Note: Descriptions are shown in the official language in which they were submitted.
CA 02253470 1998-11-03
WO 97/43370 PCT/EP97/OZ496
TECHNICAL AREA
The present invention relates to particulate zero-
phosphate laundry detergent compositions containing sodium
silicate. More particularly it relates to particulate
laundry detergent compositions built with zeolite MAP and
containing sodium percarbonate bleach.
BACKGROUND AND PRIOR ART
Sodium silicate is a well-known ingredient for
particulate laundry detergent compositions, and its
incorporation is desirable for a number of reasons, for
example, in order to provide increased protection against
corrosion of metal surfaces within the washing machine, and
to control alkalinity and pH in the wash. Granular sodium
disilicate (hydrated), which can simply be dry mixed with
other powder ingredients, provides a convenient route for
the incorporation of this ingredient, especially for
powders in which the base powder contains zeolite.
It has been found that certain particulate zeolite-
built bleaching laundry detergent compositions containing
discrete sodium disilicate granules show a tendency towards
"granulation", ie to the formation of large particles, on
usage in the home. This occurs once the composition has
been exposed to ambient conditions by opening the
packaging, even when ambient conditions are relatively dry.
CA 02253470 1998-11-03
C3724PC1
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This problem has been observed more particularly in
compositions in which the detergency builder is zeolite MAP,
the novel zeolite described and claimed in EP 384 070B
(Unilever), which is P-type zeolite having a silicon to
' aluminium ratio not exceeding 1.33. The incidence of
"granulation" is also greater in powders containing sodium
percarbonate bleach than in similar powders containing
sodium perborate monohydrate.
It has now been found that, in compositions where a
tendency toward "granulation" has been observed, the problem
may be alleviated by replacing the sodium disilicate
granules by sodium silicate/sodium carbonate cogranules.
Sodium silicate/sodium carbonate cogranules and their
use in detergent compositions are disclosed in EP 561 656A
(Rhone-Poulenc), EP 658 517A and EP 667 391A (Degussa), and
WO 95 22592A (Henkel).
WO 95 32273A (Rhone-Poulenc) discloses the use of a
cogranule of carbonate and silicate to stabilise a detergent
composition containing sodium percarbonate.
EP 488 868 (Rhone-Poulenc) discloses the use of a co-
granule of carbonate and silicate in a sodium perborate
containing powdered composition, wherein a high level of
silicate is present in the composition.
AMENDED SHEET
CA 02253470 1998-11-03
C~724PC1 ~. .
- 3 -
DEFINITION OF THE INVENTION
The present invention provides a particulate zero-
phosphate laundry detergent composition comprising:
5.
(i) from 30 to 80 wto of a granular base powder comprising
(a) from 5 to 60 wt~ (based on the composition) of
organic surfactant, and
(b) from 10 to 80 wt~ (based on the composition) of
alkali metal aluminosilicate detergency builder,
(ii) from 1 to 5 wt~ of sodium silicate not within the
granular base powder,
(iii) from 1 to 50 wt~ of separate granules of sodium
carbonate,
(iv) optionally from 10 to 35 wto of separate granules of a
peroxy bleach compound; and
(v) optionally other detergent ingredients to 100 wto,
characterised in that the sodium silicate (ii) is all
present in the form of separate cogranules consisting
essentially of sodium silicate and sodium carbonate in a
ratio within the range of from 3:1 to 1:3, whereby the
tendency of the composition to form granules having a
particle size of 2000 mm or larger on storage is less than
if the sodium silicate (ii) were present in the form of
separate granules of sodium disilicate.
AMENDED SHEET
CA 02253470 1998-11-03
C3724PC1 . , ~ ;-
.' ,.~ ,.
- 4 -
The invention further provides the use of postdosed
cogranules consisting essentially cf sodium silicate and
sodium carbonate in a ratio within the range of from 3:1 to
1:3 in a particulate zero-phosphate zeolite-built detergent
5~ composition otherwise free of postdosed sodium silicate to
reduce the tendency of the composition to form granules .
having a particle size of 2000 mm or above on storage.
DETAILED DESCRIPTIOD1 OF THE INVENTION
The invention is based on the observation that certain
zeolite-built laundry detergent powders containing postdosed
granular sodium disilicate show a tendency to "granulation"
, ie particle size increase, on storage in contact with the
atmosphere, for example, in open packages; and that this
problem is solved by replacing the postdosed granular sodium
disilicate with sodium silicate/sodium carbonate cogranules.
The particulate laundry detergent composition
The compositions of the invention comprise as essential
ingredients:
(i) a multi-ingredient granular base powder comprising
organic surfactant and alkali metal aluminosilicate builder,
and
(ii) sodium silicate in the form of separate composite
sodium silicate/sodium carbonate granules, and
(iii) granular sodium carbonate.
4ME"~~~= ~~' ~~~T
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C3724PC1 ,
- 5 -
Further separate granular or particulate ingredients
may optionally and desirably be present, notably, peroxy
bleach ingredients, especially sodium percarbonate.
5~ The granular base powder
The granular base.po~ader contains at least one organic
surfactant.
Detergent-active compounds or surfactants may be chosen
from soap and non-soap anionic, cationic, nonionic,
amphoteric and zwitterionic detergent-active compounds, and
mixtures thereof. Many suitable detergent-active compounds
are available and are fully described in the literature, for
example, in "Surface-Active Agents and Detergents", Volumes
I and II, by Schwartz, Perry and Berch.
The preferred detergent-active compounds that can be
used are soaps and synthetic non-soap anionic and nonionic
compounds.
Anionic surfactants are well-known to those skilled in
the art. Examples include alkylbenzene sulphonates,
particularly linear alkylbenzene sulphonates having an alkyl
chain length of Ce-C15; primary and secondary
alkylsulphates, particularly Cg-C15 primary alkyl sulphates;
alkyl ether sulphates; olefin sulphonates; alkyl xylene
sulphonates; dialkyl sulphosuccinates; and fatty acid
ester sulphonates. Sodium salts are generally preferred.
Nonionic surfactants that may be used include the
primary and secondary alcohol ethoxylates, especially the C8-
CZO aliphatic alcohols ethoxylated with an average of
ra.~'.:.~iJ~.t~ Jil~~~
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C~724PC1
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from 1 to 20 moles of ethylene oxide per mole of alcohol,
and more especially the C1~-C1; primary and secondary
aliphatic alcohols ethoxylated with an average of from 1. to
moles of ethylene oxide per mole of alcohol. Non-
5~ ethoxylated nonionic surfactants include
alkylpolyglycosides, glycerol monoethers, and
polyhydroxyamides (glucamide).
The~total amount of surfactant present is suitably from
10 5 to 60 wto, and preferably from 5 to 40 wto.
Laundry detergent compositions suitable for use in most
automatic washing machines generally contain anionic non-
soap surfactant, or nonionic surfactant, or combinations of
the two in any ratio, optionally together with soap.
The detergent composition of the invention also
contains an alkali metal, preferably sodium, aluminosilicate
builder. This is suitably present in an amount of from 10
to 70 wto, preferably from 15 to 70 wto and more preferably
from 20 to 60 wto.
The alkali metal aluminosilicate may be either
crystalline or amorphous or mixtures thereof, having the
general formula:
0.8-1.5 Na20. A1203. 0.8-6 Si02
These materials contain some bound water and are
required to have a calcium ion exchange capacity of at least
50 mg Ca0/g. The preferred sodium aluminosilicates contain
1.5-3.5 SiOz units (in the formula above). Both the
amorphous and the crystalline materials can be prepared
readily by reaction between sodium silicate and sodium
aluminate, as amply described in the literature.
-,. _
~..~:~..
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C3724PC1 . .
7 _
The crystalline materials (zeolites) are preferred.
The preferred detergent zeolites are zeolites A (4A),
X, and, most preferably, maximum aluminium zeolite P
(zeolite MAP) as described and claimed in EP 384 070B
5' (Unilever). Zeolite MAP is defined as an alkali metal
aluminosilicate.of the zeolite P type having a silicon to
aluminium ratio not. exceeding 1.33, and preferably not
exceeding 1.07. The:calci.um.binding capacity of zeolite
MAP is generally at least 150 mg Ca0 per g of anhydrous
material.
Preferred compositions of the invention contain zeolite
MAP, suitably in an amount of from 20 to 60 wto, and are
free of zeolite A.
Supplementary builders may also be present. These are
generally organic. Organic builders that may be present
include polycarboxylate polymers such as polyacrylates,
acrylic/maleic copolymers, and acrylic phosphinates;
monomeric polycarboxylates such as citrates, gluconates,
oxydisuccinates, glycerol mono-, di- and trisuccinates,
carboxymethyloxysuccinates, carboxymethyloxymalonates,
dipicolinates, hydroxyethyliminodiacetates, alkyl- and
alkenylmalonates and succinates; and sulphonated fatty acid
salts.
Especially preferred organic builders are citrates,
suitably used in amounts of from 5 to 30 wto, preferably
from 10 to 25 wt~; and acrylic polymers, more especially
acrylic/maleic copolymers, suitably used in amounts of from
0.5 to 15 wt~, preferably from 1 to 10 wto.
The total amount of detergency builder in the
compositions will suitably range from 10 to 80 wto,
preferably from 10 to 60 wt~.
AMENDED SHEET
CA 02253470 1998-11-03
C3724PC1
' .. ,>
__ g
Other ingredients that may suitably be incorporated in
the base powder include fluorescers; antiredeposition,
anti-dye-transfer and soil release polymers; sodium
carbonate; sodium sulphate.
5.
The base powder may also, if desired, contain. sodium
silicate. Generally the amount of sodium silicate present
in. the base powder will not exceed 10 wto of the whole
composition, for example, from 1 to 8 wt~. The composition
as a whole must, however, be free of postdosed sodium
silicate other than that contained in the cogranules.
The base powder may be prepared by any suitable process
giving composite granules, for example, spray-drying, spray-
drying followed by densification, or non-tower mixing and
granulation processes. The invention is believed to be
especially applicable to compositions in which the base
powder is not the direct process of a spray-drying process.
Preferred non-tower processes use a high-speed
mixer/granulator, for example, as described in EP 340 013A,
EP 367 339A, EP 390 251A and EP 420 317A (Unilever).
The base powder preferably has a bulk density of at
least 650 g/litre, more preferably at least 700 g/litre and
most preferably at least 800 g/litre.
The sodium silicate/sodium carbonate cogranules
The compositions of the invention contain sodium
silicate in the form of discrete cogranules comprising
sodium silicate and sodium carbonate in a weight ratio of
from 1:3 to 3:1.
AMENDED SHEET
C3724PC2
CA 02253470 1998-11-03
g _
Preferred cogranules have a sodium silicate to sodium
carbonate ratio of from 0.5:1 to 1:1 and are present in an
amount of from 2 to 15 wto, more preferably from 4 to
wto.
5
Composite sodium silicate/sodium carbonate granules and
their use in detergent compositions are disclosed in
EP 561 656A and WO 95 32273A (Rhone-Poulenc), EP 658 517A
and EP 667 391A (Degussa), and WO 95 22592A (Henkel).
10 Especially preferred granules, containing 63.7 wto (as
anhydrous) sodium carbonate and 36.3 wt~ (as hydrated
disilicate) sodium silicate, are available commercially from
Rhone-Poulenc Chimie as Nabion (Trade Mark) 15.
As previously indicated, the compositions of the
invention are free of postdosed sodium silicate other than
that contained in the cogranules. Sodium silicate may,
however, be present in the base powder.
Sodium carbonate
The compositions of the invention also contain from 1
to 50 wt~, preferably from 2 to 40 wt~, more preferably from
2 to 25 wt~, of postdosed sodium carbonate, that is to say,
sodium carbonate present as discrete granules not forming
part of the base powder. The absence of postdosed sodium
carbonate appears to exacerbate the "granulation" problem.
Bleaching compositions may suitably contain from 1 to
12 wt~, preferably from 2 to 10 wt$, of postdosed sodium
carbonate. Higher levels may be appropriate to non-
bleaching compositions. Sodium carbonate may, of course,
also be present in the base powder.
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WO 97/43370 PCT/EP97/02496
The compositions of the invention may also contain a
peroxy bleach compound. Preferred peroxy bleach compounds
5 are inorganic persalts such as the alkali metal perborates,
percarbonates, perphosphates, persilicates and
persulphates, in particular, sodium perborate monohydrate
and tetrahydrate and sodium percarbonate.
10 The present invention is especially applicable to
compositions containing sodium percarbonate, which may
suitably be present in an amount of from 10 to 35 wt%, more
preferably from 15 to 25 wto.
The peroxy bleach compound may be used in conjunction
with a bleach activator (bleach precursor) to improve
bleaching action at low wash temperatures. The bleach
precursor is suitably present in an amount of from 1 to
8 wt%, preferably from 2 to 5 wt~. Preferred bleach
precursors are peroxycarboxylic acid
precursors, more
especially peracetic acid precursors and peroxybenzoic acid
precursors; and peroxycarbonic acid precursors. An
especially preferred bleach precursor suitable for use in
the present invention is N,N,N',N'-tetracetyl
ethylenediamine (TAED).
A bleach stabiliser (heavy metal sequestrant) may also
be present. Suitable bleach stabilisers include
ethylenediamine tetraacetate (EDTA) and the
polyphosphonates such as bequest (Trade Mark), EDTMP.
As previously indicated, the scope of the invention
also extends to non-bleaching compositions.
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WO 97/43370 PCT/EP97/02496
11
Other non-base ingredients that may suitably be
present include enzyme granules, antifoam granules, polymer
granules (instead of or in addition to polymers included in
the base powder), sodium bicarbonate, perfume.
Moisture sink capacity
Without wishing to be bound by theory, it has been
observed that particulate laundry detergent compositions
that exhibit a "granulation" problem that can be solved in
accordance with the present invention are generally
characterised by a calculated moisture sink capacity at
37°C and 70% relative humidity of the overall composition
of 5 wt% or less, preferably from 3 to 5 wt% and more
preferably from 4 to 5 wt%.
Moisture sink capacity (MSC) is defined as the amount
of water a material can take up to form a stable hydrate,
under the defined conditions. Fully hydrated materials,
for example, sodium perborate tetrahydrate, have no MSC.
For a single anhydrous or not fully hydrated material
the MSC may readily be calculated, assuming that the
material will hydrate fully, on storage under defined
conditions, to the hydrate that is stable under those
conditions. For example, under conditions of 37°C and 70%
relative humidity sodium carbonate (anhydrous) will hydrate
to the monohydrate (in a closed container) or to the
monohydrate plus sesquicarbonate tin open conditions in the
presence of carbon dioxide), giving in either case an MSC
value of 17 wt%; but will not hydrate further to the
decahydrate which is only stable at higher relative
humidity.
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WO 97/43370 PCT/EP97/02496
12
For a full particulate detergent composition, or a
composite granular component of such a composition, the MSC
value is calculated, for the purposes of the present
invention, by adding up the capacities of the individual
ingredients each multiplied by the percentage (anhydrous
basis) of each present. This is necessarily an
approximation because it assumes that the moisture sink
capacity of each ingredient operates independently of the
other ingredients present, whereas in reality it is likely
that in a multiingredient component the different
ingredients will influence each other to some extent.
The calculated MSC values at 37°C and 70% relative
humidity of some ingredients used in particulate detergent
compositions of the invention and comparative compositions,
as hereinafter described, are shown below.
MSC (wt~)
Zeolite 4A zero
Zeolite MAP 12.5
Sodium carbonate* (anhydr) 17.0
Sodium disilicate (hydrated) zero
Sodium carbonate (63.7 wto)/
sodium disilicate 11.0
(36.3 wt~)
cogranules
Antifoa m granule (68 wt% carbonate) 11.6
Sodium sulphate zero
Sodium perborate monohydrate 54.0
Sodium perborate tetrahydrate zero
Sodium percarbonate zero
Tetrace tyl ethylene diamine (TAED) zero
Sodium sesquicarbonate zero
Sodium bicarbonate zero
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WO 97/43370 PCT/EP97/02496
13
The invention is illustrated by the following
Examples, in which parts and percentages are by weight
unless otherwise stated.
Example 1. Comparative Exambl_es A to C
A high bulk density detergent base powder having a
moisture sink capacity at 27°C and 70o relative humidity of
3.8 wt~ was prepared to the following formulation using a
continuous high-speed mixer/granulator:
0
Na primary alcohol sulphate 21.86
Nonionic surfactant 7E0 10.91
Soap 3.42
Zeolite MAP (as anhydrous) 42.27
Light soda ash 6.15
Sodium citrate dihydrate 4.33
Sodium carboxymethyl cellulose 1.70
Moisture, salts, etc 9.35
Four fully formulated detergent compositions were
prepared by postdosing additional ingredients. The
compositions thus obtained were tested for "granulation" by
storing 100 g samples in open tubs for 60 hours at 37°C and
70o relative humidity. Material having a particle size of
2000 um or greater was then gently removed by sieving (the
agglomerates were very fragile) and weighed. The
compositions, and the percentages of oversize material
found in each composition, are shown in the following
Table.
CA 02253470 1998-11-03
WO 97/43370 ~ 4 PCT/EP97/02496
v o ~r, <r ~ ~n o
cu o 0 0 o en
0 0 0 0 0o m
o~ rn o~ u, o o ~r, 0 0 0 ~ o
. . . , . . . . . . . .
M N M tl1 Lfl O1 U1 e-I ri c--I O (y
N ~r1 ~r1 N
N O D c~
V
0 0 0 o co mn
UW -i O M O tt1O o O d~
~o . . . ~ . . . . . . p
~ .
C~ d~ N tll 01Lflc-i~-i~-1O ri
U o H ~ m n o
'' N ~-1O O
.,
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0 0 0 0 00tr1
00 d~ ODO o o in o 0 0 ~r
o\o . . . . ~
M l~ M N u'1 O~lIW-Ir-I~-iO
Lll r-I
v o ~n r m n r-,
~,'' N ~-Io 0
0
c0 ~ ao 0 0 0 0 opm
0
i i ~n o 0 0
o\o M CO M Lf1 . . . . . p
01
L(l r1 L(lc-ic-Ic-iO
N
N
M
~
~ rtiO U r-
,p I
~ ~-a,.~~ O
S-a
~
~ t W.-i rti-n O
U
U rt5b1(U U 'z3 U O o
~
r3 ~ V
O ~ rtiN C1 i.~ C ~ o
II
O ,~ c~U +.~!~-I rd U14J ~ rtSN
~ U ~ ~ n
rt .--~ ~ p.~ ~ ,~ ~
-rl-.-I-.-i~., C~ ~ ~ ~~,4--~r~ ~ o\o
-r-I
-1-1~ r~ri W ~ N ~-1 .tJ ~ 1J
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c~ it G -~ -~O ~ C~~ ~ dl O ~ 3
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m Z ~ ~1 cna.. E-~W C7 W a, E-~ C7 ---
cn
CA 02253470 1998-11-03
WO 97/43370 PCT/EP97/02496
5
lcontaining 18 wt~ carbonate
zNabion 15 ex Rhone-Poulenc: 63.7 wto carbonate, 36.3 wto
silicate
3Sokalan (Trade Mark) HP22 soil release polymer ex BASF on
zeolite/carbonate carrier
4Sokalan (Trade Mark) CP5 acrylic/maleic copolymer ex BASF.
Comparative Example A contained no sodium silicate and
showed very low "granulation". Addition of 2 wto postdosed
disilicate (Comparative Example B), replacing the same
amount of postdosed sodium carbonate, resulted in a large
increase in "granulation". Removal of all postdosed
carbonate (replacing by base powder) caused granulation to
increase further (Comparative Example C).
However, replacement of the postdosed silicate and part
of the postdosed sodium carbonate of Comparative Example B
by sodium silicate/sodium carbonate composite granules
(Nabion 15), to give exactly the same final formulation,
caused the "granulation" level to fall back to that of
Comparative Example A containing no sodium silicate.
