with caprylic acid, pelargonic acid,
capric acid, undecanoic acid, lauric acid, tridecanoic acid, myristic
acid, pentadecanoic acid, palmitic acid, margaric acid, stearic acid,
nonadecanoic acid, arachic acid, uneicosanoic acid, behenic acid and the
corresponding unsaturated carboxylic acids occurring in the starting
products of native fats and oils normally used.
Similarly, it is possible to use adducts of ethylene oxide and/or propylene
oxide with epoxidized unsaturated carboxylic acids and with epoxidized
carboxylic acids ring-opened with monohydric alcohols after epoxidation as
surfactant component.
One feature common to all the surfactants from the abovementioned groups of
adducts, which are suitable for use in the degreasing compositions
according to the invention for aluminum surfaces, is than an average of 1
to 20 mol of the particular alkylene oxide is added onto 1 mol of the
particular fatty derivative, i.e. fatty alcohol, fatty amine or the
particular fatty acid. It is possible to use mixtures of ethylene oxide
and propylene oxide for forming adducts such as these and thus to prepare
adducts with the fatty derivatives mentioned which are both ethoxylated
and propoxylated, the sequence of the ethoxy and propoxy groups being
immaterial. A preferred number of such ethoxy and/or propoxy moieties is
in the range from 5 to 15. In view of the more or less statistical
ethoxylation or propoxylation reaction, mixtures of these adducts which
contain a more or less wide range of fatty derivatives alkoxylated to
different extents are normally used as surfactant components.
In addition to the adducts mentioned above, C.sub.6-22 alkyl
benzenesulfonic acids, C.sub.6-22 alkane sulfonic acids, C.sub.6-22 alkyl
sulfates and C.sub.6-22 alkyl ether sulfates and water soluble salts
thereof, preferably alkali metal and/or ammonium salts and, more
preferably, sodium and/or triethanolammonium salts, also may be used as
surfactants in the inventive degreasing compositions. The alkyl radicals,
which may be linear or branched, derive from the group mentioned above in
connection with the alkylphenols. Once again individual compounds or
mixtures may be used.
One or more surfactants having a HLB value in the range from 10 to 20 are
preferably used as surfactants component (D). Within the group of
surfactants having a HLB value in the range mentioned, those having an HLB
value o | | |
