Field of the Invention
-
This invention relates to laundry detergent compositions which contain
sufficient clay that the compositions provide a distinct softening effect, and in
particular it relates to such compositions in the form of tablets.
Background to the Invention
-
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.
-
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.
-
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.
-
In W098/40463 it is proposed to introduce the disintegrant substantially
only in granular form.
-
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.
-
It would be desirable to provide softening laundry tablets which contain
sufficient clay to give a significant softening effect. Although clay in low
amounts gives a disintegration effect, high local amounts of clay unfortunately
can tend to impede disintegration rather than promote it. This is because there
can be a tendency for high local clay contents to gel upon contact with water so
as to form a localised gel layer which hinders penetration of water into the
tablet, and thus inhibits tablet dispersion.
-
Other components, particularly anionic or nonionic surfactants, can
promote the tendency for gel formation, and the consequential inhibition of
dispersion, when present in high local amounts. It would be desirable to
promote effective dispersion of tablets containing such surfactants.
-
If the composition contains a flocculant for the clay, this flocculant is
usually a high molecular weight water soluble polymer and this may tend to
promote gelling and inhibit dispersion if present in high local amounts. The
purpose of including a flocculant for the clay in the softening composition is to
cause flocculation of the softening clay on to the fabrics after the clay has been
thoroughly and uniformly dispersed throughout the wash liquor. Premature
flocculation of the clay by the flocculant is undesirable and can result in uneven
deposition of the clay on the laundry which is being washed. Accordingly it
would be desirable to minimise the dispersion of the flocculant into the wash
liquor before the clay goes into full dispersion, thereby minimising the risk of
flocculation of incompletely dispersed clay.
-
Another general difficulty with formulating tablets containing sufficient
clay to give a useful softening effect is that the clay has a high bulk and it would
be desirable in practice to dilute the clay with significant amounts of other
material to minimise the risk of gelling problems.
-
It has therefore been our object to formulate softening detergent tablets
which minimise the risk of localised gelling, maximise the rate of dispersion of
the components which need to disperse fast and which minimise the risk of
premature flocculation (when flocculant is present). Further, it has been our
object to provide softening laundry tablets which allow optimisation of the
dispersion characteristics of the various components in the tablet.
Summary of the Invention
-
According to the invention we provide a softening laundry detergent
tablet comprising clay and laundry surfactant wherein the tablet comprises one
or more discrete first regions and one or more discrete second regions, and the
clay is more highly concentrated in the or each first region than in the or each
second region. The concentration of clay in the or each first region is usually at
least 1.5 times the concentration of clay in the or each second region.
-
According to another embodiment of the invention the tablet comprises
one or more discrete first regions and one or more discrete second regions, and
the percentage of the total clay content of the tablet which is in the or each first
region is higher than the percentage which is in the or each second region.
Usually at least 60% by weight of the total amount of clay and often at least 70
or 75% by weight up to about 80% or 90% of the total amount of clay is present
in the or each first region, with the balance being present in the or each second
region.
-
The amount of softening clay in the tablet is usually at least 5% by
weight of the tablet, preferably 8% by weight, more preferably at least 10% by
weight of the tablet but usually less than 25%, more preferably less than 20%,
most preferably less than 15% by weight.
-
Preferably, the concentration of clay in the or each first region is 2 to 5
times the concentration of clay in the or each second region. However in some
instances the amount of clay in the or each second region can be relatively low,
so that the concentration in the first region might be at least ten times the
concentration of clay in the or each second region. In some instances it is
desirable for the or each second region to be substantially free of clay but
usually the or each second region contains clay in a concentration of at least
0.1% and usually in a concentration of from 1 to 5%, usually 1 to 3%, by weight
of the or each second region. The clay concentration in the or each first region
is usually at least 10% (and often 15 to 30%) by weight of the or each first
region.
-
There is preferably at least 5% by weight non-ionic and/or anionic
surfactant in the tablet. The surfactant can be more highly concentrated in the
or each first region than in the or each second region. Usually at least 50%, and
generally at least 60% or 70% but not more than about 80% or 90% of the total
surfactant is in the first regions with the balance in the second regions. The
concentration of surfactant in the or each first region is usually at least 1.2 or
1.5 times, often 2 to 5 times, the concentration in the second regions.
-
The tablet may comprise a flocculant for the clay, and the flocculant is
preferably substantially absent from the or each first region. Substantially all
the flocculant may be in the or each second region.
-
The tablet is usually made by compression of particulate material.
-
The first and second regions may separately constitute individual layers
within the tablet. Preferably, the tablet is made up of two or more layers, most
preferably three layers.
Detailed Description of the Invention
-
As a result of the invention it is now possible to optimise the dispersion
characteristics of the individual components of a detergent tablet, since they do
not all have to be in a single layer.
-
When, as is preferred, flocculant is included in the tablet, at least 30%,
usually at least 70%, and preferably all or substantially all of the total flocculant
is preferably included in the or each second region and a minor amount of the
total clay is included in the or each second region. The amount of clay in the or
each second region is usually sufficient to promote slow dispersion of that
region, and thus the flocculant therein. Typically it is 1 to 10%, often 1 to 5% by
weight of the second regions. The majority of the clay is in the or each first
region from which it will disperse more quickly, because of the formulation of
that region. The rate of dispersion of the first regions should be faster than the
second regions, with the result that the majority of the clay may be fully
dispersed while flocculant (and a minor amount of the clay) is still dispersing.
-
As a result of having a significant surfactant concentration in the or each
first region but with some clay in the or each second region, the bulk of clay in
the or each first region is reduced but the dispersion of the surfactant and clay
is promoted, despite high clay and surfactant concentrations, by virtue of the
combination of the clay with the surfactant. Usually the concentration of anionic
and/or nonionic surfactant in the first regions is at least 10% and often 20 to
50% or more by weight of the first regions. Cationic and/or amphoteric
surfactants may be also included.
-
In an alternative embodiment the formulation of the first and second
regions is such that the rate of dispersion of the second regions is higher than
the rate of dispersion of the first regions. In this embodiment components
which are to be dispersed prematurely into the wash liquor, before dispersion of
the bulk of the clay and other components in the or each first region, may be
included in the or each second region instead of the flocculant, together with
enough clay to promote rapid disintegration but without any risk of gelling.
Examples are enzymes and any of the conventional bleaching additives which
should advantageously be in solution in the wash water as early as possible in
the wash cycle.
-
If desired there can be one or more second regions having a different
composition from the other second regions.
-
The discrete first and second regions may be domains or other zones
within the tablet, for instance created by forming the tablet from a particulate
mixture containing large granules, typically above 1mm, wherein some or all of
the large granules have one content and the remainder of the large granules or
the remainder of the particulate mixture have a different content, thereby
forming the first and second regions in the compressed tablet. Preferably,
however, the tablet is a multi-layer tablet and each region is a layer. If there are
three layers, the tablet is typically a sandwich having similar layers on each
outer surface and a different central layer.
-
Different layers of the tablet may be coloured; this is particularly
advisable for the first layer, or other layers containing clay, which may
otherwise tend to impart an unattractive greyish tint on the tablet.
-
Typically the first regions contain 20-80%, often around 40-60% and
usually about 50%, by weight of the tablet, with the second regions containing
the remainder.
-
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
-
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.
-
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.
-
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.
-
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.
-
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.
-
Multi-layer tablets can be made by known techniques.
Coating
-
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.
-
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.
-
Water solubility is measured following the test protocol of ASTM E1148-87
entitled, "Standard Test Method for Measurements of Aqueous Solubility".
-
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.
-
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.
-
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.
-
By "melting point" is meant the temperature at which the material when
heated slowly in, for example, a capillary tube becomes a clear liquid.
-
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.
-
The tablet coatings are preferably very hard and provide extra strength
to the tablet.
-
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
-
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.
-
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 :
= 2Fπ Dt
-
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.
-
(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.
-
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
-
In another preferred embodiment of the present invention the tablets
further comprises an effervescent.
-
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. C6H8O7 + 3NaHCO3 Na3C6H5O7 + 3CO2 + 3H2O
-
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).
-
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.
-
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.
-
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
-
Non gelling binders can be integrated to the particles forming the tablet
in order to further facilitate dispersion.
-
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.
-
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.
-
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.
-
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
-
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.
-
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 Al2(Si2O5)2(OH)2 and Mg3(Si2O5) (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.
-
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.
-
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:
smectite clay (Na) + NH4OH _ smectite clay (NH4) + NaOH.
-
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.
-
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.
-
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.
-
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.
-
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 Fe2O3) 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.
-
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.
-
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
-
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
CH3(CH2)x(CHOSO3-M+) CH3 and CH3 (CH2)y(CHOSO3-M+) CH2CH3 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 EO1-5
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.
-
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
-
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.
-
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.
-
Examples of silicate builders are the alkali metal silicates, particularly
those having a SiO2:Na2O 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-Na2SiO5 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 NaMSixO2x+1.yH2O 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-Na2SiO5 (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.
-
Examples of carbonate builders are the alkaline earth and alkali metal
carbonates as disclosed in German Patent Application No. 2,321,001 published
on November15, 1973.
-
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(zAlO2)y].xH2O
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.
-
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:
Na12[(AlO2)12(SiO2)12].xH2O
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.
-
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.
-
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.
-
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.
-
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.
-
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.
-
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.
-
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.
-
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
-
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.
-
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.
-
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.
-
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.
-
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.
-
Mixtures of bleaching agents can also be used.
-
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.
-
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.
-
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.
-
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:
-
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.
-
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.
-
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,
MnlV4(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.
-
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
-
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.
-
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.
-
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).
-
Amylases include, for example, -amylases described in GB-A-1,296,839
(Novo), RAPIDASE, International Bio-Synthetics, Inc. and TERMAMYL, Novo
Industries.
-
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 US 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.
-
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.
-
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.
-
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
-
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.
-
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.
-
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.
-
The amount of flocculant is preferably 0.5-10% by weight of the tablet,
most preferably about 2 to 6%.
-
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.
-
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.
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.
-
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.
Example 1
-
Detergent base powder of composition A-F (see table 1) was prepared
as follows. All the particulate materials of composition A were mixed together in
a homogenous particulate mixture. During this mixing the binder was sprayed
on.
-
The base powder of composition A was mixed in a mixing drum and
diluted with the described amounts of smectite clay extrudate which had been
formed using the following process. 500g of powdered clay were mixed with
250g 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 ASTM
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.
-
Tablets were then made the following way. 2.4g of powder A was
introduced into a mould of circular shape with a diameter of 5.4cm followed by
the introduction of 21.4g of powder B and compressed to a give a tablet tensile
strength (or diametrical fracture stress) of 15kPa.
-
The tablet was placed in a perforated 10cm diameter metallic cage with
a mesh size of 5mm x 5mm. The cage was 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 3 min in the pool of water is determined by
weighing. The level of residues is calculated as follows:
% residue = residue weight/original tablet weight x 100
-
The lower the residue number the better the tablet disintegration.
-
In this example one layer contained all the clay and 38 parts anionic
surfactant, while the other layer contained zero clay and 24 parts anionic
surfactant.
Example 2
-
Example 1 was repeated by with tablets made based on composition C
and D as indicated in table 1. Thus the layers contained the same surfactant
distribution as in Example 1 but the concentration of clay was the same in both
layers.
Example 3
-
Example 1 was repeated with tablets made based on composition E and
F as indicated in table 1. Thus the layers contained the same surfactant
distribution as in Example 1 but the layer containing the higher surfactant
concentration also had the higher clay concentration.
| Detergent Base Powder Composition |
| | Ex A | Ex B | Ex C | Ex D | Ex E | Ex F |
| | % | % | % | % | % | % |
| Clay Extrudate | 28.66 | - | 14.33 | 14.33 | 20.47 | 8.19 |
| Flocculant Agglomerate | 3.8 | 3.8 | 3.8 | 3.8 | 3.8 | 3.8 |
| Anionic agglomerates 1 | 38 | 24 | 38 | 24 | 38 | 24 |
| Cationic agglomerates | 5.0 | 5.0 | 5.0 | 5.0 | 5.0 | 5.0 |
| Sodium percarbonate | 8 | 8 | 8 | 8 | 8 | 8 |
| Bleach activator agglomerates | 2.31 | 2.31 | 2.31 | 2.31 | 2.31 | 2.31 |
| Sodium carbonate | 2.67 | 45.33 | 17.00 | 31.00 | 10.86 | 37.14 |
| EDDS/Sulphate particle | 0.19 | 0.19 | 0.19 | 0.19 | 0.19 | 0.19 |
| Tetrasodium salt of Hydroxyethane Diphosphonic acid | 0.34 | 0.34 | 0.34 | 0.34 | 0.34 | 0.34 |
| Fluorescer | 0.15 | 0.15 | 0.15 | 0.15 | 0.15 | 0.15 |
| Zinc Phthalocyanine sulphonate encapsulate | 0.027 | 0.027 | 0.027 | 0.027 | 0.027 | 0.027 |
| Soap powder | 1.40 | 1.40 | 1.40 | 1.40 | 1.40 | 1.40 |
| Suds suppressor | 2.6 | 2.6 | 2.6 | 2.6 | 2.6 | 2.6 |
| Citric acid | 4.0 | 4.0 | 4.0 | 4.0 | 4.0 | 4.0 |
| Protease | 0.45 | 0.45 | 0.45 | 0.45 | 0.45 | 0.45 |
| Cellulase | 0.20 | 0.20 | 0.20 | 0.20 | 0.20 | 0.20 |
| Amylase | 0.20 | 0.20 | 0.20 | 0.20 | 0.20 | 0.20 |
| Binder |
| Cationic Polymer | 0.75 | 0.75 | 0.75 | 0.75 | 0.75 | 0.75 |
| PEG 4000 | 1.25 | 1.25 | 1.25 | 1.25 | 1.25 | 1.25 |
| Clay extrudate comprise 97% of montmorillonite 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; 59% of zeolite and 29.5% of water. |
-
Example 1 gave the highest % residue. Example 2 gave a lower %
residue but Example 3 gave a very much lower % residue and so showed the
best dispersion properties.
Other examples include tablets made from a powder of the
following composition:
Examples A and B
-
|
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)
-
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)
-
| | 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
-
| |
|
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
-
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).
-
The tablet may also comprise a high molecular weight
poly(ethyleneoxide), cellulosic disintegrant, and/ or acetate. It could
also further comprise high soluble salts.