Note: Descriptions are shown in the official language in which they were submitted.
TRANSLATION
2165285
WO 94/29420 PCT/EP94/01830
-
Dishwashing detergents with a reduced tendency
toward~ bloom formation
This invention relates to dishwashing detergents for
dishwashing machines, more particularly low-alkali
dishwashing detergents with an in-use pH value of 9 to
11, which contain amino acids, preferably lower ~-amino
acids, as alkali carriers.
Low-alkali machine dishwashing detergents of the
latest generation contain alkali carriers, for example
soda, hydrogen carbonate or disilicate, in addition to
water-soluble builders, oxygen-based bleaching agents,
surfactants and enzymes.
Their in-use pH value is generally between 10 and
11. Unfortunately, the formulations involved have the
disadvantage that lime coatings build up on the articles
washed in the machine in the main wash and final rinse
cycles at residual water hardness values of 4dH and
higher. The partial replacement of carbonate by hydrogen
carbonate can reduce the in-use pH value to 9-10 which
increases the complexing effect of certain builder
~ components s-o that the tendency-to form lime coatings can
be reduced. Where very hard water (above 16dH is used,
however, the inhibiting effect on the formation of lime
coatings is not entirely satisfactory, even at a reduced
in-use pH value.
Accordingly, the problem addressed by the present
invention was to provide an alkali carrier system which
would not have any of the above-described disadvantages
of increased lime coating formation and which would be
compatible with the builder components typically used in
machine dishwashing detergents. At the same time, the
alkali carriers would be readily biodegradable substan-
ces. It has now been found that amino acids, more
~ - , WO 94/29420 2 21652~ PCT/EP94/01830
particularly lower ~-amino acids, meet the requirements
~ the new alkali carriers are expected to satisfy to a
particular degree.
DE-OS8 19 42 236 and 19 64 792 disclose laundry
detergents in which protein-dissolving enzymes are
completely or partly replaced by sulfur-free amino acids.
However, there are no references to the fact that amino
acids can be used as a replacement for conventional
alkali carriers in machine dishwashing detergents.
The use of substituted ~-alanine derivatives as
builders in machine dishwashing detergents is claimed in
DB-O~ 40 36 695.
The present invention relates to a machine dishwash-
ing detergent of which a 1% by weight aqueous solution
has a pH value of 8 to 12 and preferably 9 to 11 and
which contains water-soluble builder components and
oxygen-based bleaching agents, characterized in that it
contains one or more amino acids or alkali metal or
ammonium salts thereof as alkali carriers in a quantity
of 0.5 to 60% by weight and preferably 10 to 50% by
weight, based on the detergent as a whole.
Amino acids in the context of the invention are
- ~ amino acids of which the amino function is not substitu-
ted, i.e. of which the amino functions carry only hydro-
gens.
Suitable amino acids are synthetic or naturally
occurring amino acids obtainable, for example, by hydro-
lysis from vegetable or animal proteins, such as col-
lagen, keratin, casein, elastin, soya protein, wheat
gluten or almond protein.
Preferred amino acids are ~-amino acids, for example
serine, threonine, ornithine, arginine, lysine, aspara-
gine, glucamine, phenyl alanine or tyrosine, but especi-
ally glycine, alanine, valine, leucine and isoleucine.
Glycine or alkali metal or ammonium salts thereof, for
~ - , ~0 94/29420 216 5 2 8 5 CT/EP94/01830
example sodium glycinate, are particularly preferred.
Besides the amino acids, alkali metal, alkaline
earth metal or ammonium salts thereof, especially the
sodium salts, may also be present in the dishwashing
detergents according to the invention.
The amino acids or their salts may be used in powder
or granular form, optionally together with such auxili-
aries as, for example, sodium citrate.
By varying the ratio of amino acids to their salts,
a certain required pH value can be established as easily
as with the hydrogen carbonate/carbonate system. How-
ever, the amino acid/amino acid salt alkali carrier
system is distinctly superior to the hydrogen carbonate/
carbonate carrier system in regard to the inhibition of
lime coatings.
Amino acids or amino acid salts are present in the
detergents according to the invention in quantities of
0.5 to 60% by weight and preferably in quantities of 10
to 50% by weight. Mixtures of different amino acids or
amino acid salts may also be used. Carbonate and/or
hydrogen carbonate, more particularly alkali metal
carbonates and/or hydrogen carbonates, may optionally be
~ present in quantities of up to-15% by weight, based on
the dishwashing detergent as a whole. However, the
dishwashing detergents according to the invention are
preferably free from carbonates and/or hydrogen carbon-
ates. Highly alkaline metasilicates, for example sodium
metasilicate, are preferably not used. By contrast,
disilicates with a molar sio2 to Na20 ratio of 1.5:1 to
2.5:1 in the form of their alkali metal salts may option-
ally be present in quantities of 0.1 to 20% by weight,
based on the dishwashing detergent as a whole.
Suitable builder components which perform the actual
function of complexing hardness salts in water and
keeping lime precipitated dispersed in the wash liquor so
- ~ Wo 94/29420 4 2165 285pcT/Ep94/ol83o
- as to prevent lime coatings are, for example, organo-
phosphonic acids and salts thereof, crystalline layer
silicates, zeolites, dibasic and polybasic organic
carboxylic acids and salts thereof, oxidized starch and
polycarboxylic acids or polycarboxylates and polyamino
acids, such as polyaspartic acid for example. The
phosphates previously used, for example pentasodium
triphosphate, which may also be present in principle, are
preferably not used for ecological reasons.
Preferred builder components are dibasic or poly-
basic organic carboxylic acids and salts thereof, more
particularly citric acid and salts thereof and/or syn-
thetic polycarboxylic acids or polycarboxylates, which
are present in a total quantity of 1 to 60% by weight and
preferably 20 to 50% by weight, based on the dishwashing
detergent as a whole.
In the context of the invention, synthetic polycar-
boxylic acids and polycarboxylates are understood to be
the synthetic polymers or their salts of polymerization
products of unsaturated carboxylic acids or salts there-
of, including for example polyacrylic acid, polymethacry-
lic acid, polymaleic acid or copolymers of acrylic acid
~ with maleic-acid or maleic anhydride.
Suitable polyacrylates are, for example, Alcosperse~
102, 104, 106, 404, 406, all products of Alco; Acrysols~
A Nl, LMW 45 N, LMW 10 N, products of Norsohaas; Dega-
pas~, a product of Degussa AG. Suitable copolymers of
polyacrylic acid and maleic acid are, for example, Soka-
lan~ CP 5, CP 7, products of BASF: Acrysol~ QR 1014, a
product of Norsohaas; and Alcosperse~ 175, a product of
Alco.
In addition, the dishwashing detergents according to
the invention must contain oxygen-containing bleaching
agents, more particularly perborates and/or percarbon-
ates, in a quantity of 0.5 to 20% by weight and prefer-
- ~ WO 94/2942Q 5 ~/ ~
ably in a quantity of 5 to 12% by weight, based on the
dishwashing detergent as a whole.
Sodium perborate tetrahydrate (NaBO2 H202 3H20),
sodium perborate monohydrate (NaBO2 H202) and peroxycar-
bonate (Na2CO3 1.5 H202) are particularly important. Other
useful bleaching agents are, for example, peracidic salts
of organic acids, such as perbenzoates or salts of diper-
dodecanedioic acid. In addition, bleach activators are
optionally present. Suitable bleach activators are, in
particular, N-acyl and O-acyl compounds, preferably
tetraacylated diamines, such as N,N,N',N'-tetraacetyl
ethylenediamine (TAED). The detergents according to the
invention contain typical bleach activators such as these
in a quantity of 0.1 to 10% by weight and preferably in
a quantity of 1 to 5% by weight. The detergents accord-
ing to the invention may also optionally contain active
chlorine donors, for example trichloroisocyanuric acid.
However, they are preferably free from active chlorine
donors.
The foaming behavior of the surfactants suitable for
use in the detergents according to the invention is a key
factor. In view of the mechanics of dishwashing ma-
~ chines, low-foaming compounds are preferred. These are,
above all, nonionic surfactants. In principle, however,
the dishwashing detergents according to the invention may
also contain very small quantities of anionic, cationic
or amphoteric surfactants, but are preferably free from
such surfactants. The nonionic surfactant content is at
most 5% by weight and preferably at most 2% by weight,
based on the dishwashing detergent as a whole. Suitable
nonionic surfactants are, above all, adducts of 1 to 20
moles of ethylene oxide (EO) and/or 1 to 20 moles of
propylene oxide (PO) with 1 mole of an aliphatic compound
containing 10 to 20 carbon atoms from the group of
alcohols, carboxylic acids, fatty amines, carboxylic acid
- - i WO 94/29420 ~165285 PCT/EP94/01830
amides and alkane sulfonamides. Besides water-soluble
nonionic surfactants, however, water-insoluble or sub-
stantially water-insoluble polyglycol ethers containing
2 to 7 ethylene glycol ether groups in the molecule are
also important, preferably being used in combination with
water-soluble nonionic surfactants. In addition, alkyl
polyglycosides corresponding to the general formula
R-O-(G)~, in which R is a primary, linear or branched
aliphatic radical containing 8 to 22 and preferably 12 to
18 carbon atoms, G is a glycose unit containing 5 or 6
carbon atoms and the degree of oligomerization x is
between 1 and 10, may also be used as nonionic surfac-
tants.
To improve the removal of protein- or starch-con-
taining food residues, the detergents may advantageouslycontain enzymes, such as proteases, amylases, lipases or
cellulases, for example proteases, such as BLAP~ 140, a
product of Henkel KGaA, OptimaseX M-440, Optimase~ M-330,
Opticlean~ M-375, Opticlean~ M-250, products of Solvay
20 Enzymes: Maxacal~ CX 450.000, Maxapem~, products of Ibis;
Savinase~ 4.0 T, 6.0 T, 8.0 T, products of Novo; Ex-
perase~ T, a product of Ibis; amylases, such as TermamylX
~ ~ 60 T, 90 T,-products of Novo; Amylase-LTX, a product of
Solvay Enzymes; or MaxamylX P 5000, CXT 5000 or CXT 2900,
products of Ibis; lipases, such as Lipolase~ 30 T, a
product of Novo; cellulases, such as Celluzym~ 0.7 T, a
product of Novo Nordisk. Enzymes may be present in the
- detergents according to the invention in a quantity of
0.1 to 5% by weight and preferably in a quantity of 1 to
3% by weight, based on the dishwashing detergent as a
whole.
The dishwashing detergents according to the inven-
tion are preferably powder-form, granular or tablet-form
formulations which may be produced in known manner, for
example by mixing, granulation, roll compacting and/or by
~ - ; W0 94/29420 2 I ~ S 2 8 5 PcT/Ep94/0l830
spray drying. Another advantage of the alkali carrier
~ system consisting predominantly of organic raw materials
is that it affords advantages in terms of making-up,
particularly in the production of granules, tablets or
extrudates.
To produce the detergents according to the invention
in tablet form, all the constituents are preferably mixed
together in a mixer and the resulting mixture is tablet-
ted in conventional tablet presses, for example eccentric
presses or rotary presses, under pressures of 200-105 Pa
to 1500-105 Pa. Breaking-resistant tablets which still
dissolve sufficiently quickly under in-use conditions
with flexural strengths of normally above 150 N are nor-
mally obtained in this way. A tablet produced in this
way preferably has a weight of 15 g to 40 g and, more
particularly, 20 g to 30 g for a diameter of 35 mm to 40
mm.
The production of the machine dishwashing detergents
in the form of non-dust-emitting, storage-stable free-
flowing powders and/or granules with high apparent densi-
ties preferably in the range from 750 to 1000 g/l is
carried out, for example, by mixing the builder compo-
~ nents with at least part of the liquid mixture componentsin a first stage of the process, the apparent density of
the premix being increased, and then combining the other
constituents of the machine dishwashing detergent with
the premix thus obtained, if desired after intermediate
drying.
The liquid phase used in the first stage of the
process consists in particular of the surfactant com-
pounds liquid under normal conditions, i.e. in particular
the corresponding nonionic surfactants, and/or other
liquid components of the formulation as a whole. These
include the fragrances dissolved in the carrier liquids
and/or limited quantities of water or aqueous solutions
~ - Wo 94/29420 8 21~5285 PCT/EPg4/01830
of mixture components of the required dishwashing deter-
~ gent.
In the first stage of the mixing process, the
builder is generally mixed with the liquid components in
the form of a mixture with at least one other component
of the dishwashing detergent. This may be done, for
example, in a preliminary stage in which the builder
component is exposed to and thoroughly mixed with the
liquid nonionic surfactants and/or the solution of
fragrances in the form of a mixture with perborate. The
remaining components are then added and the mixture as a
whole is compounded and homogenized in the mixer. There
is generally no need to use additional quantities of
liquid, i.e. additional water. The mixture obtained is
a free-flowing, non-dust-emitting powder with the re-
quired high apparent densities in the range from about
800 to 900 g/l.
The machine dishwashing detergents according to the
invention containing amino acids and/or salts thereof as
alkali carriers represent products which, apart from
their ready biodegradability, are superior to convention-
al modern dishwashing detergents, in which the alkali
~ carrier system consists predominantly of carbonate and/or
hydrogen carbonate, in regard to the inhibition of lime
coatings.
E x a m p 1 e s
I. Granular dishwashing detergents with the following
composition (detergents A and B according to the inven-
tion, comparison detergent C and detergents D, E and F
according to the invention) were produced.
Detergent A contained 31.9% by weight of glycine and
17.2% by weight of sodium glycinate as the alkali carrier
system; the pH value of a 1% by weight aqueous solution
~ - , , W0 94/29420 9 ~16S285 PCT/EPg4/01830
was 9.5. Detergent B contained 49.1% by weight of sodium
glycinate as the alkali carrier system; the pH value of
a 1% by weight aqueous solution was correspondingly
higher at 10.9. Comparison detergent C contained 36.1%
by weight of sodium hydrogen carbonate and 13.0% by
weight of sodium carbonate as the alkali carrier system;
the pH value of a 1% by weight aqueous solution was 9.5.
Detergents D, E and F according to the invention
contained 24.0% by weight of glycine/16.0% by weight of
sodium glycinate (D), 25.3% by weight of glycine/10.8% by
weight of sodium glycinate (E) and 37.5% by weight of
sodium glycinate (F).
Sodium glycinate may be used in powder form or as
granules. The granules may be produced, for example, as
follows:
Na glycinate and a mixture - prepared in a standard
pilot-scale Lodige mixer - of Na glycinate and Na citrate
(90:10) was compacted in a roll press (roll temperature
20C, linear pressure 17 kN/cm) to form sheets. The
sheets were then ground and a fraction of < 1.6 mm was
removed by sieving.
This fraction was then introduced into a Niro
~ Aeromatic fluidized-bed apparatus operated in batches and
sprayed for 30 minutes with a paraffin wax (Mp. 42-45C)
which was introduced into the fluidized bed through a
two-component nozzle. The fluidizing air was kept at
30C. With a ratio of roll compactate to paraffin wax of
9:1, the granules formed were slightly tacky, but remain-
ed stable even in formulations containing "stray" water
by virtue of the externally applied hydrophobic layer.
. WO 94/29420 10 2165285 PCT/EPg4/0l830
- A B C D E F
% by % by % by % by % by % by
weight weight weight weight weight weight
Na citrate 30.0 30.0 30.0 45.0 45.0 45.0
Sokalan~ CP5
(acrylate/maleate
copolymer of
10 BASF) 10.0 10.0 10.0 - - -
Na2C03 - - 13.0
NaHCO3 - - 36.1
Glycine 31.9 - - 24.0 25.3
Sodium gly-
15 cinate 17.2 49.1 - 16.0 10.8 37.5
Na perborate
monohydrate 5.0 5.0 5.0
Na percarbonate - - - 6.5 12.0 10.0
TAED 2.0 2.0 2.0 5.0 4.0 4.0
20 Amylase 1.5 1.5 1.5 1.0 1.0 1.0
Protease 1.5 1.5 1.5 1.0 1.0 1.0
PlurafacX LF 403
(C12_l8 fatty al-
cohol-EO-4PO of
25 BASF) 0.9 0.9 0.9 1.5 0.9 1.5
Bloom inhibition
The tendency of detergents A, B and C to form lime
coatings was tested in a Miele G 590 dishwashing machine
(program: universal, 65C) with dosages of 20 g in 6.2 1
of water (16dH) containing 50 g of added pumpable soils
(mixture of ketchup, gravy, mustard, potato starch, egg
yolk, milk, margarine) in the presence of 3.0 ml of a
commercially available rinse aid over 10 wash cycles.
Bloom formation was evaluated on a scale of o (= very
heavy bloom) to 3 (= no bloom). The results of the bloom
tests obtained with detergents A and B according to the
invention and comparison detergent C are as follows:
. W0 94/29420 11 ~1~5 28~ PCT/EP94/01830
detergent A according to the invention: 1.0
detergent B according to the invention: 1.0
comparison detergent C: 0.2
detergent D according to the invention: 2.2
detergent E according to the invention: 2.6
detergent F according to the invention: 2.6
It can be seen that detergents A, B, D, E and F
according to the invention are distinctly superior to
comparison detergent C in regard to bloom inhibition.
a 1~5~5
P~ F ~ ~1
C~ c~ L~
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