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Description  |
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TECHNICAL FIELD OF THE INVENTION
The present invention relates to perfumed detergent tablets, especially
those adapted for use in washing machines, and to processes for making
such tablets.
BACKGROUND OF THE INVENTION
Perfumed products are well-known in the art. However, consumer acceptance
of such perfumed products like laundry and cleaning products is determined
not only by the performance achieved with these products but also by the
aesthetics associated therewith. The perfume components are therefore an
important aspect of the successful formulation of such commercial
products.
In addition, a clay mineral compound is a desirable ingredient of such
laundry and cleaning product, in particular those products which are in
tablet form.
Indeed, the clay can provide softening benefit but can also serve as a
disintegrant of such detergent tablets.
However, a problem encountered with perfumed detergent tablets containing a
clay mineral compound is that the clay can have a detrimental effect on
the performance of the perfume contained therein. Hence, not to be bound
by theory, it is believed that due to the close physical proximity given
by the tablet, the perfume is absorbed into the clay where it can interact
with heavy metal ions and acid or base sites within the clay which as
result may cause a discoloration of the clay. Still, the interaction
between the perfume and the clay may also result in the tablet having a
less attractive odour.
Accordingly, it is an object of the invention to provide a perfumed
detergent tablet comprising a clay mineral compound which exhibit good
perfume performance with reduced discoloration of the clay.
Further, cleaning compositions in tablet form have often been proposed,
however 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 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 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.
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 Apr. 22nd, 1965, discloses a process for
preparing a particulate detergent from surfactants and inorganic salts;
spraying on water-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 Jun. 13th, 1979, discloses a tablet coating
comprising hydrated salt such as acetate, metaborate, orthophosphate,
tartrate, and sulphate.
EP-A-0 716 144, published on Jun. 12th, 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.
WO9518215, published on Jul. 6th, 1995, provides water-insoluble coatings
for 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 10.sup.th of June 1998, provides a tablet
having a coating comprising a dicarboxylic acid, the coating material
typically having a melting point of from 40.degree. C. to 200.degree. C.
EP-A-0 846 755, published on the 10.sup.th of June 1998, provides a tablet
having a coating comprising a material insoluble in water at 25.degree.
C., such as C12-C22 fatty acids, adipic acid or C8-C13 dicarboxylic acids.
EP-A-0 846 756, published on the 10.sup.th of June 1998, provides a tablet
having a coating comprising a disintegrant material and preferably an
effervescent material.
Recently, it has been found means by which coated tablets can be provided
with a coating so that they can be stored, shipped and handled without
damage, the coating being easily broken when the tablet is in the washing
machine, releasing the active ingredients into the wash solution. Typical
of such disclosure can be found in pending European patent applications EP
99870017.3, EP 99870018.1, and EP 99870019.9.
However, whilst giving satisfactory results, it has now been found that
where a clay mineral compound is present in the coating of the detergent
tablet, the clay, for the same believed reasons stated above, can have a
detrimental effect on the performance of the perfume contained therein as
well as on the appearance of the coating, i.e. discoloration of the
coating.
These problems have further been found more acute overtime, and more
particularly where the coating also comprises an acid having a melting
point of at least 40.degree. C., more particularly with a melting point of
at least 145.degree. C.
Accordingly, the detergent formulator is also faced with the problems of
providing a coated tablet having a coating which has satisfactory
appearance, is sufficiently hard to protect the tablet from mechanical
forces when stored, shipped and handled, and disperses readily in an
aqueous solution whilst still giving satisfactory perfume performance.
Further, the perfuming of detergent tablet is a concern to the detergent
formulator. Hence, the presence of the coating on the tablet can reduce
the diffusion of the perfume from the tablet resulting in a less
attractive odour.
It has now surprising been found that perfume compositions which contain
less than 0.6% by weight of the perfume of Schiff Base in a detergent
tablet overcomes these problems. Such a finding is surprising because
Schiff bases which are generally known to have a yellow colouration to
start with, were not expected to give rise to the discolouration of the
clay, especially over time.
SUMMARY OF THE INVENTION
The present invention is a perfumed detergent tablet, the tablet comprising
a clay mineral compound; and wherein the perfume comprises less than 0.6%
of Schiff-base by weight of the perfume composition.
By "perfumed detergent tablet", it is meant that the perfume can be present
in the coating if present, or in the detergent composition, or both.
DETAILED DESCRIPTION OF THE INVENTION
Clay
An essential ingredient of the detergent tablet is a clay. The clay may be
present in any of the detergent composition, the coating if present, or
both.
By clay mineral compound (or in abbreviation, "clay"), it is meant herein a
hydrous phyllosilicate, typically having a two or three layer crystal
structure. For clarity, it is noted that the term clay mineral compound,
as used herein, excludes sodium aluminosilicate zeolite builder compounds,
which however, may be included in the compositions of the invention as
optional components. Further description of clays may be found in
Kirk-Othmer, Encyclopaedia of Chemical Technology, 4th edition, Volume 6,
page 381, as published by John Wiley and Sons.
The clay mineral compound is preferably a smectite clay compound. Smectite
clays are disclosed in the U.S. Pat. Nos. 3,862,058, 3,948,790, 3,954,632
and 4,062,647 and European Patents No.s EP-A-299,575 and EP-A-313,146 all
in the name of the Procter and Gamble Company.
The term smectite clays herein includes both the clays in which aluminium
oxide is present in a silicate lattice and the clays in which magnesium
oxide is present in a silicate lattice. Typical smectite clay compounds
include the compounds having the general formula Al.sub.2 (Si.sub.2
O.sub.5).sub.2 (OH).sub.2.nH.sub.2 O and the compounds having the general
formula Mg.sub.3 (Si.sub.2 O.sub.5).sub.2 (OH).sub.2.nH.sub.2 O. Smectite
clays tend to adopt an expandable three layer structure.
Specific examples of suitable smectite clays include those selected from
the classes of the montmorillonites, hectorites, volchonskoites,
nontronites, saponites and sauconites, particularly those having an alkali
or alkaline earth metal ion within the crystal lattice structure. Sodium
or calcium montmorillonite are particularly preferred.
Suitable smectite clays, particularly montmorillonites, are sold by various
suppliers including English China Clays, Laviosa, Fordamin, Georgia Kaolin
and Colin Stewart Minerals (CSM).
Preferred smectite clays are sold under the tradename of White Bentonite
STP by Fordamin and Detercal P7 by Laviosa Chemical Mineria SPA.
Clays for use herein may be subjected to an acid washing treatment with any
suitable mineral or organic acid. Such clays give rise to an acid pH on
dissolution in distilled water. A commercially available "acid clay" of
this type is sold under the tradename Tonsil P by Sud Chemie AG.
Substitution of small cations, such as protons, sodium ions, potassium
ions, magnesium ions and calcium ions, and of certain organic molecules
including those having positively charged functional groups can typically
take place within the crystal lattice structure of the smectite clays. A
clay may be chosen for its ability to preferentially absorb one cation
type, such ability being assessed by measurement s of relative ion
exchange capacity. The smectite clays suitable herein typically have a
cation exchange capacity of at least 50 meq/100 g. U.S. Pat. No. 3,954,632
describes a method for measurement of cation exchange capacity.
The crystal lattice structure of th e clay mineral compounds may have, in a
preferred execution, a cationic fabric softening agent substitut ed
therein. Such substituted clays have been termed `hydrophobically
activated` clays. The cationic fabric softening agents are typically
present at a weight ratio, cationic fabric softening agent to clay, of
from 1:200 to 1:10, preferably from 1:100 to 1:20. Suitable cationic
fabric softening agents include the water insoluble tertiary amines or
dilong chain amide materials as disclosed in GB-A-1 514 276 and EP-0 011
340.
A preferred commercially available "hydrophobically activated" clay is a
bentonite clay containing approximately 40% by weight of a dimethyl
ditallow quaternary ammonium salt sold under the tradename Claytone EM by
English China Clays International.
Preferably, the clay which is present in the detergent composition is
present in an intimate mixture or in a particle with a humectant and a
hydrophobic compound, preferably a wax or oil, such as paraffin oil.
Preferred humectants are organic compounds, including propylene glycol,
ethylene glycol, dimers or trimers of glycol, most preferably glycerol.
The particle is preferably an agglomerate. Alternatively, the particle may
be such that the wax or oil and optionally the humectant form an
encapsulate on the clay or alternatively, the clay be an encapsulate for
the wax or oil and the humectant. It may be preferred that the particle
comprises an organic salt or silica or silicate.
In another embodiment, the clay in the detergent composition is preferably
mixed with one or more surfactants and optionally builders and optionally
water, in which case the mixture is preferably subsequently dried.
Preferably, such a mixture is further processed in a spray-drying method
to obtain a spray dried particle comprising the clay.
It may also be preferred that the intimate mixture comprises a chelating
agent.
Depending on its end use, the clay will preferably be present in different
particles size. Hence, when softening is desired, it is preferred that at
least 50% by weight, preferably substantially all (e.g. at least 90% or
95%) by weight of the clay is present as granules. By granules, it is
meant that the particles of the clay mineral compound which is present in
the detergent composition are included as components of agglomerate
particles optionally containing other detergent compounds. Where present
as such components, the term "largest particle dimension" of the clay
mineral compound refers to the largest dimension of the clay mineral
component as such, and not to the agglomerated particle as a whole.
Typically, the granules will have a particle size of at least 100
micrometers, generally 100-1700 micrometers.
When a coating is present, it is often desired to have a clay as
disintegrant in the coating. In this instance, the clay is preferably
present in the coating, having a particle size of less than 75 .mu.m, more
preferably of less than 53 .mu.m.
Preferably, the tablet is a softening tablet. By softening tablet, it is
meant that the level of clay will typically be of at least 5%, preferably
at least 8%, and most preferably at least 10% by weight of the tablet. The
amount may be less than 25%, usually less than 20%, and preferably not
more than 15% by weight of the tablet.
Perfume
The tablets of the present invention also comprises a perfume composition,
that being either present in the coating if present, or in the detergent
composition, or even in both the coating and the detergent composition.
Suitable perfumes herein include materials which provide an olfactory
aesthetic benefit such as to make such tablets more aesthetically pleasing
to the consumer, imparting a pleasant fragrance to fabrics treated
therewith and/or cover any "chemical" odor that the product may have.
As used herein, perfume includes fragrant substance or mixture of
substances including natural (i.e., obtained by extraction of flowers,
herbs, leaves, roots, barks, wood, blossoms or plants), artificial (i.e.,
a mixture of different nature oils or oil constituents) and synthetic
(i.e., synthetically produced) odoriferous substances. Such materials are
often accompanied by auxiliary materials, such as fixatives, extenders,
stabilizers and solvents. These auxiliaries are also included within the
meaning of "perfume", as used herein. Typically, perfumes are complex
mixtures of a plurality of organic compounds.
For the purpose of the present invention, the perfume composition contains
less than 0.6% by weight of the perfume composition of Schiff-base. The
perfume for use herein is used at levels of up to 5 grams per tablet and
preferably is substantially free of Schiff-Base.
By "substantially free", it is meant that the perfume composition comprises
less than 0.4% by weight of Schiff Base, and more preferably is free of
Schiff base.
Schiff-Bases are the condensation of an aldehyde perfume ingredient with an
anthranilate. A typical description can be found in U.S. Pat. No.
4,853,369. The Schiff Bases can be added directly to the perfume
composition or can be formed in situ in the perfume composition by adding
to it an Anthranilate such as Methyl or Ethyl Anthranilate along with an
aldehyde which can react with the Anthranilate to form the Schiff Base.
Not to be bound by theory, it is believed that when this compound comes in
contact with the clay it can undergo reactions most likely catalysed by
the metal ions present in the clay and that these reactions produce more
highly coloured by-products.
Typical of Schiff bases are selected from Schiffs base of
4-(4-hydroxy-4-methylpentyl)-3-cyclohexene-1-carboxaldehyde and methyl
anthranilate; condensation products of hydroxycitronellal and methyl
anthranilate; 4-(4-hydroxy-4-methyl pentyl)-3-cyclohexene-1-carboxaldehyde
and methyl anthranilate; Methyl Anthranilate and HydroxyCitronellal
commercially available under the tradename Aurantiol; Methyl Anthranilate
and Methyl Nonyl Acetaldehyde commercially available under the tradename
Agrumea; Methyl Anthranilate and PT Bucinal commercially available under
the tradename Verdantiol; Methyl anthranilate and Lyral commercially
available under the tradename Lyrame; Methyl Anthranilate and Ligustral
commercially available under the tradename Ligantral; and mixtures
thereof.
Preferably, the perfume composition is free of perfume ingredients selected
from Methyl Anthranilate and HydroxyCitronellal commercially available
under the tradename Aurantiol; Methyl Anthranilate and Methyl Nonyl
Acetaldehyde commercially available under the tradename Agrumea; Methyl
Anthranilate and PT Bucinal commercially available under the tradename
Verdantiol; Methyl anthranilate and Lyral commercially available under the
tradename Lyrame; Methyl Anthranilate and Ligustral commercially available
under the tradename Ligantral; and mixtures thereof.
Of course, the perfume composition will contain one or more perfume
ingredients. Suitable perfume ingredients are disclosed in U.S. Pat. No.
5,500,138, said patent being incorporated herein by reference.
Examples of perfume ingredients useful in the perfume compositions include,
but are not limited to, hexyl cinnamic aldehyde; amyl cinnamic aldehyde;
amyl salicylate; hexyl salicylate; terpineol;
3,7-dimethyl-cis-2,6-octadien-1-ol; 2,6-dimethyl-2-octanol;
2,6-dimethyl-7-octen-2-ol; 3,7-dimethyl-3-octanol;
3,7-dimethyl-trans-2,6-octadien-1-ol; 3,7-dimethyl-6-octen-1-of;
3,7-dimethyl-1-octanol;
2-methyl-3-(para-tert-butylphenyl)-propionaldehyde;
4-(4-hydroxy-4-methylpentyl)-3-cyclohexene-1-carboxaldehyde;
tricyclodecenyl propionate; tricyclodecenyl acetate; anisaldehyde;
2-methyl-2-(para-iso-propylphenyl)-propionaldehyde;
ethyl-3-methyl-3-phenyl glycidate; 4-(para-hydroxyphenyly)-butan-2-one;
1-(2,6,6-trimethyl-2-cyclohexen-1-yl)-2-buten-1-one;
para-methoxyacetophenone; para-methoxy-alpha-phenylpropene;
methyl-2-n-hexyl-3-oxo-cyclopentane carboxylate; undecalactone gamma.
Additional examples of fragrance materials include, but are not limited to,
orange oil; lemon oil; grapefruit oil; bergamot oil; clove oil;
dodecalactone gamma; methyl-2-(2-pentyl-3-oxo-cyclopentyl) acetate;
beta-naphthol methylether; methyl-beta-naphthylketone; coumarin;
decylaldehyde; benzaldehyde; 4-tert-butylcyclohexyl acetate;
alpha,alpha-dimethylphenethyl acetate; methylphenylcarbinyl acetate;
cyclic ethyleneglycol diester of tridecandioic acid;
3,7-dimethyl-2,6-octadiene-1-nitrile; ionone gamma methyl; ionone alpha;
ionone beta; petitgrain; methyl cedrylone;
7-acetyl-1,2,3,4,5,6,7,8-octahydro-1,1,6,7-tetramethyl-naphthalene; ionone
methyl; methyl-1;6,10-trimethyl-2,5,9-cyclododecatrien-1-yl ketone;
7-acetyl-1,1,3,4,4,6-hexamethyl tetralin;
4-acetyl-6-tert-butyl-1,1-dimethyl indane; benzophenone;
6-acetyl-1,1,2,3,3,5-hexamethyl indane;
5-acetyl-3-isopropyl-1,1,2,6-tetramethyl indane; 1-dodecanal;
7-hydroxy-3,7-dimethyl octanal; 10-undecen-1-al; iso-hexenyl cyclohexyl
carboxaldehyde; formyl tricyclodecan; cyclopentadecanolide;
16-hydroxy-9-hexadecenoic acid lactone;
1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta-gamma-2-benzopyrane
; ambroxane; dodecahydro-3a,6,6,9a-tetramethyinaphtho-[2,1b]furan; cedrol;
5-(2,2,3-trimethylcyclopent-3-enyl)-3-methylpentan-2-ol;
2-ethyl-4-(2,2,3-trimethyl-3-cyctopenten-1-yl)-2-buten-1-ol; caryophyllene
alcohol; cedryl acetate; para-tert-butylcyclohexyl acetate; patchouli;
olibanum resinoid; labdanum; vetivert; copaiba balsam; fir balsam;
hydroxycitronellal and indol; phenyl acetaldehyde and indol;
More examples of perfume components are geraniol; geranyl acetate;
linalool; linalyl acetate; tetrahydrolinalool; citronellol; citronellyl
acetate; dihydromyrcenol; dihydromyrcenyl acetate; tetrahydromyrcenol;
terpinyl acetate; nopol; nopyl acetate; 2-phenylethanol; 2-phenylethyl
acetate; benzyl alcohol; benzyl acetate; benzyl salicylate; benzyl
benzoate; styrallyl acetate; dimethylbenzylcarbinol;
trichloromethylphenylcarbinyl methylphenylcarbinyl acetate; isononyl
acetate; vetiveryl acetate; vetiverol;
2-methyl-3-(p-tert-butylphenyl)-propanal;
2-methyl-3-(p-isopropylphenyl)-propanal; 3-(p-tert-butylphenyl)-propanal;
4-(4-methyl-3-pentenyl)-3-cyclohexenecarbaldehyde;
4-acetoxy-3-pentyltetrahydropyran; methyl dihydrojasmonate;
2-n-heptylcyclopentanone; 3-methyl-2-pentyl-cyclopentanone; n-decanal;
n-dodecanal; 9-decenol-1; phenoxyethyl isobutyrate; phenylacetaldehyde
dimethylacetal; phenylacetaldehyde diethylacetal; geranonitrile;
citronellonitrile; cedryl acetal; 3-isocamphylcyclohexanol; cedryl
methylether; isolongifolanone; aubepine nitriie; aubepine; heliotropine;
eugenol; vanillin; diphenyl oxide; hydroxycitronellal ionones; methyl
ionones; isomethyl ionomes; irones; cis-3-hexenol and esters thereof;
indane musk fragrances; tetralin musk fragrances; isochroman musk
fragrances; macrocyclic ketones; macrolactone musk fragrances; ethylene
brassylate.
The perfumes useful in the present invention compositions are substantially
free of halogenated materials and nitromusks.
Suitable solvents, diluents or carriers for perfumes ingredients mentioned
above are for examples, ethanol, isopropanol, diethylene glycol, monoethyl
ether, dipropylene glycol, diethyl phthalate, triethyl citrate, etc. The
amount of such solvents, diluents or carriers incorporated in the perfumes
is preferably kept to the minimum needed to provide a homogeneous perfume
solution.
Tablets of the present invention as well as coated tablets according to the
invention provide improved fabric perfume deposition.
Preferably, the perfume composition is present in an amount of 0.001% to
10%, preferably from 0.005% to 5%, more preferably from 0.01% to 3%, and
even more preferably from 0.02% to 2% by weight of the tablet.
The perfume can be incorporated to the tablet by any conventional means
known to the skilled person. One preferred means is by spray-on of the
perfume composition onto the tablet.
Heavy Metal Ions Sequestrants
The perfumed detergent tablets of the invention preferably also contain as
an optional component a heavy metal ion sequestrant composition, that
being either present in the coating if present, or in the detergent
composition, or even in both the coating and the detergent composition. By
heavy metal ion sequestrant, it is meant herein components which act to
sequester (chelate) heavy metal ions. These components may also have
calcium and magnesium chelation capacity, but preferentially they show
selectivity to binding heavy metal ions such as iron, manganese and
copper.
Heavy metal ion sequestrants are generally present at a level of from
0.005% to 20%, preferably from 0.1% to 10%, more preferably from 0.25% to
7.5% and most preferably from 0.5% to 5% by weight of the tablet.
Heavy metal ion sequestrants, which are acidic in nature, having for
example phosphonic acid or carboxylic acid functionalities, may be present
either in their acid form or as a complex/salt with a suitable counter
cation such as an alkali or alkaline metal ion, ammonium, or substituted
ammonium ion, or any mixtures thereof. Preferably any salts/complexes are
water soluble. The molar ratio of said counter cation to the heavy metal
ion sequestrant is preferably at least 1:1.
Suitable heavy metal ion sequestrants for use herein include organic
phosphonates, such as the amino alkylene poly (alkylene phosphonates),
alkali metal ethane 1-hydroxy disphosphonates and nitrilo trimethylene
phosphonates.
Preferred among the above species are diethylene triamine penta (methylene
phosphonate), ethylene diamine tri (methylene phosphonate) hexamethylene
diamine tetra (methylene phosphonate) and hydroxy-ethylene 1,1
diphosphonate.
Other suitable heavy metal ion sequestrant for use herein include
nitrilotriacetic acid and polyaminocarboxylic acids such as
ethylenediaminotetracetic acid, ethylenetriamine pentacetic acid,
ethylenediamine disuccinic acid, ethylenediamine diglutaric acid,
2-hydroxypropylenediamine disuccinic acid or any salts thereof.
Especially preferred is ethylenediamine-N,N'-disuccinic acid (EDDS) or the
alkali metal, alkaline earth metal, ammonium, or substituted ammonium
salts thereof, or mixtures thereof. Preferred EDDS compounds are the free
acid form and the sodium or magnesium salt or complex thereof. Examples of
such preferred sodium salts of EDDS include Na.sub.2 EDDS and Na.sub.3
EDDS. Examples of such preferred magnesium complexes of EDDS include
MgEDDS and Mg.sub.2 EDDS.
Other suitable heavy metal ion sequestrants for use herein are
iminodiacetic acid derivatives such as 2-hydroxyethyl diacetic acid or
glyceryl imino diacetic acid, described in EP-A-317,542 and EP-A-399,133.
The iminodiacetic acid-N-2-hydroxypropyl sulfonic acid and aspartic acid
N-carboxymethyl N-2-hydroxypropyl-3-sulfonic acid sequestrants described
in EP-A-516,102 are also suitable herein. The .beta.-alanine-N,N'-diacetic
acid, aspartic acid-N,N'-diacetic acid, aspartic acid-N-monoacetic acid
and iminodisuccinic acid sequestrants described in EP-A-509,382 are also
suitable.
EP-A-476,257 describes suitable amino based sequestrants. EP-A-510,331
describes suitable sequestrants derived from collagen, keratin or casein.
EP-A-528,859 describes a suitable alkyl iminodiacetic acid sequestrant.
Dipicolinic acid and 2-phosphonobutane-1,2,4-tricarboxylic acid are alos
suitable. Glycinamide-N,N'-disuccinic acid (GADS),
ethylenediamine-N,N'-diglutaric acid (EDDG) and
2-hydroxypropylenediamine-N,N'-disuccinic acid (HPDDS) are also suitable.
Most preferred heavy metal ion sequestrants for use herein is alkali metal
ethane 1-hydroxy diphosphonates, in particular when used in combination
with diethylene triamine penta (methylene phosphonate). Most preferably,
the heavy metal ion sequestrant is present in the coating.
Detergent ingredients
The tablets may comprise components such as surfactants, enzymes, detergent
etc. . . . Typical tablet compositions for the preferred embodiment of the
present invention are disclosed in the pending European applications of
the Applicant no. 96203471.6, 96203462.5, 96203473.2 and 96203464.1 for
example. Elements typically entering in the composition of detergent
tablets or of other forms of detergents such as liquids or granules are
detailed in the following paragraphs.
Detersive Surfactants
Surfactants 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 C.sub.11
-C.sub.18 alkyl benzene sulfonates ("LAS") and primary, branched-chain and
random C.sub.10 -C.sub.20 alkyl sulfates ("AS"), the C.sub.10 -C.sub.18
secondary (2,3) alkyl sulfates of the formula CH.sub.3 (CH.sub.2).sub.x
(CHOSO.sub.3- M.sup.+) CH.sub.3 and CH.sub.3 (CH.sub.2).sub.y
(CHOSO.sub.3- M.sup.+) CH.sub.2 CH.sub.3 where x and (y+1) are integers of
at least about 7, preferably at least about 9, and M is a
water-solubilizing cation, especially sodium, unsaturated sulfates such as
oleyl sulfate, the C.sub.10 -C.sub.18 alkyl alkoxy sulfates ("AE.sub.x S";
especially EO 1-7 ethoxy sulfates), C.sub.10 -C.sub.18 alkyl alkoxy
carboxylates (especially the EO 1-5 ethoxycarboxylates), the C.sub.10
-C.sub.18 glycerol ethers, the C.sub.10 -C.sub.18 alkyl polyglycosides and
their corresponding sulfated polyglycosides, and C.sub.12 -C.sub.18
alpha-sulfonated fatty acid esters. If desired, the conventional nonionic
and amphoteric surfactants such as the C.sub.12 -C.sub.18 alkyl
ethoxylates ("AE") including the so-called narrow peaked alkyl ethoxylates
and C.sub.6 -C.sub.12 alkyl phenol alkoxylates (especially ethoxylates and
mixed ethoxy/propoxy), C.sub.12 -C.sub.18 betaines and sulfobetaines
("sultaines"), C.sub.10 -C.sub.18 amine oxides, and the like, can also be
included in the overall compositions. The C.sub.10 -C.sub.18 N-alkyl
polyhydroxy fatty acid amides can also be used. Typical examples include
the C.sub.12 -C.sub.18 N-methylglucamides. See WO 9,206,154. Other
sugar-derived surfactants include the N-alkoxy polyhydroxy fatty acid
amides, such as C.sub.10 -C.sub.18 N-(3-methoxypropyl) glucamide. The
N-propyl through N-hexyl C.sub.12 -C.sub.18 glucamides can be used for low
sudsing. C.sub.10 -C.sub.20 conventional soaps may also be used. If high
sudsing is desired, the branched-chain C.sub.10 -C.sub.16 soaps may be
used. Mixtures of anionic and nonionic surfactants are especially useful.
Other 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.
Non Gelling Binders
Non gelling binders can be integrated in detergent compositions to further
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 classification: Acacia, Alginic Acid, Carbomer,
Carboxymethylcellulose sodium, Dextrin, Ethylcellulose, Gelatin, Guar gum,
Hydrogenated vegetable oil type I, Hydroxyethyi 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.degree. C., preferably
below 70.degree. C. and even more preferably below 50.degree. 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.
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 SiO.sub.2 :Na.sub.2 O ratio in the range 1.6:1 to 3.2:1 and
layered silicates, such as the layered sodium silicates described in U.S.
Pat. No. 4,664,839, issued May 12, 1987 to H. P. Rieck. NaSKS-6 is the
trademark for a crystalline layered silicate marketed by Hoechst (commonly
abbreviated herein as "SKS-6"). Unlike zeolite builders, the Na SKS-6
silicate builder does not contain aluminum. NaSKS-6 has the delta-Na.sub.2
SiO.sub.5 morphology form of layered silicate. It can be prepared by
methods such as those described in German DE-A-3,417,649 and
DE-A-3,742,043. SKS-6 is a highly preferred layered silicate for use
herein, but other such layered silicates, such as those having the general
formula NaMSi.sub.x O.sub.2x+1.yH.sub.2 O wherein M is sodium or hydrogen,
x is a number from 1.9 to 4, preferably 2, and y is a number from 0 to 20,
preferably 0 can be used herein. Various other layered silicates from
Hoechst include NaSKS-5, NaSKS-7 and NaSKS-11, as the alpha, beta and
gamma forms. As noted above, the delta-Na.sub.2 SiO.sub.5 (NaSKS-6 form)
is most preferred for use herein. Other silicates may also be useful such
as for example magnesium silicate, which can serve as a crispening agent
in granular formulations, as a stabilizing agent for oxygen bleaches, and
as a component of suds control systems.
Examples of carbonate builders are the alkaline earth and alkali metal
carbonates as disclosed in German Patent Application No. 2,321,001
published on Nov. 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 detergent formulations.
Aluminosilicate builders include those having the empirical formula:
M.sub.z (zAlO.sub.2)/.sub.y ].xH.sub.2 O
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. Pat. No. 3,985,669, Krummel, et al, issued Oct. 12, 1976.
Preferred synthetic crystalline aluminosilicate ion exchange materials
useful herein are available under the designations Zeolite A, Zeolite P
(B), Zeolite MAP and Zeolite X. In an especially preferred embodiment, the
crystalline aluminosilicate ion exchange material has the formula:
Na.sub.12 [(AlO.sub.2).sub.12 (SiO.sub.2).sub.12 ].xH.sub.2 O
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. Pat. No. 3,128,287, issued Apr. 7, 1964, and
Lamberti et al, U.S. Pat. No. 3,635,830, issued Jan. 18, 1972. See also
"TMS/TDS" builders of U.S. Pat. No. 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. Pat. Nos. 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. Pat. No. 4,566,984, Bush, issued Jan. 28, 1986. Useful
succinic acid builders include the C.sub.5 -C.sub.20 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.
Lauryisuccinates are the preferred builders of this group, and are
described in European Patent Application 86200690.5/0,200,263, published
Nov. 5, 1986.
Other suitable polycarboxylates are disclosed in U.S. Pat. No. 4,144,226,
Crutchfield et al, issued Mar. 13, 1979 and in U.S. Pat. No. 3,308,067,
Diehl, issued Mar. 7, 1967. See also Diehl U.S. Pat. No. 3,723,322.
Fatty acids, e.g., C.sub.12 -C.sub.18 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. Pat. Nos. 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 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 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.
Pat. No. 4,483,781, Hartman, issued Nov. 20, 1984, U.S. patent application
Ser. No. 740,446, Bums et al, filed Jun. 3, 1985, European Patent
Application 0,133,354, Banks et al, published Feb. 20, 1985, and U.S. Pat.
No. 4,412,934, Chung et al, issued Nov. 1, 1983. Highly preferred
bleaching agents also include 6-nonylamino-6-oxoperoxycaproic acid as
described in U.S. Pat. No. 4,634,551, issued Jan. 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 | | |
