Field of the Invention
[0001] The invention relates to laundry detergent tablets comprising laundry surfactants
and clay with improved disintegrating capabilities.
Background of the Invention
[0002] It is known to provide detergent compositions in the form of tablets made by compacting
a particulate detergent composition. Usually a small amount of binder is included
in the composition in order to promote the integrity of the tablets.
[0003] Although it is necessary that the tablets should have good integrity before use,
it is necessary also that they should disintegrate rapidly during use, when contacted
with wash water. It is known to include a disintegrant which will promote disintegration
of the tablet. Various classes of disintegrant are known, including the class in which
disintegration is caused by swelling of the disintegrant. Various swelling disintegrants
have been proposed in the literature, with the preference being directed predominantly
towards starches, celluloses and water soluble organic polymers. Inorganic swelling
disintegrants such as bentonite clay have also been mentioned, for instance in EP-A-466,484.
[0004] In that disclosure, the same material acts as binder and disintegrant. It is also
mentioned therein that the disintegrant may give supplementary building, anti-redeposition
or fabric softening properties. The amount of disintegrant is preferably 1 to 5%.
It is proposed in EP-A-466,484 that the tablet may have a heterogeneous structure
comprising a plurality of discrete regions, for example layers, inserts or coatings.
[0005] In W098/40463 it is proposed to introduce the disintegrant substantially only in
granular form.
[0006] JP-A-9/87696 is concerned with tablets containing a non-ionic detergent composition
with a non-ionic surfactant as the main component and in particular is concerned with
preventing the non-ionic surfactant from oozing out of the tablets during storage,
and it is also concerned with the fact that the non-ionic surfactant causes a loss
in the softening effect that would be expected when a softening clay is included.
It describes the formation of tablets containing finely divided clay mineral, together
with a finely divided oil absorbing carrier, and a disintegrant.
[0007] The clays which are currently used as disintegrants in detergent tablet promote adequate
breakdown of these tablets under normal wash conditions. However, it is not unusual
for some tablet material to disperse rather slowly. This is often caused by a tendency
for the clay content of the tablet to gel upon contact with water so as to form a
gel layer around the tablet which hinders penetration of water into the tablet, and
thus inhibits tablet dispersion.
[0008] The tendency for gel formation, and the consequential inhibition of dispersion, may
also arise from high local amounts of other components in the tablet such as anionic
surfactants and non-ionic surfactants. Also, if the composition contains flocculant
for the clay, this flocculant is usually a high molecular weight soluble polymer and
this may tend to promote gelling.
[0009] The risk of slow dispersion occurs particularly when the content of clay is high,
for instance as would be required in the invention if the tablet were to be a softening
tablet.
[0010] It would be desirable to provide laundry detergent tablets which have improved dispersion
and disintegration characteristics, and in particular to provide laundry detergent
softening tablets having improved dispersion and disintegration.
Summary of the Invention
[0011] According to the invention there is provided a laundry detergent tablet comprising
clay and laundry surfactant wherein the clay gives a residue number of less than 10
after 5 minutes, when a 40g, 54mm diameter tablet of the clay having a diametrical
fracture value of 5kPa and formed by compressing the clay by itself is rotated at
80rpm in a perforated 10cm diameter metallic cage having a mean mesh size of 5mm x
5mm in 5 litres demineralised water at 20°C, and the wet residue weight in the cage
is measured at the specified time and the residue number is 100 x wet residue weight,
original tablet weight.
[0012] The residue number is preferably less than 10 within 3 minutes, preferably within
one minute. The residue number is preferably below 5, (and preferably is zero) after
5 minutes, preferably within 3 minutes, most preferably within one minute.
[0013] The tablet preferably comprises clay in at least 5%, preferably at least 8%, and
most preferably at least 10% by weight of the tablet. The tablet may further comprise
flocculant for the clay.
Detailed Description of the Invention
[0014] We have realised that different grades of clays which would all be expected to be
effective disintegrants gave different disintegration performance, probably due to
the fact that high swelling (which causes disintegration) is accompanied in some clays
with a tendency to gel (which impedes disintegration when the clay is present in localised
high concentrations). Based on this, we select clay by a disintegration test which
reflects properly the tendency of gelling. Thus, by the invention we are able to select
clays which have not been used as laundry tablet disintegrants and which give good
disintegration.
[0015] Use of the clays meeting the requirements of this invention in detergent tablets
results in an improvement in the disintegration of the tablet relative to clays which
have been used or described in laundry tablets, and relative also to many of the clays
used or described in powdered softeners. The clays used in the invention inherently
have less of a tendency to gel than is characteristic of clays conventionally used
in tablets, which leads to improve tablet dispersion. The breakup of the tablet due
to the presence of clay as a disintegrant is rapid, and therefore gelling of other
components such as surfactants and/or flocculants in the tablet is also minimised.
There is a general description below of swelling clays which can be tested by the
defined test and those which satisfy the test can be selected for use in making the
tablets. Particular clays which have been found to be suitable for use in the invention
include various montmorillonites typically having a structure which corresponds to
the following formula:
[Si
8][Al
4-xMg
x]O
20(OH)
4 R
n x/n mH2O
m or n being any integer, and x being comprised between 0 and 4, R being a cationic
compound.
[0016] At low clay concentrations, such as 2 to 5% by weight of the tablet, an improvement
in disintegration of the tablet can be observed relative to conventional swelling
clays.
[0017] This improved disintegration, together with a significant fabric softening effect,
is achieved at higher concentrations, such as at least 5%, preferably at least 8%,
and most preferably at least 10% clay be weight of the tablet, but usually less than
25%, more preferably less than 20%, most preferably less than 15% by weight. It is
possible to use high concentrations of clays in the tablets of the invention with
reduced risk of experiencing clay gelling which may occur when the clay does not meet
the requirements specified herein.
[0018] If desired, the clay may be substantially uniformly distributed throughout the tablet,
in particulate or granular form. Disintegration, and possible softening effects, will
therefore be promoted throughout the tablet. Alternatively, the concentration of the
clay can be higher in one or more first regions of the tablet than in one or more
second regions of the tablet. For example in one embodiment the first regions may
contain an amount of the clay which is at least 1.5 times, and often 2 to 5 times,
the amount of clay in the second regions. By this means it is possible to arrange
for the first regions to disperse more rapidly than the second regions. The amount
of clay in the first regions is usually at least 5% and often at least 10% by weight
of the first regions. The amount of clay in the second regions is usually at least
0.1%, for instance 1 to 5%, by weight of the or each second region. Usually at least
60% by weight of the total amount of clay, and often 70 or 75% up to 80 or 90%, by
weight of the total amount of clay is in the or each first region with the balance
being present in the or each second region.
[0019] The tablet will contain at least 5% by weight laundry detergents, usually including
non-ionic and/or anionic surfactants. If desired, the surfactant also may be present
in a higher concentration in some regions than other regions (e.g., at least 1.5 times
and usually 2-5 times). Generally at least 5% by weight non-ionic and/or anionic surfactant
is present in any first regions of the tablet which have a higher clay concentration
than remaining regions of the tablet.
[0020] Laundry enzyme is usually included in the tablet. When the clay is present in a higher
concentration in one or more first regions, it is preferred for more enzyme to be
in these regions than in the other regions, for instance the amount in the first regions
should be normally at least 1.5 times and often at least 2 or at least 5 times the
amount in the other regions, in order that the enzyme is dispersed as rapidly as possible
with the fast dispersing first regions into the wash water.
[0021] The tablet often contains laundry bleach. If the clay is more highly concentrated
in one or more first regions than second regions, the concentration of bleach is preferably
higher in the second regions than the first regions. Preferably the concentration
of the bleach in the or each second region is at least 1.5 times the concentration
in the or each first region and preferably substantially all the bleach is in the
or each second region.
[0022] It is generally preferred that the tablet should also contain flocculant for the
clay, in order to aid deposition of the clay on the surface of the fabric. It is generally
preferred to include the flocculant in one or more second regions which will disperse
more slowly than the first regions. Preferably substantially all the flocculant is
in the or each second region.
[0023] It is not essential that all the second regions should be of the same composition
and there can be one or more second regions having a different composition from the
other second regions.
[0024] The discrete first and second regions (when present) may be domains or other zones
within the tablet, for instance created by forming the tablet from the granules of
clay and other coarse particulate material, typically above 1 mm, wherein some or
all of the coarse large particles have one content and the remainder have another,
thereby forming the first and second regions in the compressed tablet. Preferably,
however, each region is a layer and the tablet is a multi-layer tablet of at least
two layers. It is often preferred that there should be three layers, with the tablet
typically being a sandwich between similar layers on each outer surface and a different
central layer. Different layers may be differently coloured.
[0025] Typically the first regions contain 20 to 80%, often around 40 to 60% and usually
about 50%, by weight of the tablet with the second regions containing the remainder.
[0026] The tablets of the invention are of a size which is convenient for dosing in a washing
machine. The preferred size is 10 to 150g and the size can be selected in accordance
with the intended wash load and the design of the washing machine which is to be used.
Tablet Manufacture
[0027] Detergent tablets of the present invention can be prepared simply by mixing the solid
ingredients together and compressing the mixture in a conventional tablet press as
used, for example, in the pharmaceutical industry. Preferably the principal ingredients,
in particular gelling surfactants, are used in particulate form. Any liquid ingredients,
for example surfactant or suds suppressor, can be incorporated in a conventional manner
into the solid particulate ingredients.
[0028] The ingredients such as builder and surfactant can be spray-dried in a conventional
manner and then compacted at a suitable pressure. Preferably, the tablets according
to the invention are compressed using a force of less than 100000N, more preferably
of less than 50000N, even more preferably of less than 5000N and most preferably of
less than 3000 N. Indeed, the most preferred embodiment is a tablet compressed using
a force of less than 2500N.
[0029] The particulate material used for making the tablet of this invention can be made
by any particulation or granulation process. An example of such a process is spray
drying (in a co-current or counter current spray drying tower) which typically gives
low bulk densities 600g/l or lower. Particulate materials of higher density can be
prepared by granulation and densification in a high shear batch mixer/granulator or
by a continuous granulation and densification process (e.g. using Lodige(R) CB and/or
Lodige(R) KM mixers). Other suitable processes include fluid bed processes, compaction
processes (e.g. roll compaction), extrusion, as well as any particulate material made
by any chemical process like flocculation, crystallisation sentering, etc. Individual
particles can also be any other particle, granule, sphere or grain.
[0030] The components of the particulate material may be mixed together by any conventional
means. Batch is suitable in, for example, a concrete mixer, Nauta mixer, ribbon mixer
or any other. Alternatively the mixing process may be carried out continuously by
metering each component by weight on to a moving belt, and blending them in one or
more drum(s) or mixer(s). Non-gelling binder can be sprayed on to the mix of some,
or all of, the components of the particulate material. Other liquid ingredients may
also be sprayed on to the mix of components either separately or premixed. For example
perfume and slurries of optical brighteners may be sprayed. A finely divided flow
aid (dusting agent such as zeolites, carbonates, silicas) can be added to the particulate
material after spraying the binder, preferably towards the end of the process, to
make the mix less sticky.
[0031] The tablets may be manufactured by using any compacting process, such as tabletting,
briquetting, or extrusion, preferably tabletting. Suitable equipment includes a standard
single stroke or a rotary press (such as Courtoy(R), Korch(R), Manesty(R), or Bonals(R)).
The tablets prepared according to this invention preferably have a diameter of between
20mm and 60mm, preferably of at least 35 and up to 55 mm, and a weight between 25
and 100 g. The ratio of height to diameter (or width) of the tablets is preferably
greater than 1:3, more preferably greater than 1:2. The compaction pressure used for
preparing these tablets need not exceed 100000 kN/m2, preferably not exceed 30000
kN/m2, more preferably not exceed 5000 kN/m2, even more preferably not exceed 3000kN/m2
and most preferably not exceed 1000kN/m2. In a preferred embodiment according to the
invention, the tablet has a density of at least 0.9 g/cc, more preferably of at least
1.0 g/cc, and preferably of less than 2.0 g/cc, more preferably of less than 1.5 g/cc,
even more preferably of less than 1.25 g/cc and most preferably of less than 1.1 g/cc.
[0032] Multi-layer tablets can be made by known techniques.
Coating
[0033] Solidity of the tablet according to the invention may be further improved by making
a coated tablet, the coating covering a non-coated tablet according to the invention,
thereby further improving the mechanical characteristics of the tablet while maintaining
or further improving dispersion.
[0034] In one embodiment of the present invention, the tablets may then be coated so that
the tablet does not absorb moisture, or absorbs moisture at only a very slow rate.
The coating is also strong so that moderate mechanical shocks to which the tablets
are subjected during handling, packing and shipping result in no more than very low
levels of breakage or attrition. Finally the coating is preferably brittle so that
the tablet breaks up when subjected to stronger mechanical shock. Furthermore it is
advantageous if the coating material is dispersed under alkaline conditions, or is
readily emulsified by surfactants. This contributes to avoiding the problem of visible
residue in the window of a front-loading washing machine during the wash cycle, and
also avoids deposition of particles or lumps of coating material on the laundry load.
[0035] Water solubility is measured following the test protocol of ASTM E1148-87 entitled,
"Standard Test Method for Measurements of Aqueous Solubility".
[0036] Suitable coating materials are dicarboxylic acids. Particularly suitable dicarboxylic
acids are selected from the group consisting of oxalic acid, malonic acid, succinic
acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic
acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid and mixtures thereof.
The coating material has a melting point preferably of from 40°C to 200°C.
[0037] The coating can be applied in a number of ways. Two preferred coating methods are
a) coating with a molten material and b) coating with a solution of the material.
[0038] In a), the coating material is applied at a temperature above its melting point,
and solidifies on the tablet. In b), the coating is applied as a solution, the solvent
being dried to leave a coherent coating. The substantially insoluble material can
be applied to the tablet by, for example, spraying or dipping. Normally when the molten
material is sprayed on to the tablet, it will rapidly solidify to form a coherent
coating. When tablets are dipped into the molten material and then removed, the rapid
cooling again causes rapid solidification of the coating material. Clearly substantially
insoluble materials having a melting point below 40°C are not sufficiently solid at
ambient temperatures and it has been found that materials having a melting point above
about 200°C are not practicable to use. Preferably, the materials melt in the range
from 60°C to 160°C, more preferably from 70°C to 120°C.
[0039] By "melting point" is meant the temperature at which the material when heated slowly
in, for example, a capillary tube becomes a clear liquid.
[0040] A coating of any desired thickness can be applied according to the present invention.
For most purposes, the coating forms from 1% to 10%, preferably from 1.5% to 5%, of
the tablet weight.
[0041] The tablet coatings are preferably very hard and provide extra strength to the tablet.
[0042] In a preferred embodiment of the present invention the fracture of the coating in
the wash is improved by adding a disintegrant in the coating. This disintegrant will
swell once in contact with water and break the coating in small pieces. This will
improve the dispersion of the coating in the wash solution. The disintegrant is suspended
in the coating melt at a level of up to 30%, preferably between 5% and 20%, most preferably
between 5 and 10% by weight. Possible disintegrants are described in Handbook of Pharmaceutical
Excipients (1986). Examples of suitable disintegrants include starch: natural, modified
or pregelatinized starch, sodium starch gluconate; gum: agar gum, guar gum, locust
bean gum, karaya gum, pectin gum, tragacanth gum; croscarmylose Sodium, crospovidone,
cellulose, carboxymethyl cellulose, algenic acid and its salts including sodium alginate,
silicone dioxide, clay, polyvinylpyrrolidone, soy polysacharides, ion exchange resins
and mixtures thereof.
Tensile Strength
[0043] Depending on the composition of the starting material, and the shape of the tablets,
the used compacting force may be adjusted to not affect the tensile strength, and
the disintegration time in the washing machine. This process may be used to prepare
homogenous or layered tablets of any size or shape.
[0044] For a cylindrical tablet, the tensile strength corresponds to the diametrical fracture
stress (DFS) which is a way to express the strength of a tablet, and is determined
by the following equation :

[0045] Where F is the maximum force (Newton) to cause tensile failure (fracture) measured
by a VK 200 tablet hardness tester supplied by Van Kell industries, Inc. D is the
diameter of the tablet, and t the thickness of the tablet.
[0046] (Method Pharmaceutical Dosage Forms : Tablets Volume 2 Page 213 to 217). A tablet
having a diametral fracture stress of less than 20 kPa is considered to be fragile
and is likely to result in some broken tablets being delivered to the consumer. A
diametral fracture stress of at least 25 kPa is preferred.
[0047] This applies similarly to non cylindrical tablets, to define the tensile strength,
whereby the cross section normal to the height of the tablet is non round, and whereby
the force is applied along a direction perpendicular to the direction of the height
of the tablet and normal to the side of the tablet, the side being perpendicular to
the non round cross section.
Effervescent
[0048] In another preferred embodiment of the present invention the tablets further comprises
an effervescent.
[0049] Effervescency as defined herein means the evolution of bubbles of gas from a liquid,
as the result of a chemical reaction between a soluble acid source and an alkali metal
carbonate, to produce carbon dioxide gas,
i.e. C
6H
8O
7 + 3NaHCO
3 Na
3C
6H
5O
7 + 3CO
2 + 3H
2O
[0050] Further examples of acid and carbonate sources and other effervescent systems may
be found in : (Pharmaceutical Dosage Forms : Tablets Volume 1 Page 287 to 291).
[0051] An effervescent may be added to the tablet mix in addition to the detergent ingredients.
The addition of this effervescent to the detergent tablet improves the disintegration
time of the tablet. The amount will preferably be between 5 and 20 % and most preferably
between 10 and 20% by weight of the tablet. Preferably the effervescent should be
added as an agglomerate of the different particles or as a compact, and not as separated
particles.
[0052] Due to the gas created by the effervescency in the tablet, the tablet can have a
higher D.F.S. and still have the same disintegration time as a tablet without effervescency.
When the D.F.S. of the tablet with effervescency is kept the same as a tablet without,
the disintegration of the tablet with effervescency will be faster.
[0053] Further dispersion aid could be provided by using compounds such as sodium acetate
or urea. A list of suitable dispersion aid may also be found in Pharmaceutical Dosage
Forms: Tablets, Volume 1, Second edition, Edited by H.A. Lieberman et all, ISBN 0-8247-8044-2.
Binders
[0054] Non gelling binders can be integrated to the particles forming the tablet in order
to further facilitate dispersion.
[0055] If non gelling binders are used, suitable non-gelling binders include synthetic organic
polymers such as polyethylene glycols, polyvinylpyrrolidones, polyacrylates and water-soluble
acrylate copolymers. The handbook of Pharmaceutical Excipients second edition, has
the following binders classification: Acacia, Alginic Acid, Carbomer, Carboxymethylcellulose
sodium, Dextrin, Ethylcellulose, Gelatin, Guar gum, Hydrogenated vegetable oil type
I, Hydroxyethyl cellulose, Hydroxypropyl methylcellulose, Liquid glucose, Magnesium
aluminum silicate, Maltodextrin, Methylcellulose, polymethacrylates, povidone, sodium
alginate, starch and zein. Most preferable binders also have an active cleaning function
in the laundry wash such as cationic polymers, i.e. ethoxylated hexamethylene diamine
quaternary compounds, bishexamethylene triamines, or others such as pentaamines, ethoxylated
polyethylene amines, maleic acrylic polymers.
[0056] Non-gelling binder materials are preferably sprayed on and hence have an appropriate
melting point temperature below 90°C, preferably below 70°C and even more preferably
below 50°C so as not to damage or degrade the other active ingredients in the matrix.
Most preferred are non-aqueous liquid binders (i.e. not in aqueous solution) which
may be sprayed in molten form. However, they may also be solid binders incorporated
into the matrix by dry addition but which have binding properties within the tablet.
[0057] Non-gelling binder materials are preferably used in an amount within the range from
0.1 to 15% of the composition, more preferably below 5% and especially if it is a
non laundry active material below 2% by weight of the tablet.
[0058] It is preferred that gelling binders, such as nonionic surfactants are avoided in
their liquid or molten form. Nonionic surfactants and other gelling binders are not
excluded from the compositions, but it is preferred that they be processed into the
detergent tablets as components of particulate materials, and not as liquids.
Clays
[0059] The clay minerals used to provide the softening properties of the instant compositions
can be described as expandable, three-layer clays, i.e., alumino-silicates and magnesium
silicates, having an ion exchange capacity of at least 50 meq/100g. of clay. The term
"expandable" as used to describe clays relates to the ability of the layered clay
structure to be swollen, or expanded, on contact with water. The three-layer expandable
clays used herein are those materials classified geologically as smectites.
[0060] There are two distinct classes of smectite-type clays; in the first, aluminum oxide
is present in the silicate crystal lattice; in the second class of smectites, magnesium
oxide is present in the silicate crystal lattice. The general formulas of these smectites
are Al
2(Si
2O
5)
2(OH)
2 and Mg
3(Si
2O
5)(OH)
2 for the aluminum and magnesium oxide type clay, respectively. It is to be recognised
that the range of the water of hydration in the above formulas can vary with the processing
to which the clay has been subjected. This is immaterial to the use of the smectite
clays in the present invention in that the expandable characteristics of the hydrated
clays are dictated by the silicate lattice structure. Furthermore, atom substitution
by iron and magnesium can occur within the crystal lattice of the smectites, while
metal cations such as Na+, Ca++, as well as H+, can be co-present in the water of
hydration to provide electrical neutrality. Except as noted hereinafter, such cation
substitutions are immaterial to the use of the clays herein since the desirable physical
properties of the clays are not substantially altered thereby.
[0061] The three-layer, expandable alumino-silicates useful herein are further characterised
by a dioctahedral crystal lattice, while the expandable three-layer magnesium silicates
have a trioctahedral crystal lattice.
[0062] As noted herein above, the clays employed in the compositions of the instant invention
contain cationic counterions such as protons, sodium ions, potassium ions, calcium
ion, magnesium ion, and the like. It is customary to distinguish between clays on
the basis of one cation predominantly or exclusively absorbed. For example, a sodium
clay is one in which the absorbed cation is predominantly sodium. Such absorbed cations
can become involved in exchange reactions with cations present in aqueous solutions.
A typical exchange reaction involving a smectite-type clay is expressed by the following
equation:

[0063] Since in the foregoing equilibrium reaction, one equivalent weight of ammonium ion
replaces an equivalent weight of sodium, it is customary to measure cation exchange
capacity (sometimes termed "base exchange capacity") in terms of milliequivalents
per 100 g. of clay (meq./100 g.). The cation exchange capacity of clays can be measured
in several ways, including by electrodialysis, by exchange with ammonium ion followed
by titration or by a methylene blue procedure, all as fully set forth in Grimshaw,
"The Chemistry and Physics of Clays", pp. 264-265, Interscience (1971). The cation
exchange capacity of a clay mineral relates to such factors as the expandable properties
of the clay, the charge of the clay, which, in turn, is determined at least in part
by the lattice structure, and the like. The ion exchange capacity of clays varies
widely in the range from about 2 meq/100 g. for kaolinites to about 150 meq/100 g.,
and greater, for certain clays of the montmorillonite variety. Illite clays have an
ion exchange capacity somewhere in the lower portion of the range, i.e., around 26
meq/100 g. for an average illite clay.
[0064] Illite and kaolinite clays, with their relatively low ion exchange capacities, are
preferably not used as the clay in the instant compositions. Indeed, such illite and
kaolinite clays constitute a major component of clay soils and, as noted above, are
removed from fabric surfaces by means of the instant compositions. However, smectites,
such as nontonite, having an ion exchange capacity of around 70 meq/100 g., and montmorillonite,
which has an ion exchange capacity greater than 70 meq/100 g., have been found to
be useful in the instant compositions in that they are deposited on the fabrics to
provide the desired softening benefits. Accordingly, clay minerals useful herein can
be characterised as expandable, three-layer smectite-type clays having an ion exchange
capacity of at least about 50 meq/100 g.
[0065] While not intending to be limited by theory, it appears that advantageous softening
(and potentially dye scavenging, etc.) benefits of the instant compositions are obtainable
and are ascribable to the physical characteristics and ion exchange properties of
the clays used therein. That is to say, experiments have shown that non-expandable
clays such as the kaolinites and the illites, which are both classes of clays having
an ion exchange capacities below 50 meq/100 g., do not provide the beneficial aspects
of the clays employed in the instant compositions.
[0066] The smectite clays used in the compositions herein are all commercially available.
Such clays include, for example, montmorillonite, volchonskoite, nontronite, hectorite,
saponite, sauconite, and vermiculite. The clays herein are available under various
tradenames, for example, Thixogel #1 and Gelwhite GP from Georgia Kaolin Co., Elizabeth,
New Jersey; Volclay BC and Volclay #325, from American Colloid Co., Skokie, Illinois;
Black Hills Bentonite BH450, from International Minerals and Chemicals; and Veegum
Pro and Veegum F, from R.T. Vanderbilt. It is to be recognised that such smectite-type
minerals obtained under the foregoing tradenames can comprise mixtures of the various
discrete mineral entities. Such mixtures of the smectite minerals are suitable for
use herein.
[0067] While any of the smectite-type clays having a cation exchange capacity of at least
about 50 meq/100 g. are useful herein, certain clays are preferred. For example, Gelwhite
GP is an extremely white form of smectite clay and is therefore preferred when formulating
white granular detergent compositions. Volclay BC, which is a smectite-type clay mineral
containing at least 3% of iron (expressed as Fe
2O
3) in the crystal lattice, and which has a very high ion exchange capacity, is one
of the most efficient and effective clays for use in laundry compositions and is preferred
from the standpoint of product performance.
[0068] Appropriate clay minerals for use herein can be selected by virtue of the fact that
smectites exhibit a true 14Å x-ray diffraction pattern. This characteristic pattern,
taken in combination with exchange capacity measurements performed in the manner noted
above, provides a basis for selecting particular smectite-type minerals for use in
the granular detergent compositions disclosed herein.
[0069] The clay is preferably mainly in the form of granules, with at least 50% (and preferably
at least 75% or at least 90%) being in the form of granules having a size of at least
100mm up to 1800mm, preferably up to 1180mm, preferably 150-850mm. Preferably the
amount of clay in the granules is at least 50%, usually at least 70% or 90%, of the
weight of the granules.
Detersive surfactants
[0070] Non-limiting examples of surfactants useful herein typically at levels from about
1% to about 55%, by weight, anionics such as sulphonates, sulphates and ether sulphates.
These include the conventional C11-C18 alkyl benzene sulfonates ("LAS") and primary,
branched-chain and random C10-C20 alkyl sulfates ("AS"), the C10-C18 secondary (2,3)
alkyl sulfates of the formula CH
3(CH2)
x(CHOSO
3-M
+) CH
3 and CH
3 (CH
2)
y(CHOSO
3-M+) CH
2CH
3 where x and (y + 1) are integers of at least about 7, preferably at least about 9,
and M is a water-solubilizing cation, especially sodium, unsaturated sulfates such
as oleyl sulfate, the C10-C18 alkyl alkoxy sulfates ("AExS"; especially EO 1-7 ethoxy
sulfates), C10-C18 alkyl alkoxy carboxylates (especially the EO
1-5 ethoxycarboxylates), the C10-18 glycerol ethers, the C10-C18 alkyl polyglycosides
and their corresponding sulfated polyglycosides, and C12-C18 alpha-sulfonated fatty
acid esters. If desired, the conventional nonionic and amphoteric surfactants such
as the C12-C18 alkyl ethoxylates ("AE") including the so-called narrow peaked alkyl
ethoxylates and C6-C12 alkyl phenol alkoxylates (especially ethoxylates and mixed
ethoxy/propoxy), C12-C18 betaines and sulfobetaines ("sultaines"), C10-C18 amine oxides,
and the like, can also be included in the overall compositions. The C10-C18 N-alkyl
polyhydroxy fatty acid amides can also be used. Typical examples include the C12-C18
N-methylglucamides. See WO 92/06154. Other sugar-derived surfactants include the N-alkoxy
polyhydroxy fatty acid amides, such as C10-C18 N-(3-methoxypropyl) glucamide. The
N-propyl through N-hexyl C12-C18 glucamides can be used for low sudsing. C10-C20 conventional
soaps may also be used. If high sudsing is desired, the branched-chain C10-C16 soaps
may be used. Mixtures of anionic and nonionic surfactants are especially useful. Other
conventional useful anionic, amphoteric, nonionic or cationic surfactants are listed
in standard texts.
[0071] In preferred embodiments, the tablet comprises at least 5% by weight of surfactant,
more preferably at least 15% by weight, even more preferably at least 25% by weight,
and most preferably between 35% and 55% by weight of surfactant. The amount of anionic
is preferably at least 1.5 times, generally at least 2 or 3 times, the total amount
of other surfactants.
Builders
[0072] Detergent builders can optionally be included in the compositions herein to assist
in controlling mineral hardness. Inorganic as well as organic builders can be used.
Builders are typically used in fabric laundering compositions to assist in the removal
of particulate soils.
The level of builder can vary widely depending upon the end use of the composition.
[0073] Inorganic or P-containing detergent builders include, but are not limited to, the
alkali metal, ammonium and alkanolammonium salts of polyphosphates (exemplified by
the tripolyphosphates, pyrophosphates, and glassy polymeric meta-phosphates), phosphonates,
phytic acid, silicates, carbonates (including bicarbonates and sesquicarbonates),
sulphates, and aluminosilicates. However, non-phosphate builders are required in some
locales. Importantly, the compositions herein function surprisingly well even in the
presence of the so-called "weak" builders (as compared with phosphates) such as citrate,
or in the so-called "underbuilt" situation that may occur with zeolite or layered
silicate builders.
[0074] Examples of silicate builders are the alkali metal silicates, particularly those
having a SiO
2:Na
2O ratio in the range 1.6:1 to 3.2:1 and layered silicates, such as the layered sodium
silicates described in U.S. Patent 4,664,839, issued May 12, 1987 to H. P. Rieck.
NaSKS-6 is the trademark for a crystalline layered silicate marketed by Hoechst (commonly
abbreviated herein as "SKS-6"). Unlike zeolite builders, the Na SKS-6 silicate builder
does not contain aluminum. NaSKS-6 has the delta-Na
2SiO
5 morphology form of layered silicate. It can be prepared by methods such as those
described in German DE-A-3,417,649 and DE-A-3,742,043. SKS-6 is a highly preferred
layered silicate for use herein, but other such layered silicates, such as those having
the general formula NaMSixO
2x+1.yH
2O wherein M is sodium or hydrogen, x is a number from 1.9 to 4, preferably 2, and
y is a number from 0 to 20, preferably 0 can be used herein. Various other layered
silicates from Hoechst include NaSKS-5, NaSKS-7 and NaSKS-11, as the alpha, beta and
gamma forms. As noted above, the delta-Na
2SiO
5 (NaSKS-6 form) is most preferred for use herein. Other silicates may also be useful
such as for example magnesium silicate, which can serve as a crispening agent in granular
formulations, as a stabilizing agent for oxygen bleaches, and as a component of suds
control systems.
[0075] Examples of carbonate builders are the alkaline earth and alkali metal carbonates
as disclosed in German Patent Application No. 2,321,001 published on November 15,
1973.
[0076] Aluminosilicate builders are useful in the present invention. Aluminosilicate builders
are of great importance in most currently marketed heavy duty granular detergent compositions,
and can also be a significant builder ingredient in liquid detergent formulations.
Aluminosilicate builders include those having the empirical formula:
Mz(zAlO
2)y].xH
2O
wherein z and y are integers of at least 6, the molar ratio of z to y is in the
range from 1.0 to about 0.5, and x is an integer from about 15 to about 264.
[0077] Useful aluminosilicate ion exchange materials are commercially available. These aluminosilicates
can be crystalline or amorphous in structure and can be naturally-occurring aluminosilicates
or synthetically derived. A method for producing aluminosilicate ion exchange materials
is disclosed in U.S. Patent 3,985,669, Krummel, et al, issued October 12, 1976. Preferred
synthetic crystalline aluminosilicate ion exchange materials useful herein are available
under the designations Zeolite A, Zeolite P (B), Zeolite MAP and Zeolite X. In an
especially preferred embodiment, the crystalline aluminosilicate ion exchange material
has the formula:
Na
12[(AlO
2)
12(SiO
2)
12].xH
2O
wherein x is from about 20 to about 30, especially about 27. This material is known
as Zeolite A. Dehydrated zeolites (x = 0 - 10) may also be used herein. Preferably,
the aluminosilicate has a particle size of about 0.1-10 microns in diameter.
[0078] Organic detergent builders suitable for the purposes of the present invention include,
but are not restricted to, a wide variety of polycarboxylate compounds. As used herein,
"polycarboxylate" refers to compounds having a plurality of carboxylate groups, preferably
at least 3 carboxylates. Polycarboxylate builder can generally be added to the composition
in acid form, but can also be added in the form of a neutralized salt. When utilized
in salt form, alkali metals, such as sodium, potassium, and lithium, or alkanolammonium
salts are preferred.
[0079] Included among the polycarboxylate builders are a variety of categories of useful
materials. One important category of polycarboxylate builders encompasses the ether
polycarboxylates, including oxydisuccinate, as disclosed in Berg, U.S. Patent 3,128,287,
issued April 7, 1964, and Lamberti et al, U.S. Patent 3,635,830, issued January 18,
1972. See also "TMS/TDS" builders of U.S. Patent 4,663,071, issued to Bush et al,
on May 5, 1987. Suitable ether polycarboxylates also include cyclic compounds, particularly
alicyclic compounds, such as those described in U.S. Patents 3,923,679; 3,835,163;
4,158,635; 4,120,874 and 4,102,903.
[0080] Other useful detergency builders include the ether hydroxypolycarboxylates, copolymers
of maleic anhydride with ethylene or vinyl methyl ether, 1, 3, 5-trihydroxy benzene-2,
4, 6-trisulphonic acid, and carboxymethyloxysuccinic acid, the various alkali metal,
ammonium and substituted ammonium salts of polyacetic acids such as ethylenediamine
tetraacetic acid and nitrilotriacetic acid, as well as polycarboxylates such as mellitic
acid, succinic acid, oxydisuccinic acid, polymaleic acid, benzene 1,3,5-tricarboxylic
acid, carboxymethyloxysuccinic acid, and soluble salts thereof.
[0081] Citrate builders, e.g., citric acid and soluble salts thereof (particularly sodium
salt), are polycarboxylate builders of particular importance for heavy duty liquid
detergent formulations due to their availability from renewable resources and their
biodegradability. Citrates can also be used in granular compositions, especially in
combination with zeolite and/or layered silicate builders. Oxydisuccinates are also
especially useful in such compositions and combinations.
[0082] Also suitable in the detergent compositions of the present invention are the 3,3-dicarboxy-4-oxa-1,6-hexanedioates
and the related compounds disclosed in U.S. Patent 4,566,984, Bush, issued January
28, 1986. Useful succinic acid builders include the C5-C20 alkyl and alkenyl succinic
acids and salts thereof. A particularly preferred compound of this type is dodecenylsuccinic
acid. Specific examples of succinate builders include: laurylsuccinate, myristylsuccinate,
palmitylsuccinate, 2-dodecenylsuccinate (preferred), 2-pentadecenylsuccinate, and
the like. Laurylsuccinates are the preferred builders of this group, and are described
in European Patent Application 86200690.5/0,200,263, published November 5, 1986.
[0083] Other suitable polycarboxylates are disclosed in U.S. Patent 4,144,226, Crutchfield
et al, issued March 13, 1979 and in U.S. Patent 3,308,067, Diehl, issued March 7,
1967. See also Diehl U.S. Patent 3,723,322.
[0084] Fatty acids, e.g., C12-C18 monocarboxylic acids, can also be incorporated into the
compositions alone, or in combination with the aforesaid builders, especially citrate
and/or the succinate builders, to provide additional builder activity. Such use of
fatty acids will generally result in a diminution of sudsing, which should be taken
into account by the formulator.
[0085] In situations where phosphorus-based builders can be used, and especially in the
formulation of bars used for hand-laundering operations, the various alkali metal
phosphates such as the well-known sodium tripolyphosphates, sodium pyrophosphate and
sodium orthophosphate can be used. Phosphonate builders such as ethane-1-hydroxy-1,1-diphosphonate
and other known phosphonates (see, for example, U.S. Patents 3,159,581; 3,213,030;
3,422,021; 3,400,148 and 3,422,137) can also be used.
Bleach
[0086] The detergent compositions herein may contain bleaching agents or bleaching compositions
containing a bleaching agent and one or more bleach activators. When present, bleaching
agents will typically be at levels of from about 1% to about 30%, more typically from
about 5% to about 20%, of the detergent composition, especially for fabric laundering.
If present, the amount of bleach activators will typically be from about 0.1% to about
60%, more typically from about 0.5% to about 40% of the bleaching composition comprising
the bleaching agent-plus-bleach activator.
[0087] The bleaching agents used herein can be any of the bleaching agents useful for detergent
compositions in textile cleaning, hard surface cleaning, or other cleaning purposes
that are now known or become known. These include oxygen bleaches as well as other
bleaching agents. Perborate bleaches, e.g., sodium perborate (e.g., mono- or tetra-hydrate)
can be used herein.
[0088] Another category of bleaching agent that can be used without restriction encompasses
percarboxylic acid bleaching agents and salts thereof. Suitable examples of this class
of agents include magnesium monoperoxyphthalate hexahydrate, the magnesium salt of
metachloro perbenzoic acid, 4-nonylamino-4-oxoperoxybutyric acid and diperoxydodecanedioic
acid. Such bleaching agents are disclosed in U.S. Patent 4,483,781, Hartman, issued
November 20, 1984, U.S. Patent Application 740,446, Burns et al, filed June 3, 1985,
European Patent Application 0,133,354, Banks et al, published February 20, 1985, and
U.S. Patent 4,412,934, Chung et al, issued November1, 1983. Highly preferred bleaching
agents also include 6-nonylamino-6-oxoperoxycaproic acid as described in U.S. Patent
4,634,551, issued January 6, 1987 to Burns et al.
[0089] Peroxygen bleaching agents can also be used. Suitable peroxygen bleaching compounds
include sodium carbonate peroxyhydrate and equivalent "percarbonate" bleaches, sodium
pyrophosphate peroxyhydrate, urea peroxyhydrate, and sodium peroxide. Persulfate bleach
(e.g., OXONE, manufactured commercially by DuPont) can also be used.
[0090] A preferred percarbonate bleach comprises dry particles having an average particle
size in the range from about 500 micrometers to about 1,000 micrometers, not more
than about 10% by weight of said particles being smaller than about 200 micrometers
and not more than about 10% by weight of said particles being larger than about 1,250
micrometers. Optionally, the percarbonate can be coated with silicate, borate or water-soluble
surfactants. Percarbonate is available from various commercial sources such as FMC,
Solvay and Tokai Denka.
[0091] Mixtures of bleaching agents can also be used.
[0092] Peroxygen bleaching agents, the perborates, the percarbonates, etc., are preferably
combined with bleach activators, which lead to the in situ production in aqueous solution
(i.e., during the washing process) of the peroxy acid corresponding to the bleach
activator. Various nonlimiting examples of activators are disclosed in U.S. Patent
4,915,854, issued April 10, 1990 to Mao et al, and U.S. Patent 4,412,934. The nonanoyloxybenzene
sulfonate (NOBS) and tetraacetyl ethylene diamine (TAED) activators are typical, and
mixtures thereof can also be used. See also U.S. 4,634,551 for other typical bleaches
and activators useful herein.
[0093] Highly preferred amido-derived bleach activators are those of the formulae:
R1N(R5)C(O)R2C(O)L or R1C(O)N(R5)R2C(O)L
wherein R1 is an alkyl group containing from about 6 to about 12 carbon atoms,
R2 is an alkylene containing from 1 to about 6 carbon atoms, R5 is H or alkyl, aryl,
or alkaryl containing from about 1 to about 10 carbon atoms, and L is any suitable
leaving group. A leaving group is any group that is displaced from the bleach activator
as a consequence of the nucleophilic attack on the bleach activator by the perhydrolysis
anion. A preferred leaving group is phenyl sulfonate.
[0094] Preferred examples of bleach activators of the above formulae include (6-octanamido-caproyl)oxybenzenesulfonate,
(6-nonanamidocaproyl)oxybenzenesulfonate, (6-decanamidocaproyl)oxybenzenesulfonate,
and mixtures thereof as described in U.S. Patent 4,634,551, incorporated herein by
reference.
[0095] Another class of bleach activators comprises the benzoxazin-type activators disclosed
by Hodge et al in U.S. Patent 4,966,723, issued October 30, 1990, incorporated herein
by reference. A highly preferred activator of the benzoxazin-type is:

[0096] Still another class of preferred bleach activators includes the acyl lactam activators,
especially acyl caprolactams and acyl valerolactams of the formulae:

wherein R6 is H or an alkyl, aryl, alkoxyaryl, or alkaryl group containing from
1 to about 12 carbon atoms. Highly preferred lactam activators include benzoyl caprolactam,
octanoyl caprolactam, 3,5,5-trimethylhexanoyl caprolactam, nonanoyl caprolactam, decanoyl
caprolactam, undecenoyl caprolactam, benzoyl valerolactam, octanoyl valerolactam,
decanoyl valerolactam, undecenoyl valerolactam, nonanoyl valerolactam, 3,5,5-trimethylhexanoyl
valerolactam and mixtures thereof. See also U.S. Patent 4,545,784, issued to Sanderson,
October 8, 1985, incorporated herein by reference, which discloses acyl caprolactams,
including benzoyl caprolactam, adsorbed into sodium perborate.
[0097] Bleaching agents other than oxygen bleaching agents are also known in the art and
can be utilized herein. One type of non-oxygen bleaching agent of particular interest
includes photoactivated bleaching agents such as the sulfonated zinc and/or aluminum
phthalocyanines. See U.S. Patent 4,033,718, issued July 5, 1977 to Holcombe et al.
If used, detergent compositions will typically contain from about 0.025% to about
1.25%, by weight, of such bleaches, especially sulfonate zinc phthalocyanine.
[0098] If desired, the bleaching compounds can be catalyzed by means of a manganese compound.
Such compounds are well known in the art and include, for example, the manganese-based
catalysts disclosed in US-A-5,246,621, US-A-5,244,594; US-A-5,194,416; US-A-5,114,606;
and EP-A-549,271, EP-A-549,272, EP-A-544,440, and EP-A-544,490; Preferred examples
of these catalysts include MnlV2(u-O)3(1,4,7-trimethyl-1,4,7-triazacyclononane)2(PF6)2,
MnIII2(u-O)1(u-OAc)2(1,4,7-trimethyl-1,4,7-triazacyclononane)2-(ClO4)2, MnIV4(u-O)6(1,4,7-triazacyclononane)4(ClO4)4,
MnIIIMnIV4(u-O)1(u-OAc)2-(1,4,7-trimethyl-1,4,7-triazacyclononane)2(ClO4)3, MnIV(1,4,7-trimethyl-1,4,7-triazacyclononane)-
(OCH3)3(PF6), and mixtures thereof. Other metal-based bleach catalysts include those
disclosed in U.S. Pat. 4,430,243 and U.S. Pat. 5,114,611. The use of manganese with
various complex ligands to enhance bleaching is also reported in the following United
States Patents: 4,728,455; 5,284,944; 5,246,612; 5,256,779; 5,280,117; 5,274,147;
5,153,161; and 5,227,084.
[0099] As a practical matter, and not by way of limitation, the compositions and processes
herein can be adjusted to provide on the order of at least one part per ten million
of the active bleach catalyst species in the aqueous washing liquor, and will preferably
provide from about 0.1 ppm to about 700 ppm, more preferably from about 1 ppm to about
500 ppm, of the catalyst species in the laundry liquor.
Enzymes
[0100] Enzymes can be included in the formulations herein for a wide variety of fabric laundering
purposes, including removal of protein-based, carbohydrate-based, or triglyceride-based
stains, for example, and for the prevention of refugee dye transfer, and for fabric
restoration. The enzymes to be incorporated include proteases, amylases, lipases,
cellulases, and peroxidases, as well as mixtures thereof. Other types of enzymes may
also be included. They may be of any suitable origin, such as vegetable, animal, bacterial,
fungal and yeast origin. However, their choice is governed by several factors such
as pH-activity and/or stability optima, thermostability, stability versus active detergents,
builders and so on. In this respect bacterial or fungal enzymes are preferred, such
as bacterial amylases and proteases, and fungal cellulases.
[0101] Enzymes are normally incorporated at levels sufficient to provide up to about 5 mg
by weight, more typically about 0.01 mg to about 3 mg, of active enzyme per gram of
the composition. Stated otherwise, the compositions herein will typically comprise
from about 0.001% to about 5%, preferably 0.01%-1% by weight of a commercial enzyme
preparation. Protease enzymes are usually present in such commercial preparations
at levels sufficient to provide from 0.005 to 0.1 Anson units (AU) of activity per
gram of composition.
[0102] Suitable examples of proteases are the subtilisins which are obtained from particular
strains of B. subtilis and B. licheniforms. Another suitable protease is obtained
from a strain of Bacillus, having maximum activity throughout the pH range of 8-12,
developed and sold by Novo Industries A/S under the registered trade name ESPERASE.
The preparation of this enzyme and analogous enzymes is described in British Patent
Specification No. 1,243,784 of Novo. Proteolytic enzymes suitable for removing protein-based
stains that are commercially available include those sold under the tradenames ALCALASE
and SAVINASE by Novo Industries A/S (Denmark) and MAXATASE by International Bio-Synthetics,
Inc. (The Netherlands). Other proteases include Protease A (see EP-A-130,756, published
January 9, 1985) and Protease B (see European Patent Application 87303761.8, filed
April 28, 1987, and EP-A-130,756, Bott et al, published January 9, 1985).
[0103] Amylases include, for example, -amylases described in GB-A-1,296,839 (Novo), RAPIDASE,
International Bio-Synthetics, Inc. and TERMAMYL, Novo Industries.
[0104] The cellulase usable in the present invention include both bacterial or fungal cellulase.
Preferably, they will have a pH optimum of between 5 and 9.5. Suitable cellulases
are disclosed in U.S. Patent 4,435,307, Barbesgoard et al, issued March 6, 1984, which
discloses fungal cellulase produced from Humicola insolens and Humicola strain DSM1800
or a cellulase 212-producing fungus belonging to the genus Aeromonas, and cellulase
extracted from the hepatopancreas of a marine mollusk (Dolabella Auricula Solander).
suitable cellulases are also disclosed in GB-A-2.075.028; GB-A-2.095.275 and DE-OS-2.247.832.
CAREZYME (Novo) is especially useful.
[0105] Suitable lipase enzymes for detergent usage include those produced by microorganisms
of the Pseudomonas group, such as Pseudomonas stutzeri ATCC 19.154, as disclosed in
British Patent 1,372,034. See also lipases in Japanese Patent Application 53,20487,
laid open to public inspection on February 24, 1978. This lipase is available from
Amano Pharmaceutical Co. Ltd., Nagoya, Japan, under the trade name Lipase P "Amano,"
hereinafter referred to as "Amano-P." Other commercial lipases include Amano-CES,
lipases ex Chromobacter viscosum, e.g. Chromobacter viscosum var. lipolyticum NRRLB
3673, commercially available from Toyo Jozo Co., Tagata, Japan; and further Chromobacter
viscosum lipases from U.S. Biochemical Corp., U.S.A. and Disoynth Co., The Netherlands,
and lipases ex Pseudomonas gladioli. The LIPOLASE enzyme derived from Humicola lanuginosa
and commercially available from Novo (see also EPO 341,947) is a preferred lipase
for use herein.
[0106] Peroxidase enzymes are used in combination with oxygen sources, e.g., percarbonate,
perborate, persulfate, hydrogen peroxide, etc. They are used for "solution bleaching,"
i.e. to prevent transfer of dyes or pigments removed from substrates during wash operations
to other substrates in the wash solution. Peroxidase enzymes are known in the art,
and include, for example, horseradish peroxidase, ligninase, and haloperoxidase such
as chloro- and bromo-peroxidase. Peroxidase-containing detergent compositions are
disclosed, for example, in PCT International Application WO 89/099813, published October19,
1989, by O. Kirk, assigned to Novo Industries A/S.
[0107] A wide range of enzyme materials and means for their incorporation into synthetic
detergent compositions are also disclosed in U.S. Patent 3,553,139, issued January
5, 1971 to McCarty et al. Enzymes are further disclosed in U.S. Patent 4,101,457,
Place et al, issued July 18, 1978, and in U.S. Patent 4,507,219, Hughes, issued March
26, 1985, both. Enzyme materials useful for liquid detergent formulations, and their
incorporation into such formulations, are disclosed in U.S. Patent 4,261,868, Hora
et al, issued April 14, 1981. Enzymes for use in detergents can be stabilized by various
techniques. Enzyme stabilization techniques are disclosed and exemplified in U.S.
Patent 3,600,319, issued August 17, 1971 to Gedge, et al, and European Patent Application
Publication No. 0 199 405, Application No. 86200586.5, published October 29, 1986,
Venegas. Enzyme stabilization systems are also described, for example, in U.S. Patent
3,519,570.
Flocculants
[0108] Most clay flocculating polymers are fairly long chained polymers and copolymers derived
from such monomers as ethylene oxide, acrylamide, acrylic acid, dimethylamino ethyl
methacrylate, vinyl alcohol, vinyl pyrrolidone and ethylene imine. Gums, like guar
gum, are suitable as well.
[0109] Preferred are polymers of ethylene oxide, acrylamide or acrylic acid. These polymers
dramatically enhance the deposition of a fabric softening clay if their molecular
weights are in the range of from 100 000 to 10 million. Preferred are such polymers
having a weight average molecular weight of from 150000 to 5 million.
[0110] The most preferred polymer is poly (ethylene oxide). Molecular weight distributions
can be readily determined using gel permeation chromatography, against standards of
poly (ethylene oxide) of narrow molecular weight distributions.
[0111] The amount of flocculant is preferably 0.5-10% by weight of the tablet, most preferably
about 2 to 6%.
[0112] The flocculant is preferably mainly in the form of granules, with at least 50% by
weighty (and preferably at least 75% and most preferably at least 90%) being in the
form of granules having a size of at least 100mm up to 1800mm, preferably up to 1180mm
and most preferably 150-850mm Preferably the amount of flocculant in the granules
is at least 50%, generally at least 70% or 90%, of the weight of the granules.
[0113] Other components which are commonly used in detergent compositions and which may
be incorporated into the detergent tablets of the present invention include chelating
agents, soil release agents, soil antiredeposition agents, dispersing agents, brighteners,
suds suppressors, fabric softeners, dye transfer inhibition agents and perfumes.
[0114] It should be noted that when a clay material is compressed prior to incorporation
into a tablet or in a cleaning composition, improved disintegration or dispensing
is achieved. For example, tablets comprising clay which is compressed prior to incorporation
into a tablet, disintegrate more rapidly than tablets comprising the same clay material
which has not been compressed prior to incorporation into a tablet. In particular
the amount of pressure used for the compression of the clay is of importance to obtain
clay particles which aid disintegration or dispensing.
Further, when softening clays are compressed and then incorporated in cleaning compositions
or tablets, not only improved disintegration or dispensing is obtained, but also good
softening of the fabrics.
Preferably, the clay component is obtained by compression of a clay material. A preferred
process comprises the steps of submitting the clay material to a pressure of at least
10MPa, or even at least 20MPa or even 40MPa. This can for example be done by tabletting
or roller compaction of a clay material, optionally together with one or more other
ingredients, to form a clay tablet or sheet, preferably followed by size reduction,
such as grinding, of the compressed clay sheet or tablet, to form compressed clay
particles. The particles can then be incorporated in a tablet or cleaning composition.
[0115] Tabletting methods and roller compaction methods are known in the art. For example,
the compression of the clay can be done in a Lloyd 50K tablet press or with a Chilsonator
roller compaction equipment, available form Fitzpatrick Company.
[0116] Typically, a tablet according to the invention is used in a process to wash and soften
laundry in a laundry washing machine.
Examples
Clay Dispersibility
[0117] For the purpose of this invention, the dispersibility of the clay is characterised
by the rate at which a tablet of clay is dispersed in water. The test is conducted
as follows:
[0118] 40g of clay raw material is introduced in a circular die with a diameter of 54mm
and compressed to give a tablet with a diametrical fracture of 5kPa.
[0119] The clay tablet is placed in a perforated 10cm diameter metallic cage with a mesh
size of 5mmx5mm. The cage is placed in a pool of 51 of demineralised water at 20°C
and rotated at a rate of 80rpm. The residue left in the cage after a residence time
of 1, 3 or 5 min in the pool of water is determined by weighing. The level of clay
dispersibility is calculated as follows:

[0120] The lower the residue number the better the clay. Clays suitable for use in the tablets
of this invention have a residue number of less than 10 after a residence time of
5 min in water (preferably within 3 min or more preferably within 1 min). For instance
one typical hectorite swelling clay (A) gives a residue over 100 at 5 minutes and
1 minute, a selected swelling clay (B) gives a residue of over 100 at 1 minute but
zero at 5 minutes, and a preferred clay (C) gives a value of zero at each of 1, 3
and 5 minutes.
Example 1
[0121] A detergent base powder of composition A (see table 1) was prepared as follows: all
the particulate materials of base composition A were mixed together in a mixing drum
to form a homogeneous particulate mixture. During this mixing the binder was sprayed
on.
[0122] When clay was included, the base powder of composition A was mixed in a mixing drum
and diluted with montmorillonite clay extrudate formed using the following process.
500g of the clay were mixed with 250g of distilled water. The resulting mix was fed
to a Dome extruder with a screw set at a rpm of 80. The resulting mix was then screened
using ATSM screen sets. The extrudates made were then dried in a Sherwood Scientific
fluid bed dryer set at 90°C for 30 min. The dried extrudates were screened and the
oversize (particles larger than 1700mm) and the fines (particles smaller than 150mm)
were removed from the mix.
[0123] Tablets were then made the following way, 42.8g of the mixture was introduced into
a mould of circular shape with a diameter of 5.4cm and compressed to give a tablet
tensile strength (or diametrical fracture stress) of 15 kPa.
[0124] The level of residue in the dispenser of a washing machine was assessed by means
of the
"Tablet Dispensing Test": Two laundry tablets are placed in Baucknecht WA9850 dispenser. The water supply to
the washing machine is set to a temperature of 8°C and a hardness of 21 grains per
gram, the dispenser water inlet flowrate is set to 4 l/min and the flowtime at 78
seconds. The level of tablet residues left in the dispenser is checked by switching
the washing machine on with the wash cycle set to wash program 4 (whites/colors, short
cycle). The residue number is determined as follows:
Table 1:
Detergent base powder composition |
|
Composition A |
|
(%) |
Anionic agglomerates 1 |
21.45 |
Anionic agglomerates 2 |
13.00 |
Cationic agglomerates |
5.45 |
Layered silicate |
10.8 |
Sodium percarbonate |
14.19 |
Bleach activator agglomerates |
5.49 |
Sodium carbonate |
13.64 |
EDDS/Sulphate particle |
0.47 |
Tetrasodium salt of Hydroxyethane Diphosphonic acid |
0.73 |
Soil Release Polymer |
0.33 |
Fluorescer |
0.18 |
Zinc Phthalocyanine sulphonate encapsulate |
0.025 |
Soap powder |
1.40 |
Suds suppressor |
1.87 |
Citric acid |
7.10 |
Protease |
0.79 |
Lipase |
0.28 |
Cellulase |
0.22 |
Amylase |
1.08 |
Binder |
|
Cationic Polymer |
0.42 |
PEG 4000 |
0.725 |
PEG 1000 |
0.365 |
Anionic agglomerates 1 consist of 40% anionic surfactant, 27% zeolite and 33% carbonate. |
Anionic agglomerates 2 consist of 40% anionic surfactant, 28% zeolite and 32% carbonate. |
Cationic agglomerates consist of 20% cationic surfactant, 56% zeolite and 24% sulphate. |
Layered silicate consists of 95% SKS 6 and 5% silicate. |
Bleach activator agglomerates consists of 81% TAED, 17% acrylic/maleic copolymer (acid
form) and 2% water. |
Ethylene diamine N,N-disuccinic acid sodium salt/sulphate particles consist of 58%
ethylene diamine N,N-disuccinic acid sodium salt, 23% of sulphate and 19% water. |
Zinc phthalocyanine sulphonate encapsulates are 10% active. |
Suds suppressor consists of 11.5% silicone oil; 59% of zeolite and 29.5% of water. |
[0125] When the tablets are free of clay, the residue is high. When 2% of clay C extrudate
is included, the residue number is significantly reduced. When 5% of clay C is included,
the residue number is reduced further and is low. When 5% of clay B is included, the
residue number is similar to the value obtained using 2% clay C.
[0126] Other examples include tablets made from a powder of the following composition:
Examples A and B
[0127]
Table A:
Detergent base powder composition |
|
Ex A |
Ex B |
|
(%) |
(%) |
|
Clay Extrudate |
14.00 |
14.00 |
Flocculant Agglomerate |
3.8 |
3.8 |
Anionic agglomerates 1 |
32 |
38 |
Anionic particle 2 |
2.27 |
2.27 |
Cationic agglomerates |
4.0 |
|
Sodium percarbonate |
8.0 |
10.0 |
Bleach activator agglomerates |
2.31 |
2.8 |
Sodium carbonate |
21.066 |
16.57 |
EDDS/Sulphate particle |
0.19 |
0.19 |
Tetrasodium salt of Hydroxyethane Diphosphonic acid |
0.34 |
0.34 |
Fluorescer |
0.15 |
0.15 |
Zinc Phthalocyanine sulphonate encapsulate |
0.027 |
0.027 |
Soap powder |
1.40 |
1.40 |
Suds suppressor |
2.6 |
2.6 |
Citric acid |
4.0 |
4.0 |
Protease |
0.45 |
0.45 |
Cellulase |
0.20 |
0.20 |
Amylase |
0.20 |
0.20 |
Perfume |
1.00 |
1.00 |
Binder |
|
|
Pluriol 1000 |
2.0 |
2.0 |
|
|
|
|
|
|
Clay extrudate comprise 97% of CSM Quest 5A clay and 3% water |
Flocculant raw material is polyethylene oxide with an average molecular weight of
300,000 |
Anionic agglomerates 1 comprise of 40% anionic surfactant, 27% zeolite and 33% carbonate |
Anionic agglomerates 2 comprise of 40% anionic surfactant, 28% zeolite and 32% carbonate |
Cationic agglomerates comprise of 20% cationic surfactant, 56% zeolite and 24% sulphate |
Layered silicate comprises of 95% SKS 6 and 5% silicate |
Bleach activator agglomerates comprise of 81% TAED, 17% acrylic/maleic copolymer (acid
form) and 2% water. |
Ethylene diamine N,N-disuccinic acid sodium salt/Sulphate particle comprise of 58%
of Ethylene diamine N,N-disuccinic acid sodium salt, 23% of sulphate and 19% water. |
Zinc phthalocyanine sulphonate encapsulates are 10% active. |
Suds suppressor comprises of 11.5% silicone oil (ex Dow Corning); 59% of zeolite and
29.5% of water. |
Example C (micronised citric acid)
[0128] In composition of example B, the citric acid used was replaced with micronised citric
acid. The citric acid used was ground with a coffee grinder to the following psd prior
to use.

Example D-F (phosphated composition)
[0129]
|
Ex D |
Ex E |
Ex F |
|
(%) |
(%) |
(%) |
|
Clay Extrudate |
13.00 |
13.00 |
13.00 |
Flocculant Agglomerate |
3.5 |
3.5 |
3.5 |
Anionic particle |
38.2 |
38.2 |
38.2 |
Sodium percarbonate |
8.0 |
|
|
Sodium perborate monohydrate |
|
8.0 |
|
Sodium perborate tetrahydrate |
|
|
8.0 |
Bleach activator agglomerates |
2.3 |
2.3 |
2.3 |
HPA sodium tripolyphosphate |
15.4 |
15.4 |
15.4 |
Sodium carbonate |
10.043 |
10.043 |
10.043 |
EDDS/Sulphate particle |
0.19 |
0.19 |
0.19 |
Tetrasodium salt of Hydroxyethane Diphosphonic acid |
0.34 |
0.34 |
0.34 |
Fluorescer |
0.15 |
0.15 |
0.15 |
Zinc Phthalocyanine sulphonate encapsulate |
0.027 |
0.027 |
0.027 |
Soap powder |
1.40 |
1.40 |
1.40 |
Suds suppressor |
2.6 |
2.6 |
2.6 |
Citric acid |
1.0 |
1.0 |
1.0 |
Protease |
0.45 |
0.45 |
0.45 |
Cellulase |
0.20 |
0.20 |
0.20 |
Amylase |
0.20 |
0.20 |
0.20 |
Perfume |
1.00 |
1.00 |
1.00 |
Binder |
|
|
|
Pluriol 1000 |
2.0 |
2.0 |
2.0 |
|
|
|
|
|
|
|
|
Clay extrudate comprise 97% of CSM Quest 5A clay and 3% water |
Flocculant raw material is polyethylene oxide with an average molecular weight of
300,000 |
Layered silicate comprises of 95% SKS 6 and 5% silicate |
Bleach activator agglomerates comprise of 81% TAED, 17% acrylic/maleic copolymer (acid
form) and 2% water. |
Ethylene diamine N,N-disuccinic acid sodium salt/Sulphate particle comprise of 58%
of Ethylene diamine N,N-disuccinic acid sodium salt, 23% of sulphate and 19% water. |
Zinc phthalocyanine sulphonate encapsulates are 10% active. |
Suds suppressor comprises of 11.5% silicone oil (ex Dow Corning); 59% of zeolite and
29.5% of water. |
The anionic particle was a blown powder with the following composition: |
(%) |
Sodium linear alkylbenzene sulphonate |
17.7 |
Nonionic C35 7EO |
2.0 |
Nonionic C35 3EO |
5.9 |
Soap |
0.5 |
Sodium tripolyphosphate, (Rhodia-Phos HPA 3.5 from Rhone Poulenc) |
47.8 |
Sodium silicate |
10.8 |
Sodium carboxymethly cellulose |
0.4 |
Acrylate / maleate copolymer |
2.1 |
Salts, moisture |
12.9 |
Examples G and H
[0130]
|
Ex G |
Ex H |
|
(%) |
(%) |
Clay Extrudate |
14.0
0 |
14.0
0 |
Flocculant Agglomerate |
3.8 |
3.8 |
Anionic agglomerates 1 |
32 |
32 |
Anionic particle 2 |
2.27 |
2.27 |
Cationic agglomerates |
4.0 |
4.0 |
Sodium percarbonate |
8.0 |
8.0 |
Bleach activator agglomerates |
2.31 |
2.31 |
Sodium carbonate |
18.0
66 |
18.0
66 |
EDDS/Sulphate particle |
0.19 |
0.19 |
Tetrasodium salt of Hydroxyethane Diphosphonic acid |
0.34 |
0.34 |
Fluorescer |
0.15 |
0.15 |
Zinc Phthalocyanine sulphonate encapsulate |
0.02
7 |
0.02
7 |
Soap powder |
1.40 |
1.40 |
Suds suppressor |
2.6 |
2.6 |
Arbocel TF-30-HG |
5.0 |
|
Vivapur G22 |
|
5.0 |
Citric acid |
2.0 |
2.0 |
Protease |
0.45 |
0.45 |
Cellulase |
0.20 |
0.20 |
Amylase |
0.20 |
0.20 |
Perfume |
1.00 |
1.00 |
Binder |
|
|
Pluriol 1000 |
2.0 |
2.0 |
|
|
|
|
|
|
Clay extrudate comprise 97% of CSM Quest 5A clay and 3% water |
Flocculant raw material is polyethylene oxide with an average molecular weight of
300,000 |
Anionic agglomerates 1 comprise of 40% anionic surfactant, 27% zeolite and 33% carbonate |
Anionic agglomerates 2 comprise of 40% anionic surfactant, 28% zeolite and 32% carbonate |
Cationic agglomerates comprise of 20% cationic surfactant, 56% zeolite and 24% sulphate |
Layered silicate comprises of 95% SKS 6 and 5% silicate |
Bleach activator agglomerates comprise of 81% TAED (Tetra acetyl ethylene diamine),
17% acrylic/maleic copolymer (acid form) and 2% water. |
Ethylene diamine N,N-disuccinic acid sodium salt/Sulphate particle comprise of 58%
of Ethylene diamine N,N-disuccinic acid sodium salt, 23% of sulphate and 19% water. |
Zinc phthalocyanine sulphonate encapsulates are 10% active. |
Suds suppressor comprises of 11.5% silicone oil (ex Dow Corning); 59% of zeolite and
29.5% of water. |
Arbocel TF-30-HG and Vivapur G22 are cellulose containing disintegration agent from
the Rettenmaier company |
Example I-N
[0131] Example A-G are repeated by dipping the tablets made with the indicated composition
in a bath comprising 80 parts of adipic acid mixed with 18.5 parts of CSM Quest 9
clay and 1.5 parts of Coasol (Coasol being a diisobutyladipate).
[0132] The tablet may also comprise a high molecular weight poly(ethyleneoxide), cellulosic
disintegrant, and/ or acetate. It could also further comprise high soluble salts.