Note: Descriptions are shown in the official language in which they were submitted.
CA 02227222 1998-01-16
WO 97/04056 PCTtUS96/11428
The Use of Alkoxylat~d Alcohols To Control Foaming of Alkyl
Polyglycosi~es in Cleaning Compositions
Field of the Invention
The invention relates to the use of alkoxylated
alcohols to control foaming in alkyl polyglycoside-
cont~;n~ng compositions.
Back~round of the Invention
It is known that alkyl polyglycosides exhibit
significantly higher foaming profiles than other nonionic
surfactants, such as alcohol ethoxylates. In fact, it can
be said that the foaming tendencies of alkyl polyglycosides
more closely resemble those of anionic surfactants, such as
alcohol sulfates, than the foaming tendencies of other
nonionic surfactants. This higher foaming tendency makes
the use of alkyl polyglycosides undesirable for many
applications, e.g. cleaning-in-place for food processing
plants, high pressure spray cleaning, bottle washing, floor
cleaners and automatic dishwashing, wherein high levels of
foam interfere with the cleaning and rinsing operation and
reduce the efficiency of the operation.
Low foam nonionics, such as EO/PO block copolymers,
can be used to reduce the foaming properties of alkyl
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.
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undesirable properties, e.g. low biodegradability,
relatively high aquatic toxicity and poor caustic
compatibility.
Accordingly, there is a need for the development of
methods for decreasing the foaming tendency of alkyl
polyglycoside containing compositions without
simultaneously affecting the beneficial properties of the
alkyl polyglycosides, e.g. good cleaning ability, high
biodegradability, low a~uatic toxicity and good caustic
compatibility.
SummarY of the Invention
It has now surprisingly been found that by adding an
affective amount of an alkoxylated alcohol corresponding to
general formula I:
Rl(EO)X(PO)y-OH
wherein Rl is derived from a linear or branched alkyl chain
having from about 8 to about 14 carbon atoms; x is a number
having a value of from l to about l0; y is a number having
a value of from l to about l0, to a cleaning composition
cont~;n;ng an alkyl polyglycoside having the general
formula II:
R30(R40)b(Z)a II
wherein R3 is a monovalent organic radical having from about
6 to about 30 carbon atoms; R4 is divalent alkylene radical e
having from 2 to 4 carbon atoms; Z is a saccharide residue
having 5 or 6 carbon atoms; b is a number having a value
~rom 0 to about 12i a is a number having a value from l to
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about 6, the amount of foam generated by the composition is
significantly reduced.
Descri~tion 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".
Alkyl polyglycosides are primarily produced by two
methods, i.e., direct synthesis and transacetalization. In
the direct synthesis method, glucose is directly reacted
with an excess of fatty alcohol in the presence of an acid
as catalyst to form the glycoside. In the
transacetalization method using a lower alcohol or glycol
as solvent and reactant, a lower alkyl glycoside is
initially formed and is then reacted with a long carbon-
chain fatty alcohol in the ~ollowing step to ~orm the end
product.
It is known that alkyl polyglycosides are both readily
biodegradable and non-toxic. However, it is also known
that alkyl polyglycosides having C8-Cl5 alkyl ~h~; n~ are foam
generators. Thus, while their use in cleaning compositions
as nonionic surfactants is desirable for both environmental
and detersive reasons, their tendency towards foam
production in applications where high ~oam levels are
undesirable, such as in automatic dish washing detergents,
floor cleaners, and high pressure spray cleaners, limits
their desirability.
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Accordingly, the present invention relates to adding
a defoaming-effective amount of an alkoxylated alcohol
having the general formula I:
R1(EO)X(PO)y-oH
wherein Rl is derived from a linear or branched alkyl chain
having from about 8 to about 14 carbon atoms; x is a
number having a value of ~rom l to about l0; y is a number
having a value of from l to about l0, to a cleaning
composition cont~;n;ng an alkyl polyglycoside having the
general formula II:
R3O(R4O)b(z)a II
wherein R3 is a monovalent organic radical having from about
6 to about 30 carbon atoms; R4 is divalent alkylene radical
having from 2 to 4 carbon atoms; Z is a saccharide residue
having 5 or 6 carbon atoms; b is a number having a value
from 0 to about 12; a is a number having a value from l to
about 6. The ratio of alkoxylated alcohol of formula I to
alkyl polyglycoside of formula II is typically in the range
of from l:l0 to l0:l.
Cleaning compositions typically contain various
surfactants such as nonionic, anionic and amphoteric
surfactants, as well as mixtures thereof. Additional
components may include builders such as silicates,
phosphates, tetrasodium EDTA, and NTA.
Buffer components may also be employed in order to
regulate the pH of the cleaning composition. Examples of
suitable buffer components include sodium carbonate,
triethanolamine, NaOH, and KOH.
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Other components typically found in cl~n; ng
compositions include corrosion inhibitors, dyes,
fragrances, preservatives, and solvents.
- The surfactant employed in the cleaning composition of
the present process is an alkyl polyglycoside having the
general formula II:
R3O(R4O)b(Z)a II
wherein R3 is a monovalent organic radical having from about
6 to about 30 carbon atoms; R4 is divalent alkylene radical
having from 2 to 4 carbon atoms; Z is a saccharide residue
having 5 or 6 carbon atoms; b is a number having a value
from 0 to about 12; a is a number having a value from 1 to
about 6. Such alkyl polyglycosides are commercially
available, for example, as APG~, GLUCOPON~, or PLANTAREN~
surfactants from Henkel Gorporation, Ambler, PA., 19002.
Examples of such surfactants include but are not limited
to:
1. APG~ 225 Surfactant - an alkyl polyglycoside in which
the alkyl group contains 8 to 10 carbon atoms and having an
average degree of polymerization of 1.7.
2. APG~ 425 Surfactant - an alkyl polyglycoside in which
the alkyl group contains 8 to 16 carbon atoms and having an
average degree of polymerization of 1.6.
3. APG~ 625 Surfactant - an alkyl polyglycoside in which
the alkyl groups contains 12 to 16 carbon atoms and having
an average degree of polymerization of 1.6.
4. APG~ 325 Surfactant - an alkyl polyglycoside in which
the alkyl groups contains 9 to 11 carbon atoms and having
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an average degree of polymerization of 1.5.
5. GLUCOPON~ 600 Surfactant - an alkyl polyglycoside in
which the alkyl groups contains 12 to 16 carbon atoms and
having an average degree of polymerization of 1.4.
6. PLANTAREN~ 2000 Surfactant - a C8l6 alkyl polyglycoside
in which the alkyl group contains 8 to 16 carbon atoms and
having an average degree of polymerization of 1.4.
7. PLANTAREN~ 1300 Surfactant - a Cl2l6 alkyl polyglycoside
in which the alkyl groups contains 12 to 16 carbon atoms
and having an average degree of polymerization of 1.6.
Other examples include alkyl polyglycoside surfactant
compositions which are comprised of mixtures of compounds
~ of formula I wherein Z represents a moiety derived from a
reducing saccharide cont~;nlng 5 or 6 carbon atoms; a is a
number having a value from 1 to about 6; b is zero; and Rl
is an alkyl radical having from 8 to 20 carbon atoms. The
compositions are characterized in that they have increased
surfactant properties and an HLB in the range of about 10
to about 16 and a non-Flory distribution o~ glycosides,
which is comprised of a mixture of an alkyl monoglycoside
and a mixture of alkyl polyglycosides having varying
degrees of polymerization of 2 and higher in progressively
decreasing amounts, in which the amount by weight of
polyglycoside having a degree of polymerization of 2, or
mixtures thereof with the polyglycoside having a degree of
polymerization of 3, preAom;n~te in relation to the amount
of monoglycoside, said composition having an average degree
of polymerization of about 1.8 to about 3~ Such
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compositions, also known as peaked alkyl polyglycosides,
can be prepared by separation of the monoglycoside from the
original reaction mixture of alkyl monoglycoside and alkyl
polyglycosides after removal of the alcohol. This
separation may be carried out by molecular distillation and
normally results in the removal of about 70-95~ by weight
of the alkyl monoglycosides. After removal of the alkyl
monoglycosides, the relative distribution of the various
components, mono- and poly-glycosides, in the resulting
product changes and the concentration in the product of the
polyglycosides relative to the monoglycoside increases as
well as the concentration of individual polyglycosides to
the total, i.e. DP2 and DP3 fractions in relation to the
sum of all DP ~ractions. Such compositions are disclosed in
U.S. patent 5,266,690, the entire contents o~ which are
incorporated herein by reference.
Other alkyl polyglycosides which can be used in the
compositions according to the invention are those in which
the alkyl moiety contains from 6 tO 18 carbon atoms in
which and the average carbon chain length of the
composition is from about 9 to about 14 comprising a
mixture of two or more of at least binary components of
alkylpolyglycosides, wherein each binary component is
present in the mixture in relation to its average carbon
chain length in an amount effective to provide the
surfactant composition with the average carbon chain length
of about 9 to about 14 and wherein at least one, or both
binary components, comprise a Flory distribution of
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polyglycosides derived ~rom an acid-catalyzed reaction o~
an alcohol containing 6-20 carbon atoms and a suitable
saccharide from which excess alcohol has been separated.
As was noted previously, the use of alkyl
polyglycoside sur~actants of formula II as the nonionic
surfactant in cleaning compositions, and particularly those
alkyl polyglycosides of formula II wherein R3 is a
monovalent organic radical having from 8 to 10 carbon
atoms, b is zero and a is a number having a value o~ 1.52,
is attended by unwanted high levels of ~oaming. In order
to reduce the level of foam generated by the alkyl
polyglycosides of formula II present in cleaning
compositions, it has been found that by adding an effective
amount of an alkoxylated alcohol having the general
formula I:
Rl(EO)X(PO)y-OH
wherein R1 is derived from a linear or branched alkyl chain
having from about 8 to about 14 carbon atoms; x is a number
having a value of from 1 to about 10; y is a number having
a value o~ from 1 to about 10, the amount o~ ~oam generated
by the alkyl polyglycoside-cont~;n;ng cleaning composition
can be significantly reduced. A preferred alkoxylated
alcohol of formula I is one wherein the number y is greater
than x, i.e., there are more propylene oxides than ethylene
oxide and a particularly preferred alkoxylated alcohol is
one having a molar ratio of ethylene oxide to propylene
oxide of about 1:2, respectively.
In one embodiment of the present invention, the
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cl~n; ng composition employed in the present process
contains: up to 97.9% by weight of a builder component;
from about 1 to about 10% by weight of a buffer component;
- from about 0.1 to about 50% by weight of an alkyl
polyglycoside of formula II; and from about 1 to about 2%
by weight of an alkoxylated alcohol of formula I, all
weights being based on the weight of the cleaning
composition. The ratio by weight of alkyl polyglycoside of
formula II to alkoxylated alcohol of formula I is
preferably in the range of from 4:1 to 1:1. Preferably,
from about 0.1 to about 5%, and particularly from about 1
to about 3~ by weight, based on the weight of the cleaning
composition, of the alkoxylated alcohol of formula I is
added to the cleaning composition.
In a particularly preferred embodiment of the present
invention, the cleaning composition contains the alkyl
polyglycoside of formula II wherein R3 is an alkyl radical
having from 8 to 10 carbon atoms, b is zero, and a is a
number having a value of 1.52. This alkyl polyglycoside is
preferably present in the cleaning composition in an amount
of from about 3 to 4% by weight, based on the weight of the
composition. To this composition there is added an
effective amount of alkoxylated alcohol of formula I such
that the ratio by weight of alkyl polyglycoside of formula
II wherein R3 is a C8-C10 alkyl radical to alkoxylated
alcohol of formula I is from 1:10 to 10:1, and most
preferably 1:1, respectively.
The present invention will be better understood from
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the examples which follow, all of which are intended to be
illustrative only and not meant to unduly limit the scope
of the invention. Various blends of alkoxylated alcohols
of formula I and alkyl polyglycosides of formula II were
prepared and tested using the Ross Miles Foam Test (ASTM
D1173-53) to determine their defoaming capabilities. The
blend compositions and results obtained therefrom are
listed in Table I below. Unless otherwise indicated,
percentages are on a wt% actives basis.
Table I
Example wt% wt% BL- wt% LS- wt% APG~ Foam Height
SX-602 214 36 220 UP 1 min 5 min
(mm) (mm)
1 --- --- --- 0.1 145 145
2 --- --- 0.05 0.05 5 5
3 --- 0.05 --- 0.05 70 15
4 0.05 --- --- 0.05 15 5
(a) SX-602 = SANDOXYLATE~ X-602, an alkoxylatec
alcohol commercially available from Sandoz, Corp.
(b) BL-214 = ANTAROX~ BL-214, an alkoxylated alcohol
commercially available from Rhone-Poulenc.
(c) LS-36 = DEHYPON~ LS-36, an alkoxylated alcohol
commercially available ~rom Henkel KGaA, Dusseldorf,
Germany.
(d) APG~ 220 UP is an alkyl polyglycoside in which the
alkyl group contains 8 to 10 carbon atoms and having an
average degree of polymerization of 1.52, sold by Henkel
~orporation, Ambler, PA.
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Various formulations were also tested using the Waring
Blender test method for det~m;n;ng their de~oaming
effectiveness. The blend compositions and results obtained
'- using this test method are listed in Table II below. In
Examples 5-8 below, 0.5% active solutions were prepared at
25~C, using 150 ppm hard water. The Waring Blender was run
at constant high speed for approximately 3.5 minutes, after
which the foam height was measured
Table II
Example wt% wt% BL- wt% LS- wt% APG~ Foam Height
SX-602 214 36 220 UP Volume (ml)
--~ 0.50 800
6 -~ 0.25 0.25 168
7 --- 0.25 --- 0.25 183
8 0.25 --- --- 0.25 178
As can be seen from the results obtained in Tables I
and II, the foam produced after blending an alkoxylated
alcohol of formula I with an alkyl polyglycoside of formula
II is significantly decreased, as compared to the amount of
foam produced by an alkyl polyglycoside of formula II by
itself.
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