[0001] The present invention relates to detergent compositions comprising percarbonate bleach.
In particular it relates to compositions which have a high bulk density, improved
characteristics of dispensing from either the drawer of a washing machine, or other
dispensing device, thereby giving improved cleaning performance of bleaching compositions.
[0002] Inorganic perhydrate bleaches, such as perborate, percarbonate, and persilicate are
well-known as detergent components. Preferably they are combined with peracid precursors
which perhydrolise the perhydrate to form the active peracid. This perhydrolysis reaction
is promoted by alkaline conditions.
[0003] Compositions which comprise percarbonate and peroxy carboxylic acid bleach precursors
have been described in detail in the Applicants co-pending
application WO9206163, published on 16th April, 1992.
[0004] Compositions which aim to improve dispensing characteristics of high bulk density
detergents have also been described in the prior art.
[0005] EP-A-534525, published on 31st March, 1993 describes the use of particulate citric acid having
a specified particle size in order to aid dispensing. Bleach compounds including percarbonate
are mentioned.
However, use of particulate citric acid does not address the problem of providing
alkaline conditions in the wash liquor.
[0006] The use of water-soluble alkaline inorganic salts in the composition would address
this problem.
[0007] EP-A-229671, published on 22nd July, 1987 proposes the use of particulate carbonate or phosphonates
in specified detergent compositions. It is claimed that improved dispersibility and
solubility in cold water can be achieved.
[0008] The use of sodium silicate as a suitable particulate water-soluble alkaline inorganic
salt is known to contribute to the inhibition of corrosion of washing machine drums,
and to the rapid removal of heavy metal colloids from the laundry soil which would
otherwise tend to destabilise the peroxygen and peracid species.
[0009] Although silicate is sparingly soluble in cold water, and therefore dry mixed, fine
particles of silicate (with a particle size diameter of less than 425 micrometers)
with high surface area are preferred, it has been observed that the combination of
perborate monohydrate and fine soluble particles of inorganic salts, including silicate)
is detrimental to the dispensing profile of the product. Attempts to replace the fine
particles of silicate by coarser silicate, or to replace perborate monohydrate by
perborate tetrahydrate has been found to lead to poorer cleaning performance.
[0010] It has now been found that the replacement of perborate monohydrate with some specific
percarbonate materials permits the incorporation of a high level of fine, rapidly-soluble
silicate particles without causing any dispensing issue, and gives excellent cleaning
performance.
[0011] Consequently the detergent compositions of the present invention have both superior
dispensing and superior bleaching performance.
[0012] A granular detergent composition according to the invention is defined in claim 1.
[0013] A particularly useful component of the present invention is at least 0.5% by weight
of a peracid precursor chosen from tetraacetyl methylene diamine, tetraacetyl ethylene
diamine, tetraacetyl hexylene diamine, perbenzoic acid or hydrophobic peracid precursors
such as 2-phenyl 4h-3 1-benzoxazin-4-one, NOBS, iso-NOBS, benzoylcaprolactam, benzoyloxybenzenesulphonate
or mixtures thereof.
[0014] Amorphous silicate which is rapidly water-soluble such as sodium silicate which has
a ratio of SiO2:Na2O of less than 2.4 is preferred as component ii).
[0015] The granular percarbonate is coated with a salt, useful coating materials include
carbonate, sulphate, citrate, silicate, water-soluble anionic surfactant or mixtures
of these. Most preferred as a coating material is a mixture of sodium carbonate and
sodium sulphate. Where sodium silicate is used as a component of the coating material,
it is preferred that it does not comprise more than 2.2% by weight of percarbonate,
of sodium silicate.
[0016] Without wishing to be bound by theory, it is believed that the type of percarbonate
which is selected herein has a lower surface area and lower porosity than perborate
monohydrate. This low surface area and low porosity prevents the co-gelling with fine
particles of silicate and is therefore not detrimental to dispensing. The percarbonate
material selected herein retains comparable rates of dissolution versus perborate
monohydrate despite its low surface area/low porosity. In fact because it does not
gel, this percarbonate material disperses and dissolves better than perborate monohydrate
in real wash situations (i.e from the dispensing drawer of a conventional washing
machine or from any other dispensing device).
[0017] The components of the invention will now be described in more detail.
[0018] The water-soluble silicates of the compositions in accordance with the present invention
are amorphous.
[0019] Such silicates may be characterised by the ratio of SiO
2 to Na
2O in their structure. In the present invention, this ratio may typically be less than
3.3:1, preferably less than 2.8:1, more preferably less than 2.4:1, most preferably
about 2.0:1.
[0020] It is preferred that the silicate component of the present invention comprises from
3% to 15% by weight of water-soluble silicate. When dry added water-soluble silicate
is used, it is preferred that less than 10% by weight of the finished composition
is dry added water-soluble silicate.
[0021] It has now been found that the particle size of the silicate particles of the present
invention can contribute to the rate at which bleaching species are generated. It
is preferable that fine silicate particles are used as these particles dissolve most
rapidly in the wash solution driving the alkalinity upwards. It is believed that the
rate of alkalinity release promotes the perhydrolysis of the percarbonate. The fraction
of silicate particles which pass through a Tyler 35 mesh (aperture size 425 micrometers)
represent at least 1% by weght of the finished composition.
[0022] The upper limit on particle size of the silicate particles is generally limited by
the need to have rapidly dissolving particles. In general the fraction of silicate
particles above 2000 micrometers, and preferably the fraction above 1400 micrometers
is considered oversize and is removed.
[0023] Many grades of particulate amorphous silicates are readily available commercially
from, for example, Hoechst AG, and Akzo. The preferred grades for use in the present
invention should have at least 30% by weight of the particles having a particle size
diameter of less than 425 micrometers. Furthermore preferred silicates have a surface
area of greater than 0.05 m
2/cc, and a porosity of greater than 6.5%.
Percarbonate bleach
[0024] The compositions of the present invention will include a percarbonate bleach, normally
in the form of the sodium salt, as the source of alkaline hydrogen peroxide in the
wash liquor. This percarbonate is normally incorporated at a level of up to 25% by
weight of the total composition.
[0025] Sodium percarbonate is an addition compound having a formula corresponding to 2Na
2CO
3.3H
2O
2, and is available commercially as a crystalline solid. Most commercially available
material includes a low level of a heavy metal sequestrant such as EDTA, 1-hydroxyethylidene
1, 1-diphosphonic acid (HEDP) or an amino-phosphonate, that is incorporated during
the manufacturing process. The preferred coating is a mixed salt of an alkali metal
sulphate and carbonate. Such coatings together with coating processes have previously
been described in
GB-1,466,799, granted to Interox on 9th March 1977. The weight ratio of the mixed salt coating
material to percarbonate lies in the range from 1:200 to 1:4, more preferably from
1:99 to 1:9, and most preferably from 1:49 to 1:19. Preferably, the mixed salt is
of sodium sulphate and sodium carbonate which has the general formula Na
2SO
4.n.Na
2CO
3 wherein n is from 0.1 to 3, preferably n is from 0.3 to 1.0 and most preferably n
is from 0.2 to 0.5. Another prefered coating material is sodium citrate. Water-soluble
surfactants such as linear alkyl benzene sulphonate and alkyl ether sulphate may also
be used as co-coating agents.
[0026] An alternative, although less preferred coating material is sodium silicate. Silicate
coating materials, applied as an aqueous solution on percarbonate before drying are
less preferred since they tend to affect the dispensing properties of the composition.
The sodium silicate coating should not comprise more than 2.2% by weight of the percarbonate
material. If used as a coating material the silicate should have a SiO
2:Na
2O ratio from 2.0:1 to 3.4:1, preferably from 2.2:1 to 2.8:1. Magnesium silicate can
also be included in the coating.
[0027] The particle size range of the crystalline percarbonate is from 100 micrometers to
1500 micrometers. Preferred materials have a particle size range between 250 and 1000
micrometers with a mean particle size of between 500 and 700 micrometers.
[0028] In order for the benefits of the present invention to be fully realised, it is highly
desirable that the percarbonate material chosen can be rapidly dissolved in the wash
and the active bleaching species are readily formed. In order to choose suitable percarbonate
materials the available oxygen (AvO2) level can be measured using thiosulphate/ potassium
iodide/ ammonium molybdate titration on aliquots taken from a stirred aqueous solution
of the 1% wt./wt. concentration of the detergent composition which contains the percarbonate
after 2, 4 and 5 minutes. A sample of the composition is dissolved in a Sotax apparatus
in deionised water which has been adjusted to 25°dH water hardness by the addition
of calcium chloride and magnesium chloride (with Ca:Mg = 3:1), at 10°C. The solution
is stirred at 150 rpm. A given percarbonate is considered to be suitable for use in
the present invention if it releases at least 40% of the total AvO2 after 2 minutes,
at least 80% of the total AvO2 after 4 minutes, and at least 90% of the total AvO2
after 5 minutes.
[0029] Compositions of the present invention, which contain percarbonate, have a greatly
reduced tendency to form undesirable gels in the presence of silicates, surfactants
and water than similar compositions which contain perborate. Without wishing to be
bound by theory, it is believed that this is because the type of percarbonate which
is selected here has a lower surface area and lower porosity than perborate monohydrate.This
low surface area and low porosity prevents the co-gelling with fine particles of silicate
in the presence of anionic surfactants and water, and is therefore not detrimental
to dispensing.
Peroxyacid Bleach Precursor
[0030] In a preferred embodiment of the present invention, the composition comprises peroxyacid
bleach precursor. The solid peroxyacid bleach precursors of the present invention
comprise precursors containing one or more N- or O- acyl groups, which precursors
can be selected from a wide range of classes.
[0031] 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.
[0032] Particularly preferred precursor compounds are the N-,N,N
1N
1 tetra acetylated compounds of formula
wherein x can be O or an integer between 1 & 6.
[0033] Examples include tetra acetyl methylene diamine (TAMD) in which x=1, 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.
[0034] Other preferred bleach precursors are the perbenzoic acid precursors such as benzoyloxybenzene
sulphonate (BOBS), benzoylcaprolactam, acyloxybenzene sulphonates (NOBS, iso-NOBS),
sugar derivatives (PAG, TAG, and those described in
EP-A-257039), malonate derivatives (described in
EP-A-517482), cationic precursors (described in
EP-A-512533,
EP-A-508623 and
EP-A-405152), glycolate esters (described in
EP-A-507475) and 2-phenyl 4h-3 1-benzoxazin-4-one.
[0035] Bleach precursors will normally be in fine powder or crystalline form in which at
least 90% by weight of the powder has a particle size of less than 150 micrometers.
However such solid bleach precursors are generally reagglomerated, granulated, encapsulated
or spray dried with other components. Such peroxyacid bleach precursor granules are
dry blended in the detergent composition and generally have a particle size range
of from 300 micrometers to 1500 micrometers. Some bleach precursors are pasty or liquid
at room temperature and have to be granulated with porous substrates such as zeolite
or silica.
[0036] It is most preferred that a peroxyacid bleach precursor is present at a level of
at least 0.5% by weight of the composition. These peroxyacid bleach precursors can
be partially replaced by preformed peracids such as N,N phthaloylaminoperoxy acid
(PAP), nonyl amide of peroxyadipic acid (NAPAA), 1,2 diperoxydodecanedioic acid (DPDA)
and trimethyl ammonium propenyl imidoperoxy mellitic acid (TAPIMA).
Surfactants and Builders
[0037] 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.
[0038] The finished compositions of the present invention will preferably contain from 5%
by weight to 30% by weight, and preferably from 5% to 25% by weight of anionic surfactant,
optionally mixed with nonionic surfactant.
[0039] Water-soluble salts of the higher fatty acids, i.e., "soaps", are useful anionic
surfactants in the compositions herein. This includes alkali metal soaps such as the
sodium, potassium, ammonium, and alkylammonium salts of higher fatty acids containing
from about 8 to about 24 carbon atoms, and preferably from about 12 to about 18 carbon
atoms. Soaps can be made by direct saponification of fats and oils or by the neutralization
of free fatty acids. Particularly useful are the sodium and potassium salts of the
mixtures of fatty acids derived from coconut oil and tallow, i.e., sodium or potassium
tallow and coconut soap.
[0040] 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, most preferably from 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 C
12-C
18 fatty source, preferably from a C
16-C
18 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 lengths differ from each other. One such system comprises a
mixture of C
14-C
15 alkyl sulphate and C
16-C
18 alkyl sulphate in a weight ratio of C
14-C
15: C
16-C
18 of 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) CH
2 COOM
wherein R is a C
9-C
17 linear or branched alkyl or alkenyl group, R' is a C
1-C
4 alkyl group and M is an alkali metal ion. Preferred examples are the lauroyl, Cocoyl
(C
12-C
14), myristyl and oleyl methyl sarcosinates in the form of their sodium salts.
[0041] Also useful are the sulphonation products of fatty acid methyl esters containing
a alkyl group with from 10 to 20 carbon atoms. Preferred are the C16-18 methyl ester
sulphonates (MES), or mixtures of C16-18 and C12-14 methyl ester sulphonates.
[0042] 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 which
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.
[0043] Especially preferred nonionic surfactants of this type are the C
9-C
15 primary alcohol ethoxylates containing 3-9 moles of ethylene oxide per mole of alcohol,
particularly the C
13-C
15 primary alcohols containing 6-9 moles of ethylene oxide per mole of alcohol and the
C
11-C
15 primary alcohols containing 3-5 moles of ethylene oxide per mole of alcohol.
[0044] Another class of nonionic surfactants comprises alkyl polyglucoside compounds of
general formula
RO (C
nH
2nO)
tZ
x
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,
0075996 and
0094118.
[0045] Still another class of nonionic surfactants comprises polyhydroxy fatty acid amides
which may be produced by reacting a fatty acid ester and an N-alkyl polyhydroxy amine.
The preferred amine for use in the present invention is N-(R1)-CH2(CH2OH)4-CH2-OH
and the preferred ester is a C12-C20 fatty acid methyl ester. Most preferred is the
reaction product of N-methyl glucamine with C12-C20 fatty acid methyl ester.
[0046] Methods of manufacturing polyhydroxy fatty acid amides have been described in
WO 92 6073, published on 16th April, 1992. This application describes the preparation of polyhydroxy
fatty acid amides in the presence of solvents. In a highly preferred embodiment of
the invention N-methyl glucamine is reacted with a C12-C20 methyl ester. It also says
that the formulator of granular detergent compositions may find it convenient to run
the amidation reaction in the presence of solvents which comprise alkoxylated, especially
ethoxylated (EO 3-8) C12-C14 alcohols.
[0047] A further class of surfactants are the semi-polar surfactants such as amine oxides.
Suitable amine oxides are selected from mono C
8-C
20, preferably C
10-C
14 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.
[0048] Cationic surfactants can also be used in the detergent compositions herein and suitable
quaternary ammonium surfactants are selected from mono C
8-C
16, preferably C
10-C
14 N-alkyl or alkenyl ammonium surfactants wherein remaining N positions are substituted
by methyl, hydroxyethyl or hydroxypropyl groups.
[0049] The surfactant containing particles will further comprise components selected from
a wide range of possible ingredients which are commonly used in laundry detergents.
Preferably the particles will contain some detergent builder:
[0050] 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 aminoalkylene 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,
more preferably from 30% to 60% by weight.
[0051] Preferred builder systems are free of boron compounds and any polymeric organic materials
are preferably biodegradable.
[0052] Whilst a range of aluminosilicate ion exchange materials can be used, preferred sodium
aluminosilicate zeolites have the unit cell formula
Na
z [(AlO
2 )
z (SiO
2 )
y ] xH
2O
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 preferably from 18% to 22% water in bound form.
[0053] 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 CaCO
3 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 CaCO
3/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 CaCO
3/litre/minute/(gram/litre) [2 grains/gallon/minute/ (gram/gallon)] to 390 mg equivalent
of CaCO
3/litre/minute/ (gram/litre) [6 grains/gallon/minute/(gram/gallon)], based on calcium
ion hardness.
[0054] Optimum aluminosilicates for builder purposes exhibit a calcium ion exchange rate
of at least 260 mg equivalent of CaCO
3/litre/ minute/ (gram/litre) [4 grains/gallon/minute/(gram/gallon)].
[0055] 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. Preferred synthetic crystalline aluminosilicate ion exchange materials useful herein
are available under the designations Zeolite A, Zeolite B, Zeolite X, Zeolite HS,
Zeolite MAP and mixtures thereof. In an especially preferred embodiment, the crystalline
aluminosilicate ion exchange material is Zeolite A and has the formula
Na
12 [(AlO
2 )
12 (SiO
2)
12 ]. xH
2 O
wherein x is from 20 to 30, especially 27. Zeolite X of formula Na
86 [(A1O
2)
86(SiO
2)
106]. 276 H
2O is also suitable, as well as Zeolite HS of formula Na
6 [(A1O
2)
6(SiO
2)
6] 7.5 H
2 O).
[0056] 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 or citric acid, 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 7205873, and the oxypolycarboxylate materials such as 2-oxa-1,1,3-propane tricarboxylates
described in
British Patent No. 1,387,447.
[0057] 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.
[0058] 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.
[0059] Alicyclic and heterocyclic polycarboxylates include cyclopentane-cis,cis,cis-tetracarboxylates,
cyclopentadienide pentacarboxylates, 2,3,4,5-tetrahydrofuran - cis, cis, cis-tetracarboxylates,
- 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, pyromellitic
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.
[0060] 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.
[0061] 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 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.
[0062] Organic phosphonates and amino alkylene poly (alkylene phosphonates) include alkali
metal ethane 1-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.
[0063] The particle or particles which contain the surfactant and builder may be made by
any convenient process. Examples of useful processing routes include spray drying,
agglomeration, extrusion, prilling etc. One particularly preferred processing route
for making high bulk density, high detergent active particles is by agglomerating
detergent powders and highly viscous surfactant pastes in a high shear mixer. A more
detailed description of such a process is given in the Applicants' co-pending application
EP510746, published on 28th October, 1992
[0064] Examples of other components which may be used in laundry detergents, and which may
be incorporated into the surfactant particles are described below under "Optional
Ingredients"
Optional Ingredients
[0065] Detergent Compositions of the present invention may, optionally, include anti-redeposition
and soil suspension agents, bleach activators, optical brighteners, soil release agents,
suds suppressors, enzymes, fabric softening agents, perfumes and colours, as well
as other ingredients known to be useful in laundry detergents.
[0066] 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 1% to 6% by weight of the composition.
[0067] Other useful polymeric materials are the polyethylene glycols, particularly those
of molecular weight 1000-10000, 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.
[0068] Preferred optical brighteners are anionic in character, examples of which are disodium
4,4
1-bis-(2-diethanolamino-4-anilino -s- triazin-6- ylamino)stilbene-2:2
1 disulphonate, disodium 4,4
1-bis-(2-morpholino -4-anilino-2-triazin-6-ylaminostilbene-2:2
1-disulphonate,disodium 4, 4
1-bis-(2,4-dianilino-s-triazin-6-ylamino)stilbene-2:2
1 - disulphonate, monosodium 4
1,4
11-bis-(2,4-dianilino-s-triazin-6 ylamino)stilbene-2- sulphonate, disodium 4,4
1-bis-(2-anilino-4-(N-methyl-N-2-hydroxyethylamino)-2-triazin-6-ylamino)stilbene-2,2
1- disulphonate, disodium 4,4
1-bis-(4-phenyl-2,1,3-triazol-2-yl)stilbene-2,2
1 disulphonate, disodium 4,4
1bis(2-anilino-4-(1-methyl-2-hydroxyethylamino)-s-triazin-6-ylamino)stilbene-2,2
1disulphonate and sodium 2(stilbyl-4
11-(naphtho-1
1,2
1:4,5)-1,2,3 - triazole-2
11- sulphonate.
[0069] 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. 4116885 and
4711730 and
European Published Patent Application No. 0272033. A particular preferred polymer in accordance with
EP-A-0272033 has the formula
(CH
3(PEG)
43)
0.75(POH)
0.25(T-PO)
2.8(T-PEG)
0.4]T(PO-H)
0.25((PEG)
43CH
3)
0.75
where PEG is -(OC
2H
4)O-, PO is (OC
3H
6O) and T is (pCOC
6H
4CO).
[0070] 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.
[0071] 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 normally used in finely divided
forms, 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.
[0072] 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 m
2/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.
[0073] 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.
[0074] 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.
[0075] 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 C
20-C
24 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.
[0076] Another optional ingredient useful in the present invention is one or more enzymes.
[0077] 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.
[0078] 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.
[0079] Their combination with mono C
12-C
14 quaternary ammonium salts is disclosed in
EP-B-0026527 & 528. Other useful organic fabric softening agents are the dilong chain 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-0299575 and
0313146.
[0080] 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.
EXAMPLES
[0081] The following samples of sodium silicate having a ratio of SiO
2:Na
2O of 2.0 were used :
|
Silicate A |
Silicate B |
Sieve fractions |
|
|
>1180um |
0.0% |
3.3% |
1180>x>710 um |
0.0% |
35.5% |
710um>x>425um |
1.2% |
37.4% |
425um>x>250um |
12.2% |
19.3% |
250>x>150 |
38.5% |
0.5% |
150>x |
48.2% |
0.7% |
|
|
|
Porosity |
15% |
6% |
Specific surface area * |
0.117m2/cc |
0.0200m2/cc |
* Specific Surface area was measured with a Malvern M7.09 instrument |
[0082] In these examples the following abbreviations have been used:
- DTPMP:
- Diethylene triamine penta (methylene phosphonic acid), supplied by Monsanto as Dequest
2060 (trade name).
- Sokolan CP5:
- Co-polymer of acrylic and maleic acid, supplied by BASF.
- C14/15AE7:
- Ethoxylated alcohol having an alkyl chain length of predominantly C14 to C15 and an
average of 7 ethoxy groups per molecule
- C16/18AE11:
- Ethoxylated alcohol having an alkyl chain length of predominantly C16 to C18 and an
average of 11 ethoxy groups per molecule
- LAS:
- linear alkyl benzene sulphonate
- C16/18AS:
- Alkyl sulphate having a alkyl chain length of predominantly C16 to C18
- CMC:
- Carboxy methyl cellulose
- PB1:
- Sodium perborate, monohydrate
- PB4:
- Sodium perborate, tetrahydrate
- TAED:
- N,N,N,N-tetraacetylethylene diamine
- Percarbonate:
- Sodium percarbonate having 13%AvO2, coated 2.5% Carbonate/Sulphate
[0083] The following formulations were prepared :
|
Example 1 INVENTION |
Example 2 Comparative |
Example 3 Comparative |
Spray dried |
|
|
|
Granule |
|
|
|
a) Zeolite A |
13% |
13% |
13% |
b) DTPMP |
0.4% |
0.4% |
0.4% |
c) Sokalan CP5 |
4% |
4% |
4% |
Agglomerate (mean particle size of 600 micrometers) |
|
|
|
d) LAS |
7% |
7% |
7% |
e) C16/18AS |
2% |
2% |
2% |
f) Zeolite A |
7% |
7% |
7% |
g) Sodium |
10% |
10% |
10% |
carbonate |
|
|
|
h) CMC |
0.3% |
0.3% |
0.3% |
Spray on |
|
|
|
i) C14/15AE7 |
4% |
4% |
4% |
j) C16/18AE11 |
1% |
1% |
1% |
k) Suds suppressor |
0.5% |
0.5% |
0.5% |
Dry additives |
|
|
|
l) Sodium |
5% |
5% |
5% |
Carbonate |
|
|
|
m) Citrate |
5% |
5% |
5% |
n) TAED |
5% |
5% |
5% |
o) PB1 |
- |
12% |
12% |
p) PB4 |
- |
8% |
8% |
q) Percarbonate |
20% |
- |
- |
r1) Silicate A |
3% |
3% |
- |
(level < 425 micrometers) |
(2.96%) |
(2.96%) |
|
r2) Silicate B |
- |
- |
3% |
(level < 425micrometers) |
- |
- |
(0.62%) |
|
|
|
|
Balance to |
100% |
100% |
100% |
(moisture/miscella neous) |
|
|
|
%Av02 ex Peroxygen source |
2.60 |
2.62 |
2.62 |
[0084] The spray dried granules were made by preparing an aqueous slurry containing components
a) to c) and spraying it into a conventional drying tower.
The agglomerates were prepared by making a viscous aqueous paste containing components
d) and e) and agglomerating it with powders f) to h) in a high speed mixer. The agglomerates
were then dried in a fluid bed mixer before overspraying with components i) to k).
The spray dried granules and agglomerates were then dry mixed with powder components
l) to r).
[0085] The rates of alkalinity release of examples 1, 2 and 3 was compared:
[0086] In the beaker of a Sotax apparatus, 10 g of product is added with 5mls of a N HCl
acid to 1l of water having a hardness of 25DH (3:1 Calcium Magnesium). The temperature
of the solution is maintained at 20C and agitated with a constant agitation (100rpm
via a propeller agitator). The HCl addition mimics the level of acidic soil provided
by a very soiled load.The pH is measured after different periods of time. The experiment
is run for Example 1, 2 and 3.
|
Example 1 |
Example 2 |
Example 3 |
pH after |
|
|
|
10 seconds |
8.6 |
8.6 |
7.0 |
20 seconds |
9.2 |
9.1 |
8.3 |
30 seconds |
9.5 |
9.2 |
8.5 |
60 seconds |
9.8 |
9.5 |
9.0 |
10 minutes |
10.0 |
9.9 |
9.4 |
[0087] This shows that examples 1 and 2 with their higher level of silicate particles below
425 micrometers improves dramatically the rate of alkalinity release in a wash solution
compared with example 3. This explains why example 3 performs less well than examples
1 and 2.
[0088] Comparative example 2 has a poor dispensing profile but a good rate of alkalinity
release. This is due to the presence of small silicate particles in combination with
perborate bleach.
Comparative example 3 has a good dispensing profile but a poor rate of alkalinity
release. This is due to the presence of large silicate particles in combination with
perborate bleach.
[0089] Example 1 has a good dispensing profile and a good rate of alkalinity release. This
is due to the presence of small silicate particles in combination with percarbonate
bleach.
[0090] Compositions of examples 1, 2 and 3 were tested in realistic washing conditions in
a washing machine. Example 1 was found to outperform both comparative examples 2 and
3 over a wide range of stains, especially at low washing temperatures.