Note: Descriptions are shown in the official language in which they were submitted.
CA 02307430 2000-OS-03
Washing Process Using Detergent Tablets
Field of the Invention
This invention relates to a process for washing laundry in a domestic
washing machine using detergents in the form of shaped bodies which are
referred to in short hereinafter as detergent tablets.
Background of the Invention
Detergent compositions in the form of tablets have long been known
and are widely described in the prior art although, until recently, tablets
had
not been especially prominent on the market. The reason for this is that
tablets, despite a number of advantages, also have disadvantages which
have an adverse effect both on their production and use and on their
acceptance by consumers. The main advantages of tablets, such as
elimination of the need to measure out the quantity of product required by
the consumer, the higher density and hence the reduced packaging and
storage costs and an aesthetic aspect which should not be underestimated,
are offset by such disadvantages as the dichotomy between acceptable
hardness and sufficiently rapid disintegration and dissolution of the tablets
and numerous technological difficulties in production and packaging.
Extensive prior art literature has been available, especially recently, on
solutions to these problems and tablets are now marketed across Europe
as a supply form for detergents.
Hitherto, only two methods have been developed for the dispensing
of detergent tablets by the consumer. On the one hand, dispensing aids
are included with the tablets in the retail pack, the tablets having to be
inserted into these dispensing aids before use. The dispenser, including
the tablet inserted therein, is then added to the laundry in the washing
drum. These dispensers, which generally have a net-like construction, are
supposed to prevent direct contact between the detergent tablets and the
laundry because the sometimes fairly long dissolving times without a
dispenser would lead to direct contact between tablet residues and the
laundry which, in turn, can cause local decoloration or lightening in color of
CA 02307430 2000-OS-03
2
the laundry. Another function of the dispenser is to improve the dissolving
behavior of tablets in drum-type washing machines. Since the washing
drum is inclined slightly forwards, it can happen that the tablet is pressed
by the moving laundry into the gap between the sealing ring and the bull's-
eye. The water has hardly any chance of reaching the tablet on this rubber
collar, so that the tablet remains behind on the rubber collar either
undissolved or disintegrating too slowly. Accordingly, the consumer on the
one hand has the inconvenience of a relatively poor washing result,
because the active substance of the undissolved tablet is either unavailable
or is available too late in the wash cycle; on the other hand, having to
remove tablet remains from the rubber collar is also an inconvenience to
the consumer. The dispensers are supposed to prevent this phenomenon
because the moving laundry engages part of the dispensing "net" or solid
tablet and entrains the dispenser, even if it should happen to be present on
the rubber collar.
On the other hand, detergent tablets are available on the market
which can be flushed into the washing process from the dispensing
compartment of domestic washing machines in the same way as
conventional washing powders. Since these tablets disintegrate in the
dispensing compartment itself and hence are flushed into the machine as
powders, they are not attended by the above-mentioned problem known as
pinhole spotting. However, in view both of the small amount of water used
for flushing and the short flushing time, detergent tablets of the type in
question have to meet much more stringent requirements than conven-
tional tablets and dispensers.
The problem of spotting in the case of in-drum dispensing occurs in
particular with tablets containing bleaching agents. The direct contact of
the moistened bleach-containing tablet with the laundry results locally in a
high concentration of peroxygen which is capable of bleaching dyes.
Bleach-containing detergent tablets are also widely described in the prior
art literature:
CA 02307430 2000-OS-03
3
Thus, European patent application EP-A-0 481 793 (Unilever)
describes detergent tablets in which individual ingredients are separated
from others. The detergent tablets disclosed in this document contain
sodium percarbonate which is separated from all other components that
could influence its stability. The document in question does not contain
any particulars of the particle size or the dispensing of the final detergent
tablets.
Detergent tablets containing sodium percarbonate are described in
earlier German patent application DE 198 43 778.1 (Henkel KGaA). The
tablets described therein are distinguished by high hardness and by a high
disintegration rate because at least 60% by weight of the sodium
percarbonate present in them consists of particles smaller than 0.8 mm in
size. Following the teaching of the patent application in question, it is
possible to produce detergent tablets which can be flushed into the
washing process from the dispensing compartment of domestic washing
machines.
International patent application WO 98142816 (Unilever) describes
detergent tablets in which the bleaching agent is selected from sodium
perborate tetrahydrate, sodium percarbonate or mixtures thereof. The
document in question does not contain any particulars of the application of
these tablets.
The problem addressed by the present invention was to avoid the
disadvantages of detergent tablets designed for dispensing via the washing
drum. More particularly, the problem addressed by the present invention
was to provide a washing process in which there would be no need to use
dispensers, but which would still be free from problems in regard to
dissolving behavior and spotting. Since the insertion of the tablet into a
dispenser and the closing of the dispenser are regarded by the consumer
as additional and unnecessary steps, the invention set out to provide a
washing process which would enable the consumer to dispense tablets via
the washing drum without any burdensome extra effort.
CA 02307430 2000-OS-03
4
Description of the Invention
It has now been found that a washing process in which the
detergent tablets dispensed via the washing drum contain sodium
percarbonate fulfils the stated requirements.
The present invention relates to a process for washing laundry using
detergent tablets in a domestic washing machine, characterized in that the
detergent tablets are added to the laundry in the drum without a dispensing
aid before the washing process and contain sodium percarbonate.
It has been found that the washing process according to the inven-
tion overcomes the disadvantages described above. Detergent tablets
containing sodium percarbonate may be directly introduced into the drum in
the washing process according to the invention without any need to use a
dispensing aid to avoid dissolving or spotting problems.
To develop the required bleaching effect, the detergent tablets used
in the washing process according to the invention contain sodium
percarbonate. "Sodium percarbonate" is a non-specific term used for
sodium carbonate peroxohydrates which, strictly speaking, are not
"percarbonates" (i.e. salts of percarbonic acid), but hydrogen peroxide
adducts with sodium carbonate. The commercial material has the mean
composition 2 Na2C03 ~ 3 H202 and, accordingly, is not a peroxycarbonate.
Sodium percarbonate forms a white water-soluble powder with a density of
2.14 gcm3 which readily decomposes into sodium carbonate and bleaching
or oxidizing oxygen.
Sodium carbonate peroxohydrate was obtained for the first time in
1899 by precipitation with ethanol from a solution of sodium carbonate in
hydrogen peroxide, but was mistakenly regarded as peroxycarbonate. It
was only in 1909 that the compound was recognised as a hydrogen
peroxide addition compound. Nevertheless, the historical name "sodium
percarbonate" has been adopted in practice.
On an industrial scale, sodium percarbonate is mainly produced by
precipitation from aqueous solution (so-called wet process). In this pro-
CA 02307430 2000-OS-03
cess, aqueous solutions of sodium carbonate and hydrogen peroxide are
combined and the sodium percarbonate is precipitated by salting-out
agents (mainly sodium chloride), crystallization aids (for example polyphos-
phates, polyacrylates) and stabilizers (for example Mg2+ ions). The
5 precipitated salt which still contains 5 to 12% by weight of mother liquor
is
then removed by centrifuging and dried at 90°C in fluidized bed dryers.
The bulk density of the end product can vary between 800 and 1200 gll
according to the production process. In general, the percarbonate is
stabilized by an additional coating. Coating processes and materials are
widely described in the patent literature. Basically, any commercially
available percarbonate types as marketed, for example, by Solvay Interox,
Degussa, Kemira and Akzo may be used in accordance with the present
invention. According to the invention, the advantageousness of the rapid
tablet disintegration stems from the defined particle size of the
percarbonate.
The sodium percarbonate is used in varying quantities according to the
required performance of the product. Normal contents are between 5 and
50% by weight, preferably between 10 and 40% by weight and more
preferably between 15 and 35% by weight, based on the tablet as a whole.
Preferred washing processes according to the invention are characterized
in that the detergent tablets used contain sodium percarbonate in quantities
of 1 to 40% by weight, preferably in quantities of 5 to 30% by weight and
more preferably in quantities of 10 to 25% by weight, based on tablet
weight.
The advantageousness of using sodium percarbonate within certain
particle size ranges described in the prior art literature can also be applied
to the process according to the invention. Thus, preferred washing
processes are characterized in that at least 60% by weight, preferably at
least 70% by weight, more preferably at least 80% by weight and most
preferably at least 90% by weight of the sodium percarbonate particles
present in the detergent tablets have a particle size below 0.8 mm. In one
CA 02307430 2000-OS-03
6
particularly preferred embodiment, the sodium percarbonate present in the
tablets is substantially free from particles larger than 1.2 mm in size.
In addition to the sodium percarbonate, the detergent tablets used in
the washing process according to the invention may contain bleach
activators) which represents a preferred embodiment of the present
invention. Bleach activators are incorporated in detergents in order to
obtain an improved bleaching effect at washing temperatures of 60°C or
lower. According to the invention, compounds which form aliphatic
peroxocarboxylic acids preferably containing 1 to 10 carbon atoms and
more preferably 2 to 4 carbon atoms andlor optionally substituted
perbenzoic acid under perhydrolysis conditions may be used as bleach
activators. Suitable bleach activators are substances which contain O-
and/or N-acyl groups with the number of carbon atoms indicated and/or
optionally substituted benzoyl groups. Preferred bleach activators are
polyacylated alkylenediamines, more especially tetraacetyl
ethylenediamine (TAED), acylated triazine derivatives, more particularly
1,5-diacetyl-2,4-dioxohexahydro-1,3,5-triazine (DADHT), acylated glycol
urils, more particularly tetraacetyl glycol uril (TAGU), N-acylimides, more
particularly N-nonanoyl succinimide (NOSI), acylated phenol sulfonates,
more particularly n-nonanoyl- or isononanoyl-oxybenzenesulfonate (n- or
iso-NOBS), carboxylic anhydrides, more especially phthalic anhydride,
acylated polyhydric alcohols, more especially triacetin, ethylene glycol
diacetate and 2,5-diacetoxy-2,5-dihydrofuran.
In addition to or instead of the conventional bleach activators, so-
called bleach catalysts may also be incorporated in the tablets. Bleach
catalysts are bleach-boosting transition metal salts or transition metal
complexes such as, for example, Mn-, Fe-, Co-, Ru- or Mo-salen
complexes or carbonyl complexes. Mn-, Fe-, Co-, Ru-, Mo-, Ti-, V- and Cu-
complexes with N-containing tripod ligands and Co-, Fe-, Cu- and Ru-
ammine complexes may also be used as bleach catalysts.
The tablets used in the washing process according to the invention
CA 02307430 2000-OS-03
7
normally contain between 0.5 and 30% by weight, preferably between 1
and 20% by weight and more preferably between 2 and 15% by weight -
based on the tablet as a whole - of one or more bleach activators or bleach
catalysts. These quantities may vary according to the application
envisaged for the tablets. Thus, in typical heavy-duty detergent tablets,
bleach activator contents of 0.5 to 10% by weight, preferably 2 to 8% by
weight and more preferably 4 to 6% by weight are normal whereas bleach
tablets can have much higher contents, for example between 5 and 30% by
weight, preferably between 7.5 and 25% by weight and more preferably
between 10 and 20% by weight. The expert is not restricted in his freedom
of formulation and is able in this way to produce laundry detergent tablets,
dishwasher tablets or bleach tablets with a stronger or weaker bleaching
effect by varying the contents of bleach activator and bleaching agent.
Particularly preferred bleach activators are N,N,N',N'-tetraacetyl
ethylenediamine, which is widely used in laundry/dishwasher detergents,
and n-nonanoyloxybenzenesulfonate (NOBS). Accordingly, preferred
detergent tablets are characterized in that they contain tetraacetyl
ethylenediamine in the quantities mentioned above as bleach activator.
Besides the ingredients mentioned above, the detergent tablets
used in the washing process according to the invention may contain other
ingredients in quantities determined by the particular application envisaged
for the tablets. Thus, substances from the groups of surfactants, builders
and polymers are particularly suitable for use in the detergent tablets
according to the invention. The expert will again have no difficulty in
selecting the individual components and the quantities in which to use
them. Thus, a heavy-duty detergent tablet will contain relatively large
quantities of surfactants) whereas a bleach tablet may well contain no
surfactant at all. The quantity of builders) used also varies according to
the particular application envisaged.
The detergent tablets used in the washing process according to the
invention according to the invention may contain any of the builders
CA 02307430 2000-OS-03
8
normally used in detergents, i.e. in particular zeolites, silicates,
carbonates,
organic co-builders and - providing there are no ecological objections to
their use - also phosphates.
Suitable crystalline layered sodium silicates correspond to the
general formula NaMSixO~+~A y H20, where M is sodium or hydrogen, x is
a number of 1.9 to 4 and y is a number of 0 to 20, preferred values for x
being 2, 3 or 4. Crystalline layered silicates such as these are described,
for example, in European patent application EP-A-0 164 514. Preferred
crystalline layered silicates corresponding to the above formula are those in
which M is sodium and x assumes the value 2 or 3. Both ~3- and 8-sodium
disilicates Na2Si205A y H20 are particularly preferred, ~3-sodium disilicate
being obtainable, for example, by the process described in International
patent application WO-A- 91!08171.
Other useful builders are amorphous sodium silicates with a
modulus (Na20:Si02 ratio) of 1:2 to 1:3.3, preferably 1:2 to 1:2.8 and more
preferably 1:2 to 1:2.6 which dissolve with delay and exhibit multiple wash
cycle properties. The delay in dissolution in relation to conventional
amorphous sodium silicates can have been obtained in various ways, for
example by surface treatment, compounding, compacting or by overdrying.
In the context of the invention, the term "amorphous" is also understood to
encompass "X-ray amorphous". In other words, the silicates do not
produce any of the sharp X-ray reflexes typical of crystalline substances in
X-ray diffraction experiments, but at best one or more maxima of the
scattered X-radiation which have a width of several degrees of the
diffraction angle. However, particularly good builder properties may even
be achieved where the silicate particles produce crooked or even sharp
diffraction maxima in electron diffraction experiments. This may be
interpreted to mean that the products have microcrystalline regions
between 10 and a few hundred nm in size, values of up to at most 50 nm
and, more particularly, up to at most 20 nm being preferred. So-called X-
ray amorphous silicates such as these, which also dissolve with delay in
CA 02307430 2000-OS-03
9
relation to conventional waterglasses, are described for example in
German patent application DE-A-44 00 024. Compacted amorphous
silicates, compounded amorphous silicates and overdried X-ray-amorphous
silicates are particularly preferred.
The finely crystalline, synthetic zeolite containing bound water used
in accordance with the invention is preferably zeolite A andlor zeolite P.
Zeolite MAP~ (Crosfield) is a particularly preferred P-type zeolite.
However, zeolite X and mixtures of A, X and/or P are also suitable.
According to the invention, it is also preferred to use, for example, a co-
crystallizate of zeolite X and zeolite A (ca. 80% by weight zeolite X) which
is marketed by CONDEA Augusta S.p.A. under the name of VEGOBOND
AX~ and which may be described by the following formula:
nNa20 ~ (1-n)K20 ~ AI203 ~ (2 - 2.5)Si02 ~ (3.5 - 5.5) H20.
The zeolite may be used both as a builder in a granular compound and as
a kind of "powder" to be applied to the entire mixture to be tabletted, both
routes normally being used to incorporate the zeolite in the premix.
Suitable zeolites have a mean particle size of less than 10 ~m (volume
distribution, as measured by the Coulter Counter Method) and contain
preferably 18 to 22% by weight and more preferably 20 to 22% by weight of
bound water.
The generally known phosphates may of course also be used as
builders providing their use should not be avoided on ecological grounds.
Among the large number of commercially available phosphates, alkali
metal phosphates have the greatest importance in the detergent industry,
pentasodium triphosphate and pentapotassium triphosphate (sodium and
potassium tripolyphosphate) being particularly preferred.
"Alkali metal phosphates" is the collective term for the alkali metal
(more particularly sodium and potassium) salts of the various phosphoric
acids, including metaphosphoric acids (HP03)~ and orthophosphoric acid
CA 02307430 2000-OS-03
(H3P04) and representatives of higher molecular weight. The phosphates
combine several advantages: they act as alkalinity sources, prevent lime
deposits on machine parts and lime incrustations in fabrics and, in addition,
contribute towards the cleaning effect.
5 Sodium dihydrogen phosphate (NaH2P04) exists as the dihydrate
(density 1.91 gcm3, melting point 60°) and as the monohydrate (density
2.04 gcm3). Both salts are white readily water-soluble powders which, on
heating, lose the water of crystallization and, at 200°, are converted
into the
weakly acidic diphosphate (disodium hydrogen diphosphate, Na2H2P20~)
10 and, at higher temperatures, into sodium trimetaphosphate (Na3P309) and
Maddrell's salt (see below). NaH2P04 shows an acidic reaction. It is
formed by adjusting phosphoric acid with sodium hydroxide to a pH value
of 4.5 and spraying the resulting "mash". Potassium dihydrogen phosphate
(primary or monobasic potassium phosphate, potassium biphosphate,
KDP), KH2P04, is a white salt with a density of 2.33 gcm3, has a melting
point of 253° [decomposition with formation of potassium polyphosphate
(KP03)X] and is readily soluble in water.
Disodium hydrogen phosphate (secondary sodium phosphate),
Na2HP04, is a colorless, readily water-soluble crystalline salt. It exists in
water-free form and with 2 moles (density 2.066 gcm3, water loss at
95°), 7
moles (density 1.68 gcm3, melting point 48° with loss of 5 H20) and 12
moles of water (density 1.52 gcm3, melting point 35° with loss of 5
H20),
becomes water-free at 100° and, on fairly intensive heating, is
converted
into the diphosphate Na4P207. Disodium hydrogen phosphate is prepared
by neutralization of phosphoric acid with soda solution using phenol-
phthalein as indicator. Dipotassium hydrogen phosphate (secondary or
dibasic potassium phosphate), K2HP04, is an amorphous white salt which
is readily soluble in water.
Trisodium phosphate, tertiary sodium phosphate, Na3P04, consists
of colorless crystals which have a density of 1.62 gcm' and a melting point
of 73-76° (decomposition) as the dodecahydrate, a melting point of
100° as
CA 02307430 2000-OS-03
11
the decahydrate (corresponding to 19-20% P205) and a density of 2.536
gcm3 in water-free form (corresponding to 39-40% P2O5). Trisodium
phosphate is readily soluble in water through an alkaline reaction and is
prepared by concentrating a solution of exactly 1 mole of disodium
phosphate and 1 mole of NaOH by evaporation. Tripotassium phosphate
(tertiary or tribasic potassium phosphate), K3P04, is a white deliquescent
granular powder with a density of 2.56 gcm3, has a melting of 1340° and
is
readily soluble in water through an alkaline reaction. It is formed, for
example, when Thomas slag is heated with coal and potassium sulfate.
Despite their higher price, the more readily soluble and therefore highly
effective potassium phosphates are often preferred to corresponding
sodium compounds in the detergent industry.
Tetrasodium diphosphate (sodium pyrophosphate), Na4P207, exists
in water-free form (density 2.534 gcm3, melting point 988°, a figure of
880°
has also been mentioned) and as the decahydrate (density 1.815 - 1.836
gcm3, melting point 94° with loss of water). Both substances are
colorless
crystals which dissolve in water through an alkaline reaction. Na4P207 is
formed when disodium phosphate is heated to >200° or by reacting
phosphoric acid with soda in a stoichiometric ratio and spray-drying the
solution. The decahydrate complexes heavy metal salts and hardness
salts and, hence, reduces the hardness of water. Potassium diphosphate
(potassium pyrophosphate), K4P207, exists in the form of the trihydrate and
is a colorless hygroscopic powder with a density of 2.33 gcm3 which is
soluble in water, the pH value of a 1 % solution at 25° being 10.4.
Relatively high molecular weight sodium and potassium phosphates
are formed by condensation of NaH2P04 or KH2P04. They may be divided
into cyclic types, namely the sodium and potassium metaphosphates, and
chain types, the sodium and potassium polyphosphates. The chain types
in particular are known by various different names: fused or calcined
phosphates, Graham's salt, Kurrol's salt and Maddrell's salt. All higher
sodium and potassium phosphates are known collectively as condensed
CA 02307430 2000-OS-03
12
phosphates.
The industrially important pentasodium triphosphate, Na5P30~o
(sodium tripolyphosphate), is a non-hygroscopic white water-soluble salt
which crystallizes without water or with 6 HZO and which has the general
formula Na0-[P(O)(ONa)-O]~-Na where n = 3. Around 17 g of the salt free
from water of crystallization dissolve in 100 g of water at room temperature,
around 20 g at 60° and around 32 g at 100°. After heating of the
solution
for 2 hours to 100°, around 8% orthophosphate and 15% diphosphate are
formed by hydrolysis. In the preparation of pentasodium triphosphate,
phosphoric acid is reacted with soda solution or sodium hydroxide in a
stoichiometric ratio and the solution is spray-dried. Similarly to Graham's
salt and sodium diphosphate, pentasodium triphosphate dissolves many
insoluble metal compounds (including lime soaps, etc.). Pentapotassium
triphosphate, K5P30~o (potassium tripolyphosphate), is marketed for
example in the form of a 50% by weight solution (> 23% P205, 25% K20).
The potassium polyphosphates are widely used in the detergent industry.
Sodium potassium tripolyphosphates, which may also be used in
accordance with the invention, also exist. They are formed for example
when sodium trimetaphosphate is hydrolyzed with KOH:
(NaP03)3 + 2 KOH ~ Na3K2P30~o + H20
According to the invention, they may be used in exactly the same
way as sodium tripolyphosphate, potassium tripolyphosphate or mixtures
thereof. Mixtures of sodium tripolyphosphate and sodium potassium
tripolyphosphate or mixtures of potassium tripolyphosphate and sodium
potassium tripolyphosphate or mixtures of sodium tripolyphosphate and
potassium tripolyphosphate and sodium potassium tripolyphosphate may
also be used in accordance with the invention.
Organic cobuilders suitable for use in the detergent tablets
according to the invention are, in particular, polycarboxylateslpolycarboxylic
acids, polymeric polycarboxylates, aspartic acid, polyacetals, dextrins,
CA 02307430 2000-OS-03
13
other organic cobuilders (see below) and phosphonates. These classes of
substances are described in the following.
Useful organic builders are, for example, the polycarboxylic acids
usable, for example, in the form of their sodium salts, polycarboxylic acids
in this context being understood to be carboxylic acids which bear more
than one acid function. Examples of such carboxylic acids are citric acid,
adipic acid, succinic acid, glutaric acid, malic acid, tartaric acid, malefic
acid,
fumaric acid, sugar acids, aminocarboxylic acids, nitrilotriacetic acid (NTA),
providing their use is not ecologically unsafe, and mixtures thereof.
Preferred salts are the salts of the polycarboxylic acids, such as citric
acid,
adipic acid, succinic acid, glutaric acid, tartaric acid, sugar acids and
mixtures thereof.
The acids per se may also be used. Besides their builder effect, the
acids also typically have the property of an acidifying component and,
hence, also serve to establish a relatively low and mild pH value in
detergents. Citric acid, succinic acid, glutaric acid, adipic acid, gluconic
acid and mixtures thereof are particularly mentioned in this regard.
Other suitable builders are polymeric polycarboxylates such as, for
example, the alkali metal salts of polyacrylic or polymethacrylic acid, for
example those with a relative molecular weight of 500 to 70,000 g/mole.
The molecular weights mentioned in this specification for polymeric
polycarboxylates are weight-average molecular weights MW of the particular
acid form which, basically, were determined by gel permeation
chromatography (GPC) using a UV detector. The measurement was
carried out against an external polyacrylic acid standard which provides
realistic molecular weight values by virtue of its structural similarity to
the
polymers investigated. These values differ distinctly from the molecular
weights measured against polystyrene sulfonic acids as standard. The
molecular weights measured against polystyrene sulfonic acids are
generally higher than the molecular weights mentioned in this specification.
Particularly suitable polymers are polyacrylates which preferably
CA 02307430 2000-OS-03
14
have a molecular weight of 2,000 to 20,000 glmole. By virtue of their
superior solubility, preferred representatives of this group are the short-
chain polyacrylates which have molecular weights of 2,000 to 10,000
glmole and, more particularly, 3,000 to 5,000 glmole.
Also suitable are copolymeric polycarboxylates, particularly those of
acrylic acid with methacrylic acid and those of acrylic acid or methacrylic
acid with malefic acid. Acrylic acidlmaleic acid copolymers containing 50 to
90% by weight of acrylic acid and 50 to 10% by weight of malefic acid have
proved to be particularly suitable. Their relative molecular weights, based
on the free acids, are generally in the range from 2,000 to 70,000 g/mole,
preferably in the range from 20,000 to 50,000 g/mole and more preferably
in the range from 30,000 to 40,000 glmole.
The (co)polymeric polycarboxylates may be used either in powder
form or in the form of an aqueous solution. The content of (co)polymeric
polycarboxylates in the detergent is preferably from 0.5 to 20% by weight
and more preferably from 3 to 10% by weight.
In order to improve solubility in water, the polymers may also contain
allyl sulfonic acids, such as allyloxybenzene sulfonic acid and methallyl
sulfonic acid, as monomer.
Other particularly preferred polymers are biodegradable polymers of
more than two different monomer units, for example those which contain
salts of acrylic acid and malefic acid and vinyl alcohol or vinyl alcohol
derivatives as monomers or those which contain salts of acrylic acid and 2-
alkylallyl sulfonic acid and sugar derivatives as monomers.
Other preferred copolymers are those which are described in
German patent applications DE-A-43 03 320 and DE-A-44 17 734 and
which preferably contain acrolein and acrylic acidlacrylic acid salts or
acrolein and vinyl acetate as monomers.
Other preferred builders are polymeric aminodicarboxylic acids, salts
or precursors thereof. Particular preference is attributed to polyaspartic
acids or salts and derivatives thereof which, according to German patent
CA 02307430 2000-OS-03
application DE-A-195 40 086, are also said to have a bleach-stabilizing
effect in addition to their co-builder properties.
Other suitable builders are polyacetals which may be obtained by
reaction of dialdehydes with polyol carboxylic acids containing 5 to 7
5 carbon atoms and at least three hydroxyl groups. Preferred polyacetals
are obtained from dialdehydes, such as glyoxal, glutaraldehyde, terephthal-
aldehyde and mixtures thereof and from polyol carboxylic acids, such as
gluconic acid andlor glucoheptonic acid.
Other suitable organic builders are dextrins, for example oligomers
10 or polymers of carbohydrates which may be obtained by partial hydrolysis
of starches. The hydrolysis may be carried out by standard methods, for
example acid- or enzyme-catalyzed methods. The end products are
preferably hydrolysis products with average molecular weights of 400 to
500,000 glmole. A polysaccharide with a dextrose equivalent (DE) of 0.5 to
15 40 and, more particularly, 2 to 30 is preferred, the DE being an accepted
measure of the reducing effect of a polysaccharide by comparison with
dextrose which has a DE of 100. Both maltodextrins with a DE of 3 to 20
and dry glucose sirups with a DE of 20 to 37 and also so-called yellow
dextrins and white dextrins with relatively high molecular weights of 2,000
to 30,000 g/mole may be used.
The oxidized derivatives of such dextrins are their reaction products
with oxidizing agents which are capable of oxidizing at least one alcohol
function of the saccharide ring to the carboxylic acid function. Dextrins thus
oxidized and processes for their production are known, for example, from
European patent applications EP-A-0 232 202, EP-A-0 427 349, EP-A-0
472 042 and EP-A-0 542 496 and from International patent applications
WO 92118542, WO 93/08251, WO 93116110, WO 94128030, WO 95107303,
WO 95112619 and WO 95120608. An oxidized oligosaccharide
corresponding to German patent application DE-A-196 00 018 is also
suitable. A product oxidized at C6 of the saccharide ring can be particularly
advantageous.
CA 02307430 2000-OS-03
16
Other suitable co-builders are oxydisuccinates and other derivatives
of disuccinates, preferably ethylenediamine disuccinate. Ethylenediamine-
N,N'-disuccinate (EDDS) is preferably used in the form of its sodium or
magnesium salts. Glycerol disuccinates and glycerol trisuccinates are also
preferred in this connection. The quantities used in zeolite-containing
and/or silicate-containing formulations are from 3 to 15% by weight.
Other useful organic co-builders are, for example, acetylated
hydroxycarboxylic acids and salts thereof which may optionally be present
in lactone form and which contain at least 4 carbon atoms, at least one
hydroxy group and at most two acid groups. Co-builders such as these are
described, for example, in International patent application WO-A-95120029.
Another class of substances with co-builder properties are the
phosphonates, more particularly hydroxyalkane and aminoalkane phos-
phonates. Among the hydroxyalkane phosphonates, 1-hydroxyethane-1,1-
diphosphonate (HEDP) is particularly important as a co-builder. It is
preferably used in the form of the sodium salt, the disodium salt showing a
neutral reaction and the tetrasodium salt an alkaline reaction (pH 9).
Preferred aminoalkane phosphonates are ethylenediamine tetramethylene
phosphonate (EDTMP), diethylenetriamine pentamethylenephosphonate
(DTPMP) and higher homologs thereof. They are preferably used in the
form of the neutrally reacting sodium salts, for example as the hexasodium
salt of EDTMP or as the hepta- and octasodium salts of DTPMP. Of the
phosphonates, HEDP is preferably used as a builder. In addition, the
aminoalkane phosphonates have a pronounced heavy metal binding
capacity. Accordingly, it can be of advantage, particularly where the
detergents also contain bleach, to use aminoalkane phosphonates, more
particularly DTPMP, or mixtures of the phosphonates mentioned.
In addition, any compounds capable of forming complexes with
alkaline earth metal ions may be used as co-builders.
The quantity of builder used is normally between 10 and 70% by
weight, preferably between 15 and 60% by weight and more preferably
CA 02307430 2000-OS-03
17
between 20 and 50% by weight. The quantity of builder used is again
dependent upon the particular application envisaged, so that bleach tablets
can contain larger quantities of builders (for example between 20 and 70%
by weight, preferably between 25 and 65% by weight and more preferably
between 30 and 55% by weight) than, for example, laundry detergent
tablets (normally 10 to 50% by weight, preferably 12.5 to 45% by weight
and more preferably 17.5 to 37.5% by weight).
In preferred washing processes acording to the invention, the
detergent tablets additionally contain one or more surfactant(s). Anionic,
nonionic, cationic andlor amphoteric surfactants or mixtures thereof may be
used in the detergent tablets used in the washing process according to the
invention. Mixtures of anionic and nonionic surfactants are preferred from
the performance point of view. The total surfactant content of the tablets is
from 5 to 60% by weight, based on the weight of the tablet, surfactant
contents above 15% by weight being preferred.
The anionic surfactants used are, for example, those of the sulfonate
and sulfate type. Preferred surfactants of the sulfonate type are C9_~3 alkyl
benzenesulfonates, olefin sulfonates, i.e. mixtures of alkene and hydroxy-
alkane sulfonates, and the disulfonates obtained, for example, from C~2_~8
monoolefins with an internal or terminal double bond by sulfonation with
gaseous sulfur trioxide and subsequent alkaline or acidic hydrolysis of the
sulfonation products. Other suitable surfactants of the sulfonate type are
the alkane sulfonates obtained from C~2_~8 alkanes by sulfochlorination or
sulfoxidation and subsequent hydrolysis or neutralization. The esters of a-
sulfofatty acids (ester sulfonates), for example the a-sulfonated methyl
esters of hydrogenated coconut oil, palm kernel oil or tallow fatty acids.
Other suitable anionic surfactants are sulfonated fatty acid glycerol
esters, i.e. the monoesters, diesters and triesters and mixtures thereof
which are obtained where production is carried out by esterification of a
monoglycerol with 1 to 3 moles of fatty acid or in the transesterification of
triglycerides with 0.3 to 2 moles of glycerol. Preferred sulfonated fatty acid
CA 02307430 2000-OS-03
18
glycerol esters are the sulfonation products of saturated C6_22 fatty acids,
for example caproic acid, caprylic acid, capric acid, myristic acid, lauric
acid, palmitic acid, stearic acid or behenic acid.
Preferred alk(en)yl sulfates are the alkali metal salts and, in
particular, the sodium salts of the sulfuric acid semiesters of C~2_~8 fatty
alcohols, for example coconut alcohol, tallow alcohol, lauryl, myristyl, cetyl
or stearyl alcohol, or C~o_zo oxoalcohols and the corresponding semiesters
of secondary alcohols with the same chain length. Other preferred
alk(en)yl sulfates are those with the chain length mentioned which contain
a synthetic, linear alkyl chain based on a petrochemical and which are
similar in their degradation behavior to the corresponding compounds
based on oleochemical raw materials. C~2_~s alkyl sulfates and C~2_~5 alkyl
sulfates and also C1a_~5 alkyl sulfates alkyl sulfates are particularly
preferred
from the washing performance point of view. Other suitable anionic
surfactants are 2,3-alkyl sulfates which may be produced, for example, in
accordance with US 3,234,258 or US 5,075,041 and which are
commercially obtainable as products of the Shell Oil Company under the
name of DAN~.
The sulfuric acid monoesters of linear or branched C~_2~ alcohols
ethoxylated with 1 to 6 moles of ethylene oxide, such as 2-methyl-branched
C9_,~ alcohols containing on average 3.5 moles of ethylene oxide (EO) or
C~2_~$ fatty alcohols containing 1 to 4 EO, are also suitable. In view of
their
high foaming capacity, they are normally used in only relatively small
quantities, for example in quantities of 1 to 5% by weight, in dishwashing
detergents.
Other suitable anionic surfactants are the salts of alkyl sulfosuccinic
acid which are also known as sulfosuccinates or as sulfosuccinic acid
esters and which represent monoesters and/or diesters of sulfosuccinic
acid with alcohols, preferably fatty alcohols and, more particularly,
ethoxylated fatty alcohols. Preferred sulfosuccinates contain Cs_~8 fatty
alcohol molecules or mixtures thereof. Particularly preferred
CA 02307430 2000-OS-03
19
sulfosuccinates contain a fatty alcohol molecule derived from ethoxylated
fatty alcohols which, considered in isolation, represent nonionic surfactants
(for a description, see below). Of these sulfosuccinates, those of which the
fatty alcohol molecules are derived from narrow-range ethoxylated fatty
alcohols are particularly preferred. Alk(en)yl succinic acid preferably
containing 8 to 18 carbon atoms in the alk(en)yl chain or salts thereof may
also be used.
Other suitable anionic surfactants are, in particular, soaps. Suitable
soaps are, in particular, saturated fatty acid soaps, such as the salts of
lauric acid, myristic acid, palmitic acid, stearic acid, hydrogenated erucic
acid and behenic acid, and soap mixtures derived in particular from natural
fatty acids, for example coconut, palm kernel or tallow acids.
The anionic surfactants, including the soaps, may be present in the
form of their sodium, potassium or ammonium salts and as soluble salts of
organic bases, such as mono-, di- or triethanolamine. The anionic
surfactants are preferably present in the form of their sodium or potassium
salts and, more preferably, in the form of their sodium salts.
Preferred nonionic surfactants are alkoxylated, advantageously
ethoxylated, more especially primary alcohols preferably containing 8 to 18
carbon atoms and, on average, 1 to 12 moles of ethylene oxide (EO) per
mole of alcohol, in which the alcohol radical may be linear or, preferably,
methyl-branched in the 2-position or may contain linear and methyl-
branched radicals in the form of the mixtures typically present in oxoalcohol
radicals. However, alcohol ethoxylates containing linear radicals of
alcohols of native origin with 12 to 18 carbon atoms, for example coconut
oil, palm oil, tallow or oleyl alcohol, and on average 2 to 8 EO per mole of
alcohol are particularly preferred. Preferred ethoxylated alcohols include,
for example, C~2_~4 alcohols containing 3 EO or 4 EO, C9_» alcohol
containing 7 EO, C~3_~5 alcohols containing 3 EO, 5 EO, 7 EO or 8 EO,
C~2_~8 alcohols containing 3 EO, 5 EO or 7 EO and mixtures thereof, such
as mixtures of C~2_~4 alcohol containing 3 EO and C~2_~$ alcohol containing
CA 02307430 2000-OS-03
5 EO. The degrees of ethoxylation mentioned represent statistical mean
values which, for a special product, can be a whole number or a broken
number. Preferred alcohol ethoxylates have a narrow homolog distribution
(narrow range ethoxylates, NRE). In addition to these nonionic surfactants,
5 fatty alcohols containing more than 12 EO may also be used, examples
including tallow fatty alcohol containing 14 EO, 25 EO, 30 EO or 40 EO.
Suitable other nonionic surfactants are alkyl glycosides with the
general formula RO(G)X where R is a primary, linear or methyl-branched,
more particularly 2-methyl-branched, aliphatic radical containing 8 to 22
10 and preferably 12 to 18 carbon atoms and G stands for a glycose unit
containing 5 or 6 carbon atoms, preferably glucose. The degree of
oligomerization x, which indicates the distribution of monoglycosides and
oligoglycosides, is a number of 1 to 10 and preferably 1.2 to 1.4.
Another class of preferred nonionic surfactants which may be used
15 either as sole nonionic surfactant or in combination with other nonionic
surfactants are alkoxylated, preferably ethoxylated or ethoxylated and
propoxylated, fatty acid alkyl esters preferably containing 1 to 4 carbon
atoms in the alkyl chain, more especially the fatty acid methyl esters which
are described, for example, in Japanese patent application JP 58!217598
20 or which are preferably produced by the process described in International
patent application WO-A-90113533.
Nonionic surfactants of the amine oxide type, for example N-
coconutalkyl-N,N-dimethylamine oxide and N-tallowalkyl-N,N-dihydroxy-
ethylamine oxide, and the fatty acid alkanolamide type are also suitable.
The quantity in which these nonionic surfactants are used is preferably no
more than the quantity in which the ethoxylated fatty alcohols are used
and, more preferably, no more than half that quantity.
Other suitable surfactants are polyhydroxyfatty acid amides
corresponding to formula (I):
R~
CA 02307430 2000-OS-03
21
R-C O-N-[Z] ( I )
in which RCO is an aliphatic acyl group containing 6 to 22 carbon atoms,
R' is hydrogen, an alkyl or hydroxyalkyl group containing 1 to 4 carbon
atoms and [Z] is a linear or branched polyhydroxyalkyl group containing 3
to 10 carbon atoms and 3 to 10 hydroxyl groups. The polyhydroxyfatty acid
amides are known substances which may normally be obtained by
reductive amination of a reducing sugar with ammonia, an alkylamine or an
alkanolamine and subsequent acylation with a fatty acid, a fatty acid alkyl
ester or a fatty acid chloride.
The group of polyhydroxyfatty acid amides also includes compounds
corresponding to formula (II):
R'-O-R2
R-C O-N-[Z] ( I I )
in which R is a linear or branched alkyl or alkenyl group containing 7 to 12
carbon atoms, R~ is a linear, branched or cyclic alkyl group or an aryl group
containing 2 to 8 carbon atoms and R2 is a linear, branched or cyclic alkyl
group or an aryl group or an oxyalkyl group containing 1 to 8 carbon atoms,
C~.~ alkyl or phenyl groups being preferred, and [Z] is a linear polyhydroxy-
alkyl group, of which the alkyl chain is substituted by at least two hydroxyl
groups, or alkoxylated, preferably ethoxylated or propoxylated, derivatives
of that group.
[Z] is preferably obtained by reductive amination of a reduced sugar,
for example glucose, fructose, maltose, lactose, galactose, mannose or
xylose. The N-alkoxy- or N-aryloxy-substituted compounds may then be
converted into the required polyhydroxyfatty acid amides by reaction with
fatty acid methyl esters in the presence of an alkoxide as catalyst, for
example in accordance with the teaching of International patent application
WO-A-95!07331.
CA 02307430 2000-OS-03
22
According to the invention, preferred washing processes are
characterized in that the detergent tablets used contain anionic and
nonionic surfactant(s). Performance-related advantages can arise out of
certain quantity ratios in which the individual classes of surfactants are
used. Particularly preferred washing processes are characterized in that
the detergent tablets contain anionic and/or nonionic surfactants) and
have total surfactant contents above 2.5% by weight, preferably above 5%
by weight and more preferably above 10% by weight, based on the weight
of the tablet.
For example, in particularly preferred washing processes, the ratio of
anionic surfactants) to nonionic surfactants) in the tablets used is from
10:1 to 1:10, preferably from 7.5:1 to 1:5 and more preferably from 5:1 to
1:2. In other preferred washing processes, the detergent tablets contain
surfactant(s), preferably anionic andlor nonionic surfactants, in quantities
of
5 to 40% by weight, preferably 7.5 to 35% by weight, more preferably 10 to
30% by weight and most preferably 12.5 to 25% by weight, based on tablet
weight.
It can be of advantage from the performance point of view if certain
classes of surfactants are missing from certain phases of the detergent
tablets or from the entire tablet, i.e. from every phase. In another important
embodiment of the present invention, therefore, at least one phase of the
tablets used in the washing process is free from nonionic surfactants.
Conversely, a positive effect can also be obtained through the
presence of certain surfactants in individual phases or in the tablet as a
whole, i.e. in every phase. Introducing the alkyl polyglycosides described
above has proved to be of particular advantage, so that washing processes
in which at least one phase of the tablets used contains alkyl
polyglycosides are preferred.
As with the nonionic surfactants, the omission of anionic surfactants
from individual phases or from all phases can result in detergent tablets
which are more suitable for certain applications. Accordingly, washing
CA 02307430 2000-OS-03
23
processes using detergent tablets where at least one phase of the tablet is
free from anionic surfactants are also possible in accordance with the
present invention.
The detergent tablets used in the washing process according to the
invention may also contain a so-called "disintegrator". In order to facilitate
the disintegration of heavily compacted tablets, disintegration aids, so-
called tablet disintegrators, may be incorporated in them to shorten their
disintegration times. According to Rompp (9th Edition, Vol. 6, page
4440) and Voigt "Lehrbuch der pharmazeutischen Technologie" (6th
Edition, 1987, pages 182-184), tablet disintegrators or disintegration
accelerators are auxiliaries which provide for the rapid disintegration of
tablets in water or gastric juices and the release of the pharmaceuticals in
an absorbable form.
These substances, which are also known as "disintegrators" by
virtue of their effect, are capable of undergoing an increase in volume on
contact with water so that, on the one hand, their own volume is increased
(swelling) and, on the other hand, a pressure can be generated through the
release of gases which causes the tablet to disintegrate into relatively small
particles. Well-known disintegrators are, for example, carbonatelcitric acid
systems, although other organic acids may also be used. Swelling dis-
integration aids are, for example, synthetic polymers, such as polyvinyl
pyrrolidone (PVP), or natural polymers and modified natural substances,
such as cellulose and starch and derivatives thereof, alginates or casein
derivatives.
Detergent tablets preferably used in the washing process according
to the invention additionally contain a disintegration aid, preferably a
cellulose-based disintegration aid, preferably in granular, co-granulated or
compacted form, in quantities of 0.5 to 10% by weight, preferably 3 to 7%
by weight and more preferably 4 to 6% by weight, based on the weight of
the tablet.
According to the invention, preferred disintegrators are cellulose-
CA 02307430 2000-OS-03
24
based disintegrators, so that preferred detergent tablets contain a
cellulose-based disintegrator in quantities of 0.5 to 10% by weight,
preferably 3 to 7% by weight and more preferably 4 to 6% by weight. Pure
cellulose has the formal empirical composition (C6H~o05)" and, formally, is
a ~i-1,4-polyacetal of cellobiose which, in turn, is made up of two molecules
of glucose. Suitable celluloses consist of ca. 500 to 5000 glucose units
and, accordingly, have average molecular weights of 50,000 to 500,000.
According to the invention, cellulose derivatives obtainable from cellulose
by polymer-analog reactions may also be used as cellulose-based
disintegrators. These chemically modified celluloses include, for example,
products of esterification or etherification reactions in which hydroxy
hydrogen atoms have been substituted. However, celluloses in which the
hydroxy groups have been replaced by functional groups that are not
attached by an oxygen atom may also be used as cellulose derivatives.
The group of cellulose derivatives includes, for example, alkali metal
celluloses, carboxymethyl cellulose (CMC), cellulose esters and ethers and
aminocelluloses. The cellulose derivatives mentioned are preferably not
used on their own, but rather in the form of a mixture with cellulose as
cellulose-based disintegrators. The content of cellulose derivatives in
mixtures such as these is preferably below 50% by weight and more
preferably below 20% by weight, based on the cellulose-based
disintegrator. In one particularly preferred embodiment, pure cellulose free
from cellulose derivatives is used as the cellulose-based disintegrator.
The cellulose used as disintegration aid is preferably not used in
fine-particle form, but is converted into a coarser form, for example by
granulation or compacting, before it is added to and mixed with the
premixes to be tabletted. Detergent tablets which contain granular or
optionally co-granulated disintegrators are described in German patent
applications DE 197 09 991 (Stefan Herzog) and DE 197 10 254 (Henkel)
and in International patent application WO-A-98140463 (Henkel). Further
particulars of the production of granulated, compacted or co-granulated
CA 02307430 2000-OS-03
cellulose disintegrators can also be found in these patent applications. The
particle sizes of such disintegration aids is mostly above 200 Nm, at least
90% by weight of the particles being between 300 and 1600 Nm in size
and, more particularly, between 400 and 1200 pm in size. According to the
5 invention, the above-described relatively coarse-particle cellulose-based
disintegrators described in detail in the cited patent applications are
preferably used as disintegration aids and are commercially obtainable, for
example under the name of Arbocel~ TF-30-HG from Rettenmaier.
Microcrystalline cellulose may be used as another cellulose-based
10 disintegration aid or as part of such a component. This microcrystalline
cellulose is obtained by partial hydrolysis of the celluloses under conditions
which only attack and completely dissolve the amorphous regions (ca. 30%
of the total cellulose mass) of the celluloses, but leave the crystalline
regions (ca. 70%) undamaged. Subsequent de-aggregation of the
15 microfine celluloses formed by hydrolysis provides the microcrystalline
celluloses which have primary particle sizes of ca. 5 Nm and which can be
compacted, for example, to granules with a mean particle size of 200 Nm.
In many cases, so-called "effervescent systems" are also used as
disintegration-promoting systems in detergent tablets. Oligomeric
20 oligocarboxylic acids, such as succinic acid, malefic acid and above all
citric
acid, in combination with carbonates or hydrogen carbonates are normally
used in effervescent systems. In preferred embodiments of the present
invention, however, the detergent tablet used is not an "effervescent
tablet", i.e. preferred detergent tablets are free from oligomeric
25 oligocarboxylic acids, more particularly citric acid.
Besides the ingredients mentioned (bleaching agent, bleach
activator, builder, surfactant and disintegration aid), the detergent tablets
used in the washing process according to the invention may contain other
typical detergent ingredients from the group of dyes, perfumes, optical
brighteners enzymes, foam inhibitors, silicone oils, redeposition inhibitors,
discoloration inhibitors, dye transfer inhibitors and corrosion inhibitors.
CA 02307430 2000-OS-03
26
In preferred washing processes, the detergent tablets additionally
contain one or more substances from the group of bleach activators,
enzymes, pH regulators, perfumes, perfume carriers, fluorescers, dyes,s
foam inhibitors, silicone oils, redepositioo inhibitors, optical brighteners,
discoloration inhibitors, dye transfer inhibitors and corrosion inhibitors.
Suitable enzymes are, in particular, those from the classes of
hydrolases, such as proteases, esterases, lipases or lipolytic enzymes,
amylases, cellulases or other glycosyl hydrolases and mixtures thereof. All
these hydrolases contribute to the removal of stains, such as protein-
containing, fat-containing or starch-containing stains, and discoloration in
the washing process. Cellulases and other glycosyl hydrolases can
contribute towards color retention and towards increasing fabric softness by
removing pilling and microfibrils. Oxidoreductases may also be used for
bleaching and for inhibiting dye transfer. Enzymes obtained from bacterial
strains or fungi, such as Bacillus subtilis, Bacillus licheniformis,
Streptomyces griseus, Coprinus cinereus and Humicola insolens and from
genetically modified variants are particularly suitable. Proteases of the
subtilisin type are preferably used, proteases obtained from Bacillus lentus
being particularly preferred. Of particular interest in this regard are enzyme
mixtures, for example of protease and amylase or protease and lipase or
lipolytic enzymes or protease and cellulase or of cellulase and lipase or
lipolytic enzymes or of protease, amylase and lipase or lipolytic enzymes or
protease, lipase or lipolytic enzymes and cellulase, but especially protease-
andlor lipase-containing mixtures or mixtures with lipolytic enzymes.
Examples of such lipolytic enzymes are the known cutinases. Peroxidases
or oxidases have also been successfully used in some cases. Suitable
amylases include in particular a-amylases, isoamylases, pullanases and
pectinases. Preferred cellulases are cellobiohydrolases, endoglucanases
and ~-glucosidases, which are also known as cellobiases, and mixtures
thereof. Since the various cellulase types differ in their CMCase and
avicelase activities, the desired activities can be established by mixing the
CA 02307430 2000-OS-03
27
cellulases in the appropriate ratios.
The enzymes may be adsorbed to supports andlor encapsulated in
membrane materials to protect them against premature decomposition.
The percentage content of the enzymes, enzyme mixtures or enzyme
granules may be, for example, from about 0.1 to 5% by weight and is
preferably from 0.5 to about 4.5% by weight.
In addition, the detergent tablets used in the washing process
according to the invention may also contain components with a positive
effect on the removability of oil and fats from textiles by washing (so-called
soil repellents). This effect becomes particularly clear when a textile which
has already been repeatedly washed with a detergent according to the
invention containing this oil- and fat-dissolving component is soiled.
Preferred oil- and fat-dissolving components include, for example, nonionic
cellulose ethers, such as methyl cellulose and methyl hydroxypropyl
cellulose containing 15 to 30% by weight of methoxyl groups and 1 to 15%
by weight of hydroxypropoxyl groups, based on the nonionic cellulose
ether, and the polymers of phthalic acid andlor terephthalic acid known
from the prior art or derivatives thereof, more particularly polymers of
ethylene terephthalates and/or polyethylene glycol terephthalates or
anionically andlor nonionically modified derivatives thereof. Of these, the
sulfonated derivatives of phthalic acid and terephthalic acid polymers are
particularly preferred.
The tablets may contain derivatives of diaminostilbenedisulfonic acid
or alkali metal salts thereof as optical brighteners. Suitable optical
brighteners are, for example, salts of 4,4'-bis-(2-anilino-4-morpholino-1,3,5-
triazinyl-6-amino)-stilbene-2,2'-disulfonic acid or compounds of similar
composition which contain a diethanolamino group, a methylamino group,
an anilino group or a 2-methoxyethylamino group instead of the morpholino
group. Brighteners of the substituted Biphenyl styryl type, for example
alkali metal salts of 4,4'-bis-(2-sulfostyryl)-Biphenyl, 4,4'-bis-(4-chloro-3-
sulfostyryl)-Biphenyl or 4-(4-chlorostyryl)-4'-(2-sulfostyryl)-Biphenyl, may
CA 02307430 2000-OS-03
28
also be present. Mixtures of the brighteners mentioned above may also be
used.
Dyes and perfumes are added to the detergent tablets used in the
washing process according to the invention to improve the aesthetic
impression created by the products and to provide the consumer not only
with the required washing performance but also with a visually and
sensorially "typical and unmistakable" product. Suitable perfume oils or
perfumes include individual perfume compounds, for example synthetic
products of the ester, ether, aldehyde, ketone, alcohol and hydrocarbon
type. Perfume compounds of the ester type are, for example, benzyl
acetate, phenoxyethyl isobutyrate, p-tert.butyl cyclohexyl acetate, linalyl
acetate, dimethyl benzyl carbinyl acetate, phenyl ethyl acetate, linalyl
benzoate, benzyl formate, ethyl methyl phenyl glycinate, allyl cyclohexyl
propionate, styrallyl propionate and benzyl salicylate. The ethers include,
for example, benzyl ethyl ether; the aldehydes include, for example, the
linear alkanals containing 8 to 18 carbon atoms, citral, citronellal,
citronellyloxyacetaldehyde, cyclamen aldehyde, hydroxycitronellal, lilial and
bourgeonal; the ketones include, for example, the ionones, a-isomethyl
ionone and methyl cedryl ketone; the alcohols include anethol, citronellol,
eugenol, geraniol, linalool, phenyl ethyl alcohol and terpineol and the
hydrocarbons include, above all, the terpenes, such as limonene and
pinene. However, mixtures of various perfumes which together produce an
attractive perfume note are preferably used. Perfume oils such as these
may also contain natural perfume mixtures obtainable from vegetable
sources, for example pine, citrus, jasmine, patchouli, rose or ylang-ylang
oil. Also suitable are clary oil, camomile oil, clove oil, melissa oil, mint
oil,
cinnamon leaf oil, lime blossom oil, juniper berry oil, vetiver oil, olibanum
oil, galbanum oil and labdanum oil and orange blossom oil, neroli oil,
orange peel oil and sandalwood oil.
The detergent tablets used in the washing process according to the
invention normally contain less than 0.01 % by weight of dyes whereas
CA 02307430 2000-OS-03
29
perfumes/fragrances can make up as much as 2% by weight of the
formulation as a whole.
The perfumes may be directly incorporated in the detergent tablets
to be used in the washing process according to the invention, although it
can also be of advantage to apply the perfumes to supports which
strengthen the adherence of the perfume to the washing and which provide
the textiles with a long-lasting fragrance through a slower release of the
perfume. Suitable support materials are, for example, cyclodextrins, the
cyclodextrin/perfume complexes optionally being coated with other
auxiliaries.
In order to improve their aesthetic impression, the detergents
according to the invention may be colored with suitable dyes. Preferred
dyes, which are not difficult for the expert to choose, have high stability in
storage, are not affected by the other ingredients of the detergents or by
light and do not have any pronounced substantivity for textile fibers so as
not to color them.
It has been found that detergent tablets having a high specific
gravity can be used with advantage in the washing process according to
the invention. According to the invention, washing processes in which the
detergent tablets have a density above 1000 gcm3, preferably above 1050
gcm3 and more preferably above 1100 gcm3 are preferred.
The process according to the invention comprises the washing of
laundry in a normal domestic washing machine using a detergent tablet
which is introduced into the washing drum without a dispensing aid. The
consumer may decide how the tablet (or tablets where several tablets are
to be used) should be placed in the drum. Thus, the laundry may be
loaded into the machine first followed by addition of the detergent tablets)
which islare placed in or on the laundry. A washing process in which the
detergent tablets are placed in or on the laundry loaded into the drum
before the washing process represents a preferred embodiment of the
present invention.
CA 02307430 2000-OS-03
The detergent tablets may of course also be introduced into the
drum first and the laundry subsequently loaded into the washing machine.
A washing process in which the detergent tablets are introduced into the
drum and the laundry is placed on the tablets before the washing process
5 is another preferred embodiment of the present invention.
In order not to restrict the consumer in regard to the potential uses of
the tablets placed at his disposal, it is preferred to achieve high
performance levels even in applications which are not covered by the
recommended dosages. If conventional detergent tablets which can only
10 be dispensed from dispensers are introduced into the dispensing
compartment by the consumer, the poor dispensing behavior and the poor
washing result attributable to the lack of detergent can frustrate the
consumer. In a preferred embodiment of the present invention, therefore,
the detergent tablets are designed to be dispensed without leaving any
15 residues, even when dispensed from a dispensing compartment, so that
the detergent is available to the washing process. Accordingly, a preferred
washing process according to the invention is characterized in that the
detergent tablets can be dispensed without leaving any residues, even
from dispensing compartments.
20 In the context of the present invention, the expression "without
leaving any residues" means that at most 5% by weight of the quantity of
detergent originally dispensed is present in the dispensing compartment
after the dispensing process, the quantity left in the compartment being
weighed out after drying.
25 Embodiments of the invention are described in the following
examples which are not to be construed as limiting.
Examples
To produce detergent tablets containing sodium percarbonate,
surfactant granules were mixed with other detergent ingredients and the
30 resulting mixture was tabletted (tablet diameter 44 mm, tablet height 22
mm, tablet weight 37.5 g). The composition of the surfactant granules are
CA 02307430 2000-OS-03
31
shown in Table 1 below while the composition of the premix to be tabletted
(and hence the composition of the tablets) is shown in Table 2.
Table 1:
Surfactant granules [% by weight]
C9_~3 alkyl benzenesulfonate 18.4
C~2_~8 fatty alcohol sulfate 4.9
C~2_~8 fatty alcohol ~ 7 EO 4.9
Soap 1.6
Sodium carbonate 18.8
Sodium silicate 5.5
Zeolite A (water-free active substance)31.3
Optical brightener 0.3
Na hydroxyethane-1,1-diphosphonate0.8
Acrylic acid/maleic acid copolymer5.5
Water, salts Balance
Table 2:
Premix [% by weight]
Surfactant granules 60.0
Sodium perborate monohydrate19.0
Tetraacetyl ethylenediamine 7.0
Foam inhibitor 3.5
Enzymes 2.5
Perfume 0.5
Zeolite A 1.0
Cellulose 5.5
For disintegration trials, two tablets were tested in various washing
machines. To this end, each machine was loaded with 3.5 kg of laundry,
two tablets were placed in the laundry and a 40°C colors program was
started without any prewash. Commercially available tablets which,
CA 02307430 2000-OS-03
32
according to the dosage instructions, had to be dispensed via the drum
using a net dispenser, were used for comparison. These comparison
tablets contained sodium perborate as their bleaching agent and were
added without dispensers similarly to the washing process according to the
invention. On completion of the wash program, the residues left on the
rubber collar of the washing machine were visually evaluated.
Discoloration of the laundry was also evaluated, the following scheme
being used for both evaluations:
++ no residues on the collarlno discoloration
+ slight residues on the collarlslight lightening of black fabrics
- distinct residues on the collarlvisible discoloration of colored fabrics
-- large residues (tablet remains) on the collarldistinct discoloration of
colored laundry.
The results of the two washing processes in various machines are
set out in Table 3:
Table 3:
Washing processes (comparison)
Machine type Invention Comparison
Residue DiscolorationResidueDiscoloration
Whirlpool AWG 780 ++ ++ _ _
Siemens Siwamat plus ++ ++ - _
3773
Matura ~5kostar 9150 ++ + _ _
AEG ~5ko-Lavamat 6955 ++ + __ _
Bauknecht WA 2381 ++ ++ _ _
Miele W 918 ++ ++ + -
