Note: Descriptions are shown in the official language in which they were submitted.
. ,214~~~~
Case CM712/AA
TITLE: GRANULAR DETERGENT COMPOSITION
The present invention relates to a granular detergent composition and,
in particular, to improvements in the detergency performance of
laundry detergent compositions comprising zeolites as sequestering
agents for water hardness.
Detergent compositions for heavy-duty fabric washing conventionally
contain detergency builders which lower the concentration of calcium
and magnesium water hardness ions in the wash liquor and thereby
provide good detergency effect in both hard and soft water.
Conventionally, inorganic phosphates, such as sodium
tripolyphosphate, have been used as builders for laundry detergents.
More recently, alkali metal aluminosilicate ion-exchangers, particularly
crystalline sodium aluminosilicate zeolite A, have been proposed as
replacements for the inorganic phosphates.
For example, EP 21 491A (Procter & Gamble) discloses detergent
compositions containing a building system which includes zeolite A, X
or P (B) or a mixture thereof. EP 384070A (LTnilever) discloses
specific zeolite P materials having an especially low silicon to
aluminium ratio not greater than 1.33 (hereinafter referred to as zeolite
MAP) and describes its use as a detergency builder. To date, however,
zeolite A is the preferred aluminosilicate detergency builder in
commercially available products.
However, it has been found that there are problems associated with the use
of conventional detergency builders including aluminosilicates such as
zeolite A. One problem is evident in granular detergent products, especially
compact products, incorporating a perfume.
Perfumes are commonly employed in detergent compositions to deliver a
pleasant odour on detergent bases and on fabrics or dishes during and after a
2
wash treatment. It is known to use soluble encapsulates of perfume
incorporated in a
granular detergent composition to increase the perfume delivery through the
wash and
on fabrics without increasing the odour impact on product beyond the threshold
of
consumer acceptance. A further advantage of soluble capsules is that they
permit
reduced perfume loses on storage as compared with sprayed on perfumes,
particularly
in high density detergents which have a low porosity and hence are poor
substrates for
sprayed on perfumes. Soluble perfume capsules also have a particular advantage
in
detergent compositions containing percarbonate which are poorer substrates
than
perborate-based compositions for retaining sprayed on perfume.
However, perfume capsules incorporated in detergent compositions have a
tendency to
leak, particularly if stored in high temperature and/or high moisture
conditions. As a
result the odour impact on the product is increased beyond consumer
acceptance.
We have found that this problem can be obviated by using, as the detergency
builder,
zeolite MAP.
Thus, the present invention provides a granular detergent compositions
comprising:
(a) an effective concentration of a surfactant selected from anionic,
nonionic,
cationic, amphoteric and zwitterionic detergent-active compounds and mixtures
thereof;
(b) an effective concentration of a detergency builder comprising zeolite P
having a silicon to aluminum ratio not greater than 1.33 (zeolite MAP); and
(c) soluble encapsulates of perfume.
According to the present invention zeolite MAP may be the sole detergency
builder or
it may be employed together with a co-builder known in the art. If zeolite A
is
employed as co-builder the formulation should contain preferably not more than
2%
by weight zeolite A or not more than 6% by weight zeolite A if the composition
is
overdried, i.e. has a moisture level
A
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below 12% by weight.
The detergent composition according to the invention contains, as an
essential ingredient, one or more surfactants selected firom anionic,
nonionic,
cationic, amphoteric and zwitterionic detergent-active compounds and
mixtures thereof. Such surfactants are well known and described in the
literature, for example, in "Surface-Active Agents and Detergents", Volumes
I and II by Schwartz, Perry and Berch.
Examples of suitable anionic surfactants include alkylbenzene sulphonates,
particularly sodium linear alkylbenzene sulphonates having an alkyl chain
length of C8-C 15; C 12-C 15 primary alkyl sulphates and their ethoxylated
analogues containing from 0.25 to 6 moles of ethylene oxide per mole of
alkyl sulphate; olefin sulphonates; alkyl xylene sulphonates; dialkyl
sulphosuccinates; and fatty acid ester sulphonates. Sodium salts are
generally preferred.
Examples of suitable nonionic surfactants include alkoxylated adducts of
fatty alcohols containing an average of less than S alkylene oxide groups per
molecule, for example less than 4 alkylene oxide groups per molecule e.g.
3.5 and usefully 3 alkylene oxide groups per molecule or less and usefully
also greater than 0.5, or 1, or 2 alkylene oxide groups per molecule.
Alkylene oxide adducts of fatty alcohols are useful as hydrophobic
alkoxylated nonionic surfactants for incorporation in the detergent
composition of the present invention. Suitable alkylene oxide adducts of
fatty alcohols can suitably be chosen from those of the general formula:
R-O-(CnH2n0)yH
wherein R is an alkyl or alkenyl group having at least 10 carbon atoms, most
preferably from 10 to 22 carbon atoms, y is preferably from about 0.5 to
about 3.5 and n is 2 or 3.
Preferred nonionic surfactants include primary C 11-C 15 aliphatic alcohols
condensed with an average of no more than five ethylene oxide groups per
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4
mole of alcohol, having an ethylene oxide content of less than 50% by
weight.
A particularly preferred aliphatic alcohol ethoxylate is a primary alcohol
having an average of 12 to 15 carbon atoms in the alkyl chain condensed
with an average of three ethoxy groups per mole of alcohol.
Specific examples of suitable alkoxylated adducts of fatty alcohols are
Synperonic A3 (ex ICI), which is a C 13-C 15 alcohol with about three
ethylene oxide groups per molecule and Empilan KB3 (ex Marchon), which
is lauric alcohol 3E0.
Another class of nonionic surfactants comprises alkyl polyglucoside
compounds of general formula
RO(CnH2n0)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 1.1 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, 0075996 and 0094118.
Where the composition comprises an aliphatic alcohol ethoxylate as
surfactant it is present in an amount of at least 1 wt.%, preferably from 1
wt.% to 10 wt.% and more preferably 1 wt.% to 6 wt.% of the composition.
The detergent composition of the invention generally contains a detergent
surfactant in a range of from 5 to 60 wt.%, preferably 5 to 40 wt.% and most
preferably from 10 to 25 wt.% of the composition.
According to the present invention the detergency builder system is based on
zeolite MAP, optionally in conjunction with one or more supplementary
builders. The amount of zeolite MAP employed may range, for example,
from 5 to 60 wt.%, more preferably from 5 to 45 wt.%.
2146686
Zeolite MAP is described in EP 384070A (Unilever). It is defined as an
alkali metal alumino-silicate of the zeolite P type having a silicon to
aluminium ratio not greater than 1.33, preferably within the range from 0.9
to 1.33 and more preferably within the range of from 0.9 to 1.2.
Of particular interest is zeolite MAP having a silicon to aluminium ratio not
greater than 1.15 and, more particularly, not greater than 1.07.
Zeolite P having a Si:AI ratio of 1.33 or less may be prepared by the
following steps:
(i) mixing together a sodium aluminate having a mole ratio
Na20:A1203 within the range of from 1.4 to 2.0 and a sodium
silicate having a mole ratio Si02:Na20 within the range of from
0.8 to 3.4 with vigorous stirring at a temperature within the
range of from 25°C to boiling point usually 95°C, to give a gel
having the following composition;
A1203: (1.75-3.5) Si02 : (2.3-7.5) Na20 :P (80-450)H20;
(ii) ageing the gel composition for 0.5 to 10 hours, preferably 2 to 5
hours, at a temperature within the range of from 70°C to boiling
point, usually to 95°C, with sufficient stirring to maintain any
solids present in suspension;
(iii) separating the crystalline sodium aluminosilicate thus formed,
washing to a pH within the range of from 10 to 12.5, and drying,
preferably at a temperature not exceeding 150°C, to a moisture
content of not less than 5 wt.%.
Preferred drying methods are spray-drying and flash drying. It appears that
oven drying at too high a temperature may adversely affect the calcium
binding capacity of the product under certain circumstances.
Commercial sodium metasilicate pentahydrate dissolved in water and
commercial sodium silicate solution (waterglass) are both suitable silica
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6
sources for the production of zeolite P in accordance with the invention.
The reactants may be added together in any order either rapidly or slowly.
Rapid addition at ambient temperature, and slow addition at elevated
temperature (90-95°C) both give the desired product.
Vigorous stirring of the gel during the addition of the reactants, and at
least
moderate stirring during the subsequent ageing step, however, appear to be
essential for the formation of pure zeolite P. In the absence of stirring,
various mixtures of crystalline and amorphous materials may be obtained.
Zeolite MAP generally has a calcium binding capacity of at least 150 mg
Ca0 per g of anhydrous aluminosilcate, as measured by the standard method
described in GB 1473201 (Henkel). The calcium binding capacity is
normally 160 mg Ca0/g and may be as high 170 mg Ca0/g.
Although zeolite MAP like other zeolites contains water of hydration, for the
purposes of the present invention amounts and percentages of zeolite are
expressed in terms of the notional anhydrous material.
The amount of water present in hydrated zeolite MAP at ambient
temperature and humidity is generally about 20 wt.%.
Preferred zeolite MAP for use in the present invention is finely divided and
has a d50 (as defined hereinafter) within the range of from 0.1 to 5.0
micrometres. The quantity "d50" indicates that 50 wt.% of the particles
have a diameter smaller than that figure.
A preferred zeolite MAP for use according to the present invention has a
d50 of from 1.0 to 5.0 micrometres, for example 2.25 to 5 micrometres,
more particularly 2.75 to 5 micrometres.
According to one embodiment of the invention the zeolite MAP detergent
builder is in powder form.
For convenience in handling, however, the material may be granulated by
conventional techniquessuch as spray drying or by a non-tower method to
2~~668~~
form larger particles.
The detergent composition according to the invention comprises soluble
encapsulates of perfume.
The encapsulated perfumes comprise perfume dispersed in certain Garner
materials.
In the context of this specification, the term "perfume" means any
odoriferous material or any material which acts as a malodor counteractant.
In general, such materials are characterised by a vapor pressure greater than
atmospheric pressure at ambient temperatures. The perfume or deodorant
materials employed herein will most often be liquid at ambient temperatures,
but also can be solids such as the various tamphoraceous perfumes known in
the art. A wide variety of chemicals are known for perfumery uses,
including materials such as aldehydes, ketones, esters and the like. More
commonly, naturally occurring plant and animal oils and exudates
comprising complex mixtures of various chemical components are known
for use as perfumes, and such materials can be used herein. The perfumes
herein can be relatively simple in their composition or can comprise highly
sophisticated, complex mixtures of natural and synthetic chemical
components, all chosen to provide any desired odor.
Perfumes which are normally solid can also be employed in the present
invention. These may be admixed with a liquefying agent such as a solvent
prior to incorporation into the particles, or may be simply melted and
incorporated, as long as the perfume would not sublime or decompose upon
heating.
The invention also encompasses the use of materials which act as malodor
counteractants. These materials, although termed "perfumes" hereinafter,
may not themselves have a discernible odor but can conceal or reduce any
unpleasant odors. Examples of suitable malodor counteractants are
disclosed in U. S. Patent No. 3,102,101, issued August 27,1963, to Hawley et
al.
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8
A wide variety of capsules exist which will allow for delivery of perfume
effect at various times in the cleaning or conditioning process. The less
protection provided results in greater perfume effect in product or
washing/conditioning process. More protection results in greater perfume
effect during the drying process or even later, after the surface has been
treated.
Examples of such capsules with different encapsulated materials are
capsules provided by microencapsulation. Here the perfume comprise a
capsule core which is coated completely with a material which may be
polymeric. U.S. Patent 4,145,184, Brain et al, issued March 20,1979, and
U.S. Patent 4,234,627, Schilling, issued November 18,1980, teach using a
tough coating material which essentially prohibits the diffusion out of the
perfume. The perfume is delivered to fabric via the microcapsules and is
then released by rupture of the microcapsules such as would occur with
manipulation of the fabric.
Greater protection can be provided by choice of encapsulating material to be
used to form the capsules, ratio of perfume to encapsulation or
agglomeration of particles.
The choice of encapsulated material to be used in the perfume particles of
the present invention will depend to some degree on the particular perfume
to be used. Some perfumes will require a greater amount of protection than
others and the encapsulating material to be used therewith can be chosen
accordingly.
Nonlimiting examples of suitable water-soluble coating materials include
such substances as methyl cellulose, maltodextrin and gelatin. Such
coatings can comprise from about 1% to about 25% by weight of the
particles.
Especially suitable water soluble encapsulating materials are capsules which
consist of a matrix of polysaccharide and polyhydroxy compounds such as
described in GB 1,464,616.
CA 02146686 1999-04-15
9
Other suitable water soluble or water dispersible encapsulating materials
comprise dextrins
derived from ungelatinized starch acid-esters of substituted dicarboxylic
acids such as
described in US 3,455,838. These acid-ester dextrins are, preferably, prepared
from such
starches as waxy maize, waxy sorghum, sago, tapioca and potato. Suitable
examples of
said encapsulating materials are N-Lok R, manufactured by National Starch,
Narlex R (ST
and ST2), and Capsul E R. These encapsulating materials comprise
pregelatinized waxy
maize starch and, optionally, glucose. The starch is modified by adding
monofunctional
substituted groups such as octenyl succinic acid anhydride.
The perfume may also be encapsulated with a material that makes the particles
more
substantive to the surface being treated for example, fabric in the laundry
process. Such
materials help to deliver the particles to the fabric and maximize perfume
release directly
on the fabric. Generally, these materials are water-insoluble cationic
materials. Examples
of useful material include any of the cationic (including imidazolinium)
compounds listed
in U.S. Patent 3,686,025, Morton, issued August 22, 1972. Such materials are
well known
in the art and include, for example, the quaternary ammonium salts having at
least one,
preferably two, C 10-C20 fatty alkyl substituent groups; alkyl imidazolinium
salts wherein
at least one alkyl group contains a C8-C25 carbon "chain"; the C12-C20 alkyl
pyridinium
salts, and the like.
Alternative materials useful for encapsulating materials to make them more
fabric
substantive are described in U. S. Patent 4,234,627, Schilling, issued
November 18, 1980.
The encapsulated perfume particles can be made by mixing the perfume with the
encapsulating matrix by spray-drying emulsions containing the encapsulating
material and
the perfume. In addition, the particle size of the product from the spray-
drying tower can
be modified. These modifications can comprise specific processing steps such
as post-
tower agglomeration steps (e.g. fluidised bed) for enlarging the particle size
and/or
processing steps wherein the surface properties of the encapsulates are
modified, e.g.
dusting with hydrophobic silica in order to reduce the hygroscopicity of the
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encapsulates.
A particularly preferred encapsulation process is an emulsification process
followed by spray-drying and finally dusting with silica. The emulsion is
formed by:
a) dispersing the starch matrix in water at room temperature in a 1:2
ratio. It is preferred that the starch is pregelatinised so that the
emulsion can be carried out at this temperature. This in turn
minimises perfume loss. There must be a "low viscosity" starch
to achieve high starch concentrations in water and high perfume
loadings.
b) the perfume oil is then added to the above mixture in the ratio of
0.8-1.05 :1: 2, and the mixture is then emulsified using a high
shear mixer. The shearing motion must produce oil droplets
below 1 micron and the emulsion must be stable in this form for
at least 20 rains (the function of the starch is to stabilise the
emulsion once its mechanically made).
c) the mixture is spray-dried in a co-current tower fitted with a
spinning disk atomiser. The drying air inlet temperature is low
150-200°C. This type of spray-drying ensures minimum loss of
perfume and high drying rate. The granules have a particulate
size of 50-150 microns.
d) the resulting dried encapsulates can contain up to 5%
unencapsulated oil at the surface of the granules. To improve
the flow characteristics up to 2% hydrophobic silica can be
optionally added to the encapsulates via a ribbon blender.
It may be desirable to add additional perfume to the composition, as is,
without protection via the capsules. Such perfume loading would allow for
aesthetically pleasing fragrance of the composition itself. Upon opening the
package containing the composition and as the product is added to water,
this immediate release of fragrance may be desirable.
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This perfume would be added via conventional means, e.g., mixing, as is,
into a liquid composition or spraying onto dry product compositions.
In the granular detergent compositions according to the invention, the
detergency builder can be zeolite MAP alone or a combination of zeolite
MAP with an organic or inorganic cobuilder.
Suitable organic cobuilders can be monomeric or polymeric carboxylates
such as citrates or polymers of acrylic, methacrylic andlor malefic acids in
neutralised form. Suitable inorganic cobuilders include carbonates and
amorphous and crystalline lamellar sodium silicates.
Suitable lamellar silicates have the composition:
NaMSix02x+1 , yH20
where M is sodium or hydrogen, preferably sodium; x is a number from 1.9
to 4; and y is a number from 0 to 20. Such materials are described in US
Patents No. 4664839; No. 4728443 and No. 4820439 (Hoechst AG).
Especially preferred are compounds in which x = 2 and y = O. The
synthetic material is commercially available from Hoechst AG as S-Na2
Si205 (SKS6) and is described in US Patent No. 4664830.
The total amount of detergency builder in the granular composition ranges
from 10 to 80 wt.%, more preferably from 15 to 60 wt% and most
preferably from 10 to 45 wt.%.
Detergent compositions according to the invention may also suitably contain
a bleach system. This preferably comprises one or more peroxy bleach
compounds, for example, inorganic persalts or organic peroxyacids, which
may be employed in conjunction with bleach precursors to improve
bleaching action at low temperatures.
The bleach system preferably comprises a peroxy bleach compound,
preferably an inorganic persalt, optionally in conjunction with a precursor.
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Suitable persalts include sodium perborate monohydrolate and tetrahydrolate
and sodium percarbonate, with sodium percarbonate being most preferred.
The Applicants have found that the present invention is particularly useful in
detergent compositions comprising a percarbonate. Percarbonate is a
poorer substrate to perfume than for example perborate and in conventional
detergent compositions containing zeolite A as detergency builder, when
perfume is sprayed on large perfume losses result on storage.
Percarbonate can be satisfactorily incorporated in the detergent
compositions according to the invention employing zeolite MAP as
detergency builder and using soluble capsules of perfume.
Preferred bleach precursors are peracetic acid precursors, such as
tetraacetylethylene diamine (TAED); and peroxybenzoic acid precursors
such as benzoyloxybenzene sulphonate (BOBS) and benzoyl caprolactam
(BZCL).
The advantages afforded by the detergent composition of the present
invention are particularly apparent in alkaline compositions, i.e. those which
have a pH > 9.5 when measured on a 1% solution in distilled water. The
composition according to the invention will preferably contain less than 6%
by weight sulphate and less than 6% by weight bicarbonate.
Other materials which may be present in the detergent compositions of the
invention include, for example, fluorescers, antiredeposition agents,
inorganic salts such as sodium sulphate, enzymes, lather control agents,
fabric softening agents, pigments, and coloured speckles.
The detergent compositions of the invention may be prepared by any
suitable method. The particulate detergent compositions are suitably
prepared by any tower (spray-drying) or non-tower process.
In processes based around a spray-drying tower, a base powder is first
prepared by spray-drying a slurry and then other components, such as
enzymes, unsuitable for processing via the slurry can be sprayed on or
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admixed (postdosed). The perfume capsules will generally be subsequently
incorporated.
The zeolite MAP is suitable for inclusion in the slurry, although it may be
advantageous for processing reasons for part of the zeolite MAP to be
incorporated post-tower. The lamellar silicate, where this is employed, is
also incorporated via a non-tower process and is preferably postdosed.
Alternatively, particulate detergent compositions in accordance with the
invention may be prepared by wholly non-tower processes such as
granulation.
The granular detergent compositions of the invention may be prepared to
any suitable bulk density. The compositions should have a bulk density of at
least preferably 400 g/1 preferably at least 650 g/1, and, with particular
preference at least 800 g/1.
The benefits of the present invention are particularly evident in powders of
high bulk density, for example, of 700 g/1 or above, which have a low
porosity and hence are a poor substrate for sprayed-on perfume. Such
powders may be prepared either by post-tower densification of spray-dried
powder, or by wholly non-tower methods such as dry mixing and
granulation; in both cases a high-speed mixer/granulator may
advantageously be used. Processesusing high-speed mixer/granulators are
disclosed, for example, in EP340 013A, EP 367 339A, EP 390 251A and EP
420 317A (IJnilever).
The detergent composition according to the invention generally has a pH (as
measured with a 1 % solution in distilled water) of above 9.0, preferably
above 9.5 and with particular preference about 10.
According to a further aspect, the invention provides use of a composition
comprising zeolite MAP and soluble perfume capsules as an additive for a
detergent composition.
Illustrative compositions according to the present invention are presented in
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the following Examples.
The following abbreviations are used in the Examples
AS : Sodium alkyl sulphate
LAS : linear C8-11 alkyl benzene sulphonate.
TAED : Tetraacetyl ethylene diamine.
DTPMP : Diethylene triamine penta (methylene
phosphoric acid), marketed by Monsanto
under the Trade Name bequest 2060.
MA/AA : Copolymer of 1:4 maleic/acrylic acid (Mw
80,000).
Citrate : Trisodium citrate dehydrate.
CMC : Sodium carboxymethyl cellulose
SKS 6 : Lamellar sodium silicate (Hoechst AG).
TAE11 : tallow alcohol having an average of 11
ethylene oxide groups per mole
45AE7 : C 14 - C 15 ~cohol ethoxylate having an
average of 7 ethoxy groups per mole of
alcohol.
AE3 S : alcohol ethoxysulphate having an average of 3
ethoxy groups per mole.
silicone : mixture of silanated silica : silicone in ratio of
suds supressor 1:1.5 (M.wt.100,000)
2~~~~a~
EXAMPLE S
Particulate components and compositions were prepared as follows
A B C D E
Spray dried component
10%
Zeolite MAP 13% 13% - -
MA/AA 4% 4% _ _ 1.82%
DTPMP 0.5% 0.5% - _ 0.2%
Brightener 0.2% 0.2% - -
MgS04 0.4% 0.4% -
Spray on
Perfume 0.1 % - - - _
45 AE7 4% 4% - _
Silicone suds suppressor 0.5% 0.5%
TAE11 1% 1% - _
Post additives
Percarbonate 18% 18% 18% 18%
TAED 5% 5% 5% 5%
SKS6 - - 12% 12%
CITRATE 10% 10% 10% 10% 10%
Savinase (Trade Mark)
5% 5%
1 1
4.0 KNPU/g 1.5% 1.5% 1.5% . .
Na Carbonate 8% 8% 12% 12% 20%
Na Bicarbonate 2% 2% 2% 2% 5%
Surfactant agglomerate
LAS 7% 7% -
C16/18AS 2% 2% - -
C14/15AS - - 7% 7% 7%
C12/15AE3 S 0.2% 0.2% 1.5% 1.5% 1.5%
CMC 0.3% 0.3% 0.3% 0.3% 0.3%
°
"""~' 1 6
zeolite MAP 5% 5% 10% 10% 10%
Na Carbonate 7% 7% 7% 7% 7%
Mp,/~ _ _ 2% 2% 2%
Perfume level (delivered0.2% 0.3% 0.5% 0.3% 0.5%
in
40% active in dextrine
capsules)
MiscellaneousBalance 100% 100% 100% 100% 100%
Density 700g/1 700g/1 800g/1 800g/1 800g/1
