Note: Descriptions are shown in the official language in which they were submitted.
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1
COATED DETERGENT TABLET
The present invention relates to coated detergent tablets, especially those
adapted for use in washing machines, and to processes for making the coated
~o detergent tablets.
Although cleaning compositions in tablet form have often been proposed, these
have not (with the exception of soap bars for personal washing) gained any
substantial success, despite the several advantages of products in a unit
~ 5 dispensing form. One of the reasons for this may be that detergent tablets
require a relatively complex manufacturing process. In particular, it is often
desirable to provide the tablet with a coating and this adds to the
difficulties of
manufacture.
While tablets without a coating are entirely effective in use, they usually
lack the
2o necessary surface hardness to withstand the abrasion that is a part of
normal
manufacture, packaging and handling. The result is that non-coated tablets
suffer from abrasion during these processes, resulting in chipped tablets and
loss
of active material.
25 Finally, coating of tablets is often desired for aesthetic reasons, to
improve the
outer appearance of the tablet or to achieve some particular aesthetic effect.
Numerous methods of tablet coating have been proposed, and many of these
have been suggested for detergent tablets. However, all of these methods have
certain disadvantages, as will be explained below.
GB-A-0 989 683, published on 22nd April 1965, discloses a process for
preparing
a particulate detergent from surfactants and inorganic salts; spraying on
water-
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soluble silicate; and pressing the detergent particles into a solid form-
retaining
tablet. Finally a readily water-soluble organic film-forming polymer (for
example,
polyvinyl alcohol) provides a coating to make the detergent tablet resistant
to
abrasion and accidental breakage.
EP-A-0 002 293, published on 13th June 1979, discloses a tablet coating
comprising hydrated salt such as acetate, metaborate, orthophosphate,
tartrate,
and sulphate.
EP-A-0 716 144, published on 12th June 1996, also discloses laundry detergent
tablets with water-soluble coatings which may be organic polymers including
acrylic/maleic co-polymer, polyethylene glycol, PVPVA, and sugar.
W09518215, published on 6th July 1995, provides water-insoluble coatings for
~5 solid cast tablets. The tablets are provided with hydrophobic coatings
including
wax, fatty acid, fatty acid amides, and polyethylene glycol.
EP-A-0 846 754, published on the 10t" of June 1998, provides a tablet having a
coating comprising a dicarboxylic acid, the coating material typically having
a
2o melting point of from 40°C to 200°C.
EP-A-0 846 755, published on the 10'" of June 1998, provides a tablet having a
coating comprising a material insoluble in water at 25°C, such as C12-
C22 fatty
acids, adipic acid or C8-C13 dicarboxylic acids.
EP-A-0 846 756, published on the 10'" of June 1998, provides a tablet having a
coating comprising a disintegrant material and preferably an effervescent
material.
so The present invention provides a means by which coated tablets can be
provided
with a coating so that they can be stored, shipped and handled without damage,
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the coating being easily broken when the tablet is in the washing machine,
releasing the active ingredients into the wash solution.
The object of the present invention is to provide a tablet having a coating
which
is sufficiently hard to protect the tablet from mechanical forces when stored,
shipped and handled, and is sufficiently flexible for not breaking when
submitted
to mechanical stress.
Summary of the Invention
The object of the invention is achieved by providing a coated detergent tablet
characterised in that the coating comprises a component which is liquid at
25°C.
Detailed Description of the Invention
Coating
Solidity of a tablet may be improved by making a coated tablet, the coating
covering a non-coated tablet, thereby further improving the mechanical
2o characteristics of the tablet while maintaining or further improving
dissolution.
This very advantageously applies to multi-layer tablets, whereby the
mechanical
characteristics of a more elastic layer can be transmitted via the coating to
the
rest of the tablet, thus combining the advantage of the coating with the
advantage of the more elastic layer. Indeed, mechanical constraints will be
transmitted through the coating, thus improving mechanical integrity of the
tablet.
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
3o than very low levels of breakage or attrition. Finally the coating is
preferably
brittle so that the tablet breaks up quickly when subjected to stronger
mechanical
shock. Furthermore it is advantageous if the coating material is dissolved
under
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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 undissolved
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".
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.
2o During the solidification phase, the coating undergoes some internal stress
(e.g.
shrinkage upon cooling) and external stress (e.g. tablet relaxation). This
will
likely cause some cracks in the structure such as edge splitting if the
coating
material is too brittle to withstand these mechanical stress, which is the
case
when a coating is solely made from components solid at 25°C. Indeed,
25 according to the invention, the coating comprises a component which is
liquid at
25°C. It is believed that this liquid component will allow the coating
to better
withstand and absorb mechanical stress by rendering the coating structure more
flexible. The component which is liquid at 25°C is preferably added to
the coating
materials in proportions of less than 10% by weight of the coating, more
3o preferably less than 5% by weight, and most preferably of less than 3% by
weight. The component which is liquid at 25°C is preferably added to
the coating
materials in proportions of more than 0.1 % by weight of the coating, more
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preferably more than 0.3% by weight, and most preferably of more than 0.5% by
weight. Further preferred is the addition of reinforcing fibres to the coating
in
order to further reinforce the structure.
5
Preferably, the coating comprises a crystallised structure. By crystallised,
it
should be understood that the coating comprises a material which is solid at
ambient temperature (25°C) and has a structure exhibiting some order.
This can
be detected typically by usual crystallography techniques e.g. X-ray analysis,
on
the material itself. In a more preferred embodiment, the material forming the
crystallised structure does not co-crystallised or only partially with the
optional
component which is liquid at 25°C mentioned above. Indeed, it is
preferred that
the optional component remains in the liquid state at 25°C in the
coating
crystalline structure in order to provide flexibility to the structure and
resistance to
~5 mechanical stress. In another embodiment, the optional component which is
liquid at 25°C may advantageously have a functionality in the washing
of laundry,
for example silicone oil which provides suds suppression benefits or perfume
oil..
The coating comprises materials other than the component which is liquid at
20 25°C. Suitable coating materials are for example 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. Most preferred is adipic acid.
25 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, an acid having a melting point of more than 145°C such as
adipic
3o acid was found particularly suitable.
By "melting point" is meant the temperature at which the material when heated
slowly in, for example, a capillary tube becomes a clear liquid.
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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.
Tablet coatings are very hard and provide extra strength to the tablet.
Examples of optional components which are liquid at 25° are
including
PolyEthylene Glycols, thermal oil, silicon oil, esters, esters of dicarboxylic
acids,
mono carboxylic acids, paraffin, triacetin, perfumes or alkaline solutions. It
is
preferred that the structure of the components which is liquid at 25°C
is close to
the material forming the crystallised structure, so that the structure is not
excessively disrupted. In a most preferred embodiment, the crystallised
structure
is made of adipic acid, the component which is liquid at 25°C being
available
under the name CoasoIT"" from Chemoxy International, being a blend of the di-
isobutyl esters of the glutaric, succinic and adipic acid. The advantage of
the use
of this component being the good dispersion in the adipic acid to provide
flexibility. It should be noted that disintegration of the adipic acid is
further
improved by the adipate content of CoasoIT"".
Fracture of the coating in the wash can be improved by adding a disintegrant
in
the coating. This disintegrant will swell once in contact with water and break
the
2o coating in small pieces. This will improve the dissolution 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, polymers containing cationic (e.g.
so quaternary ammonium) groups, amine-substituted polyacrylates, polymerised
cationic amino acids such as poly-L-lysine, polyallylamine hydrochloride) and
mixtures thereof.
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In a most preferred embodiment, the coating according to the invention
comprises adipic acid as well as a clay, whereby the clay is used as a
disintegrant and also to render the structure of adipic acid more favourable
for
s water penetration, thus improving the dispersion of the adipic acid in a
aqueous
medium. Preferred are clays having a particle size of less than 75 pm, more
preferably of less than 53 Nm, in order to obtain the desired effect on the
structure of the adipic acid. Preferred are bentonite clays. Indeed the adipic
acid
has a melting point such that traditional cellulosic disintegrants undergo a
o thermal degradation during the coating process, whereas such clays are more
heat stable. Further, traditional cellulosic disintegrant such as NymceITM for
example are found to turn brown at these temperatures.
In another preferred embodiment, the coating further comprises reinforcing
15 fibres. Such fibres have been found to improve further the resistance of
the
coating to mechanical stress and minimize the splitting defect occurence. Such
fibres are preferably having a length of at least 100 Nm, more preferably of
at
least 200 pm and most preferably of at least 250 pm to allow structure
reinforcement. Such fibres are preferably having a length of at less than 500
pm,
2o more preferably of less than 400 pm and most preferably of less than 350 pm
in
order not to impact onto dispersion of the coating in an aqueous medium.
Materials which may be used for these fibres include viscose rayon, natural
nylon, synthetic nylon (polyamides types 6 and 6,6), acrylic, polyester,
cotton
and derivatives of cellulose such as CMCs. Most preferred is a cellulosic
material
25 available under the trade mark Solka-FIocT"~ from Fibers Sales &
Development. It
should be noted that such fibres do not normally need pre-compression for
reinforcing the coating structure. Such fibres are preferably added at a level
of
less than 5% by weight of the coating, more preferably less than 3% by weight.
Such fibres are preferably added at a level of more than 0.5% by weight of the
3o coating, more preferably more than 1 % by weight.
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A preferred process for making a tablet according to the invention comprises
the
steps of:
(a) forming a core by compressing a particulate material, the particulate
material
comprising surfactant and detergent builder;
(b) applying a coating material to the core, the coating material being in the
form
of a melt;
(c) allowing the molten coating material to solidify;
characterised in that the coating material comprises a component which is
liquid
o at 25°C.
Another preferred process for making a tablet according to the invention
comprises the steps of
(a) forming a core by compressing a particulate material, the particulate
material
5 comprising surfactant and detergent builder;
(b) applying a coating material to the core, the coating material being
dissolved in
a solvent or water;
(c) allowing the solvent or water to evaporate;
characterised in that the coating material comprises a component which is
liquid
2o at 25°C.
An even more preferred process is as above, wherein the coating material, or
mixture of materials, has a melting point of at least 145°C, the
coating comprising
a clay. Indeed, typical cellulisic disintegrants would start degrading at such
a
2s temperature. This particularly applies when using adipic acid.
The tablets may comprise components such as fragrance, surfactants, enzymes,
detergent etc.... Typical tablet compositions for the preferred embodiment of
the
present invention are disclosed in the pending European applications of the
3o Applicant n° 96203471.6, 96203462.5, 96203473.2 and 96203464.1 for
example. Elements typically entering in the composition of detergent tablets
or of
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other forms of detergents such as liquids or granules are detailed in the
following
paragraphs.
Highly soluble Compounds
The tablet may comprise a highly soluble compound. Such a compound could be
formed from a mixture or from a single compound. A highly soluble compound is
defined as follow:
A solution is prepared as follows comprising de-ionised water as well as 20
o grams per litre of a specific compound:
1- 20 g of the specific compound is placed in a Sotax Beaker. This beaker is
placed in a constant temperature bath set at 10°C. A stirrer with a
marine
propeller is placed in the beaker so that the bottom of the stirrer is at 5 mm
above the bottom of the Sotax beaker. The mixer is set at a rotation speed of
200 turns per minute.
2- 980 g of the de-ionised water is introduced into the Sotax beaker.
3- 10 s after the water introduction, the conductivity of the solution is
measured,
using a conductivity meter.
4- Step 3 is repeated after 20, 30, 40, 50, 1 min, 2 min, 5 min and 10 min
after
2o step 2.
5- The measurement taken at 10 min is used as the plateau value or maximum
value.
The specific compound is highly soluble according to the invention when the
conductivity of the solution reaches 80% of its maximum value in less than 10
seconds, starting from the complete addition of the de-ionised water to the
compound. Indeed, when monitoring the conductivity in such a manner, the
conductivity reaches a plateau after a certain period of time, this plateau
being
considered as the maximum value. Such a compound is preferably in the form of
a flowable material constituted of solid particles at temperatures comprised
3o between 10 and 80°Celsius for ease of handling, but other forms may
be used
such as a paste or a liquid.
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Example of highly soluble compounds include Sodium di isoalkylbenzene
sulphonate (DIBS) or Sodium toluene sulphonate.
s Cohesive Effect
The tablet may comprise a compound having a Cohesive Effect on the
particulate material of a detergent matrix forming the tablet. The Cohesive
Effect
on the particulate material of a detergent matrix forming the tablet or a
layer of
1o the tablet is characterised by the force required to break a tablet or
layer based
on the examined detergent matrix pressed under controlled compression
conditions. For a given compression force, a high tablet or layer strength
indicates that the granules stuck highly together when they were compressed,
so
that a strong cohesive effect is taking place. Means to assess tablet or layer
1s strength (also refer to diametrical fracture stress) are given in
Pharmaceutical
dosage forms : tablets volume 1 Ed. H.A. Lieberman et al, published in 1989.
The cohesive effect is measured by comparing the tablet or layer strength of
the
original base powder without compound having a cohesive effect with the tablet
or layer strength of a powder mix which comprises 97 parts of the original
base
2o powder and 3 parts of the compound having a cohesive effect. The compound
having a cohesive effect is preferably added to the matrix in a form in which
it is
substantially free of water (water content below 10% (pref. below 5%)). The
temperature of the addition is between 10 and 80C, more pref. between 10 and
40C.
25 A compound is defined as having a cohesive effect on the particulate
material
according to the invention when at a given compacting force of 3000N, tablets
with a weight of 50g of detergent particulate material and a diameter of 55mm
have their tablet tensile strength increased by over 30% (preferably 60 and
more
preferably 100%) by means of the presence of 3% of the compound having a
3o cohesive effect in the base particulate material.
An example of a compound having a cohesive effect is Sodium di
isoalkylbenzene sulphonate.
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When integrating a highly soluble compound having also a cohesive effect on
the
particulate material used for a tablet or layer formed by compressing a
particulate
material comprising a surfactant, the dissolution of the tablet or layer in an
aqueous solution is significantly increased. In a preferred embodiment, at
least
1 % per weight of a tablet or layer is formed from the highly soluble
compound,
more preferably at least 2%, even more preferably at lest 3% and most
preferably at least 5% per weight of the tablet or layer being formed from the
highly soluble compound having a cohesive effect on the particulate material.
It should be noted that a composition comprising a highly soluble compound as
1o well as a surfactant is disclosed in EP-A-0 524 075, this composition being
a
liquid composition.
A highly soluble compound having a cohesive effect on the particulate material
allows to obtain a tablet having a higher tensile strength at constant
compacting
force or an equal tensile strength at lower compacting force when compared to
traditional tablets. Typically, a whole tablet will have a tensile strength of
more
than 5kPa, preferably of more than 10kPa, more preferably, in particular for
use
in laundry applications, of more than 15kPa, even more preferably of more than
30 kPa and most preferably of more than 50 kPa, in particular for use in dish
washing or auto dish washing applications; and a tensile strength of less than
300 kPa, preferably of less than 200 kPa, more preferably of less than 100
kPa,
even more preferably of less than 80 kPa and most preferably of less than 60
kPa. Indeed, in case of laundry application, the tablets should be less
compressed than in case of auto dish washing applications for example,
whereby the dissolution is more readily achieved, so that in a laundry
application,
the tensile strength is preferably of less than 30 kPa.
This allows to produce tablets or layers which have a solidity and mechanical
resistance comparable to the solidity or mechanical resistance of traditional
tablets while having a less compact tablet or layer thus dissolving more
readily.
Furthermore, as the compound is highly soluble, the dissolution of the tablet
or
layer is further facilitated, resulting in a synergy leading to facilitated
dissolution
for a tablet according to the invention.
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Tablet Manufacture
s The tablet may comprise several layers. For the purpose of manufacture of a
single layer, the layer may be considered as a tablet itself.
Detergent tablets 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
1o 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.
In particular for laundry tablets, the ingredients such as builder and
surfactant
can be spray-dried in a conventional manner and then compacted at a suitable
15 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 suitable for laundry
compressed using a force of less than 2500N, but tablets for auto dish washing
2o may also be considered for example, whereby such auto dish washing tablets
are usually more compressed than laundry tablets.
The particulate material used for making a tablet 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
2s gives low bulk densities 600g/I 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~ CB and/or Lodige~ KM mixers). Other suitable processes include
fluid bed processes, compaction processes (e.g. roll compaction), extrusion,
as
3o 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.
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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 drums) 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
1o 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~, Korch~,
Manesty0, or Bonals~). 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
2o 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
2s 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 layered tablets are typically formed in rotating presses by placing the
matrices of each layer, one after the other in matrix force feeding flasks. As
the
3o process continues, the matrix layers are then pressed together in the pre
compression and compression stages stations to form the multilayer layer
tablet.
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With some rotating presses it is also possible to compress the first feed
layer
before compressing the whole tablet.
Hydrotrope compound
A highly soluble compound having a cohesive effect may be integrated to a
detergent tablet, whereby this compound is also a hydrotrope compound. Such
hydrotrope compound may be generally used to favour surfactant dissolution by
1o avoiding gelling. A specific compound is defined as being hydrotrope as
follows
(see S.E. Friberg and M. Chiu, J. Dispersion Science and Technology, 9(5&6),
pages 443 to 457, (1988-1989)):
1. A solution is prepared comprising 25% by weight of the specific compound
and 75% by weight of water.
2. Octanoic Acid is thereafter added to the solution in a proportion of 1.6
times
the weight of the specific compound in solution, the solution being at a
temperature of 20°Celsius. The solution is mixed in a Sotax beaker with
a stirrer
with a marine propeller, the propeller being situated at about 5mm above the
bottom of the beaker, the mixer being set at a rotation speed of 200 rounds
per
minute.
3. The specific compound is hydrotrope if the the Octanoic Acid is completely
solubilised, i.e . if the solution comprises only one phase, the phase being a
lipuid phase.
It should be noted that in a preferred embodiment of the invention, the
hydrotrope compound is a flowable material made of solid particles at
operating
conditions between 15 and 60° Celsius.
Hydrotrope compounds include the compounds listed thereafter:
A list of commercial hydrotropes could be found in McCutcheon's Emulsifiers
and
Detergents published by the McCutcheon division of Manufacturing
3o Confectioners Company. Compounds of interest also include:
1. Nonionic hydrotrope with the following structure:
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R - O - (CH2CH20)x( CH -CH20)yH
CH3
where R is a C8-C10 alkyl chain, x ranges from 1 to 15, y from 3 to 10.
2. Anionic hydrotropes such as alkali metal aryl sulfonates. This includes
alkali
metal salts of benzoic acid, salicylic acid, bezenesulfonic acid and its many
5 derivatives, naphthoic acid and various hydroaromatic acids. Examples of
these
are sodium, potassium and ammonium benzene sulfonate salts derived from
toluene sulfonic acid, xylene sulfonic acid, cumene sulfonic acid, tetralin
sulfonic
acid, naphtalene sulfonic acid, methyl- naphtalene sulfonic acid, dimethyl
naphtalene sulfonic acid, trimethyl naphtalene sulfonic acid=
1o Other examples include salts of dialkyl benzene sulfonic acid such as salts
of di-
isopropyl benzene sulfonic acid, ethyl methyl benzene sulfonic acid, alkyl
benzene sulfonic acid with an alkyl chain length with 3 to 10, (pref. 4 to 9),
linear
or branched alkyl sulfonates with an alkyl chain with 1 to 18 carbons.
3. Solvent hydrotropes such as alkoxylated glycerines and alkoxylated
15 glycerides, esters slakoxylated glycerines, alkoxylated fatty acids, esters
of
glycerin, polyglycerol esters. Preferred alkoxylated glycerines have the
following
structure:
R
CHz-O(-CH2CH-0-~"H
R
CHZ-O(-CHzCH-0-)mH
R
CHZ-0(-CHZCH-0-~,H
where I, m and n are each a number from 0 to about 20, with I+m+n = from about
2 to about 60, preferably from about 10 to about 45 and R represents H, CH3 or
C2H5
Preferred alkoxylated glycerides have the following struture
H2~-R~
H Ry Rs
H2~-O-(CHZCH-O)-H
where R1 and R2 are each C~COO or -(CH2CHR3 O),-H where R3 = H, CH3 or
CZHS and I is a number from 1 to about 60, n is a number from about 6 to about
24.
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16
4. Polymeric hydrotropes such as those described in EP636687:
R R~
-(CH2- )X - (CHz- )y-
E RZ
where E is a hydrophilic functional group,
R is H or a C1-C10 alkyl group or is a hydrophilic functional group;
R1 is H a lower alkyl group or an aromatic group,
R2 is H or a cyclic alkyl or aromatic group.
The polymer typically has a molecular weight of between about 1000 and
1000000.
5. Hydrotrope of unusual structure such as 5-carboxy-4-hexyl-2-cyclohexene-1-
yl
octanoic acid (Diacid~)
Use of such compound in the invention would further increase the dissolution
rate of the tablet, as a hydrotrope compound facilitates dissolution of
surfactants,
for example. Such a compound could be formed from a mixture or from a single
compound.
Tensile Strength
For the purpose of measuring tensile strength of a layer, the layer may be
2o considered as a tablet itself.
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 or
layer,
and is determined by the following equation
Tensile strength = 2 F/ ~cDt
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17
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 or layer, and t the thickness of the
tablet or
layer. For a non round tablet, ~D may simply be replaced by the perimeter 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.
1o 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.
Tablet Dispensing
The rate of dispensing of a detergent tablet can be determined in the
following
2o way:
Two tablets, nominally 50 grams each, are weighed, and then placed in the
dispenser of a Baucknecht~ WA9850 washing machine. The water supply to the
washing machine is set to a temperature of 20 °C and a hardness of 21
grains
per gallon, the dispenser water inlet flow-rate being set to 8 I/min. The
level of
tablet residues left in the dispenser is checked by switching the washing on
and
the wash cycle set to wash program 4 (white/colors, short cycle). The
dispensing
percentage residue is determined as follows:
dispensing = residue weight x 100 / original tablet weight
The level of residues is determined by repeating the procedure 10 times and an
3o average residue level is calculated based on the ten individual
measurements. In
this stressed test a residue of 40 % of the starting tablet weight is
considered to
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18
be acceptable. A residue of less than 30% is preferred, and less than 25% is
more preferred.
It should be noted that the measure of water hardness is given in the
traditional
"grain per gallon" unit, whereby 0.001 mole per litre = 7.0 grain per gallon,
s representing the concentration of Ca2+ ions in solution.
Effervescent
Detergent tablets may further comprise 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. CgH8O7 + 3NaHC03 -~ Na3CgH5O7 + 3C02 T + 3H20
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
2o 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.
2s 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.
3o Further dissolution aid could be provided by using compounds such as sodium
acetate or urea. A list of suitable dissolution aid may also be found in
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19
Pharmaceutical Dosage Forms: Tablets, Volume 1, Second edition, Edited by
H.A. Lieberman et all, ISBN 0-8247-8044-2.
s Detersive surfactants
Surfactant are typically comprised in a detergent composition. The dissolution
of
surfactants is favoured by the addition of the highly soluble compound.
Nonlimiting examples of surfactants useful herein typically at levels from
about
1 % to about 55%, by weight, include the conventional C1 ~ _C1 g alkyl benzene
sulfonates ("LAS") and primary, branched-chain and random C10_C20 alkyl
sulfates ("AS"), the C1 p_C1 g secondary (2,3) alkyl sulfates of the formula
CHg(CH2)x(CHOS03_M+) CH3 and CH3 (CH2)y(CHOS03-M+) CH2CH3 where
x and (y + 1 ) are integers of at least about 7, preferably at least about 9,
and M is
1s a water-solubilizing cation, especially sodium, unsaturated sulfates such
as oleyl
sulfate, the C10_C1g alkyl alkoxy sulfates ("AEXS"; especially EO 1-7 ethoxy
sulfates), C1p_C1g alkyl alkoxy carboxylates (especially the EO 1-5
ethoxycarboxylates), the C10-18 glycerol ethers, the C1p_C1g alkyl
polyglycosides and their corresponding sulfated polyglycosides, and C12_C18
2o alpha-sulfonated fatty acid esters. If desired, the conventional nonionic
and
amphoteric surfactants such as the C12_C1g alkyl ethoxylates ("AE") including
the so-called narrow peaked alkyl ethoxylates and Cg-C12 alkyl phenol
alkoxylates (especially ethoxylates and mixed ethoxy/propoxy), C12_C18
betaines and sulfobetaines ("sultaines"), C1p_C1g amine oxides, and the like,
2s can also be included in the overall compositions. The C10-C1g N-alkyl
polyhydroxy fatty acid amides can also be used. Typical examples include the
C12-C1g N-methylglucamides. See WO 9,206,154. 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
3o glucamides can be used for low sudsing. C10-C20 conventional soaps may also
be used. If high sudsing is desired, the branched-chain C10-C1 g soaps may be
used. Mixtures of anionic and nonionic surfactants are especially useful.
Other
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conventional useful surfactants are listed in standard texts. In a preferred
embodiment, the tablet comprises at least 5% per weight of surfactant, more
preferably at least 15% per weight, even more preferably at least 25% per
weight, and most preferably between 35% and 45% per weight of surfactant.
5
Non gelling binders
Non gelling binders can be integrated in detergent compositions to further
o facilitate dissolution.
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
~5 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
2o 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,
malefic 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
so which have binding properties within the tablet.
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21
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
s 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.
1o 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
15 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
20 (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-
25 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 Si02:Na20 ratio in the range 1.6:1 to 3.2:1 and layered silicates,
such
3o 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
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22
zeolite builders, the Na SKS-6 silicate builder does not contain aluminum.
NaSKS-6 has the delta-Na2Si05 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
s other such layered silicates, such as those having the general formula
NaMSix02x+1 ~yH20 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-
o Na2Si05 (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
~5 carbonates as disclosed in German Patent Application No. 2,321,001
published
on November 15, 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
2o detergent formulations. Aluminosilicate builders include those having the
empirical formula:
Mz(zA102)y]~xH20
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.
2s 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
3o crystalline aluminosilicate ion exchange materials useful herein are
available
under the designations Zeolite A, Zeolite P (B), Zeolite MAP and Zeolite X. In
an
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23
especially preferred embodiment, the crystalline aluminosilicate ion exchange
material has the formula:
Nal2L(A102)12(Si02)121~xH20
wherein x is from about 20 to about 30, especially about 27. This material is
s 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.
~o 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.
15 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.
2o 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,
25 copolymers of malefic 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
3o acid, polymaleic acid, benzene 1,3,5-tricarboxylic acid,
carboxymethyloxysuccinic acid, and soluble salts thereof.
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24
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.
o 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,
~5 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,
2o issued March 7, 1967. See also Diehl U.S. Patent 3,723,322.
Fatty acids, e.g., C12-C1 g 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
25 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
3o 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.
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Bleach
5 The detergent compositions herein may optionally 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
~o 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
~5 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
2o 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
25 Patent Application 0,133,354, Banks et al, published February 20, 1985, and
U.S. Patent 4,412,934, Chung et al, issued November 1, 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
3o compounds include sodium carbonate peroxyhydrate and equivalent
"percarbonate" bleaches, sodium pyrophosphate peroxyhydrate, urea
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26
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
o 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
~5 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
2o activators useful herein.
Highly preferred amido-derived bleach activators are those of the formulae:
R1 N(R5)C(O)R2C(O)L or R1 C(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,
25 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.
3o Preferred examples of bleach activators of the above formulae include (6-
octanamido-caproyl)oxybenzenesulfonate, (6-nonanamidocaproyl)oxybenzene-
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27
sulfonate, (6-decanamido-caproyl)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,
s incorporated herein by reference. A highly preferred activator of the
benzoxazin
type is:
O
II
CEO
I
'C
N
Still another class of preferred bleach activators includes the acyl lactam
activators, especially acyl caprolactams and acyl valerolactams of the
formulae:
O O
II II
O C-C H2-C H2 O C-C H2- ~ H2
6- II I \ 6- II I
R C-NBC H2-C H2 C H2 R C-NBC H2-C H2
,
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
1s 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.
2o 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
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28
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 U.S. Pat. 5,246,621,
U.S. Pat. 5,244,594; U.S. Pat. 5,194,416; U.S. Pat. 5,114,606; and European
Pat. App. Pub. Nos. 549,271 A1, 549,272A1, 544,440A2, and 544,490A1;
Preferred examples of these catalysts include MnIV2(u-O)3(1,4,7-trimethyl-
1,4,7-
triazacyclononane)2(PFg)2, Mn1112(u-O)1 (u-OAc)2(1,4,7-trimethyl-1,4,7-
o triazacyclononane)2-(CI04)2, MnIV4(u-O)6(1,4,7-triazacyclononane)4(C104)4,
Mnl I IMnIV4(u-O)1 (u-OAc)2_(1,4,7-trimethyl-1,4,7-triazacyclononane)2(C104)3,
MnIV(1,4,7-trimethyl-1,4,7-triazacyclononane)- (OCH3)3(PFg), 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
~5 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
2o 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
so 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
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29
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
o 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.
2o 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
European Patent Application 130,756, published January 9, 1985) and Protease
B (see European Patent Application Serial No. 87303761.8, filed April 28,
1987,
and European Patent Application 130,756, Bott et al, published January 9,
1985).
Amylases include, for example, a-amylases described in British Patent
Specification No. 1,296,839 (Novo), RAPIDASE, International Bio-Synthetics,
3o 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.
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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
5 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
o 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,
~5 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
2o 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.
25 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 October 19,
1989, by O. Kirk, assigned to Novo Industries A/S.
3o 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.
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31
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,
1o in U.S. Patent 3,519,570.
Other components which are commonly used in detergent compositions and
which may be incorporated into detergent tablets include chelating agents,
soil
release agents, soil antiredeposition agents, dispersing agents, suds
suppressors, fabric softeners, dye transfer inhibition agents and perfumes.
The compounds disclosed above for a product are advantageously packed in a
packaging system.
A packaging system may be formed from a sheet of flexible material. Materials
2o suitable for use as a flexible sheet include mono-layer, co-extruded or
laminated
films. Such films may comprise various components, such as poly-ethylene, poly-
propylene, poly-styrene, poly-ethylene-terephtalate. Preferably, the packaging
system is composed of a poly-ethylene and bi-oriented-poly-propylene co-
extruded film with an MVTR of less than 5 g/day/m2. The MVTR of the packaging
system is preferably of less than 10 g/day/m2, more preferably of less than 5
g/day/m2. The film (2) may have various thicknesses. The thickness should
typically be between 10 and 150 Vim, preferably between 15 and 120 Vim, more
preferably between 20 and 100 Vim, even more preferably between 25 and 80
pm and most preferably between 30 and 40 ~.m.
3o A packaging material preferably comprises a barrier layer typically found
with
packaging materials having a low oxygen transmission rate, typically of less
than
300 cm3/m2/day, preferably of less than 150 cm3/m2/day, more preferably of
less
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32
than 100 cm3/m2/day, even more preferably of less than 50 cm3/m2/day and most
preferably of less than 10 cm3/m2/day. Typical materials having such barrier
properties include bi oriented polypropylene, poly ethylene terephthalate,
Nylon,
polyethylene vinyl alcohol) , or laminated materials comprising one of these,
as
well as SiOx (Silicium oxydes), or metallic foils such as aluminium foils for
example. Such packaging material may have a beneficial influence on the
stability of the product during storage for example.
Among the packing method used are typically the wrapping methods disclosed in
W092/20593, including flow wrapping or over wrapping. When using such
processes, a longitudinal seal is provided, which may be a fin seal or an
overlapping seal, after which a first end of the packaging system is closed
with a
first end seal, followed by closure of the second end with a second end seal.
The
packaging system may comprise re-closing means as described in W092/20593.
In particular, using a twist, a cold seal or an adhesive is particularly
suited.
~5 Indeed, a band of cold seal or a band of adhesive may be applied to the
surface
of the packaging system at a position adjacent to the second end of the
packaging system, so that this band may provide both the initial seal and re-
closure of the packaging system. In such a case the adhesive or cold seal band
may correspond to a region having a cohesive surface, i.e. a surface which
will
2o adhere only to another cohesive surface. Such re-closing means may also
comprise spacers which will prevent unwanted adhesion. Such spacers are
described in WO 95/13225, published on the 18'" of May 1995. There may also
be a plurality of spacers and a plurality of strips of adhesive material. The
main
requirement is that the communication between the exterior and the interior of
2s the package should be minimal, even after first opening of the packaging
system.
A cold seal may be used, and in particular a grid of cold seal, whereby the
cold
seal is adapted so as to facilitate opening of the packaging system.
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EXAMPLES
Example 1
i) A detergent base powder of composition A was prepared as follows: all the
particulate material of base composition were mixed together in a mixing
drum or spray drum to form a homogenous particulate mixture, apart from the
binder spray-on system, the fluorescer or brightener, and the photobleach
Zinc Phthalocyanine sulphonate. The particulate mixture was thereafter
divided in two equal parts, one part for making a white layer, another part
for
making a green layer. The white layer material is obtained by spraying the
brightener or fluorescer together with half of the binder. The green layer
material is obtained by spraying the photobleach Zinc Phthalocyanine
~5 sulphonate together with the rest of the binder. The layer where then
processed independently in a Loedige KM 600~.
ii) Using a Bonals~ rotary press both matrices were filled in two independent
force feeding flasks. Both layers are compressed together in the pre-
compression and compression stations to form a dual layer tablet.
2o iii) In this particular example, the tablets have a square cross section of
45 mm
side, a height of 24 mm and a weight of 45 gr. The height of the green bottom
layer corresponded to 50% of the total height of the tablet. The tensile
strength of the uncoated tablets was 5 kpa.
iv) The tablet was thereafter coated with 2.5 g of coating formed from 90% by
25 weight of adipic acid and 10% by weight of Bentonite clay from CSM.
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Composition
A
(%)
Anionic agglomerates 1 9.1
Anionic agglomerates 2 22.5
Nonionic agglomerates 9.1
Cationic agglomerates 4.6
Layered silicate 9.7
Sodium percarbonate 12.2
Bleach activator agglomerates 6.1
Sodium carbonate 7.67
EDDS/Sulphate particle 0.5
Tetrasodium salt of Hydroxyethane 0.6
Diphosphonic acid
Soil Release Polymer 0.3
Fluorescer 0.2
Zinc Phthalocyanine sulphonate 0.03
Soap powder 1.2
Suds suppressor 2.8
Citric acid 5.5
Protease 1
Lipase 0.35
Cellulase 0.2
Amylase 1.1
Binder spray-on system 4.75
Perfume spray-on 0.5
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
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Nonionic agglomerate comprise 26% nonionic surfactant, 6% Lutensit K-HD 96,
40% Sodium acetate anhydrous, 20% carbonate and 8% zeolite.
Cationic agglomerates comprise of 20% cationic surfactant, 56% zeolite and 24%
sulphate
5 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
10 19% water.
Suds suppressor comprises of 11.5% silicone oil (ex Dow Corning); 59% of
zeolite and 29.5% of water.
Binder spray-on system comprises 16% by weight of polymer of the following
kind:
H3
H3
(EO)za~~ N (EO)za
I (EO)z4
15 (EO)za
68 % by weight of: PEG4000 and 16% by weight of: DIBS (Sodium di
isoalkylbenzene sulphonate or Sodium toluene sulphonate).
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An other example of a composition which may have been used is as follows:
Composition
B
(%)
Anionic agglomerates 1 9.1
Anionic agglomerates 2 22.5
Nonionic agglomerates 9.1
Cationic agglomerates 4.6
Layered silicate 9.7
Sodium percarbonate 12.2
Bleach activator agglomerates 6.1
Sodium carbonate 7.67
EDDS/Sulphate particle 0.5
Tetrasodium salt of Hydroxyethane 0.6
Diphosphonic acid
Soil Release Polymer 0.3
Fluorescer 0.2
Zinc Phthalocyanine sulphonate 0.03
Soap powder 1.2
Suds suppressor 2.8
Citric acid 5.5
Protease 1
Lipase 0.35
Cellulase 0.2
Amylase 1.1
Binder spray-on system 4.75
Perfume spray-on 0.5
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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
s Nonionic agglomerate comprise 26% nonionic surfactant, 6% Lutensit K-HD 96,
40% Sodium acetate anhydrous, 20% carbonate and 8% zeolite.
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.
15 Suds suppressor comprises of 11.5% silicone oil (ex Dow Corning); 59% of
zeolite and 29.5% of water.
Binder spray-on system comprises 16% by weight of polymer of the following
kind:
H3
H3
(EO)za~~ N-(EO)za
(EO)Za
(EO)Za
20 68 % by weight of: PEG4000 and 16% by weight of: DIBS (Sodium di
isoalkylbenzene sulphonate or Sodium toluene sulphonate).
2s Example 2
i) A detergent base powder of composition A was prepared as follows: all the
particulate material of base composition were mixed together in a mixing
drum or spray drum to form a homogenous particulate mixture, apart from the
3o binder spray-on system, the fluorescer or brightener, and the photobleach
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38
Zinc Phthalocyanine sulphonate. The particulate mixture was thereafter
divided in two equal parts, one part for making a white layer, another part
for
making a green layer. The white layer material is obtained by spraying the
brightener or fluorescer together with half of the binder. The green layer
material is obtained by spraying the photobleach Zinc Phthalocyanine
sulphonate together with the rest of the binder. The layer where then
processed independently in a Loedige KM 600~.
ii) Using a Bonals~ rotary press both matrices were filled in two independent
force feeding flasks. Both layers are compressed together in the pre-
compression and compression stations to form a dual layer tablet.
iii) In this particular example, the tablets have a square cross section of 45
mm
side, a height of 24 mm and a weight of 45 gr. The height of the green bottom
layer corresponded to 50% of the total height of the tablet. The tensile
strength of the uncoated tablets were 5 kpa.
iv) The tablet was thereafter coated with 2.5 g of coating formed from 89% by
weight of adipic acid, 10% by weight of Bentonite clay from CSM, and 1 % by
weight of CoasoIT"'
Example 3
i) A detergent base powder of composition A was prepared as follows: all the
particulate material of base composition was mixed together in a mixing drum
or spray drum to form a homogenous particulate mixture. The binder system
was then sprayed on. The powder where then processed in a Loedige KM
600~.
ii) Using a Instron~ Laboratory bench press, detergent powder was filled in
the
die. The powder had been compressed with a force so that the tensile
strength of the tablet was 1 Okpa.
iii) In this particular example, the tablets have a diameter of 54 mm side, a
height
of 24 mm and a weight of 45 gr.
iv) The tablet was thereafter coated with 2.5 g of coating formed from 90% by
weight of Adipic acid and 10% by weight of bentonite clay from CSM.
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Example 4
s i) A detergent base powder of composition A was prepared as follows: all the
particulate material of base composition were mixed together in a mixing
drum or spray drum to form a homogenous particulate mixture. The binder
system was then sprayed on. The powder where then processed in a Loedige
KM 600~.
~o ii) Using a Instron~ Laboratory bench press, detergent powder was filled in
the
die. The powder had been compressed with a force so that the tensile
strength of the tablet was 10kpa.
iii) In this particular example, the tablets have a diameter of 54 mm side, a
height
of 24 mm and a weight of 45 gr.
15 The tablet was thereafter coated with 2.5 g of coating formed from 89% by
weight
of Adipic acid, 10% by weight of bentonite clay from and 1 % of CoasoITM
Example 5
2o i) A detergent base powder of composition A was prepared as follows: all
the
particulate material of base composition were mixed together in a mixing
drum or spray drum to form a homogenous particulate mixture. The binder
system was then sprayed on. The powder where then processed in a Loedige
KM 600~.
2s ii) Using a Instron~ Laboratory bench press, detergent powder was filled in
the
die. The powder had been compressed with a force so that the tensile
strength of the tablet was l0kpa.
iii) In this particular example, the tablets have a diameter of 54 mm side, a
height
of 24 mm and a weight of 45 gr.
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The tablet was thereafter coated with 2.5 g of coating formed from 87% by
weight
of Adipic acid, 10% by weight of bentonite clay from and 1 % of CoasoITM and 2
of Solka-FIocT"" 1016.
5
Results
It was observed that:
For about 500 tablets made for each of examples 1 and 2, when a coated tablet
is fully immersed in 1 litre of city water at 20°C, the coating
disintegrates in about
8 seconds for example 1, and in about 5 seconds for example 2.
Further, it was observed that the tablets made according to example 1 have a
~ 5 split coating once the coating has crystallised, whereas the tablets made
according to example 2 have no split.
Furthermore, by comparing 10 tablets made according to example 3, 4 and 5, it
was observed the following coating splitting occurrence:
Example 3 Example 4 Example 5
Splitting occurrence 100% 20% 0%
(Tablets of 10kpa
when non-coated)
