Note: Descriptions are shown in the official language in which they were submitted.
1 32~2~2
. 32ds1
LIQUID CLEANING PRODUCTS
The present invention comprises substantially
non-aqueous liquid cleaning products of the kind
comprising solid particles dispersed in a liquid phase.
For reasons precisely unknown, when such products are
manufactured in large quantities and then stored, in the
hours immediately after preparation, the temperature in
the bulk of the liquid can rise considerably. We have
termed this effect "self-heating". As well as being a
safety hazardl there is also the possibility that some
components in the product can thereby decompose.
15The applicants have now found that this problem can
be mitig~ted if a free radical scavenger is included in
the product.
Thus, acc~rding to the invention there is provided a
substantially non-aqueous liquid cleaning compositlon
comprising a dispersion ot solid particles in a liquid
phase, said composition containing bleach and a
free-radical scavenger agent.
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1 3232~2
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The problem is particularly acute when a bleach
especially an inorganic persalt, optionally in the
presence of a precursor therefor, is included in the
product. Thus, such bleach containing products are a
preferred form of the present invention since in these,
the action of the scavenger is particularly beneficial.
The persalt may be sodium perborate, especially in the
monohydrate form. Other persalts are mentioned
hereinbelow.
Free radical scavengers are well known in the art of
organic chemistry and thus the particular agent used may
be chosen from a very wide range of known compounds.
However, two typical examples are butylhydroxytoluene
(BHT) and l,l,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl)
butane, sold under the tradename Topanol CA (ex ICI).
Mixtures of different scavengers may also be employed.
Usually, the scavenger may be incorporated at from
0.1% to l~ by weight of the total composition, typically
from 0.25~ to 0.5%.
We are aware o~ European pa~ent specification
EP-A-209228 (Chlorox) which describes the use of a free
radical scavenging agent to stabilize aqueous bleach
compositions, thereby to prevent the nonionic surfactant
or any other ingredients from being attacked by the
bleach.
We are also aware o~ United States patent
specification US 4088594 (Fernley/Shell) which discloses
the stabilization of nonionic surfactants with alkylidene
bisphenols even in the absence of water.
Neither of the above mentioned specifications however
discloses that the self-heating o~ bleach containing
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1 3232~2
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non-aqueous liquids can be reduced by the use o~ a
scavenging agent.
The bleach may comprise a halogen, particularly a
chlorine bleach such as is provided in the form o~ the
known alkalimetal hypohalites, e.g. hypochlorites. In the
application of fabrics washing, the oxygen bleaches are
preferred, for example in the form of an inorganic
persalt, preferably with an precursor, or as a peroxy acid
compound.
The inorganic persalt bleaches are most pref2rred.
It is also then preferred to include a precursor which
makes the bleaching more effective at lower temperatures,
i.e. in the range from ambient temperature to about 60~C,
so that such bleach systems are commonly known as
low-temperature bleach systems and are well known in the
art. The inorganic persalt such as, sodium perborate, both
the monohydrate and the tetrahydrate, acts to release
active oxygen in solution, and the precursor is usually an
organic compound having one or more~ reactive acyl
residues, which cause the formatio~ of peracids, the
latter providing for a more effective bleaching action at
lower temperatures than the peroxybleach compsund alone.
The ratio by weight o~ the peroxy bleach compound to the
precursor is from about 15:1 to about 2:1, preferably from
about 10:1 to about 3.5:1. Whilst the amount of the
bleach system, i.e. peroxy bleach compound and precursor,
may be varied between about S~ and about 35% by weight of
the total liquid, it is preferred to use from about 6% to
about 30~ of the ingredient~ forming the bleach system.
Thus, the preferred level of th~ peroxy bleach compound in
the composition is between about 5.5~ and abou~ ~7% by
weight, while the preferred level of the precursor is
between about 0.5~ and about 10%, most preferably between
about 1% and about 5% by weight.
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7 323282
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Typical examples of the suitable peroxybleach
compounds are alkalimetal peroborates, both tetrahydrates
and monohydrates, alkali metal percarbonates, persilicates
and perphosphates, of which sodium perborate is preferred.
Precursors for peroxybleach compounds have been amply
described in the literature, including in British patent
specifications 836,988, 855,735, 907,356, 907,358,
907,950, 1,003,310, and 1,246,339, US patent
10 specifications 3,332,882, and 4,128,494, Canadian patent
specification 844,481 and South African patent
specification 68/6,344.
The exact mode of action of such precursors is not
known, but it is believed that peracids are formed by
reaction of the precursors with the inorganic peroxy
compound, which peracids then liberate active-oxygen by
decomposition.
They are generally compounds which contain N-acyl or
O-acyl or O-aryl residues in the molecule and which exert
their activating action on the peroxy compounds on contact
with these in the washing liquor.
Typical examples of precursors within these groups
are polyacylated alkylene diamines, such as
N,N,N ,N -tetraacetylethylene diamine ~TAED) and
N,N,N ,N -tetraacetylmethylene diamine (TAMD); acylated
glycolurils, such as tetraacetylgylcoluril (TAGU);
triacetylcyanurate and sodi~m sulphophenyl ethyl carbonic
acid ester.
A particularly preferred precursor is
N,N,N ,N -tetra- ace~ylethylene diamine (TAED).
~5
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1 323282
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The organic peroxyacid compound bleaches are
preferably those which are solid at room temperature and
most preferably should have a melting point of at least
50C. Most commonly, they are the organic peroxyacids and
water-soluble salts thereof having the general formula
HO-O-C-R-Y
wherein R is an alkylene or substituted alkylene group
containing 1 to 20 carbon atoms or an arylene group
containing from 6 to 8 carbon atoms, and Y is hydrogen,
halogen, alkyl, aryl or any group which provides an
anionic moiety in aqueous solution.
Another preferred class of peroxygen compounds which
can be incorporated to enhance dispensing/dispersibility
in water are the anhydrous perborates described ~or that
purpose in European patent specification EP-A-217,454
(Unllever).
In the compositions of the pr~!sent invention, the
liquid phase can be a liquid surfactant, an organic
non-aqueous non-surfactant liquid, or a mixture of such
materials. Many of the compositions do contain a
surfactant as a dispersed or dissolved solid, or more
often, as all or part of said liquid phase. These
surfactant compositions are liquid detergent products,
e.g. for fabrics washing or hard surface cleaning.
However, the ~ider term 'liquid cleaning product' also
lncludes non-surfactant liquids which are still useful in
cleaning, for exampla non-aqueous bleach products or those
in which the liquid phase consists of onP or more light,
non-surfactant solvents for greasy stain pre-treatment of
~5 fabrics prior to washing. Such pre-treatment products can
contain solid bleaches, dispersed enz~mes and the like.
:
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The solid particles can be maintained in dispersion
in the liquid phase (i.e. resist settling, even if not
perfectly) by a number of means. For example, settling
may be inhibited purely by virtue of the relative small
size of the particles and the relatively high viscosity of
the solvent phase. In other words, the particles settle
very slowly at a rate predicted by Stokes' law or due to
the formation of a loosely aggregated network of particle
flocs. This e~ect is utilised in the compositions
10 described in patent specifications EP-A-30 096 IICI) and
GB 2 158 838A (Colgate-Palmolive). However, there have
also been several prlor proposals to utilise additional
means to enhance solid-suspending properties in such
non-aqueous liquids. These are somewhat analogous to
so-called external structuring techniques used in aqueous
systems; i.e., in addition to the particulate solids and
the liquid phase in which they are to be suspended, an
additional dispersant is used which by one means ox
another, acts to aid stable dispersion or suspension of
the solids for a finite period. Any o~ these means may be
employed in the compositions accordin~ to the present
invention.
One such sultable stabilisation involves use of
nonionic surfac~ant as the liquid phase and to add an
inorganic carrier material as the dispersant, in
particular highly voluminous silica. This ac$s by forming
a solid-s~spending network. This silica is highly
voluminous by virtue of having an extremely small particle
size, hence high sur~ace area. This is described in GB
patent specifications 1,205,711 (Unilever) and 1,270,040
(Unilever)~
A similar sultable structuring can be effected using
fine particulate chain structure-type clay, as described
in specification EP-A-34,387.
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Another appropriate known use of a substance as a
dispersant for particles in nonionic-based non-aqueous
compositions entails incorporating a hydrolyzable
co-polymer of maleic anhydride with ethylene or
vinylmethylether, which co-polymer is at least 30%
hydrolyzed. This is described in specification
EP-A-28,849.
Another appropriate means by which such dispersions
have been stabilised is the use of a dispersant material
which has been termed 'a deflocculant', according to the
disclosure of European Patent Specification EP-A-266 l99
(Unilever).
All compositions according to the present invention
are liquid cleaning products. They may be formulated in a
very wide range of specific forms, according to the
intended use. They may be formulated as cleaners for hard
surfaces (with or without abrasive) or as agents for
warewashing (cleaning of dishes, cutlery etc) either by
hand or mechanical means, as well as in the form of
specialised cleaning products, such as for surgical
apparatus or artificial dentures. They may also be
formulated as agents ~or washing and/or conditioning of
fabrics.
In the case of hard-surface cleaning, the
compositions may be formulated as main cleaning agents, or
pre-treatment products to be sprayed or wiped on prior to
removal, e.q~ by wiping off or as part of a main cleaning
operation.
In the case of warewashin~, the compositions may also
be ~he main cleaning agent or a pre-treatment product, e.g
applied by spray or used for soaking utensils in an
aqueous solution and/or suspension thereof.
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Those products which are formulated for the cleaning
and/or conditioning of fabrics constitute an especially
preferred form of the present invention. These
compositions may for example, be of the kind used for
pre-treatment of fabrics (e.g. for spot stain removal)
with the composition neat or dilu~ed, before they are
r1nsed and/or subjected to a main wash. The compositions
may also be formulated as main wash products, being
dissolved and/or dispersed in the water with which the
fabrics are contacted. In that case, the composition may
be the sole cleaning agent or an adjunct to another wash
product. Within the context of the present invention, the
term 'cleaning product' also embraces compositions o~ the
kind used as fabric conditioners (including fabric
softeners) which are only added in the rinse water
tsometimes referred to as 'rinse conditioners').
Thus, the compositions will contain at least one
agent which promotes the cleaning and/or conditioning of
the article(s) in question, selected according to the
intended application. Usually, this agent will be
selected from surfactants, enzymes r bleaches,
microbiocides, (for fabrics) fabrlc softening agents and
(in the case of hard surface cleaning) abrasives. Of
course in many cases, more than one of these agents will
be present, as well as other ingredients commonly used in
the relevant product form.
The compositions will be substantially free from
agents which are detrimental to the article(s) to be
treated. For example, they will be substantially free
from pigments or dyes, although of course they may contain
small amoun~s of those dyes (colourants~ of the kind often
used to impart a pleasing colour to liquid cleaning
products, as well as ~luorescers, bluing agents and the
like.
1 323282
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All ingredients before incorporation will either be
liquld, in which case, in the composition they will
constitute all or part of the liquid phase, or they will
be solids, in which case, in the composition they will
either be dispersed as deflocculated particles in the
liquld phase or they will be dissolved in the liquid
phase. Thus as used herein, the term "solids" is to be
construed as referring to materials in the solid phase
which are added to the composition and are dispersed
thereln in solid form, those solids which dissolve in the
liquid phase and those in the liquid phase which solidify
(undergo a phase change) in the composition, wherein they
are then dispersed.
1~ If a deflocculant is incorporated, some liquids are
alone, unlikely to be suitable to per~orm the function of
liquid phase for any combination of solids and
dispersant/deflocculant. However, they will be able to be
incorporated if used with another liquid which does have
the required properties, the only requirement being that
where the liquid phase comprises two or more liquid
ingredients, they are miscible when in the total
composition or one can be dispersible in the other, in the
form of fine droplets.
Where sur~actants are solids, 'they will usually be
dlssolved or dispersed in the liquid phase. Where they
are liquids, they will usually constitute all or part of
the solvent. Also, some surfactants are eminentlv
suitable as deflocculants.
In general, however, surfactants may be chosen from
any of the classes, sub-classes and specific materials
described in 'Surface Active Agents' Vol. I, by Schwartz &
Perry, Interscience 1949 and 'Surface Active Agents' Vol.
II by Schwartz, Perry & Berch (Interscience 1958~, in the
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1 323282
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current edition of "McCutcheon's Emulsifiers ~ Detergents"
published by the McCutcheon division of Manufacturing
Confectioners Company or in 'Tensid-Taschenbuch', ~.
Stache, 2nd Edn., Caxl Hanser Verlag, M~nchen ~ Wien,
1981.
Liquid surfactants are an especially preferred class
of material to use in the liquid phase, especially
polyalkoxylated types and in particular polyalkoxylated
nonionic surfactants.
As a general rule, the applicants have found that the
most suitable liquids to choose for the liquid phase are
those organic materials having polar molecules. In
particular, those comprising a relatively lipophilic part
and a relatively hydrophilic part, especially a
hydrophilic part rich in electron lone pairs, tend to be
well suited. This is completely in accordance with the
observation that liquid surfactants, especially
polyalkoxylated nonionics, are one preferred class of
liquid.
Nonionic detergent surfactants are well-known in the
art. They normally consist of a watar-solubllizing
polyalkoxylene or a mono- or di-alkanolamide group in
chemical comblnation with an organic hydrophobic group
derived, for example, from alkylphenols in which the alkyl
group contains from about 6 to about 12 carbon atoms,
dialkylphenols in which each alkyl group contains from 6
to 12 carbon atoms, primary, secondary or tertiary
aliphatic alcohols (or alkyl-capped derivatives thereof),
preferably having from 8 to 20 carbon atoms,
monocarboxylic acids having from 10 to about 24 carbon
atoms in the alkyl group and polyoxypropylenes. Also
common are fatty acid mono- and dialkanolamides in which
the alkyl group of the fatty acid radical contains from 10
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1 323282
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to about 20 carbon atoms and the alkyloyl group having
from 1 to 3 carbon atoms. In any of the mono- and di-
alkanolamide derivatives, optionally, there may be a
polyoxyalkylene moîety joining the latter groups and the
hydrophobic part of the molecule. In all polyalkoxylene
containing surfactants, the polyalkoxylene moiety
preferably consists of from 2 to 20 groups of ethylene
oxide or of ethylene oxide and propylene oxide groups.
Amongst the latter class, particularly preferred are those
described in European specification EP-A-225,65~
(Unilever), especially for use as all or part of the
solvent. Also preferred are those ethoxylated nonionics
which are the condensation products o~ fatty alcohols with
from 9 to 15 carbon atoms condensed with from 3 to 11
moles of ethylene oxide. Examples of these are the
condensation products o~ Cll 13 alcohols with (say) 3 or 7
moles o~ ethylene oxide. These may be used as the sole
nonionic surfactants or in combination with those
described in the last-mentioned European specification,
especially as all or part of the solvent.
Another class of suitable nonionics comprise the
alkyl polysaccharides (polyglycosides/oligosaccharides)
such as described in any of specifications US 3,640,998;
US 3,346,558; US 4,223,129; EP-A-92,355; EP-A-99,183;
EP-A-70,074, '7~, '76, '77; EP-A-75,99~, '95, '96.
Nonionic detergent surfactants normally have
molecular weights of from about 300 to about 11,000.
Mixtures of different nonionic detergent surfactants may
also be used, provided the mixture is liquid at room
~emperature. Mixtures of nonionic detergent surfactants
with other detergent surfactants such as anionic, cationic
or ampholytic detergent surfactants and soaps may also be
used. If such mixtures are used, the mixture must be
liquid at room temperature.
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Examples of suitable anionic detergent surfactants
are alkali metal, ammonium or alkylolamine salts of
alkylbenzene sulphonates having from 10 to 18 carbon atoms
in the alkyl group, alkyl and alkylether sulphates having
from 10 to 24 carbon atoms in the alkyl group, the
alkylether sulphates having from 1 to 5 ethylene ~xide
groups, olefin sulphonatPs prepared by sulphonation o~
C10-C2~ alpha-olefins and subsequent neutralization and
hydrolysis of the sulphonation reaction product.
Other surfactants which may be used include alkali
metal soaps of a fatty acid, preferably one containing 12
to 18 carbon atoms. Typical such acids are oleic acid,
ricinoleic acid and fatty acids derived from castor oil,
rapeseed oil, groundnut oil, coconut oil, palmkernal oil
or mlxtures t:hereof. The sodium or potassium soaps of
these acids can be used. As well as fulfilling the role
of surfactants, soaps can act as detergency builders or
fabrlc conditioners, other examples of which will be
described in more detail hereinbelo~. It can also be
remarked that the oils mentioned in this paragraph may
themselves constitute all or part oE the liquid phase,
whilst the corresponding low molecu:Lar weight ~atty acids
(triglycerides) can be dispersed as solids or function as
struc~urants.
Yet again, it is also possible to utilise cationic,
zwitterionic and amphoteric surfactants such as referred
to in the general surfactant texts referred to
hereinbefore. Examples of cationic detergent surfactants
are aliphatic or aromatic alkyl-di(alkyl) ammonlum halides
and examples o~ soaps are the alkali metal salts of
C12-C24 fatty acids. Ampholytic detergent surfactants are
e.g. the sulphobetalnes. Combinations of surfactants from
within the same, or from dif~erent classes may be employed
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1 323282
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to advantage for optimising structuring and/or cleaning
performance.
Non-surfactants which are suitable as solvents
include those having the pre~erred molecular forms
referred to above although other kinds may be used,
especially if combined with those of the ~ormer, more
preferred types. In general, the non-surfactant solvents
can be used alone or with in comb1nation with liquid
surfactants. Non-surfactant solvents which have molecular
structures which fall into the former, more preferred
category include ethers, polyethers, alkylamines and fatty
amines, (especially di- and tri-alkyl- and/or fatty- N-
substituted amin~s), alkyl (or fatty) amides and mono- and
di- N-alkyl substituted derivatives thereof, alkyl (or
fatty) carboxylic acid lower alkyl esters, ketones,
aldehydes, and glycerides. Specific examples include
respectively, di-alkyl ethers, polyethylene glycols, alkyl
ketones (such as acetone) and glyceryl
trialkylcarboxylates (such as glyceryl tri-acetate),
glycerol, propylene glycol, and sorbitol.
Preferably, the compositions of the invention contain
the liquid phase (whether or not comprising liquid
surfactant) in an amount of at least 10~ by weight of the
total ~omposition. The amount of ~he li~uid phase present
in the composition may be as high as about 90%, but in
most cases th~ practical amount will lie between 20 and
70% and preferably between 20 and 50~ by weight of the
composition.
Preferably also, the compositions of the present
invention contain a deflocculant which may be any of ~hose
r~ferred to in the published prior art, most preferably
35 any descrihed in EP-A-266 199.
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1 323282
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The level of any deflocculant material in the
composition in very many cases is at least 0.01~, usually
0.1% and preferably at least 1% by weight, and may be as
high as 15~ by weight. For most practical purposes, the
amount ranges from 2-12~, preferably from 4-10% by weight,
based on the final composition.
The compositions according to the present invention
preferably also contain one or more other functional
ingredients, for example selected from detergency builders
and (for hard surface cleaners) abrasives.
Detergency builders are those materials which
counteract the effects of calcium, or other ion, water
hardness, either by precipitation or by an ion
sequestering eft~ct.. They comprise both inorganic and
organic builders. They may also be sub-divided into the
phosphorus-containing and non-phosphorus types.
Suitable inorganic builders comprise the various
phosphate~, carbonate-, silicate-, borate- and
aliminosllicate-type materals, particularly the
alkali-metal salt forms. Mlxtures of these may also be
used.
Examples of phosphorus-containing inorganic builders
include the water-soluble salts, especially alkali metal
pyrophosphates, orthophosphates, polyphosphates and
phosphonates. Specific examples of inorganic phosphate
builders include sodium and potassium phosphates and
hexametaphosphates, as well as potassium tripolyphosphate.
Examples of non-phosphorus-containing inorganic
builders include water-soluble alkali metal carbonates,
bicarbonates, borates, silicates, metasilicates, and
crystalline and amorphous alumino silicates. Specific
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1 323282
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examples include sodium carbonate (with or without calcite
seeds), potassium carbonate, sodium and potassium
bicarbonates, silicates and zeoli~es.
Examples of organic builders include the alkali
metal, ammonium and substitut2d, citrates, succinates,
malonates, fatty acid sulphonates, carboxymethoxy
succinates, ammonium polyacetates, carboxylates,
polycarboxylates, aminopolycarboxylates, polyacetal
carboxylates and polyhydroxysulphonates. Specific
examples include sodium, potassium, lithium, ammonium and
substituted ammonium salts of ethylenediaminetetraacetic
acid, nitrilotriacetic acid, o~ydisuccinic acid, melitic
acid, benzene polycarboxylic acids and citric acid. Other
examples are organic phosphonate type sequestering agents
such as those sold by Monsanto under the tradename of the
Dequest range and alkanehydroxy phosphonates.
Other suitable organic builders include the higher
molecular weight polymers and co-polymers known to have
huilder properties, for example appropriate polyacrylic
acid, polymaleic acid and polyacrylic/polymaleic acid
co-polymers and their salts, such as those sold by ~ASF
under the Sokalan Trade Mark.
The aluminosilicates are an especially preferred
class of non-phosphorus inorganic builders. These for
example are crystalline or ~morphous materials having the
general formula:
~0
Na~ (AlO2)z (SiO2)y x H2O
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 0.5, and x is
an integer from 6 to 189 such that the moisture content is
from above 6% to about 20~ by weight ~ermed h~rein,
,
1 3232182
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'partially hydratPd'). This water content provides the
best rheological properties in the liquid. Above this
level (e.g. from about l9~i to about 28% by weight water
content), the water level can lead to network formation.
~owever, for increased inhibition of self-heating, i~ is
most preferred for the aluminosilicate to be substantially
anhydrous (e.g. having from 0 to about 6% by weight water
content, typically around 4~i). The anhydrous materials
(i.e. with 0 to about 6% by weight of water) can also in
some circumstances, be used as structurants. The
preferred range of aluminosilicate is from about 12% to
about 30% on an anhydrous basis. The aluminosilicate
preferably has a particle size of from 0.1 to 100 microns,
ideally betweeen 0.1 and 10 microns and a calcium ion
exchange capacity of at least 200 mg calcium carbonate/g.
When the composition contains abrasives for hard
surface cleaning (i.e. is a liquid abrasive cleaner),
these will inevitably be incorporated as particulate
solids. They may be those of the kind which are water
insoluble, for example calcite. Suitable materials of
this ~ind are disclosed in patent specifications
EP-A-50,887; EP-~-80,221; EP-A-140,452; EP-A-214,540 and
EP 9,942 ~all Unilever), which relate to such abrasives
when suspended in aqueous media. Water soluble abrasives
may also be used.
The compositions of the invention optionally may also
contain one or more minor ingredients such as fabric
conditioning agents, enzymes, perfumes (includlng
deoperfumes), micro-biocides, colouring agents,
fluorescers, soil-suspending agents (anti-redeposition
agents), corrosion inhibitors, enzyme stabilizing agents,
and lather depressants.
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In general, the solids content o~ the product may be
within a very wide range, for example from 1-90~, usually
from 10-80% and preferably ~rom 15-70%, especially 15-50%
by weight of the final composition. The solid phase
should be in particulate form and have an average particle
size of less than 300 microns, preferably less than 200
microns, more preferably less than 100 microns, especially
less than 10 microns. The particle size may even be of
sub-micron size. The proper particle size can be obtained
by using materials of the appropriate size or by milling
the total product in a suitable milling apparatus.
The compositions are substantially non-aqueous, i.e.
they contain llttle or no free water, preferably no more
than 5%, preferably less than 3%, especially less than 1~
by weight o~ the total composition. It has been found by
the applicants that the higher the ~ater content, the more
likely it is for the viscosity to be too high, or even for
setting to occur, and also, the more likely for
self-heating to occur. ~owever, this may at least in part
be overcome by use of deflocculants, especially in
relatively high amounts.
Since the objective of a non-aqueous liquid will
generally be to enable the formulator to avoid the
negative influence of water on the components, e.g.
causing incompatibllity of functional ingredients, it is
clearly necessary to avold the accidental or deliberate
addition of water to the product at any stage in its life.
For this reason, special precautions are necessary in
manufacturing procedures and pack designs for use b~ the
consumer.
Thus during manufacture, it is preferred that all raw
materials should be dry and (in the case of hydratable
saltsJ in a low hydration state, e.g. anhydrous phvsphate
,'I ,,
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1 323282
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builder, sodium perborate monohydrate and dry calcite
abrasive, where these are employecl in the composition. In
a preferred process, the dry, substantially anhydrous
solids are blended with the liquid phase in a dry vessel.
In order to minimise the rate of sedimentation of the
solids, this blend is passed through a grinding mill or a
combination of mills, e.g. a colloid mill, a corundum disc
mill, a hsrizontal or vertical agitated ball mill, to
achieve a particle size of 0.1 to 100 microns, preferably
0.5 to 5~ microns, ideally 1 to 10 microns. A preferred
combination of such mil:Ls is a colloid mill followed by a
horizontal ball mill since these can be operated under the
conditions required to provide a narrow size distribution
in the final product. Of course particulate material
already having the desired particle size need not be
sub~ected to this procedure and if desired, can be
incorporated during a later stage of processing.
During this milling procedure, the energy input
~0 results in a temperature rise in the product and the
liberation of alr entrapped in or between the particles of
the solid ingredients. It is therefore highly deslrable
to mix any heat sens~tive ingredie~ts into the product
after the milling stage and a subsequent cooling step. It
may also be desirable to de-aerate the product be~ore
addition of these (usually minor) ingredients and
optionally, at any other stage of the process. Typical
ingredients which might be added at this stage are
perfumes and enzymes, but might also include highly
temperature sensitive bleach components or volatile
solvent components which may be desirable in the final
composition. However, it is especially preferred that
volatile material be introduced after any step of
de~aeration. Suitable equipment ~or cooling (e.g. heat
exchang~rs) and de-aeration will be known to those skilled
in the art.
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- 19 - C.3241
It follows that all equipment used in this process
should be completely dry, special care being taken after
any cleaning operations. The same is irue for subsequent
storage and packing equipment.
The present invention will now b~ illustrated by way
of the following Examples.
Two compositions were prepared each with the
~ollowing 'base' formulation:-
Parts by wei~t
Nonionic (1) 36.6
15 Glyceryl Triacetate 5.0
ABSA (2) 3.0
Sodium Carbonate O.aq 4.~
Sodium Tripolyphosphate O.aq 30.0
Sodium Perborate Monohydrate 15.0
20 EDTA 0.1
SCMC 1.0
TAED 4 0
Minors (3) o.g
25 (1) C9 11 fatty alcohol alkoxylated with an average of 9
moles of ethylene oxide.
(2) Dodecyl benzene sulphonic (free) acid.
(3) ~leach stabiliser, enzyme, perfume.
To this base formulation various amounts of two
different scavengers were added, aither by post-dosing or
by including with other ingredients at the milling stage.
The sample under tes~ is put into a vacuum flask,
which is then placed in an oven which is at a temperature
of 100C. The temperature of the sample is monitored
.
- : - ! ' . ,
~ ' ,
,,
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' i ' ` :
.,`........... . -.:.. ~
1 323282
- 20 - C.3241
using a fine thermocouple and the rate of temperature rise
as the sample passes the oven temperature is noted. This
information is then used to determine the rate of heat
generation of the sample. The heat generated over the
temperature range 50~80C is a useful indicator for a
likely processing temperature range. Using this technique
the heat generated ~rom a 200g sample over the temperature
range 50 - 80C was measured and found to be as ~ollows.
10 Scavenger Heat generated (KJ)
None 7.37
BHT (0.2~ post-dosed) 5.31
Topanol CA (0.3% via mill) 5.36
n,1tes tr~le ~6~rl~
~. : . .
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:
