Note: Descriptions are shown in the official language in which they were submitted.
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WASHING BAR
The invention relates to a washing bar, i.e. a detergent compo-
sition in bar form.
It is known to include bleaches in cleaning products, in parti-
cu1ar in detergent compositions for cleaning fabrics and hard
surfaces, for example. It is known for these bleaches to be
photobleaches or to be bleaches activated by photosensitive
bleach activators. For example, United States Patent Specifica-
tion No. 4,033,818 describes a detergent composition containing
particular species of zinc phthalocyanine as an oxygen bleach
activator.
It is also known to use alkali metal chlorites as a bleach.
For example, it is known to bleach cellulose with sodium chlorite
in an acid medium, the chlorite in the acid medium producing
chlorine dioxide, which is the species responsible for the actual
bleaching. Acidic media are generally unsuitable for domestic
cleaning processes. It is also known to activate chlorites at high
pH with activators such as hydroxylammonium salts (see US Patent
Specification No. 3,836,475), but such activators are expensive
and may also be toxic. For these reasons they have not found
commercial success in domestic situations.
It is further known from British Patent Specification ~o. 1,397,595
to use alkalimetal chlorite, particularly sodium chlorite, activated
by high energy radiation, particular from X-rays, ~-rays and elec-
tron rays, for bleaching fabrics under alkaline conditions.
It is an object of the present invention to provide a detergent
composition in bar form which imparts a bleaching effect at al-
kaline or neutral pH without the use of high cost activators
or high energy X-rays, y-rays or electron rays.
We have discovered that satisfactory washing and bleaching of
fabrics can be obtained by using a washing bar containing a
chlorite or other halite, if the liquor containing the formula-
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tion or fabrics in contact therewith are irradiated with ultra-
violet light. The present invention therefore provides a deter-
gent composition in bar form for washing under ultra-violet
light radiation.
Thus, according to the invention there is provided a de-
tergent composition in bar form comprising:
(i) at least about 10%, preferably from about 15% to
about 99.5% by weight of a detersive surfactant
with or without a detergency builder;
(ii) at least about 0.1%, preferably from about 0.5%
to about 40% by weight of a material yielding halite
ions in aqueous media;
(iii) less than about 20% by weight of water; and optionally
(iv) up to about 50% by weight of an inert filler,
the composition yielding a pH of at least 6.0 when dispersed in
one part by weight of water.
The detersive surfactant may be selected from soaps; anionic,
zwitterionic, amphoteric, semi-polar, nonionic or cationic
surfactants; and any mixtures thereof. Suitable such surfactants
are for example sodium soaps of C12-C18 fatty acids, sodium al-
kyl benzene sulphates, sodium alkane sulphonates, sod1um olefin
sulphonates, sodium alkyl sulphates and ethylene oxide or ethyl-
ene oxide/propylene oxide condensation products.
Further suitable surfactant materials are disclosed in Schwartz-
Perry: "Surface-active agents and detergents", Vol. II, 1958.
In laundry bars for cleaning fabrics the detersive surfactant
may include a detergency builder in an amount of up to about
80%, preferably about 15% to about 40% by weight of the composi-
tion. The builder may be selected from alkali metal phosphates
and carbonates, aluminosilicates and other known inorganic and
organic builders.Examples of such builders are sodium tripoly-
phosphate, sodium pyrophosphate, sodium orthophosphate, sodium
carbonate, zeolite and nitrilotriacetate. A particularly pre-
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ferred composition contains a synthetic anionic surfactant and
a detergency builder.
The material yielding halite ions in aqueous media is prefer-
ably selected from chlorites and bromites, particularly chlori-
tes, of substituted or unsubsituted ammonium, alkali metals (for
example sodium, potassium or lithium) or alkaline earth metals
(for example calcium or magnesium). The preferred material is
sodium chlorite.
The inert filler, when present, may be selected from sodium
sulphate, calcite and clays and mixtures thereof.
It is usual for the bar to be rubbed onto fabrics which have
already been wetted, after which the fabrics are agitated in
water. The amount of water present depends to a large extent
on the user. Generally more than one part by weight of water
will be present for each part by weight of the composition.
For a laundry bar it is essential that the composition should
yield a pH of at least 6.0, preferably from about 8.5 to about
11.0, when dispersed in one part by weight of water.
The desired pH may be achieved by the addition of buffering
agents, although where the various components of the composi-
tion have a suitable natural pH, no buffering agent needs to
be added.
The exposure to ultra-violet light may be achieved by exposing
the dispersed composition of the fabrics in contact therewith
to daylight or to an artificial source of ultra-violet light.
Thus the dispersed composition may be irradiated before contact
with the fabrics or while the dispersed composition is in con-
tact with the fabrics, or alternatively the fabrics may be ir-
radiated while in contact with the dispersed composition or
thereafter. It is essential that this radiation should occur
before the halite is removed, e.g. by rinsing, from the fabrics.
The ultra-violet light preferably has a component with a wave-
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length of between about 200 nm and about 400 nm, most preferably
less than 370 nm. The intensity of the ultra-violet light, as
measured at the fabric surface or at the surface of the liquor
is preferably from about 0.01 to about 10.0, more preferably from
S about 0.05 to about 0.2 Wm 2nm 1. Typical bright sunlight has an
intensity over most wavelengths of 0.1-0.2 Wm 2nm 1. Under these
conditions a suitable exposure time is between about 10 minutes
and about 10 hours, more preferably between about 30 minutes and
about 4 hours, depending on the concentration of the chlorite in
the liquor and on the degree of bleaching required. The preferred
light intensity can alternatively be expressed as from about 10 1
to about 10 6, preferably from about 10 2 to about 10 4 Einsteins
of energy in the 200 nm to 370 nm wavelength region per litre of
liquor.
The detergent composition may contain one or more ingredients other
than those specified above, for example other bleaches, bleach pre-
cursors and colorants, including photoactivated bleaches such as
sulphonated zinc phthalocyanine, anti-foaming agents, anti-rede-
position agents, perfumes, perfume carriers, enzymes, organic sol-
vents, optical brightening agents, thickeners, preservatives, dyes,
plasticizers, processing aids, whitening agents, colouring agents
or electrolytes.
Preferred optical brightening agents for use in the present inven-
tion are disodium-4,4'-bis(2-sulphostyryl)-biphenyl and disodium-
4,4'-bis(4-phenyl-1,2,3-triazol-2-yl)-2,2'-stilbene-disulphonate.
The composition should, before use, contain substantially no ma-
terial which in the aqueous liquor will react with and remove the
halite ions. Thus, chlorite ions are known to react with chlorite
or chlorine producing materials such as calcium hypochlorite or
sodium dichloroisocyanurate to produce chlorir.e dioxide. Thus,
the compcsition preferably contains, for each part by weight of
halite-yielding material, less than 0.4 parts, advantageously
less than 0.1 part by weight of a material which in aqueous media
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in the absence of UV-light reacts to a substantial extent with
the halite ions, that is reacts with at least a major proportion
of the halite ions.
In order to achieve adequate soil removal from the substrate,
in addition to bleaching, it is desirable for the ratio of the
total weight of the surfactant and builder ~when present) to
the weight of the halite yielding material to be in excess of
1:1, preferably in excess of 3.5:1, ideally in excess of 5.0:1.
The invention can also be applied to give an improved persona~
washing bar for washing the skin. In such bars the detersive
surfactant will normally be soap, but may also be selected from
synthetic anionic, zwitterionic, amphoteric, semi-polar, cation-
ic and nonionic surfactants and mixtures thereof or mixtures there-
of with soap, though generally without the inclusion of a deter-
gent builder.
In use the composition of the personal washing bar comes into
contact with the skin in the presence of water. Simultaneously
with, or subsequent to, the contact between the composition and
the skin, the skin is exposed to ultra-violet light. ~hile this
may be derived from an artificial source, it is most convenient
if the source of radiation is daylight.
There are no specific requirements in the methods used to pre-
pare the bars of the invention. A number of methods are known
in the art (see e.g. U.S. Patent Specificatio~ No. 3,291,744
and 3,178,370) and these methods are suitable for the manufac-
ture of bars with the material yielding halite ions being added
at a suitable stage.
:
The invention will now be illustrated by the following non-
limiting Examples, in which percentages and parts are by weight
unless otherwise specified.
In the following Examples 1 and 2, a pyrex cell was partially
filled with water. Heavily tea-stained cloths were soaked with
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water, rubbed with the surfactant bar being tested and then im-
mersed in the water in the cell, with a cloth:liquor ratio of
1:4 and an effective liquor concentration of 20 g/l. The cell
was then placed in the chamber of an ATLAS WEATHEROMETER which
had been adjusted to an output to simulate solar radiation both
in intensity and energy distribution. The chamber had an initial
temperature of about 22C. After irradiating the cloths from one
side only for a selected time, the reflectance of the treated
cloths changes (a R460~), both of those regions of the cloths
which are immersed in the liquor and of those regions of the
cloths which were suspended above the liquor. Reflectance changes
of both front and back of each cloth were measured, and the
average taken.
The totally immersed cloth simulates a method of bowl-washing
fabrics in daylight, whereas the suspended cloth simulates a
re-wet sun-bleaching operation.
EXAMPLE 1
20 Non-soap detergent test bars were used having the following
approximate formulations:
Ingredient _ % % %_ _
Sodium alkyl benzene sulphonate 28 28 28 28
Sodium pyrophosphate 16 16 16 16
Sodium carbonate 10 10 10 10
Calcite 32 27 22 17
Sodium carboxymethyl cellulose 2 2 2 2
Sodium sulphate 6 6 6 6
Water 6 6 6 6
Sodium chlorite 0 5 10 15
The bars were prepared in the following manne~: In a Planetex
high shear mixer alkyl benzene sulphonic acid was neutralized
with excess sodium carbonate. After about 5 minutes water; cal-
cite; sodium carboxymethyl cellulose + sodium chlorite; sodiumpyrophosphate + remaining water, were added and mixed in the
gîven sequential order at approximately 5 minutes' intervals.
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The mass was then milled twice in a 3-roller mill, followed by
plodding and cutting into bars.
The results are set out in the following Table I.
TABLE I
~ R 460 ~
Chlorite Irradiation Suspended Immersed
Concentration time cloth cloth
0 1 hour 0.1 0.0
0 1.5 hours 3.0 1.5
0 2 hours 3.3 4~1
5% 1 hour 3.7 1.7
5% 1.5 hours 6.4 3.2
5% 2 hours 7.8 6.3
10% 1 hour 5.4 5.1
10% 1.5 hours 11 . 4 10 . 4
10% 2 hours 12.2 14.7
15% 1 hour 5.6 6.7
15% 1.5 hours 11.4 13.5
15% 2 hours 12.0 18.5
EXAMPLE 2
Example 1 was repeated using non-soap detergent test bars of
25 the following approximate formulations:
~ % % % %
Sodium alkylbenzene sulphate 20 20 20 20
Sodium tripolyphosphate 30 30 30 30
Sodium orthophosphate 3 3 3 3
Sodium carboxymethyl cellulose 2 2 2 2
Water 9 9 9 9
Calcite 29 24 19 14
Sodium chlorite 0 5 10 15
Sodium carbonate 7 7 7 7
The bars were prepared by mixing the ingredients in the follow-
ing order:
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In a Planetex high shear mixer sodium carbonate and sodium tri-
polyphosphate were mixed with alkyl benzene sulphonic acid and
a small amount of water for 15 minutes to neutralize the alkyl
benzene sulphonic acid to sodium alkyl benzene sulphonate. There-
after the calcite; sodium carboxy methyl cellulose + sodiumchlorite + sodium orthophosphate, and water were added and mixed
in the given sequential order at approximately 5 minutes' inter-
vals.
The mass was then milled and plodded to form bars in the manner
as described in Example 1.
The results are set out in the following Table II.
TABLE II
~ R460*
Chlorite TreatmentSuspended Immersed
time cloth cloth
0 1 hour - 2.0 - 2.1
0 1.5 hours 1.4 - 2.9
~0 0 2 hours 5.4 - 2.0
1 hour 6.8 1.4
1.5 hours 7.4 1.6
2 hours 19.8 9.7
1 hour 7.3 3.6
1.5 hours 13.0 9.7
2 hours 8.5 9.7
1 hour 12.2 17.2
1.5 hours 14.5 45.6
2 hours 21.3 38.0
The treatment liquids containing sodium chlorite in the above
Examples had a pH of between 8.5 and 11Ø
EXAMPLES 3 to 5
The following compositions were made into personal washing bars
and were found to exhibit a refreshing effect when used for
skin washing in daylight.
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EXAMPLE 3
Ingredient %
Sodium soap of tallow fatty acid 45.26
Sodium soap of coconut fatty acid 37.04
Coconut fatty acid 4.50
Sodium chlorite 1.00
Butylated hydroxy toluene 0.13
Phosphoric acid 0.12
Titanium dioxide 0.24
Water and minor ingredients balance
EXAMPLE 4
Ingredient
Sodium acyl isethionate 48.6
Sodium dodecyl benzene sulphonate 2.0
Sodium soap of coconut fatty acid 11.0
Coconut fatty acid 3.0
Sodium chlorite 0.5
Stearic acid 21.7
Water and minor ingredients balance
EXAMPLE 5
Ingredient
Sodium C11-C14 alkane sulphonate 22.1
Sodium C15-C18 alkane sulphonate 29.4
Sodium C16-C18 olefin sulphonate 22.1
Myristyl alcohol 6.3
Cetyl alcohol 5,0
Stearyl alcohol 5,0
Sodium chlorite 2.0
Water and minor ingredients balance
