Note: Descriptions are shown in the official language in which they were submitted.
-
W094/03395 ~ 5~6 PCT/US93/06801
PEROXYACID BLEACH PR~CURSOR COMPOSITIONS
Technical Field
This invention relates to solid peroxy acid bleach
precursor compositi~ns an~ especi~lly to particulate
detergen~ compositions incorp~rating inorganic perhydrate
bleaches ~ogether with N- or O- acyl group - containing
peroxycarDoxylic acid bleach precursors (so-called bleach
activators).
Backqround of the Invention
Bleach precursor compositions have come into widespread
use in recent years as heavy duty fabric cleaning
products, particularly in automatic washing machines. The
growth in usage of bleach activators has mirrored a
decrease in fabric wash temperatures which itself has
accompanied an increase in the proportion of fabrics that
are coloured.
one problem that has become more significant as a result
of these trends is that of damage to fabric colours and
materials caused by the development of localised high
-
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WO 94/03395 ~141~ PCT/US93/06801 -
concentrations of bleaching species. High bleach
concentrations can arise around any particulate bleaching
species for several reasons. The bleaching species may
itself have an intrinsically low solubility, its
solubility may have been hindered by the presence of other
materials such as viscous surfactant phases or the
agitation regime in the immediate environment of the
bleach species may not be high enough to disperse the
dissolved bleach. Where a bleach activator forms a
component of the composition the potential problem is
increased. In addition to the potential for localised
high concentrations of perhydroxyl ion arising from
dissolution of the inorganic perhydrate normally contained
in laundry detergent compositions, the perhydrolysis of
the bleach activator to form peroxycarboxyl anions can
give rise to significant localised peroxycarboxylate
bleach concentrations.
The development of so-called concentrated products and
their delivery via dispensing devices placed in the
machine drum together with the fabric load has merely
served to exacerbate these problems. Accordingly a need
exists to provide detergent compositions in which the
bleach activator is incorporated in a form that minimises
and preferably eliminates damage to fabric colours and
materials during its dissolution and perhydrolysis in the
wash liquor.
The prior art contains numerous examples of bleach
activators coated or agglomerated so as to increase their
stability on storage in detergent compositions and/or to
influence their solution behaviour.
EP-A-0070474 discloses granulate bleach activators
prepared by spray drying an aqueous pumpable dispersion
containing an N-acyl or 0-acyl compound together with at
least one water-soluble cellulose ether, starch or starch
Z~1586
W094/03395 3 PCT/US93/06801
.... j~ .
derivative in a weight ratio of activator to coating of
from 98:2 to 90:10.
GB-A-1507312 discloses the coating of bleach activators
with a mixture of alkali metal C8 - C22 fatty acid salts
in admixture with the corresponding fatty acids. GB-A-
1381121 employs a molten coating of inter alia C14 - C18
fatty acid mixtures to protect solid bleach activators.
GB-A-1441416 discloses a similar process employing a
mixture of C12-C14 fatty acids and C10-C20 aliphatic
alcohols. EP-A-0375241 describes stabilised bleach
activator extrudates in which C~-C1g alkyl peroxy
carboxylic acid precursors are mixed with a binder
selected from anionic and nonionic surfactants, film
forming polymers fatty acids or mixtures of such binders.
EP-A-0356700 discloses compositions comprising a bleach
activator, a water-soluble film forming polymer and 2-15%
of a C3-C6 polyvalent carboxylic acid or hydroxycarboxylic
acid for enhanced stability and ease of
dispersion/solubility. The carboxylic acid, of which a
preferred example is citric acid, is dry mixed with the
bleach activator and then granulated with the film forming
polymer. The citric acid is asserted to provide an
enhanced rate of dissolution ~f the bleach activator
granules.
EP-A-0382464 concerns a process for coating or
encapsulation of solid particles including bleaching
compounds and bleach activators in which a melt is formed
of coating material in which the particles form a disperse
phase, the melt is destabilised and then caused to crumble
to a particulate material in which the disperse phase
particles are embedded in the continuous (coating) phase.
A variety of coating materials are disclosed and certain
materials such as polyacrylic acid and cellulose acetate
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W O 94/03395 PC~r/US93/06801
phthalate are taught as being useful where release of the
coated material is dependent on pH.
The overall emphasis in the prior art has thus been on the
protection of the bleach activator against a hostile
environment during storage and relatively little attention
has been paid to the dissolution characteristics of the
coated or agglomerated material in use. Where coating
and/or agglomeration has been proposed with poorly soluble
materials such as fatty acids, this has resulted in a rate
of perhydrolysis of the bleach activator which is slower
than that which would occur if it had not been so
protected. Any use of more rapidly soluble materials such
as citric acid has been in the context of an agglomerate
component in which more rapid solution of the bleach
activator has been the objective. In both instances,
because perhydrolysis commences as soon as the detergent
product starts to dissolve and form an alkaline hydrogen
peroxide solution the problem of localised peroxy acid
bleach concentrations has remained unsolved.
one solution to this problem would be to delay the start
of perhydrolysis in order to avoid the fabric colour
damage problems associated with the dissolution behaviour
of other detergent product components. However it is
important that perhydrolysis of the bleach precursor and
subsequent dispersion of the peroxycarboxylate bleach is
as rapid as possible when it commences because of the
short wash times of modern automatic washing machines.
The problem that arises in simultaneously satisfying these
two objectives does not appear to have been recognised in
the prior art.
It is known that the rate of perhydrolysis of a
percarboxylic acid bleach precursor in an aqueous
oxidising medium is progressively reduced as the pH of the
W094/03395 Z~ 6 PCT/US93/06801
medium is reduced, particularly when the pH falls below
the pKa of the parent acid of the precursor leaving group.
However the fatty acids taught as coating agents in the
prior art are not useful as a means of providing a low pH
environment in an aqueous wash liquor because of their
insolubility. Moreover fatty acids used as coating and/or
agglomerating agents for peroxy acid bleach precursors
have been found to reduce the rate of perhydrolysis of the
latter, thereby reducing the effectiveness of the
resultant peroxycarboxylic acid bleach.
Another problem encountered within the compositions of the
prior art relates to the storage and handling properties
of said compositions, and is thus an additional object of
the present invention to provide a bleach precursor
composition as a free-flowable powder which remains as
such throughout prolonged storage time.
Co-pending application GB-91-02507.2 proposes to use
various water-soluble organic materials, including certain
monomeric and olygomeric carboxylates as coating materials
for such bleach precursor compositions.
The Applicant has now surprisingly found that certain
acidic polymeric materials having certain specified
characteristics can be used as agglomerating and coating
materials for peroxy acid bleach precursors, to delay the
onset of perhydrolysis during dissolution of the product
under the constrained agitation conditions of a lo~d~d
washing machine drum without adversely hinde- .g
perhydrolysis when it occurs, and to provide peroxyacid
bleach precursor compositions as a storage-stable free-
flowable powder.
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W094/0339~ PCT/US93/06801 ~
SummarY of the Invention
The present invention is directed to a solid peroxyacid
bleach precursor composition comprising a particulate
peroxyacid bleach precursor material, said precursor
comprising one or more N-, or o- acyl groups and having a
Mpt>30C, wherein said precursor is coated with a coating
material, characterized in that said coating material is
selected from water-soluble acidic polymers, wherein said
polymers have a water solubility greater than 5 g/l at
20C, a molecular weight of from 1000 to 250,000,
preferably 1500 to 150,000, and wherein a 1% solution of
said polymers has a pH of less than 7, preferably less
than 5.5. Preferably, said precursor is co-agglomerated
with a said water-soluble acidic polymer before it is
coated.
Detailed Description of the Invention
As a first essential ingredient, the solid peroxyacid
bleach precursor compositions of the present invention
incorporate precursors containing one or more N- or O-
acyl groups, which precursors can be selected from a wide
range of classes. Suitable classes include anhydrides,
esters, imides and acylated derivatives of imidazoles and
oximes, and examples of useful materials within these
classes are disclosed in GB-A-1586789. The most preferred
classes are esters such as are disclosed in GB-A-836988,
864,798, 1147871 and 2143231 and imides such as are
disclosed in GB-A-855735 & 1246338.
.
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W O 94/03395 PC~r/US93/06801
Particularly pre~erred precursor compounds are the N-
,N,NlN1 tetra acetylated compounds of formula
o O
Il 11
CH3 - C / C - CH3
\ N - (CH2) X - N \
CH3 - C C - CH3
Il 11
O O
wherein x can be 0 or an integer between 1 & 6. Examples
include tetra acetyl methylene diamine (TAMD) in which
x=l, tetra acetyl ethylene diamine (TAED) in which x=2 and
tetraacetyl hexylene diamine (TAHD) in which x=6. These
and analogous compounds are described in GB-A-907356. The
most preferred peroxyacid bleach precursor is TAED.
Solid peroxyacid bleach precursors useful in the present
invention have a Mpt>30C and preferably >40C. Such
precursors will normally be in fine powder or crystalline
form in which at least 90% by weight of the powder has a
particle size < 150 micrometers.
Another essential ingredient of the compositions according
to the present invention is a water-soluble acidic
polymer. Said polymer is used in the compositions
according to the present invention as the coating material
to coat said peroxyacid bleach precursor. In a preferred
embodiment of the present invention, said peroxyacid
bleach precursor is co-agglomerated before it is coated,
preferably with a said water-soluble acidic polymer. In
one embodiment of the invention the binder material and
the coating material are different water-soluble acidic
polymers, but in another, preferred embodiment of the
present invention, the binder material and the coating
material are the same water-soluble acidic polymer.
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W094/0339~ 8 PCT/US93/06801 -
Suitable polymers for use herein are water-soluble. By
water-soluble, it is meant herein that the polymers have a
solubility greater than 5 g/l at 20C.
Suitable polymers for use herein are acidic. By acidic,
it is meant herein that a 1~ solution of said polymers has
a pH of less than 7, preferably less than 5.5.
Suitable polymers for use herein have a molecular weight
in the range of from 1000 to 280,000, preferably from 1500
to 150,000, preferably, suitable polymers for use herein
have a melting point superior to 30C.
Suitable polymers which meet the above criteria and are
therefore particularly useful in the present invention,
include those having the following empirical formula I :
R1 yp - (- X - CR3 -) R2
I
_ CO2M - n
wherein X is O or CH2; Y is a comonomer or comonomer
mixture; Rl and R2 are bleach-stable polymer-end groups;
R3 is H, OH or Cl_4 alkyl; M is H, and mixtures thereof
with alkali metal, alkaline earth metal, ammonium or
substituted ammonium; p is from 0 to 2; and n is at least
10, and mixtures thereof. The proportion of M being H in
such polymers must be such as to ensure that the polymer
is sufficiently acidic to meet the acidity criteria as
hereinbefore defined.
Polymers according to formula I are known in the field of
laundry detergents, and are typically used as chelating
agents, as for instance in GB-A-1,597,756. Preferred
polycarboxylate polymers fall into several categories. A
first category belongs to the class of copolymeric
W094/0339~ 9 ~ 8~ PCT/US93/06801
polycarboxylate polymers which, formally at least, are
formed from an uns~turated polycarboxylic acid such as
maleic acid, citraconic acid, itaconic acid and mesaconic
acid as first monomer, and an unsaturated monocarboxylic
acid such as acrylic acid or an alpha -Cl_4 alkyl acrylic
acid as second monomer. Referring to formula I,
therefore, preferred polycarboxylate polymers of this type
are those in which X is CH2, R3 is H or Cl_4 alkyl,
especially methyl, p is from about 0.l to about l.9,
preferably from about 0.2 to about l.5, n averages from
about l0 to about 1500, preferably from about 50 to about
l000, more preferably from l00 to 800, especially from 120
to 400 and Y comprises monomer units of formula II
CH CH
C2M C2M II
Such polymers are available from BASF under the trade name
Sokalan(R) CP5 (neutralized form) and Sokalan(R) CP45
(acidic form).
A second category belongs to the class of polycarboxylate
polymers in whic~, referring to formula I, X is CH2, R3 is
OH, p is from 0 to 0.l, preferably 0 and n averages from
about 50 to about 1500, preferably from about l00 to l000.
Y, if present, can be a polycarboxylic acid such as II
above, or an ethylene oxide moiety.
A third category belongs to the class of acetal
polycarboxylate polymers in which, referring to formula I,
X is (oR4)2 where ~4 is Cl-C4 alkyl , R3 is H, p is from 0
to 0.l, preferably 0 and n averages from l0 to 500. If
present, Y again can be a polycarboxylic acid such as II
above or an ethyleneoxide moiety.
S8~
W094/03395 PCT/US93/06801
1(~
A fourth category belongs to the class of polycarboxylate
polymers in which referring to formula I, X is CH2, R3 is
H or C1_4 alkyl, p is 0 and n averages from about 10 to
1500, preferably from about 500 to 1000.
A fifth category of polycarboxylate polymers has the
formula I in which X is CH2, R3 is H or Cl-4 alkyl,
especially methyl, p is from 0.01 to 0.09, preferably from
0.02 to 0.06, n averages from about 10 to about 1500,
preferably from about 15 to about 300 and Y is a
polycarboxylic acid formed from maleic acid, citraconic
acid,m itaconic acid or mesaconic acid, highly preferred
being maleic acid-derived comonomers of formula II above.
The bleach-stable polymer end groups in formula I suitably
include alkyl groups, oxyalkyl groups and alkyl carboxylic
acid groups and salts and esters thereof.
In formula I above, M is H or mixtures thereof with alkali
metal, alkaline earth metal, ammonium or substituted
ammonium. The proportion of M which is H is such as to
ensure that the polymer meets the pH criteria described
herein above.
In the above, n, the degree of polymerization of the
polymer can be determined from the weight average polymer
molecular weight by dividing the latter by the average
monomer molecular weight. Thus, for a maleic-acrylic
copolymer having a weight average molecular weight of
15,500 and comprising 30 mole % of maleic acid derived
units, n is 182 (i.e. 15,500/tl16 x 0.3 + 72 x 0.7).
In case of doubt, weight-average polymer molecular weights
can be determined herein by gel permeation chromotography
using Water rmu] Porasil (RTM) GPC 60 A2 and [mu] Bondagel
(RTM) E-125, E-500 and E-1000 in series, temperature-
controlled columns at 40C against sodium polystyrene
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W O 94/03395 1I PC~r/US93/06801
sulphonate polymer standards, available from Polymer
Laboratories Ltd., Shropshire, UK, the polymer standards
being 0.15M sodium dihydrogen phosphate and 0.02M
tetramethyl ammonium hydroxide at pH 7.0 in 80/20
water/acetonitrile.
.
Mixtures of polycarboxylate polymers are also suitable
herein, especially mixtures comprising a high molecular
weight component having an n value of at least 100,
preferably at least 120, and a low molecular weight
component having an n value of less than 100, preferably
from 10 to 90, more preferably from 20 to 80. Such
mixtures are optimum from the viewpoint of providing
excellent bleach stability and anti-incrustation
performance in the context of a zerophosphate detergent
formula.
In mixtures of this type, the weight ratio of high
molecular weight component to low molecular weight
component is generally at least l:1, preferably from about
1:1 to about 20:1, more preferably from about 1.5:1 to
about 10.1, especially from about 2:1 to about 8:1.
Preferred polycarboxylate polymers of the low molecular
weight type are polycarboxylate polymers of the fourth
category (homopolyacrylate polymers) listed above.
of all the above, highly preferred polycarboxylate
polymers herein are those of the first category in which n
averages from 100 to 800, preferalby from 120 to 400 and
mixtures thereof with polycarboxylate polymers of the
fourth category in which n averages from 10 to 90,
preferably from 20 to 80.
Other suitable polymers for use herein include polymers
derived from amino acids such as polyglutamine acid, as
disclosed in co-pending application GB 91-20653.2, and
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W O 94/03395 PC~r/US93/06801 -
l_
polyaspartic acid, as disclosed in EP 305 282, and EP 351
629.
A process for manufacturing a preferred solid peroxyacid
bleach precursor according to the present invention
includes the steps of : `
- co-agglomerating a peroxyacid bleach precursor with a
binder material as hereinbefore defined;
- optionally drying said co-agglomerate;
- coating said dried co-agglomerate with a coating
material as hereinbefore defined;
- drying said coated co-agglomerate.
According to said process, the peroxyacid bleach precursor
powder must be co-agglomerated into a water-soluble acidic
polymer binder material as hereinabefore defined. Any
agglomerating technique known to the man skilled in the
art is suitable for use herein.
The co-agglomerated particulate material does not itself
provide the full benefits of the invention, and said co-
agglomerated material needs to be coated with a water-
soluble acidic polymer as hereinabove defined.
The coating of the co-agglomerated material with the
coating material can be carried out in several ways:
The coating material may be sprayed on as a molten
material or as a solution or dispersion in a
solvent/carrier liquid which is subsequently removed by
evaporation. The coating material can also be applied as a
powder coating e.g. by electrostatic techniques although
this is less preferred as the adherence of powdered
coating material is more difficult to achieve and can be
more expensive.
~141586
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W O 94/03395 13 PC~r/US93/06801
Molten coatlng is a preferred technique for coating
materials of Mpt<80C but is less convenient for higher
Melting Point acids (i.e. >100C). For coating materials
of Mpt>80C, spray on as a solution or dispersion is
preferred. organic solvents such as ethyl and isopropyl
alcohol can be used to form the solutions or dispersions,
although this will necessitate a solvent recovery stage in
order to make their use economic. However, the use of
organic solvents also gives rise to safety problems such
as flammability and operator safety and thus aqueous
solutions or dispersions are preferred.
Aqueous solutions are particularly advantageous as the
coating materials herein have a high a~ueous solubility,
provided the solution has a sufficiently low viscosity to
enable it to be handled. Preferably a concentration of at
least 25% by weight of the coating material in the solvent
is used in order to reduce the drying/evaporation load
after surface treatment has taken place. The treatment
apparatus can be any of those normally used for this
purpose, such as inclined rotary pans, rotary drums and
fluidised beds.
The solid peroxyacid bleach precursor compositions
according to the present invention comprise from 30% to
93% by weight of the total composition of said peroxyacid
bleach precursor, preferably 70% to 88% and from 7% to 60%
of said polymer,preferably 12 % to 30%.
The solid peroxyacid bleach precursor compositions
according to the present invention comprise particles of
different sizes which can be separated using sieves.
Another advantage of the present invention is that it
allows to use peroxyacid bleach precursor particles of
smaller size than the compositions of the prior art, thus
allowing significant improvement in the bleaching
performance without increasing fabric damage.
86
W094/0339~ l~ PCT/US93/06801 -
Accordingly, in a preferred embodiment of the present
invention, said particles have a particle size ranging
from 100 micrometers to 1700 micrometers, i.e. said
particles pass through a sieve of 1700 micrometers and do
not pass through a sieve of 100 micrometers, with a mean
particle size of from 2~0 to 800 micrometers. As used
herein, the mean particle size refers to the weighted
average particle size in the total composition. In a
further preferred embodiment, particles in the composition
range from 150 to 1700 micrometers, most preferably 250 to
1700 micrometers, with a preferred mean particle size of
from 400 to 600 micrometers, most preferably 450 to 550
micrometers.
In a preferred embodiment, the compositions according to
the present invention have a mean coating level of from 2%
to 25% by weight of the total composition, preferably 5~
to 15%, and the coating level for any given particle, or
the mean coating level for any particle class, ranges from
-15% to +15% of the mean coating level of the composition.
As used herein, the mean coating level refers to the
weight % of coating material in the total composition.
Similarly, the mean coating level of a particle class
refers to the weight % of coating material in the
particles of a given size class. Depending on the polymer
used, the amount of coating material in a given sample can
be determined by a variety of methods, including
colorimetric titration with ferrothiocyanate, photometric
titration with chromotropes, gas chromatography etc. A
preferred and simple method is an acid-base titration
calibrated with the polymer. In the preferred embodiment
of the invention where the polymer used for binding and
coating is the same, the amount of coating material can be
calculated by determining the amount of polymer in an
agglomerated but uncoated sample, then measuring the
amount of polymer in an agglomerated and coated sample of
W O 94/0339~ 3Çi PC~r/US93/06801
same weight, then calculating the difference between both
samples.
Solid peroxyacid bleach precursor compositions in
accordance with the invention can be used in a variety of
applications. Thus the peroxyacid bleach compositions may
themselves be incorporated into other solid compositions
such as tablets, extrudates and agglomerates. The
compositions can also be suspended in nonaqueous liquid
compositions in wh -h the organic acid surface treating
material is insoluble and inert. However, the preferred
application for the solid peroxybleach precursor
compositions of the invention is as particulate components
of granular detergent composi'ions, particularly the so-
called concentrated detergent compositions that are added
to a washing machine by means of a dosing device placed in
the machine drum with the soiled fabric load.
Concentrated granular detergent compositions dispensed
into the wash liquor via a dosing device are more subject
to dissolution problems than compositions added via the
dispensing compartment of a washing machine because, in
the initial stages of a wash cycle, the agitation in the
immediate environment of the product is inhibited by the
presence of the fabric load. Whilst this can constitute a
benefit in permitting the development of high transient
concentrations of builder and surfactant, the development
of high transient peroxyacid concentrations can, as noted
previously, lead to fabric and colour damage. The
compositions of the present invention, when incorporated
into concentrated detergent products delivered to the wash
liquor via a dispensing device, mitigate if not eliminate
this problem.
Detergent compositions incorporating the coated peroxy
acid bleach precursor particulates will normally contain
from 0.5% to 20% of the precursor~ more frequently from 1%
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W O 94/03395 16 PC~r/US93/0680t -
to 9% and most preferably from 3~ to 8%, on a composition
weight basis.
Such detergent compositions will, of course, contain a
source of alkaline hydrogen peroxide necessary to form a
peroxyacid bleaching species in the wash solution and
preferably will also contain other components conventional
in detergent compositions. Thus preferred detergent
compositions will incorporate one of more of surfactants,
organic and inorganic builders, soil suspending and anti-
redeposition agents, suds suppressors, enzymes,
fluorescent whitening agents, photo activated bleaches,
perfumes and colours.
Detergent compositions incorporating the coated
particulate peroxyacid precursors of the present invention
will include an inorganic perhydrate bleach, normally in
the form of the sodium salt, as the source of alkaline
hydrogen peroxide in the wash liquor. This perhydrate is
normally incorporated at a level of from 3% to 35% by
weight, more preferably from 5% to 30~ by weight and most
preferably from 8% to 25% by weight of the composition.
The perhydrate may be any of the inorganic salts such as
perborate, percarbonate, perphosphate and persilicate
salts but is conventionally an alkali metal perborate or
percarbonate. Whilst fabric colour damage arising from
composltions in accordance with the invention is low,
irrespective of whether a perborate or percarbonate salt
is employed, the improvement in comparison with uncoated
precursor particulates is more noticeable with
percarbonate bleach as this causes greater fabric colour
damage in the absence of any coating on the bleach
precursor.
Sodium percarbonate, which is the preferred perhydrate, is
an addition compound having a formula corresponding to
W094/033g5 ~ 6 PCT/US93/06801
2Na2CO3-3H2O2l and is available commercially as a
crystalline solid. Most commercially available material
includes a low level of a heavy metal sequestrant such as
EDTA, l-hydroxyethylidene l, l-diphosphonic acid (HEDP) or
an amino-phosphonate, that is incorporated during the
manufacturing process. For the purposes of the detergent
composition aspect of the present invention, the
percarbonate can be incorporated into detergent
compositions without additional protection, but preferred
executions of such compositions utilise a coated form of
the material. A suitable coating is sodium silicate of
SiO2:Na2O ratio from l.6:l to 3.4:l, preferably 2.8:l,
applied as an aqueous solution to give a level of from 2%
to 10%, (normally from 3% to 5%) of silicate solids by
weight of the percarbonate. Another coating is a mixed
salt of an alkali metal sulphate and carbonate. Such
coatings together with coating processes have previously
been described in GB-l,466,799, granted to Interox on 9th
March 1977. The weight ratio of the mixed salt coating
material to percarbonate lies in the range from l:200 to
l:4, more preferably from l:99 to l:9, and most preferably
from 1:49 to l:l9. Preferably, the mixed salt is of
sodium sulphate and sodium carbonate which has the general
formula Na2S04.n.Na2C03 wherein n is from O.l to 3,
preferably n is from 0.3 to l.0 and most preferably n is
from 0.2 to 0.5. Magnesium silicate can also be included
in the coating.
The particle size range of the crystalline percarbonate is
from 350 micrometers to 450 micrometers with a mean of
approximately 400 micrometers. When coated, 60% to 80% by
weight of the crystals have a size greater than 425
micrometers, with a mean of approximately 650 micrometers.
Whilst heavy metals present in the sodium carbonate used
to manufacture the percarbonate can be controlled by the
inclusion of sequestrants in the reaction mixture, the
2~ 58fi
W O 94/03395 18 PC~r/US93/06801 -
percarbonate still requires protection from heavy metals
present as impurities in other ingredients of the product.
Accordingly, in detergent compositions utilising
percarbonate as the perhydrate salt, the total level of
Iron, Copper and Manganese ions in the product should not
exceed 25 ppm and preferably should be less than 20 ppm in
order to avoid an unacceptably adverse effect on
percarbonate stability. Detergent compositions in which
alkali metal percarbonate bleach has enhanced stability
are disclosed in the Applicants copending British Patent
Application No. 9021761.3 (Attorney's Docket No. CM343).
A wide range of surfactants can be used in the detergent
compositions. A typical listing of anionic, nonionic,
ampholytic and zwitterionic classes, and species of these
surfactants, is given in U.S.P. 3,929,678 issued to
Laughlin and Heuring on December, 30, 1975. A list of
suitable cationic surfactants is given in U.S.P. 4,259,217
issued to Murphy on March 31, 1981.
Mixtures of anionic surfactants are suitable herein,
particularly blends of sulphate, sulphonate and/or
carboxylate surfactants. Mixtures of sulphonate and
sulphate surfactants are normally employed in a sulphonate
to sulphate weight ratio of from 5:1 to 1:2, preferably
from 3:1 to 2:3, more preferably from 3:1 to 1:1.
Preferred sulphonates include alkyl benzene sulphonates
having from 9 to 15, especially 11 to 13 carbon atoms in
the alkyl radical, and alpha-sulphonated methyl fatty acid
esters in which the fatty acid is derived from a C12-C18
fatty source, preferably from a Cl6-Clg fatty source. In
each instance the cation is an alkali metal, preferably
sodium. Preferred sulphate surfactants in such sulphonate
sulphate mixtures are alkyl sulphates having from 12 to
22, preferably 16 to 18 carbon atoms in the alkyl radical.
Another useful surfactant system comprises a mixture of
two alkyl sulphate materials whose respective mean chain
W094/033g5 1~ PCT/US93/06801
lengths differ from each other. One such system comprises
a mixture of C14-C15 alkyl sulphate and C16-C18 alkyl
sulphate in a weight ratio of C14-Cls: C16-C18 f from 3 1
to 1:1. The alkyl sulphates may also be combined with
alkyl ethoxy sulphates having from 10 to 20, preferably 10
to 16 carbon atoms in the alkyl radical and an average
degree of ethoxylation of 1 to 6. The cation in each
instance is again an alkali metal, preferably sodium.
other anionic surfactants suitable for the purposes of the
invention are the alkali metal sarcosinates of formula
R-CON (R) CH2 COOM
wherin R is a Cg-Cl7 linear or branched alkyl or alkenyl
group, R' is a C1-C4 alkyl group and M is an alkali metal
ion. Preferred examples are the lauroyl, Cocoyl (C12-
C14), myristyl and oleyl methyl sarcosinates in the form
of their sodium salts.
one class of nonionic surfactants useful in the present
invention comprises condensates of ethylene oxide with a
hydrophobic moiety, providing surfactants having an
average hydrophilic-lipophilic balance (HLB) in the range
from 8 to 17, preferably from 9.5 to 13.5, more preferably
from 10 to 12.5. The hydrophobic (lipophilic) moiety may
be aliphatic or aromatic in nature and the length of the
polyoxyethylene group ~ich is condensed with any
particular hydrophobic group can be readily adjusted to
yield a water-soluble compound having the desired degree
of balance between hydrophilic and hydrophobic elements.
Especially preferred nonionic surfactants of this type are
the C3-C15 primary alcohol ethoxylates containing 3-B
moles of ethylene oxide per mole of alcohol, particularly
the C14-C15 primary alcohols containing 6-8 moles of
ethylene oxide per mole of alcohol and the C12-C14 primary
alcohols containing 3-5 moles of ethylene oxide per mole
of alcohol.
fi
W O 94/03395 20 PC~r/US93/06801
Another class of nonionic surfactants comprises alkyl
polyglucoside compounds of general formula
R0 (cnH2n)tzx
wherein Z is a moiety derived from glucose; R is a
saturated hydrophobic alkyl group that contains from 12 to
18 carbon atoms; t is from 0 to 10 and n is 2 or 3; x is
from 1.3 to 4, the compounds including less than 10%
unreacted fatty alcohol and less than 50% short chain
alkyl polyglucosides. Compounds of this type and their
use in detergent compositions are disclosed in EP-B
0070074, 0070077, 007S996 and 0094118.
A further class of surfactants are the semi-polar
surfactants such as amine oxides. Suitable amine oxides
are selected from mono C8-c20~ preferably ClO-Cl4 N-alkyl
or alkenyl amine oxides and propylene-1,3-diamine dioxides
wherein the remaining N positions are substituted by
methyl, hydroxyethyl or hydroxpropyl groups.
Cationic surfactants can also be used in the detergent
compositions herein and suitable quaternary ammonium
surfactants are selected from mono C8-C16, preferably C10-
C14 N-alkyl or alkenyl ammonium surfactants wherein
remaining N positions are substituted by methyl,
hydroxyethyl or hydroxypropyl groups.
The detergent compositions comprise from 5% to 20% of
surfactant but more usually comprise from 7% to 20%, more
preferably from 10% to 15% surfactant by wei~ht of the
compositions.
Combinations of surfactant types are preferred, more
especially anionic-nonionic and also anionic-nonionic-
cationic blends. Particularly preferred combinations are
described in GB-A-2040987 and EP-A-0087914. Although the
%~ PCT/US93/06801
surfactants can be incorporated into the compositions as
mixtures, it is preferable to control the point of
addition of each surfactant in order to optimise the
physical charact~ristics of the composition and avoid
processing problems. Preferred modes and orders of
surfactant addition are described hereinafter.
Another highly preferred component of detergent
compositions incorporating the coated peroxy acid
precursor particulates of the invention is a detergent
builder system comprising one or more non-phosphate
detergent builders. These can include, but are not
restricted to alkali metal carbonates, bicarbonates,
silicates, aluminosilicates, monomeric polycarboxylates,
homo or copolymeric polycarboxylic acids or their salts in
which the polycarboxylic acid comprises at least two
carboxylic radicals separated from each other by not more
than two carbon atoms, organic phosphonates and
ami~oalkylene poly (alkylene phosphonates) and mixtures of
any of the foregoing. The builder system is present in an
amount of from 25% to 60% by weight of the composition,
mor~ preferably from 30% to 60% by weight.
Preferred builder systems are free of boron compounds and
any polymeric organic materials are preferably
biodegradable.
Suitable silicates are those having an SiO2:Na2O ratio in
the range from 1.6 to 3.4, the so-called amorphous
silicates of sio2 : Na2O ratios from 2.0 to 2.8 being
preferred. These materials can be added at various points
of the manufacturing process, such as in a slurry of
components that are spray dried or in the form of an
aqueous solution serving as an agglomerating agent for
other solid components, or, where the silicates are
themselves in particulate form, as solids to the other
particulate components of the compositon. However, for
36
W094/03395 PCT/US93/06801 -
22
compositions in which the percentage of spray dried
components is low i.e. 30~, it is preferred to include the
amorphous silicate in the spray-dried components.
Within the silicate class, highly preferred materials are
crystalline layered sodium silicates of general formula
NaMSix02x+l YH20
wherein M is sodium or hydrogen, x is a number from 1.9 to
4 and y is a number from o to 20. Crystalline layered
sodium silicates of this type are disclosed in EP-A-
0164514 and methods for their preparation are disclosed in
DE-A-3417649 and DE-A-3742043. For the purposes of the
present invention, x in the general formule above has a
value of 2, 3 or 4 and is preferably 2. More preferably M
is sodium and y is 0 and preferred examples of this
formula comprise the ~ and ~ forms of Na2Si2O5.
These materials are available from Hoechst AG FRG as
respectively NaSKS-ll and NaSKS-6. The most preferred
material is ~-Na2Si2O5, (NaSKS-6). Crystalline layered
silicates are incorporated either as dry mixed solids, or
as solid components of agglomerates with other components.
Whilst a range of aluminosilicate ion exchange materials
can be used, preferred sodium aluminosilicate zeolites
have the unit cell formula
Naz [(A102 ) z (si2 )y ] xH 2
wherein z and y are at least 6; the molar ratio of z to y
is from 1.0 to 0.5 and x is at least 5, preferably from
7.5 to 276, more preferably from 10 to 264. The
aluminosilicate materials are in hydrated form and are
preferably crystalline, containing from 10% to 28~, more
prefera~ly from 18% to 22% water in bound form.
21 ~
W094/0339~ PCT/US93/06801
23
The above aluminosilicate ion exchange materials are
further characterised by a particle size diameter of from
0.1 to 10 micrometers, preferably from 0.2 to 4
micrometers. The term "particle size diameter" herein
represents the average particle size diameter of a given
ion exchange material as determined by conventional
analytical techniques such as, for example, microscopic
determination utilizing a scanning electron microscope or
by means of a laser granulometer. The aluminosilicate ion
exchange materials are further characterised by their
calcium ion exchange capacity, which is at least 200 mg
equivalent of CaC03 water hardness/g of aluminosilicate,
calculated on an anhydrous basis, and which generally is
in the range of from 300 mg eq./g to 352 mg eq./g. The
aluminosilicate ion exchange materials herein are still
further characterised by their calcium ion exchange rate
which is at least 130 mg equivalent of
CAC03/litre/minute/(g/litre) [2 grains ca++/
gallon/minute/gram/gallon)] of aluminosilicate (anhydrous
basis), and which generally lies within the range of from
130 mg equivalent of CaC03/litre/minute/(gram/litre) [2
grains/gallon/minute/ (gram/gallon)] to 390 mg equivalent
of CaC03/litre/minute/ (gram/litre) [6
grains/gallon/minute/(gram/gallon)], based on calcium ion
hardness.
optimum aluminosilicates for builder purposes exhibit a
calcium ion exchange rate of at least 260 mg equivalent of
CaCO3/litre/ minute/ (gram/litre) t4
grains/gallon/minute/(gram/gallon)].
Aluminosilicate ion exchange materials useful in the
practice of this invention are commercially available and
can be naturally occurring materials, but are preferably
synthetically derived. A method for producing
aluminosilicate ion exchange materials is discussed in US
Patent No. 3,985,669. Prefe~red synthetic crystalline
5~36
W O g4/0339~ 24 PC~r/US93/06801 -
aluminosilicate ion exchange materials useful herein are
available under the designations Zeolite A, Zeolite B,
Zeolite X, Zeolite HS and mixtures thereof. In an
especially preferred embodiment, the crystalline
aluminosilicate ion exchange material is Zeolite A and has
the formula
Na 12 [(A12 ) 12 (Si2)12 ]- xH2 O
wherein x is from 20 to 30, especially 27. Zeolite X of
formula Na86 [(A12)s6(si2)l06]- 276 H2O is also
suitable, as well as Zeolite HS of formula Na6
[(AlO2)6(SiO2)6] 7.5 H2 )
Suitable water-soluble monomeric or oligomeric carboxylate
builders include lactic acid, glycolic acid and ether
derivatives thereof as disclosed in Belgian Patent Nos.
831,368, 821,369 and 821,370. Polycarboxylates containing
two carboxy groups include the water-soluble salts of
succinic acid, malonic acid, (ethylenedioxy) diacetic
acid, maleic acid, diglycolic acid, tartaric acid,
tartronic acid and fumaric acid, as well as the ether
carboxylates described in German Offenlegenschrift
2,446,686, and 2,446,687 and U.S. Patent No. 3,935,257 and
the sulfinyl carboxylates described in Belgian Patent No.
840,623. Polycarboxylates containing three carboxy groups
include, in particular, water-soluble citrates,
aconitrates and citraconates as well as succinate
derivatives such as the carboxymethyloxysuccinates
described in British Patent No. 1,379,241,
lactoxysuccinates described in British Patent No.
1,389,732, and aminosuccinates described in Netherlands
Application 720S873, and the oxypolycarboxylate materials
such as 2-oxa-1,1,3-propane tricarboxylates described in
British Patent No. 1,387,447.
094/03395 ~ PCT/US93/06801
Polycarboxylates containing four carboxy groups include
oxydisuccinates disclosed in British Patent No. 1,261,829,
1,1,2,2-ethane tetracarboxylates, 1,1,3,3-propane
tetracarboxylates and 1,1,2,3-propane tetracarboxylates.
Polycarboxylates containing sulfo substituents include the
sulfosuccinate derivatives disclosed in British Patent
Nos. 1,398,421 and 1,398,422 and in U.S. Patent No.
3,936,448, and the sulfonated pyrolysed citrates described
in British Patent No. 1,439,000.
Alicyclic and heterocyclic polycarboxylates include
cyclopentane-cis,cis,cis-tetracarboxylates,
cyclopentadienide pentacarboxylates, 2,3,4,5-
tetrahydrofuran - cis, cis, cis-tetracarboxylates, 2,5-
tetrahydrofuran - cis - dicarboxylates, 2,2,5,5-
tetrahydrofuran - tetracarboxylates, 1,2,3,4,5,6-hexane -
hexacarboxylates and carboxymethyl derivatives of
polyhydric alcohols such as sorbitol, mannitol and
xylitol. Aromatic polycarboxylates include mellitic acid,
~yromellitic acid and the phthalic acid derivatives
disclosed in British Patent No. 1,425,343.
Of the above, the preferred polycarboxylates are
hydroxycarboxylates containing up to three carboxy groups
per molecule, more particularly citrates. The parent
acids of the monomeric or oligomeric polycarboxylate
chelating agents or mixtures thereof with their salts,
e.g. citric acid or citrate/citric acid mixtures are also
contemplated as components of builder systems of detergent
compositions in accordance with the present invention.
Other suitable water-soluble organic salts are the homo-
or co-polymeric polycarboxylic acids or their salts in
which the polycarboxylic acid comprises at least two
carboxyl radicals separated from each other by not more
than two carbon atoms. Polymers of the latter type are
disclosed in GB-A-1,596,756. Examples of such salts are
21~8~
W O 94/03395 26 PC~r/US93/06801
polyacrylates of MWt 2000-5000 and their copolymers with
maleic anhydride, such copolymers having a molecular
weight of from 20,000 to 70,000, especially about 40,000.
Such builder polymeric materials may be identical to the
polymeric materials as binder materials and coating
materials, as described hereinabove. These materials are
normally used at levels of from 0.5% to 10% by weight more
preferably from 0.75% to 8%, most preferably from 1% to 6
by weight of the composition.
Another preferred polycarboxylate builder 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 thereof. Examples of such preferred sodium
salts of EDDS include NaEDDS, Na2EDDS and Na4EDDS.
Examples of such preferred magnesium salts of EDDS include
Mg EDDS and Mg2EDDS. The magnesium salts are the most
preferred for inclusion in compositions in accordance with
the invention.
The structure of the acid form of EDDS is as follows :
H-N-CH2-CH2-N-H
CH2 CIH CII FH2
COOH COOH COOH COOH
EDDS can be synthesised, for example, from readily
available, inexpensive starting material such as maleic
anhydride and ethylene diamine as follows :
2 O=C / \ C=O + NH2-CH2-CH2-NH2+NaOH~ EDDS
I
CH - CH
36
-
W O 94/0339~ PC~r/US93/06801
A more complete disclosure of methods for synthesising
EDDS from commercially available starting materials can be
found in US Patent 3,158,635, Kezerian and Ramsay, issued
November 24, 1964.
The synthesis of EDDS from maleic anhydride and ethylene
diamine yields a mixture of three optical isomers,
[R,R],[S,S], and [S,R], due to the two asymmetric carbon
atoms. The biodegradation of EDDS is optical
isomerspecific, with the [S,S] isomer degrading most
rapidly and extensively, and for this reason the [S,S]
isomer is most preferred for inclusion in the compositions
of the invention.
The [S,S] isomer of EDDS can be synthesised from L-
aspartic acid and 1,.2-dibromoethane, as follows :
1 2 IH NH2 + Br-CH2-CH2-BR NaOH~[S S]EDDS
COOH COOH
A more complete disclosure of the reaction of L-aspartic
acid with 1,2-dibromoethane to form the [S,S] isomer of
EDDS can be found in Neal and Rose, Stereospecific Ligands
and Their Complexes of Ehtylenediaminediscuccinic Acid,
Inorqanic Chemistry Vol 7 (1968), pp. 2405-2412.
Organic phosphonates and amino alkylene poly (alkylene
phosphonates) include alkali metal ethane l-hydroxy
diphosphonates, nitrilo trimethylene phosphonates,
ethylene diamine tetra methylene phosphonates and
diethylene triamine penta methylene phosphonates, although
these materials are less preferred where the minimisation
of phosphorus compounds in the compositions is desired.
For the purposes of detergent compositions embodying the
surface treated bleach precursor particulates of the
invention , the non-phosphate builder ingredient will
S86
W094/03395 28 PCT/US93/06801
comprise ~rom 25% to 60% by weight of the compositions,
more preferably from 30% to 60% by weight. Within the
preferred compositions, sodium aluminosilicate such as
Zeolite A will comprise from 20% to 60~ by weight of the
total amount of builder, a monomeric or oligomeric
carboxylate will comprise from 10% to 30% by weight of the
total amount of builder and a crystalline layered silicate
will comprise from l0~ to 65% by weight of the total
amount of builder. In such compositions the builder
ingredient preferably also incorporates a combination of
auxiliary inorganic and organic builders such as sodium
carbonate and maleic anhydride/acrylic acid copolymers in
amounts of up to 35% by weight of the total builder.
Anti-redeposition and soil-suspension agents suitable
herein include cellulose derivatives such as
methylcellulose, carboxymethylcellulose and
hydroxyethycellulose, and homo-or co-polymeric
polycarboxylic acids or their salts. Polymers of this
type include copolymers of maleic anhydride with ethylene,
methylvinyl ether or methacrylic acid, the maleic
anhydride constituting at least 20 mole percent of the
copolymer. These materials are normally used at levels of
from 0.5% to 10% by weight, more preferably from 0.75% to
8%, most preferably from l~ to 6% by weight of the
composition.
Other useful polymeric materials are the polyethylene
glycols, particularly those of molecular weight l000-
l0000, more particularly 2000 to 8000 and most preferably
about 4000. These are used at levels of from 0.20% to 5%
more preferably from 0.25% to 2.5% by weight. These
polymers and the previously mentioned homo- or co-
polymeric polycarboxylate salts are valuable for improving
whiteness maintenance, fabric ash deposition, and cleaning
performance on clay, proteinaceous and oxidizable soils in
the presence of transition metal impurities.
W094/03395 29 PCT/US93/06801
Preferred optical brighteners are anionic in character,
examples of which are disodium 4,41-bis-(2-diethanolamino-
4-anil no -s- triazin-6- ylamino)stilbene-2:21
disulphonate, disodium 4,41-bis-(2-morpholino -4-anilino-
2-triazin-6-ylaminostilbene-2:21-disulphonate,disodium 4,
41-bis-(2,4-dianilino-s-triazin-6-ylamino)stilbene-2:21 -
disulphonate, monosodium 41~4~1-bis-(2,4-dianilino-s-
triazin-6 ylamino)stilbene-2- sulphonate, disodium 4,41_
bis-(2-anilino-4-(N-methyl-N-2-hydroxyethylamino)-2-
triazin-6-ylamino)stilbene-2,21 - disulphonate, disodium
4,41-bis-(4-phenyl-2,1,3-triazol-2-yl)stilbene-2,21
disulphonate, disodium 4,41bis(2-anilino-4-(1-methyl-2-
hydroxyethylamino)-s-triazin-6-ylamino)stilbene-
2,21disulphonate and sodium 2(stilbyl-411-(naphtho-
11,21:4,5)-1,2,3 - triazole-211_ sulphonate.
Soil-release agents useful in compositions of the present
invention are conventionally copolymers or terpolymers of
terephthalic acid with ethylene glycol and/or propylene
glycol units in various arrangements. Examples of such
polymers are disclosed in the commonly assigned US Patent
Nos. 411688S and 4711730 and European Published Patent
Application No. 0272033. A particular preferred polymer
in accordance with EP-A-0272033 has the formula
3 430.75( )025( PO)2.8(T-PEG)04]T(PO-H)025((PEG) CH )
where PEG is-(OC2H4)O-,PO is(OC3H6O)and T is(pCOC6H4CO)
Certain polymeric materials such as polyvinyl pyrrolidones
typically of MWt 5000-20000, preferably 10000-15000, also
form useful agents in preventing the transfer of labile
dyestuffs between fabrics during the washing process.
Another optional detergent composition ingredient is a
suds suppressor, exemplified by silicones, and silica-
silicone mixtures. Silicones can be generally represented
by alkylated polysiloxane materials while silica is
W O 94/03395 30 PC~r/US93/06801
normally used in finely divided forms r exemplified by
silica aerogels and xerogels and hydrophobic silicas of
various types. These materials can be incorporated as
particulates in which the suds suppressor is
advantageously releasably incorporated in a water-soluble
or water-dispersible, substantially non-surface-active
detergent-impermeable carrier. Alternatively the suds
suppressor can be dissolved or dispersed in a liquid
carrier and applied by spraying on to one or more of the
other components.
As mentioned above, useful silicone suds controlling
agents can comprise a mixture of an alkylated siloxane, of
the type referred to hereinbefore, and solid silica.
Such mixtures are prepared by affixing the silicone to the
surface of the solid silica. A preferred silicone suds
controlling agent is represented by a hydrophobic
silanated (most preferably trimethyl-silanated) silica
having a particle size in the range from 10 nanometers to
20 nanometers and a specific surface area above 50 m2/g,
intimately admixed with dimethyl silicone fluid having a
molecular weight in the range from about 500 to about
200,000 at a weight ratio of silicone to silanated silica
of from about 1:1 to about 1:2.
A preferred silicone suds controlling agent is disclosed
in Bartollota et al. US Patent 3,933,672. Other
particularly useful suds suppressors are the self-
emulsifying silicone suds suppressors, described in German
Patent Application DTOS 2,646,126 published April 28,
1977. An example of such a compound is DC0544,
commercially available from Dow Corning, which is a
siloxane/glycol copolymer.
The suds suppressors described above are normally employed
at levels of from 0.001% to 0.5% by weight of the
composition, preferably from 0.01% to 0.1% by weight.
W094/03395 PCT/US93/06801
31
The preferred methods of incorporation comprise either
application of the suds suppressors in liquid form by
spray-on to one or more of the major components of the
composition or alternatively the formation of the suds
suppressors into separate particulates that can then be
mixed with the other solid components of the composition.
The incorporation of the suds modifiers as separate
particulates also permits the inclusion therein of other
suds controlling materials such as C20-C24 fatty acids,
microcrystalline waxes and high MWt copolymers of
ethylene oxide and propylene oxide which would otherwise
adversely affect the dispersibility of the matrix.
Techniques for forming such suds modifying particulates
are disclosed in the previously mentioned Bartolotta et al
US Patent No. 3,933,672.
Another optional ingredient useful in the present
invention is one or more enzymes.
Preferred enzymatic materials include the commercially
available amylases, neutral and alkaline proteases,
lipases, esterases and cellulases conventionally
incorporated into detergent compositions. Suitable enzymes
are discussed in US Patents 3,519,570 and 3,533,139.
Fabric softening agents can also be incorporated into
detergent compositions in accordance with the present
invention. These agents may be inorganic or organic in
type. Inorganic softening agents are exemplified by the
smectite clays disclosed in GB-A-1,400,898. Organic
fabric softening agents include the water- insoluble
tertiary amines as disclosed in GB-A-1514276 and EP-B-
0011340.
Their combination with mono C12-C14 quaternary ammonium
salts is disclosed in EP-B-0026527 & 528. Other useful
organic fabric softening agents are the dilong chain
8~
W O 94/03395 PC~r/US93/06801 3~
amides as disclosed in EP-B-0242919. Additional organic
ingredients of fabric softening systems include high
molecular weight polyethylene oxide materials as disclosed
in EP-A-0299S75 and 0313146.
Levels of smectite clay are normally in the range from 5%
to 15%, more preferably from 8% to 12% by weight, with the
material being added as a dry mixed component to the
remainder of the formulation. Organic fabric softening
agents such as the water-insoluble tertiary amines or
dilong chain amide materials are incorporated at levels of
from 0.5% to 5% by weight, normally from 1% to 3% by
weight, whilst the high molecular weight polyethylene
oxide materials and the water-soluble cationic materials
are added at levels of from 0.1% to 2%, normally from
0.15% to 1.5% by weight. Where a portion of the
composition is spray dried, these materials can be added
to the aqueous slurry fed to the spray drying tower,
although in some instances it may be more convenient to
add them as a dry mixed particulate, or spray them as a
molten liquid on to other solid components of the
composition.
The coated peroxyacid bleach precursor particulates of the
present invention are particularly useful in concentrated
granular detergent compositions that are characterised by
a relatively high density in comparison with conventional
laundry detergent compositions. Such high density
compositions have a bulk density of at least 650 g/litre,
more usually at least 700 g/litre and more preferably in
excess of 800 g/litre.
Bulk density is measured by means of a simple funnel and
cup device consisting of a conical funnel moulded rigidly
on a base and provided with a flap valve at its lower
extremity to allow the contents of the funnel to be
emptied into an axially aliqned cylindrical cup disposed
~ 5~6
~VO 94/03395 33 PC~r/US93/06801
below the funnel. The funnel is 130 mm and 40 mm at its
respective upper and lower extremities. It is mounted so
that the lower extremity is 140 mm above the upper surface
of the base. The cup has an overall height of 90 mm, an
internal height of 87 mm and an internal diameter of 84
mm. Its nominal volume is 500 ml.
To carry out a measurement, the funnel is filled with
powder by hand pouring, the flap valve is opened and
powder allowed to overfill the cup. The filled cup is
removed from the frame and excess powder removed from the
cup by passing a straight edged implement e.g. a knife,
across its upper edge. The filled cup is then weighed and
the value obtained for the weight of powder doubled to
provide the bulk density in g/litre. Replicate
measurements are made as required.
Concentrated detergent compositions also normally
incorporate at least one multi-ingredient component i.e.
they do not comprise compositions formed merely by dry-
mixing individual ingredients. Compositions in which each
individual ingredient is dry-mixed are generally dusty,
slow to dissolve and also tend to cake and develop poor
particle flow characteristics in storage.
Subject to the above bulk density and component content
limitations, the compositions of the invention can be made
via a variety of methods including dry mixing, spray
drying, agglomeration and granulation and preferred
methods involve combinations of these techniques. A
preferred method of making the compositions involves a
combination of spray drying, agglomeration in a high speed
mixer and dry mixing.
Preferred detergent compositions in accordance with the
invention comprise at least two particulate multi-
ingredient components. The first component comprises at
W094/03395 34 PCT/US93/0680l
least 15%, conventionally from 25% to 50%, but more
preferably no more than 35% by weight of the composition
and the second component from 1% to 50%, more preferably
10% to 40% by weight of the composition.
The first component comprises a particulate incorporating
an anionic surfactant in an amount of from 0.75% to 40% by
weight of the powder and one or more inorganic and/or
organic salts in an amount of from 99.25% to 60% by weight
of the powder. The particulate can have any suitable form
such as granules, flakes, prills, marumes or noodles but
is preferably granular. The granules themselves may be
agglomerates formed by pan or drum agglomeration or by in-
line mixers but are customarily spray dried particles
produced by atomising an aqueous slurry of the ingredients
in a hot air stream which removes most of the water. The
spray dried granules are then subjected to densification
steps, e.g. by high speed cutter mixers and/or compacting
mills, to increase density before being reagglomerated.
For illustrative purposes, the first component is
described hereinafter as a spray dried powder.
Suitable anionic surfactants for the purposes of the first
component have been found to be slowly dissolving linear
alkyl sulfate salts in which the alkyl group has an
average of from 16 to 22 carbon atoms, and linear alkyl
carboxylate salts in which the alkyl group has an average
of from 16 to 24 carbon atoms. The alkyl groups for both
types of surfactant are preferably derived from natural
sources such as tallow fat and marine oils.
The level of anionic surfactant in the spray dried powder
forming the first component is from 0.75% to 40% by
weight, more usually 2.5% to 25% preferably from 3% to 20%
and most preferably from 5~ to 15~ by weight. Water-
soluble surfactants such as linear alkyl benzene
sulphonates or C14-C15 alkyl sulphates can be included or
~ ~1415t~
~094/0339~ PCT/US93/06801
alternatively may be applied subsequently to the spray
dried powder by spray on.
The other major ingredient of the spray dried powder is
or or more inorganic or organic salts that provide the
c- .alline structure for the granules. The inorganic
an~/or organic salts may be water-soluble or water-
insoluble, the latter type being comprised by the, or the
major part of the, water-insoluble builders where these
form part of the builder ingredient. Suitable water-
soluble inorganic salts include the alkali metal
carbonates and bicarbonates. Alkali metal silicates other
than crystalline layered silicates can also be present in
the spray dried granule provided that aluminosilicate does
not form part of the spray dried component.
However, in concentrated detergent compositions it is
preferred that water-soluble sulphate, particularly sodium
sulphate, should not be present at a level of more than
2.5% by weight of the composition. Preferably no sodium
sulphate is added as a separate ingredient and its
incorporation as a by-product e.g. with sulph(on)ated
surfactants, should be minimised.
Where an aluminosilicate zeolite forms the, or part of
the, builder ingredient, it is preferred that it is not
added directly by dry-mixing to the other components, but
is incorporated into the multi-ingredient component(s).
Where incorporation of the zeolite takes place in the
spray-dried granule, any silicate present should not form
part of the spray-dried granule. In these circumstances,
incorporation of the silicate can be achieved in several
ways, e.g. by producing a separate silicate-containing
spray-dried particulate, by incorporating the silicate
into an agglomerate of other ingredients, or more
p-eferably by adding the silicate as a dry mixed solid
ingredient.
:
W094/03395 PCT/US93/06801
36
The first component can also include up to 15% by weight
of miscellaneous ingredients such as brighteners, anti-
redeposition agents, photoactivated bleaches (such as
tetrasulfonated zinc phthalocyanine) and heavy metal
se~uestering agents. Where the first component is a spray
dried powder it will normally be dried to a moisture
content of from 7% to 11~ by weight, more preferably from
8% to 10~ by weight of the spray dried powder. Moisture
contents of powders produced by other processes such as
agglomeration may be lower and can be in the range 1-10%
by weight.
The particle size of the first component is conventional
and preferably not more than 5% by weight should be above
1.4mm, while not more than 10~ by weight should be less
than 0.15 mm in maximum dimension. Preferably at least
60%, and most preferably at least 80%, by weight of the
powder lies between 0.7 mm and 0.25 mm in size. For spray
dried powders, the bulk density of the particles from the
spray drying tower is conventionally in the range from
540 to 600 g/litre and this is then enhanced by further
processing steps such as size reduction in a high speed
cutter/mixer followed by compaction. Alternatively,
processes other than spray drying may be used to form a
high density particulate directly.
A second component of -a preferred composition in
accordance with the invention is another multi-ingredient
particulate containing a water-soluble surfactant.
This may be anionic, nonionic, cationic or semipolar in
type or a mixture of any of these. Suitable surfactants
are listed hereinbefore but preferred surfactants are C14-
C15 alkyl sulphates, linear C11-C15 alkyl benzene
sulphonates and fatty C14-C18 methyl ester sulphonates.
if3fi
094/0339s PCT/US93/06801
37
The second component may have any suitable physical form,
i.e. it may take the form of flakes, prills, marumes,
noodles, ribbons, or granules which may be spray-dried or
non spray-dried agglomerates. Although the second
component could in theory comprise the water-soluble
surfactant on its own, in practice at least one organic or
inorganic salt is included to facilitate processing. This
provides a degree of crystallinity, and hence acceptable
flow characteristics, to the particulate and may be any
one or more of the organic or inorganic salts present in
the first component.
The particle size range of the second component should be
such as to obviate segregation from the particles of the
first component when blended therewith. Thus not more
than 5% by weight should be above 1.4 mm while not more
than 10% should be less than 0.15 mm in maximum dimension.
The bulk density of the second component will be a
function of its mode of preparation. However, the
preferred form of the second component is a mechanically
mixed agglomerate which may be made by adding the
ingredients dry or with an agglomerating agent to a pan
agglomerator, Z blade mixer or more preferably an in-line
mixer such as those manufactured by Schugi (Holland) BV,
29 Chroomstraat 8211 AS, Lelystad, Netherlands and
Gebruder Lodige Maschinenbau GmbH, D-4790 Paderborn 1,
Elsenerstrasse 7-9, Postfach 2050 F.R.G. By this means
the second component can be given a bulk density in the
range from 650 g/litre to ll9o g/litre more preferably
from 750 g/litre to 850 g/litre.
Preferred compositions include a level of alkali metal
carbonate in the second component corresponding to an
amount of from 3% to 15% by weight of the composition,
more preferably from 5% to 12% by weight. This will
8~
W 0 94/03395 PC~r/US93/06801
38
provide a level of carbonate in the second component of
from 2~% to 40~ by weight.
A highly preferred ingredient of the second component is
also a hydrated water-insoluble aluminosilicate ion
exchange material of the synthetic zeolite type, described
hereinbefore, present at from 10% to 35% by weight of the
second component. The amount of water-insoluble
aluminosilicate material incorporated in this way is from
1% to 10% by weight of the composition, more preferably
from 2~ to 8% by weight.
In one process for preparing the second component, the
surfactant salt is formed in situ in an inline mixer. The
liquid acid form of the surfactant is added to a mixture
of particulate anhydrous sodium carbonate and hydrated
sodium aluminosilicate in a continuous high speed blender,
such as a Lodige KM mixer, and neutralised to form the
surfactant salt whilst maintaining the particulate nature
of the mixture. The resultant agglomerated mixture forms
the second component which is then added to other
components of the product. In a variant of this process,
the surfactant salt is pre-neutralised and added as a
viscous paste to the mixture of the other ingredients. In
the variant, the mixer serves ~erely to agglomerate the
ingredients to form the second component.
In a particularly preferred process for making detergent
compositions incorporating the coated peroxyacid bleach
precursor particulates of the invention, part of the spray
dried product comprising the first granular component is
diverted and subjected to a low level of nonionic
surfactant spray on before being reblended with the
remainder. The second granular component is made using
the preferred process described above. The first and
second components together with the coated bleach
precursor particulate and the perhydrate bleach, other dry
094/03395 ~ 9~ ~ PCT/US93/06801
mix ingredients such as any carboxylate chelating agent,
soil-release polymer, silicate of conventional or
crystalline iayered type, and enzyme are then fed to a
conveyor belt, from which they are transferred to a
horizontally rotating drum in which perfume and silicone
suds suppressor are sprayed on to the product. In highly
preferred compositions, a further drum mixing step is
employed in which a low (approx. 2% by weight) level of
finely divided crystalline material is introduced to
increase density and improve granular flow
characteristics.
In preferred concentrated detergent products incorporating
an alkali metal percarbonate as the perhydrate salt it has
been found necessary to control several aspects of the
product such as its heavy metal ion content and its
equilibrium relative humidity. Sodium percarbonate-
containing compositions of this type having enhanced
stability are disclosed in the commonly assigned British
Application No. 9021761.3 filed October 6, 1990,
Attorney's Docket No. CM343.
Com~ Jsitions in accordance with the invention can also
benefit from delivery systems that provide transient
localised high concentrations of product in the drum of an
automatic washing machine at the start of the wash cycle,
thereby also avoiding problems associated with loss of
product in the pipework or sump of the machine.
Delivery to the drum can most easily be achieved by
incorporation of the composition in a bag or container
from which it is rapidly releasable at the start of the
wash cycle in response to agitation, a rise in temperature
or immersion in the wash water in the drum. Alternatively
the washing machine itself may be adapted to permit direct
addition of the composition to the drum e.g. by a
dispensing arrangement in the access door.
W094/03395 PCT/US93/06801
Products comprising a detergent composition enclosed in a
bag or container are usually designed in such a way that
container integrity is maintained in the dry state to
prevent egress of the contents when dry, but are adapted
for release of the container contents on exposure to a
washing environment, normally on immersion in an aqueous
solution.
Usually the container will be flexible, such as a bag or
pouch. The bag may be of fibrous construction coated with
a water impermeable protective material so as to retain
the contents, such as is disclosed in European published
Patent Application No. 0018678. Alternatively it may be
formed of a water-insoluble synthetic polymeric material
provided with an edge seal or closure designed to rupture
in aqueous media as disclosed in European published Patent
Application Nos. 0011500, 0011501, 0011502, and 0011968.
A convenient form of water frangible closure comprises a
water-soluble adhesive disposed along and sealing one edge
of a pouch formed of a water impermeable polymeric film
such as polyethylene or polypropylene.
In a variant of the bag or container form, laminated sheet
products can be employed in which a central flexible layer
is impregnated and/or coated with a composition and then
one or more outer layers are applied to produce a fabric-
like aesthetic effect. The layers may be sealed together
so as to remain attached during use or may separate on
contact with water to facilitate the release of the coated
or impregnated material.
An alternative laminate form comprises one layer embossed
or deformed to provide a series of pouch-like containers
into each of which the detergent components are deposited
in measured amounts, with a second layer overlying the
first layer and sealed thereto in those areas beteen the
pouch-like containers where the two layers are in contact.
O9~/0339~ '?~ ~ PCT/US93/06801
The components may be deposited in particulate, paste or
molten form and the laminate layers should prevent egress
of the contents of ~he pouch-like containers prior to
their addition to water. The layers may separate or may
remain attached together on contact with water, the only
requirement being that the structure should permit rapid
release of the contents of the pouch-like containers into
solution. The number of pouch-like containers per unit
area of substrate is a matter of choice but will normally
vary between 500 and 25,000 per square metre.
-
Suitable materials which can be used for the flexiblelaminate layers in this aspect of the invention include,
among others, sponges, paper and woven and non-woven
fabrics.
However the preferred means of carrying out the process of
th- invention is to introduce the composition into the
liquid surrounding the fabrics that are in the drum via a
reusable dispensing device having walls that are permeable
to liquid but impermeable to the solid composition.
Devices of this kind are disclosed in European Patent
Application Publication Nos. 0343069 & 0343070. The
latter Application discloses a device comprising a
flexible sheath in the form of a bag extending from a
support ring defining an orifice, the orifice being
adapted to admit to the bag sufficient product for one
washing cycle in a washing cycle. A portion of the
washing medium flows through the orifice into the bag,
dissolves the product, and the solution then passes
outwardly through the orifice into the washing medium.
The support ring is provided with a masking arrangement to
prevent egress of wetted, undissolved, product, this
arrangement typically comprising radially extending walls
extending from a central boss in a spoked wheel
W O 94/03395 PC~r/US93/06801 -
~ 42
configuration, or a similar structure in which the walls
have a helical form.
The invention is illustrated in the following non limiting
Example, in which all percentages are on a weight basis
unless otherwise stated.
ExamPles
Example 1:
Tetra Acetyl Ethylene Diamine (TAED) in fine powder form
(purity ca 99.0%, particle size 90% by weight less than
150 micrometers) was agglomerated with a 40% aqueous
solution of Sokalan(R) CP45 at a binder level of 24% (by
weight). The agglomeration was carried out in a plough-
share mixer and the resultant, wet, agglomerate was then
dried in a fluid-bed dryer.
After drying, the agglomerate was then spray-coated with a
further quantitiy (12.5% by weight) of the said polymer
solution. The coated agglomerate was then dried again
using a fluid-bed and screened to provide a finished
material with particle size where more than 90% lay
between 425 micrometers and 1700 micrometers.
The composition of the final agglomerate was as follows :
TAED 82.0%
Sokalan(R) CP45 15.0%
Water/miscellaneous up to lOo
A reference TAED agglomerate was prepared by agglomerating
the same TAED powder with molten TAE25 as binder in the
-W094/03395 ~ PCT/US93/06801
same mixing device as above. Particles were then cooled
and sized to the same standards as above. Agglomerate
composition was :
r TAED 87.0%
TAE25 13%
The detergent agglomerates were tested for colour damage
potential when incorporated into the following detergent
matrix (composition in parts by weight) :
Cl2 Linear Alkyl Benzene Sulfonate 9.0
Tallow Alkyl Sulphate 2.8
Dobanol 45E7 3.8
Zeolite A 20
Citrate 6.5
Carbonate l5.0
Silicate (SiO2:Na20=2:l) 3.5
Perborate monohydrate 16.0
Sokalan(R) CP45* 4.0
Miscellaneous up to lO0
* The detergent matrix already contains Sokalan(R) CP45
a~ ~ co-builder, independently from the Sokalan(R) CP45
present in the agglomerates.
The amount of agglomerate in the composition was such as
to provide an active level of 5% by weight of TAED versus
the total composition.
The formulations containing the TAED agglomerates were
subjected to a full scale washing machine test using Miele
automatic washing machines (Model W754) set to the Short
Wash cycle at 40C.
Bleach-sensitive coloured fabric swatches were used, a 43
cm2 swatch being wrapped around the dispensing device in
hich lOOg of the formulation was added. In each machine,
8~
W O 94/03395 ~4 PC~r/US93/06801
3.3 kg of white cotton bedsheets were used as ballast. 12
litres of water of 150 ppm hardness (expressed as CaCo3)
with a Ca:Mg ratio of 3:1 was fed to each machine. The
swatches were made of 100% lambswool woven fabric with
purple 48 dye (Design No. W3970) supplied by Borval
Fabrics, Albert Street, Huddersfield, West Yorkshire,
England. 24 replicates of each treatment were performed
and the swatches were then graded visually for fabric
colour damage by an expert panel using the following
grading system.
Three coloured swatches demonstrating differing degrees of
colour damage are used as standards to establish a 4 point
scale in which 1 represents 'virtually no damage' and 4
represents 'very damaged'. The three standards are used to
define the mid points between the various descriptions of
colour damage viz
1 virtually no damage
2 slight damage
3 damage
4 very damaged
Two expert panellists are used and their results are
averaged.
Using this technique to compare colour damage resulting
from use of the formulations above the following results
were obtained:
Formulations ~ of swatches havin~ ~erade Overall Grade
2 3
(Reference) TAE2S/TAED 4.2 4.2 20.8 70.8 3.S8
(Invention): 4.2 33.3 20.8 41.7 3.0
Sokalan(R) CP45/TAED
~ 4~5~;
94/03395 45 PCT/US93/06801
It can be seen that the formulation incorporating the
agglomerate in accordance with the invention produces
appreciably less fabric colour damage than the reference
agglomerate.
Examle 2
Tetra acetyl Ethylene Diamine (TAED) in fine powder
form (purity ca. 99.0~) and particle size 90% by
weight less than 150 micrometers was agglomerated
with a 40 % aqueous solution of Sokalan(R) CP45 at a
binder level of 24% by weight. The agglomeration was
carried out in Lodige high shear mixer and the
resultant moist agglomerate was then dried in a
fluid-bed to a residual moisture content of less than
10%.
After drying the agglomerate was then spray-coated
with a further quantity of Sokalan (R) CP45 (25.0% by
weight) in a Lodige plough-share mixer and again the
moist agglomerate dried in a fluid-bed to a residual
moisture content of less than 5% ( by weight). The
agglomerate was then screened to provide a finished
agglomerate where 85% by weight lay between 1700
micrometers and 425 micron.
The composition of the final agglomerate was:
TAED 77.0%
Sokalan tR) CP45 18.9~
Water and miscellaneous to 100%.
.
The mean coating level of the composition, which was
determined by acid-base titration and calculation of the
difference, was 9.1%.
ii8Ç~ ~
W094/03395 PCT/US93/06801
46
Using sieves, the composition was then separated into four
classes of particles. In each class, the mean coating
level was determined by acid-base tritration and
calculation of the difference. The mean coating
distribution was as follows:
>1180mic. 850mic. > 425mic. <425mic.
% Sokolan(R)CP45 9.9 9.1 9.1 8.3
The composition according to this example was evaluated as
in example 1. Results were:
Formulations % of s~atches having grade Overall Grade
1 2 3 4
(Reference) TAE25/TAED 13 17 58 12 2.69
(Invention): 17 13 62 8 2.61
Sokalan(R) CP45/TAED
It can be seen that the formulation incorporating the
agglomerate in accordance with the invention produces
appreciably less fabric colour damage than the reference
agglomerate. Further testing evidenced that the
compositions of the present invention also provided
superior bleaching.
