Note: Descriptions are shown in the official language in which they were submitted.
~1661~
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WO 95/00623 PCT/EP94/02000
Dishwashing detergents cont~; ni ng a biologically
degradable builder component
This invention relates to low-alkali dishwashing
detergents for dishwashing machines containing a biologi-
cally degradable builder component.
In addition to oxygen-based bleaching agents,
surfactants and enzymes, low-alkali machine dishwashing
detergents of the latest generation contain a combination
of water-soluble builders consisting of complexing
agents, for example citrate, alkali carriers, for example
soda, hydrogen carbonate or disilicate, and dispersants,
for example polycarboxylates. Other possible builder
components are organophosphonic acids, aminocarboxylic
acids or crystalline layer silicates. The phosphates
previously used, for example pentasodium tripolyphos-
phate, are now being phased out on ecological grounds.
The polycarboxylates, for example maleate/acrylate
copolymers, used in modern detergents prevent the forma-
tion of lime coatings in the presence of excessive
residual water hardness in the main wash and final rinse
cycles. In addition, they improve the clear rinse effect
at high salt concentrations in the wash liquor.
The disadvantage of these polycarboxylates is that
they are not readily biodegradable. Accordingly, there
is a need for machine dishwashing detergents which con-
tain biodegradable builder components, but which at the
same time have the established performance spectrum of
modern dishwashing detergents. Although many readily
biodegradable builder components, such as for example
oxidized starch or polyaspartic acid, have a good dis-
persing effect on precipitated calcium carbonate, they
are poor complexing agents for water hardness.
US 3,887,480 discloses dishwashing and laundry
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WO 95/00623 2 PCT/EP94/02000
detergents which contain a polymer consisting of 35 to 70
mole-% of maleic acid, 20 to 45 mole-% of vinyl acetate
and 2 to 40 mole-% of acrylic acid. EP 0 193 360 Bl
describes zeolite-containing laundry detergents contain-
ing polycarboxylate polymers produced from a C310 monocar-
boxylic acid, a C4-6 dicarboxylic acid and a nonionic
spacer, for example vinyl alcohol. US 3,755,264 dis-
closes copolymers produced, for example, from 85 to 99
mole-% of maleic anhydride and 1 to 15 mole-% of a
10mixture of acrylic acid and vinyl acetate. EP 0 076 992
A1 discloses inter alia the use of polymers produced from
50 to 95% by weight of acrylic acid, 0.5 to 5% by weight
of vinyl acetate and up to 49% by weight of maleic acid
as incrustation inhibitors in detergents.
15It has now surprisingly been found that copolymers
produced from (meth)acrylic acid or (meth)acrylate,
maleic acid or maleate and vinyl alcohol and/or vinyl
acetate in certain quantity ratios not described in the
documents cited above are eminently suitable for use as
builder components in machine dishwashing detergents.
The present invention relates to a low-alkali
machine dishwashing detergent of which a 1% by weight
aqueous solution has a pH value of 8 to 11.5 and prefer-
ably 9 to lO.S and which contains water-soluble builder
components and oxygen-based bleaching agents, charac-
terized in that it contains as the water-soluble builder
component a copolymer of which 60 to 95% by weight and
preferably 70 to 90% by weight consists of (meth)acrylic
acid or (meth)acrylate, preferably acrylic acid or
acrylate, and maleic acid or maleate and 5 to 40% by
weight and preferably 10 to 25% by weight of vinyl
alcohol and/or vinyl acetate, the ratio by weight of
(meth)acrylic acid or (meth)acrylate to maleic acid or
maleate being from 1.5:1 to 4:1 and preferably from 2:1
to 2.5:1, both the quantities and the ratios by weight
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WO 95/00623 3 PCT/EP94/02000
being based on the acids and a copolymer of the salts of
the acids and vinyl alcohol being preferred.
The copolymers used in accordance with the invention
may be produced by any of the known and usual processes.
More particularly, (meth)acrylic acid, preferably acrylic
acid, and maleic acid are reacted with vinyl alcohol
and/or vinyl acetate, after which the acids are optional-
ly neutralized, preferably to their alkali metal salts,
such as the sodium or potassium salts, or ammonium salts
or alkanolamine salts, such as the monoethanolamine salt
or the triethanolamine salt, and the vinyl acetate is
optionally partly or completely decomposed into vinyl
alcohol.
Similarly to the known (co)polymeric polycarboxylic
acids or polycarboxylates, such as homopolymeric or
copolymeric acrylic acids or acrylates, copolymers which
are either completely or at least partly neutralized,
more particularly to more than 50%, based on the carboxyl
groups present, are also preferred. A particularly
preferred copolymer is a completely neutralized copoly-
mer, i.e. a copolymer consisting of the salts of (meth)-
acrylic acid, preferably acrylic acid, and maleic acid,
more particularly the sodium or potassium salts, and
vinyl alcohol. The copolymers generally have a relative
molecular weight in the range from 1,000 to 200,000,
preferably in the range from 2,000 to 50,000 and more
- preferably in the range from 3,000 to 10,000. They are
preferably used in the form of spray-dried powders.
Particularly preferred copolymers are produced by the
process described in earlier German patent application P
43 00 772.4.
- Preferred dishwashing detergents according to the
invention contain the copolymer in quantities of 0.5 to
30% by weight and preferably in quantities of 2 to 20% by
weight and also contain 0.5 to 20% by weight and prefer-
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WO 95/00623 4 PCT/EP94/02000
ably 5 to 15% by weight of an oxygen-based bleaching
agent, more particularly alkali metal perborate and/or
percarbonate, and nonionic surfactants in a quantity of
at most 5% by weight and preferably at most 2% by weight,
the detergents being free from anionic, cationic or
amphoteric surfactants.
In one preferred embodiment, alkali metal carbonates
and/or hydrogen carbonates, more particularly the sodium
salts, are present as alkali carriers in a quantity of up
to 60% by weight and preferably in a quantity of 5 to 50%
by weight.
The dishwashing detergents according to the inven-
tion may contain other water-soluble builder components,
for example synthetic polymers which are understood to be
the salts of polymerization products of unsaturated
carboxylic acids and which include, for example, poly-
acrylates, polymethacrylates, polymaleates or copolymers
of acrylic acid with maleic acid or maleic anhydride, in
a quantity of 0.5 to 30% by weight and preferably in a
quantity of 2 to 20% by weight. Suitable polyacrylates
are, for example, AlcosperseX 102, 104, 106, 404, 406,
products of Alco; AcrysolsX A N1, LMW 45 N, LMW 10 N,
products of Norsohaas: DegapasX, a product of Degussa AG.
Suitable copolymers of polyacrylic acid and maleic acid
are, for example, Sokalan~ CP 5, SP 7, products of BASF;
Acrysol~ QR 1014, a product of Norsohaas; Alcosperse~
175, a product of Alco. In principle, phosphates or
zeolites may also be present, although the dishwashing
detergents are preferably free from zeolites and phos-
phate-containing builder components.
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. Accordingly, the
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WO 95/00623 5 PCT/EP94/02000
dishwashing detergents according to the invention are
preferably free from anionic, cationic or amphoteric
surfactants. The nonionic surfactant content is at most
5% by weight and preferably at most 2% by weight.
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 (P0) with 1 mole of an aliphatic
compound containing 10 to 20 carbon atoms from the group
of alcohols, carboxylic acids, fatty amines, carboxylic
acid amides and alkane sulfonamides. In addition to the
water-soluble nonionic surfactants, however, water-
insoluble or substantially water-insoluble polyglycol
ethers containing 2 to 7 ethylene glycol ether groups in
the molecule are also important and are preferably used
in combination with water-soluble nonionic surfactants.
In addition, alkyl polyglycosides corresponding to the
general formula R-O-(G)X, where R is a primary, linear or
branched aliphatic radical containing 8 to 22 and prefer-
ably 12 to 18 carbon atoms, G is a glycose unit contain-
ing 5 or 6 carbon atoms and the degree of oligomerizationx is between 1 and 10, may also be used as nonionic
surfactants.
Preferred dishwashing detergents according to the
invention additionally contain complexing agents from the
group of dibasic and polybasic organic carboxylic acids
and salts thereof, for example nitrilotriacetic acid, but
especially citric acid or salts thereof, in a quantity of
0.5 to 60% by weight and preferably in a quantity of 20
to 50% by weight.
Typical alkalizing agents used in low-alkali machine
dishwashing detergents include alkali metal carbonates
and hydrogen carbonates and alkali metal silicates with
an Sio2:M2o (M = alkali metal atom) molar ratio of 1.5:1
to 2.5:1. The alkali metal carbonates and hydrogen
carbonates preferably used in the detergents according to
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WO 95/00623 6 PCT/EP94/02000
the invention are the sodium carbonates and hydrogen car-
bonates which are present in the quantities mentioned
above. The high-alkali metasilicates are preferably not
used as alkali carriers. Instead of the metasilicates,
alkali metal silicates, preferably sodium silicates with
a molar SiO2:NazO ratio of 1.5:1 to 2.5:1, are preferably
used in quantities of up to 30% by weight and, more
preferably, in quantities of 5 to 20% by weight, based on
the dishwashing detergent as a whole.
Among the compounds used as oxygen-based bleaching
agents, sodium perborate tetrahydrate (NaBO2 H2O2 3H2O),
sodium perborate monohydrate (NaBO2 H2O2) and the peroxy-
carbonate (Na2CO3 l.5 H2O2) are particularly important.
Other useful bleaching agents are, for example, peracidic
salts of organic acids, such as perbenzoates, or salts of
diperdodecanedioic acid. The detergents preferably
contain 0.5 to 20% by weight and, more preferably, 5 to
15% by weight of an oxygen-based bleaching agent, more
particularly alkali metal perborates and/or percarbon-
ates. Moreover, the addition of small quantities ofknown bleach stabilizers, such as borates or metaborates
and metasilicates and also magnesium salts, for example,
magnesium sulfate, can be useful.
Suitable bleach activators for these oxidizing
agents 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 these typical bleach
activators in a quantity of 0.1 to 10% by weight and
preferably in a quantity of 1 to 5% by weight. The
detergents according to the invention are preferably free
from active chlorine donors, such as trichloroisocyanuric
acid for example.
To improve the removal of protein- or starch-con-
taining food residues, the detergents may contain en-
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zymes, such as proteases, amylases, lipases or cellu-
lases, for example proteases, such as BLAP0 140, a
product of Henkel KGaA, Optimase~ M-440, Optimase0 M-330,
Opticlean~ M-375, Opticlean~ M-250, products of Solvay
Enzymes; Maxacal~ CX 450.000, Maxapem~, products of Ibis;
Savinase~ 4.0 T, 6.0 T, 8.0 T, products of Novo; or Ex-
perase0 T, a product of Ibis; amylases, such as Termamyl0
60 T, 9O T, products of Novo; Amylase-LTX, a product of
Solvay Enzymes; or Maxamyl0 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
O.1 to 5% by weight and preferably in a quantity of 0.5
to 2% by weight, based on the dishwashing detergent as a
whole.
To prevent the tarnishing of silver tableware, so-
called silver protectives of the type described in
earlier German patent application P 43 15 397.6, more
particularly water-soluble Mn(II) salts, may optionally
be present in a quantity of up to 2% by weight and
preferably in a quantity of O.l to 0.5% by weight.
The dishwashing detergents according to the inven-
tion are preferably present in the form of powder-form,
granular or tablet-form preparations which may be pro-
duced by methods known per se, for example by mixing,
granulation, roll compacting and/or by spray drying. The
- polymers used in accordance with the invention may also
be employed in the form of a compound to be added to
other granular constituents of the detergents.
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
35 presses or rotary presses, under pressures of 200-105 Pa
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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
readily 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 800 to 90o g/l is
carried out, for example, by mixing the builder compo-
nents with at least part of the liquid mixture components
in 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.
Since the alkali metal carbonate content has a
considerable bearing on the alkalinity of the product,
the intermediate drying step should be carried out in
such a way that decomposition of the sodium bicarbonate
to sodium carbonate is kept to a minimum (or at least
substantially constant). This is because any sodium
carbonate additionally formed as a result of drying would
have to be taken into consideration in the formulation of
the granules. Low drying temperatures not only counter-
act the decomposition of sodium bicarbonate, they also
increase the solubility of the granulated detergent in
use. Accordingly, the intermediate drying step is
advantageously carried out at a feed air temperature
which, on the one hand, should be as low as possible to
avoid decomposition of the bicarbonate but which, on the
other hand, should be as high as necessary to obtain a
product with good storage properties. The drying step is
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WO 95/00623 9 PCT/EP94/02000
preferably carried out at a feed air temperature of
around 80C. The granules themselves should not be
heated to temperatures above about 60C.
In the first stage of the mixing process, the
builder is exposed to the liquid components generally 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 preliminary granules are then mixed with the
missing components of the dishwashing detergent to form
the end product. In all the cases illustrated here, the
mixing time both in the preliminary stage of compacting
mixing in the presence of liquid components and in the
following final mixing phase with the other components is
of the order of a few minutes, for example 1 to 5 min-
utes.
In one particular embodiment, it can be useful in
the production of fine granules to subject the granules
formed to further stabilization and equalization by
dusting their surfaces with powder. Small amounts of
waterglass powder or powder-form alkali metal carbonate
are particularly suitable for this purpose.
The machine dishwashing detergents according to the
invention represent products which, apart from their
better biodegradability, are superior to conventional
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modern dishwashing detergents above all in regard to
bloom inhibition and the clear rinse effect on glasses
and knifes.
The following Examples are intended to illustrate
the invention without limiting it in any way.
B x a m p 1 e -q
Granular dishwashing detergents with the following
composition (detergent A according to the invention,
comparison detergent B and detergent C according to the
invention) were produced.
Detergent A contained 10~ by weight of the copolymer
which had been produced in accordance with the disclosure
of earlier German patent application P 43 00 772.4 from
80% by weight of acrylic acid and maleic acid in a ratio
by weight of 7:3 and from 20% by weight of vinyl acetate
and then completely neutralized.
Comparison Example B contained 10% by weight of an
acrylate/maleate copolymer marketed by BASF under the
name of Sokalan~ CP5.
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WO 95/00623 11 PCT/EP94/02000
A B C
% by % by % by
weight weight weight
_______________________________________________ _________
Na Citrate 30.0 30.0 40.0
Sokalan CP5 --- 10.0 ---
Above-mentioned copolymer 10.0 --- 5.0
Na2CO3 13.0 13.0 6.0
NaHCO3 35.5 35.5 30.1
Na Perborate 5.0 5.0 ---
Na Percarbonate --- --- 12.0
TAED 2.0 2.0 3.0
Amylase 1.5 1.5 1.0
Protease 1.5 1.5 1.0
Plurafac LF403 of BASF
(C12/18 Fatty alcohol EO-4PO) 0.9 0.9 o.g
Perfume oil 0.6 0.6 0.6
MnSO4 --- --- 0.4
Cle~n; ng performance
The cleaning performance of detergents A and B was
tested in a Miele G 531 dishwashing machine (program:
universal, 65C) with dosages of 30 g in 7.0 1 of water
(16dH) in the main wash cycle (soil types as described
in Th. Altenschopfer, SOFW, 98 (1972), 763 - 756, namely:
tea, milk, minced meat, pudding, lipstick, starch, oat
flakes).
Detergent A according to the invention was superior
in its cleaning performance to comparison detergent B,
particularly in regard to the removal of starch, minced
meat, lipstick and oat flakes and, more particularly, in
regard to the removal of tea stains.
Bloom inhibition
The bloom forming effect of detergents A and B was
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WO 95/00623 12 PCT/EP94/02000
tested in a Miele G 590 dishwashing machine (program:
universal, 65C) with dosages of 20 g in 7.0 l 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 commer-
cially available rinse aid over 10 wash cycles. The
clear rinse effect ("spotting") was evaluated on a scale
of 1 (= very poor clear rinse effect) to 8 (= very good
clear rinse effect, no water stains). The results of the
clear rinse effects obtained with detergent A according
to the invention and comparison detergent B on glasses,
knifes and china plates are shown in Table 1.
Table 1
A B
___________________________________
Glasses 5
Knifes 5 3
China plates 5 6
It can be seen that detergent A according to the
invention is superior to comparison detergent B above all
in regard to the clear rinse effect on glasses and
knifes.
25Detergent C according to the invention was com-
parable with detergent A according to the invention in
- its cleaning performance and bloom inhibiting effect. By
virtue of the presence of MnSO4, it showed superior
properties above all in regard to preventing the tarnish-
ing of silverware.
