[0001] This invention relates to the use of a fabric softening clay as an additive in a
fabric washing composition comprising an anionic surfactant, a nonionic surfactant
and a proteolytic enzyme.
[0002] In GB 1 400 898 (Procter & Gamble/STORM) a detergent and softening composition is
taught which includes a smectite clay containing material having a cation exchange
capacity of at least 50 meq/100g, together with a detergent active material. Enzymes
are suggested as a possible additive to the composition.
[0003] Recently it has become the practice to incorporate more enzymes in fabric washing
compositions so that the compositions can be used at lower temperatures to save energy
and reduce the damage to clothes caused by high temperature washing. There is also
a trend towards washing woollen garments in the washing machine, even if they are
marked 'hand wash only'. The damage caused by washing wool in a fabric washing composition
containing high levels of proteolytic enzyme can be considerable in terms of weight
loss of the fabric, shrinkage and eventual disintegration of the garment by formation
of holes. According to the present invention there is provided the use of from 2 to
30% by weight of a fabric softening clay as an additive to reduce or prevent wash
damage of woollen articles in a fabric washing composition comprising an anionic surfactant,
a nonionic surfactant and a proteolytic enzyme. The advantage of such a use of a fabric
softening clay is that the damage to the woollen clothes may be considerably reduced
without a reduction in the detergency of the fabric washing composition. It might
be expected that if the clay were inhibiting the enzyme activity, then this would
result in reduced detergency, especially of proteinaceous stains. Surprisingly this
does not happen.
[0004] The clay may be added in the form of a granule comprising 10 to 30% by weight nonionic
surfactant. Such a mode of addition is advantageous for a granular detergent composition
because it enables the clay to be conveniently post-dosed to the formulation. The
non-ionic provides for easy granulation of the clay.
[0005] Preferably the clay is selected from layered smectites and hectorites as these are
the common naturally occurring fabric softening clays. Clay mineral containing materials
useful in the present invention include dioctahedral and trioctahedral three layer
smectite clays, ideally of the calcium and/or sodium montmorillonite type. For example
PRASSA clay from Greece, GELWHITE from Texas USA, Willemse from South Africa and VOLCLAY
BC from Wyoming. The effectiveness of a clay containing material as a fabric softener
will depend partly on the level of clay mineral in the material. Most preferably the
clay is a bentonite such as a montmorillonite.
[0006] The composition may further comprises Lipolytic enzyme, such as Lipolase. The clay
also prevents some damage to wool which may be attributable to such other enzymes.
[0007] Clay protection appears to be particularly beneficial if the pH of the composition
in the wash is between 7.5 and 10.5, preferably between 9 and 10.
[0008] Anionic surfactants useful in the present invention include: Linear alkyl sulphonates.
Examples of suitable synthetic anionic detergent compounds are sodium and potassium
alkyl sulphates, especially those obtained by sulphating higher (C₈-C₁₈) alcohols
produced for example from tallow or coconut oil, sodium and potassium alkyl (C₉-C₂₀)
benzene sulphonates, particularly sodium linear secondary alkyl (C₁₀-C₁₅) benzene
sulphonates; sodium alkyl glyceryl ether sulphates, especially those ethers of the
higher alcohols derived from tallow or coconut oil and synthetic alcohols derived
from petroleum; sodium coconut oil fatty monoglyceride sulphates and sulphonates;
sodium and potassium salts of sulphuric acid esters of higher (C₈-C₁₈) fatty alcohol-alkylene
oxides, particularly ethylene oxide, reaction products; the reaction products of fatty
acids such as coconut fatty acids esterified with isethionic acid and neutralised
with sodium hydroxide; sodium and potassium salts of fatty acid amides of methyl taurine;
alkane monosulphonates such as those derived by reacting alpha-olefins (C₈-C₂₀) with
sodium bisulphite and those derived from reacting paraffins with SO₂ and Cl₂ and then
hydrolysing with a base to produce a random sulphonate; and olefin sulphonates, which
term is used to describe the material made by reacting olefins, particularly C₁₀-C₂₀
alpha-olefins, with SO₃ and then neutralising and hydrolysing the reaction product.
The preferred anionic detergent compounds are sodium (C₁₁-C₁₅) alkyl benzene sulphonates
and sodium (C₁₆-C₁₈) alkyl sulphates.
[0009] Suitable nonionic surfactants which may be used include in particular the reaction
products of compounds having a hydrophobic group and a reactive hydrogen atom, for
example aliphatic alcohols, acids, amide or alkyl phenols with alkylene oxides, especially
ethylene oxide either alone or with propylene oxide. Specific nonionic detergent compounds
are alkyl (C₆-C₂₂) phenols-ethylene oxide condensates, generally up to 25 EO, i.e.
up to 25 units of ethylene oxide on average per molecule, the condensation products
of aliphatic (C₈-C₁₈) primary or secondary linear or branched alcohols with ethylene
oxide, generally up to 40 EO, and products made by condensation of ethylene oxide
with the reaction products of propylene oxide and ethylenediamine. Other so-called
nonionic detergent compounds include long chain tertiary amine oxides, long chain
tertiary phosphine oxides and dialkyl sulphoxides.
[0010] Mixtures of detergent compounds, for example mixed anionic or mixed anionic and nonionic
compounds may be used in the detergent compositions, particularly in the latter case
to provide controlled low sudsing properties. This is beneficial for compositions
intended for use in suds-intolerant automatic washing machines.
[0011] Amounts of amphoteric or zwitterionic detergent compounds can also be used in the
compositions of the invention but this is not normally desired due to their relatively
high cost. If any amphoteric or zwitterionic detergent compounds are used it is generally
in small amounts in compositions based on the much more commonly used synthetic anionic
and/or nonionic detergent compounds.
[0012] A detergency builder may also be present. This may be any material capable of reducing
the level of free calcium ions in the wash liquor and will preferably provide the
composition with other beneficial properties such as the generation of an alkaline
pH, the suspension of soil removed from the fabric and the suspension of the fabric
softening clay material. The level of the detergency builder may be from 10% to 70%
by weight, most preferably from 25% to 50% by weight.
[0013] Examples of detergency builders include precipitating builders such as the alkali
metal carbonates (with or without seed crystals such as calcite), bicarbonates, ortho
phosphates, sequestering builders such as the alkali metal tripolyphosphates or nitrilotriacetates,
or ion-exchange builders such as the amorphous alkalimetal aluminosilicates or the
zeolites.
[0014] The clay material can be added in various physical forms. It may, for example, be
spray-dried with other components of the formulation or it may be added separately.
In the latter case the clay may be ground to a suitable size, say 5 to 2000 microns,
or may be in the form of granulated fine particles optionally containing a binder
such as an inorganic salt or a surfactant.
[0015] Proteolytic enzymes that may be used in the present invention include the Savinases,
such as Savinase 6.0T (ex Novo), Opticlean (Solvay) and Maxacal (Ibis) also Alcalases
such as Alcalase 2.34 LVX and Esperase 8.0 (Novo), Optimase (Solvay) and Maxatase
(Ibis). Lipases and cellulases may also be included in the composition.
[0016] Apart from the components already mentioned, a detergent composition of the invention
can contain any of the conventional additives in the amounts in which such additives
are normally employed in fabric washing detergent compositions. Examples of these
additives include additional fabric softening agents such as a cationic fabric softening
agent or a fatty amine. Further examples of these additives include the lather boosters
such as alkanolamides, particularly the monoethanolamides derived from palm kernel
fatty acids and coconut fatty acids, lather depressants, oxygen-releasing bleaching
agents such as sodium perborate and sodium percarbonate, peracid bleach precursors,
chlorine-releasing bleaching agents such as trichlorisyocyanuric acid, inorganic salts
such as sodium sulphate, other fillers such as kaolin, and, usually present in very
minor amounts, fluorescent agents, perfumes, other enzymes such as amylases, germicides
and colorants.
[0017] The invention will now be described with reference to the following non-limiting
examples and with reference to the accompanying drawings, of which:
Figure 1 is a photograph of lambs wool cloths washed in compositions with and without
clay;
Figure 2 is a photograph of Botany wool cloths washed in compositions with and without
clay; and
Figure 3 is a photograph of Shetland wool cloths washed in compositions with and without
clay.
Example 1
[0018] Fabric washing powders of the following compositions were prepared by conventional
techniques. The clay nonionic granule used for composition B was prepared by aggregation
and post dosed to the base powder. The base powder for composition B was the same
as that for composition A except for the addition of the clay/nonionic granules.
Table 1
|
Composition A |
Composition B |
Anionic |
18.5 |
16.65 |
Nonionic |
4.6 |
4.14 |
Savinase 6.0T |
0.65 |
0.85 |
Zeolite |
35.9 |
32.31 |
Sodium carbonate |
12.4 |
11.16 |
Polymer |
4.4 |
3.96 |
Sodium bicarbonate |
4.0 |
3.6 |
Water |
14.5 |
13.05 |
Lipolase 100T |
0.30 |
0.27 |
Minor Ingredients |
4.75 |
4.275 |
Clay/nonionic |
- |
10 |
[0019] In the following examples these compositions were used in a computer controlled Miele
washing machine using a 40°C cotton programme. This programme was selected in order
to show the damage effects of washing with a powder containing an enzyme more rapidly
than would have been the case if the wool wash programme had been used. The order
of the different compositions should not be affected by this procedure although the
relative positioning may be changed by the amplification of damage resulting from
increased agitation.
Example 2
[0020] Various wool fabrics were tested for weight loss due to repeated washing in either
composition A(prior art) or composition B(the invention).
[0021] The fabrics were:
2.1 A lambs wool jumper
2.2 A botany wool jumper
2.3 A Shetland wool jumper
2.4 A wool/acrylic mixture jumper
[0023] It can be seen that the inclusion of the clay in Composition B reduces the weight
loss. This is further demonstrated by Figures 1 to 3 which show the generally less
damaged and holed cloths which have been washed in composition B as compared with
Composition A.
Example 3
[0024] To show that detergency is not being traded for reduced damage a series of detergency
tests were carried out on standard test cloths. Reflectance measurements were made
on the clothes before and after washing using an Ultrascan spectrophotometer. ΔR460*
values were calculated and are tabulated in Table 7. It can be seen that the addition
of the clay does not have an adverse effect on detergency even though the dilution
caused by the addition results in a lower level of surfactant and enzyme in composition
B.
1. Use of from 2 to 30% by weight of a fabric softening clay as an additive to reduce
or prevent wash damage of woollen articles in a fabric washing composition comprising
an anionic surfactant, a nonionic surfactant and a proteolytic enzyme.
2. Use according to claim 1 wherein the clay is added in the form of a granule comprising
10 to 30% by weight nonionic surfactant.
3 Use according to claim 1 wherein the clay is selected from layered smectites and
hectorites.
4 Use according to claim 1 wherein the clay is bentonite.
5. Use according to claim 1 wherein the composition further comprises Lipolytic enzyme.
6. Use according to claim 1 wherein the pH of the composition in the wash is between
7.5 to 10.5, preferably 9 to 10.