[0001] The present invention relates to a solid composition for the pretreatment of fabric
prior to laundering which improves removal of oxidisable stains.
[0002] Prewash stain removal compositions which are applied locally to stains on fabric
before laundering are known. Some of these are provided in liquid form, for example
supplied in a form suitable for dabbing onto the fabric or sprayed onto the fabric
or in the form of a viscous liquid. Liquid preparations have various problems; the
liquid solvent may cause several components to be insufficiently storage stable, the
treated fabric must be laundered immediately after application, i.e. before the compositions
have dried and the application of such compositions is in many cases inconvenient.
[0003] Other prewash compositions are in solid form. One example is sold under the trade
name Vanish and is a soap type formulation with added solvent in bar form. Another
composition is sold under the trade name Polystik which is a nonionic solid surfactant
in stick form. In EP-A-205999 there is provided an enzyme-containing stick form composition
comprising sodium stearate as the carrier and various inorganic salts. Although the
product described has a satisfactory effect on proteinaceous stains, it is insufficiently
effective on oxidisable stains, such as tea and red wine. It is necessary to add additional
"colouring or opacifying" ingredients to render the composition white or coloured
to make it visible on the fabric and of an acceptable colour.
[0004] In US-A-4145183 there are disclosed solid compositions which may be provided in stick
form, comprising a bleach activator dispersed in a water soluble non-ionic surfactant.
Although the compositions are improved as compared to compositions containing no activator,
the composition still fail to remove many stains satisfactorily. The activator used
to make the compositions is described as "finely ground" but there is no specific
disclosure of the particle sizes.
[0005] In GB-A-2053998 granules of bleach activator are formed by spraying a liquid onto
a particulate mass of activator having particle sizes mainly in the range 100-150
microns. Less than 20% by weight of the particles have sizes less than 20 micron since
in processes of the type described smaller particles of the activator become difficult
to handle.
[0006] In EP-A-0062523 "noodles", i.e. of diameter of 0.5 to 2mm of activator are produced
by extruding a mixture of molten surfactant and particulate activator through a screen,
in which the activator is preferably such that 80% passes a 250 micron screen or more
preferably a 100 micron screen.
[0007] According to the invention a new laundry pre-treatment composition in stick form
comprises a water-soluble surfactant binder having a dropping point in the range of
30 to 100°C and bleach activator and bleach stabiliser dispersed in the binder.
[0008] The new stick form compositions according to the invention which contain a bleach
stabiliser in addition to the bleach activator provide stain removal properties greatly
improved as compared to the composition in US-A-4145183, when the pretreated fabric
is washed in a laundry liquor containing a peroxy bleach compound. The prewash compositions
are effective on localised stain removal since they provide a high concentration of
bleaching entities at the position where they are required, during the wash.
[0009] Although some bleach activators are liquids at room temperature and may be used in
the present invention, the most preferred activators are particulate. Activator of
conventional particle size profile, i.e. produced by conventional milling, for example
comprising particles having sizes in the range 50 to 500 microns and an average size
of about 50 to 250, may be used in this aspect of the present invention.
[0010] We have found that particularly advantageous properties are achieved if the particles
are smaller. Suitably substantially all the activator particles have sizes less than
50 microns. Preferably substantially all the particles have sizes less than 20 microns
for example less than 10 microns. Preferably the average size of the particles is
in the range 2 to 20 microns, preferably in the range 3 to 10 microns and most preferably
around 5 microns. The small particles are formed from larger particles, usually by
attrition in a microniser.
[0011] By utilising particles of the reduced sizes the stick composition has improved mechanical
and spreadability properties, improved visual appearance and improved performance
in stain removal. The improved appearance is achieved since the small particles render
the composition whiter and thus easier for the user to see when it is applied to the
fabric. This eliminates or reduces the necessity of adding colouring agents or fillers
to increase the opacity of the compositions. The incorporation of such additives is
generally disadvantageous since it merely reduces the concentration of the active
ingredients in the composition.
[0012] The activators are mono- or di-functional acyl derivatives or, less frequently, oxime
derivatives e.g. esters of imidic acids (imidates); examples of acyl derivatives are
esters including esters of enols, imides, including glycourils, acylated urea derivatives,
acylated hydantion derivatives and N, N-diacyl methlenediformamides, imidazoles and
oximes as well as triacyl guanidines, acyl sulphonamides, triazine derivatives, piperazine
derivatives. Preferred derivatives are imides, oximes and esters, especially optionally
substituted phenol esters and imides.
[0013] The acyl group of the activator may be one which confers some degree of surface activity
upon the activator compound, such as an acyl group including a relatively hydrophobic
alkyl, aralkyl, alkaryl or aryl. Examples are C₅₋₁₅ alkyl, preferably C₅₋₉ alkyl.
Preferably, however, the activator is a relatively non-surface active activator, such
as one in which the acyl group is a C₂₋₄ alkanoyloxy group, preferably an acetyl group.
[0014] The activator is preferably tetra acetyl ethylene diamine but may be any of the known
relatively non-surface active detergent bleach activators, such as those described
in EP-A-0062523. Other preferred activators include polyacetyl mono-, di-, or polysaccharides
such as penta acetyl glucose, glycourils such as tetra acetyl glycouril, N-acyl amides,
acylated diketopiperazines, and other N-acyl amines, in which the acyl group(s) each
has less than 5 usually 2 carbon atoms.
[0015] The bleach stabiliser is a compound which enhances the stability of the peracid species
formed on the reaction of the bleach activator with a bleach compound in the wash
liquor. Usually the bleach stabiliser is a sequestering agent or mixture of sequestering
agents. It may be an amino carboxylic acid sequestering agent, for instance nitrilo
triacetic acid (NTA) or ethylene diamine tetra acetic (EDTA) acid or diethylene triamine
penta acetic acid (DTPA) (or salts thereof) or a low molecular weight anionic polymer
formed from ethylenically unsaturated monomers e.g. unsaturated carboxylic acid or
sulphonic acid monomers, such as acrylic acid, but preferably the stabiliser is a
phosphonic acid stabiliser or a salt thereof. The stabilisers have the further property
that they may increase the rate of dissolution of a film of the composition from fabric
during the laundering process.
[0016] Any of the phosphonic acid compounds conventionally present in detergents as stabilisers
or sequestrants may be used including ethylene diamine tetra (methylene phosphonic
acid) (EDTMP) for instance as the free acid or as the hexa sodium salt, diethylene
triamine penta (methylene phosphonic acid) (DTPMP), hexamethylene diamine tetraphosphonic
acid (HMDTP), nitrilotrismethylenephosphonic acid (NTMP) or its sodium salt or hydroxyethyl-1,
1-diphosphonic acid (HEDP). The phosphonic acids may be present in the body as free
acid or as acceptable and active salts which are solid e.g. with ammonia, alkali metal
(generally sodium) or alkaline earth metal (generally calcium or magnesium) or as
complexes with, for instance, zinc or aluminium.
[0017] The composition may additionally comprise water-soluble inorganic salts, such as
alkali metal or alkaline earth metal salts, preferably sodium, potassium or calcium
salts or mixtures. The salts may be the water-soluble sulphates, carbonates or halides,
usually chlorides. Mixtures can be used. Preferably hygroscopic salts are used to
promote the most rapid dissolution of the composition. A particularly suitable example
is sodium sulphate. The salts may have an advantageous effect on the manufacturing
and handling properties of the composition of the invention.
[0018] The binder should enable the product to be flexible when it has been applied to the
article to be laundered. A flexible film has less tendency to crack and peel off the
fabric. Furthermore the binder should be one which is solid at room temperature and
at the temperature of storage but which melts at a temperature such that the composition
may be formed whilst the binder is molten, and thus at a temperature at which the
other components of the composition are stable. That temperature is usually at least
40°C, preferably at least 50°C for, for instance around 60°C. Flexibility and softness
of the binder enable the composition to be applied to the fabric and to adhere to
it. Further properties of the binder are that it must be readily water soluble and
be compatible with detergent formulations at present in use. The binder can consist
of a mixture of compounds.
[0019] Preferably the hardness of the composition is in the range 5 to 200, more preferably
20 or 50 to 150 or 140. In this specification the hardness is measured using a Seta
1719 Universal Penetrometer (Stanhope-Seta Ltd.) and the values given are in units
of 0.1mm for a 10 second penetration time using the standard weight and cone size.
If the binder is very hard for instance has a hardness of less than 50 or 20 then
liquids, for instance glycols, may be added in small amounts to soften the composition.
[0020] Suitable binder systems for stick form compositions of the invention are disclosed
in US-A-4145183 and EP-A-205999. Preferably non-ionic binders such as those disclosed
in US-A-4145183 are used. Particularly preferred binders comprise ethoxylated alcohol
compounds, especially derivatives of C₁₂₋₁₈ alkyl, more preferably C₁₃₋₁₅ alkyl alcohols.
The compounds preferably comprise between 2 and 20 ethoxy moieties. Some suitable
compounds have quite low numbers of ethoxyl group for instance in the range 2 to 10,
preferably 3-5. Other suitable compounds have higher ethoxyl content for instance
10 to 20 ethoxy groups preferably between 12 and 16. Such compounds themselves have
useful stain-removing properties, especially on fatty stains and sebum stains.
[0021] The binder can comprise alternatively or additionally fatty alcohols, such as C₁₂₋₁₈,
preferably C₁₃₋₁₇, branched or preferably straight chain alkyl alcohols. Such alcohols
have stain removing properties and also lubricating properties which improve application
of the composition to the fabric.
[0022] The binder can also comprise poly(alkylene glycols) for instance polyethyleneglycol
which can be added to alter the hardness and/or dropping point of the composition.
For instance where compositions contain some of the relatively low ethoxyl content
ethoxylated alcohols, which can be liquid at room temperature, it may be useful to
incorporate a solid polyethylene glycol (PEG), that is a high molecular weight PEG
e.g. greater than 5000, for instance around 8000.
[0023] Mixtures of an ethoxylated alcohol, a fatty alcohol and a poly(alkylene glycol) are
found to be particularly suitable. The relative amounts of the components of a binder
mixture are determined for instance by experiment so as to give the desired dropping
point and hardness.
[0024] The composition preferably contains 10-90% by weight of binder, more preferably 20
to 85% and most preferably 40 to 85% binder. The bleach activator content is preferably
in the rang 10 to 90%. More preferably the activator content is in the range 10 to
80% or 70%, most preferably 15 to 50%. Any stabiliser is present in the composition
in an amount of 0.5 to 20% preferably 0.5 to 15% and most preferably 1 to 5%.
[0025] The composition may contain further additives, but preferably in amounts less than
5% by weight of the total composition, such as enzymes, enzyme stabilisers, perfumes,
colouring agents, fillers, abrasives, antiseptics, optical brighteners or agents to
provide desirable physical properties, such as solvents or fabric softening agents.
Furthermore the compositions may themselves contain bleaching compounds, such as perborates
or percarbonates. Since the compositions are substantially anhydrous and since particulate
components of the composition will be surrounded by the continuous binder matrix,
a composition containing both bleach and activator is relatively storage stable. However,
in general it is unnecessary to include a bleach in the composition since many laundry
detergents at least in Europe contain a bleaching compound.
[0026] The present invention further provides a process for forming the new composition
which comprises forming a dispersion of the solid components in the molten binder
and mixing to obtain an homogeneous dispersion and then moulding the composition and
cooling it to form a stick-shaped composition. It is convenient for some or all of
the solid components to be premixed before their addition to the melt of binder. Mixing
may be done in a conventional mixer, such as for instance a heated, twin-screw extruder
or ribbon blender. It is preferred that the compositions are maintained at the raised
temperature at which the binder is molten for as short a time as possible in order
that any temperature sensitive components are not damaged. The minimisation of the
processing time limits any damage that could be done to any of the further additives
mentioned above, for instance temperature-sensitive enzymes. Furthermore it minimises
any undesired dissolution of particulate activator into the mix, which can sometimes
lead to reformation of undesirable large crystals of the activator on cooling.
[0027] The homogeneous mixture may be moulded to form a stick-shaped composition and then
inserted into an applicator, or, more preferably, it may be filled directly into the
applicator itself which is therefore used as the mould. In order for conventional
applicators to be filled with the composition the binder should preferably be molten
at a temperature of about 75°C, preferably about 50°C.
[0028] The following examples illustrate the invention.
EXAMPLES
[0029] In the examples the following abbreviations are used:
TAED : tetraacetylethylene diamine
ISONOBS : isononanoyloxybenzene sulphonate
EDTMPA : ethylenediaminetetra (methylene phosphonic acid)
PB1 : perborate monohydrate
Synperonic A14 is a C₁₃₋₁₅ alcohol ethoxylated with 14 moles ethylene oxide, dropping
point about 35°C hardness 160.
Genapol T250 is a C₁₈-based alcohol ethyoxylated with 25 moles ethylene oxide having
a dropping point of about 50°C and hardness of 10.
[0030] The coarse TAED was made by conventional milling and the fine TAED was made by treating
coarse TAED in a microniser to form the following size fractions: fine, having average
particle size of 5 microns and coarse having an average particle size of 100 microns.
Compositions having the components and amounts shown in the following table were made
by melting the binder and mixing it with the particulate components. Swatches of fabric
were stained with one of three different stains, as indicated in the table. The composition
was applied to the stained fabric in an amount of 2g total composition per swatch
of fabric.
[0031] The stained and treated fabric swatches are washing in a standard detergent solution
formed by dissolving a solid composition containing base detergent (88% by weight)
and PB1 (12% by weight). Stained clothes were washed in the detergent to establish
the level of performance of the conventional powder. All wash tests were carried out
in a Hoover Computer Control 1100 using water hardness 100 ppm Ca²⁺, using wash programme
4 (HLCC) at a temperature of 50°C.
[0032] The stained clothes are (before addition of the prewash composition) measured on
an ICS computer and the reflectance values recorded. The Reflectance of the cloths
is remeasured after washing and the %ge stain removal calculated according to the
following equation:

where
R
f = reflectance of the washed stained (i.e. test) cloth.
R
i = reflectance of the stained cloth before washing.
R
s = standard reflectance, of an unstained cloth after washing.
[0033] The table shows the percentage improvement in stain removal in the laundering process
using the prewash treatment compositions. Amounts are in weight percent.
TABLE
Variable |
Component |
FORMULATION |
|
|
A |
B |
C |
D |
E |
F |
1 |
2 |
3 |
4 |
Binder |
Synperonic A14 |
100 |
95 |
|
50 |
50 |
50 |
50 |
50 |
50 |
49 |
Genapol T250 |
|
|
55 |
|
|
|
|
|
|
|
ACTIVATOR |
TAED (coarse) |
|
|
45 |
50 |
25 |
25 |
45 |
|
|
45 |
TAED (fine) |
|
|
|
|
|
|
|
|
45 |
|
Isonobs |
|
|
|
|
25 |
|
|
45 |
|
|
Stabiliser |
EDTMPA |
|
5 |
|
|
|
|
5 |
5 |
5 |
5 |
Inorganic Salts |
Perborate Monohydrate |
|
|
|
|
|
25 |
|
|
|
|
Na₂SO₄ |
|
|
|
|
|
|
|
|
|
1 |
% Improvement on control |
Tea |
- |
0 |
5.6 |
5.7 |
6.0 |
0 |
4.5 |
- |
9 |
6.2 |
Wine |
3.5 |
0 |
19.5 |
15.2 |
19.4 |
17.4 |
26.9 |
34.7 |
35.2 |
29.2 |
Sebum |
4.2 |
- |
- |
- |
13.0 |
- |
- |
11.9 |
12.1 |
- |
Penetrometer Hardness (0.1 mm units) |
160 |
- |
6 |
130 |
- |
- |
135 |
- |
120 |
|
[0034] The table shows the improved performance of compositions containing a stabiliser,
as compared to those which do not (compare directly formulations D and 1). The table
also shows the improvement that can be obtained by using small particle sizes (comparing
formulations 1 and 3). It was furthermore noted that composition 3, containing fine
TAED, had a particularly good appearance, being very white and opaque and easy to
see on the stained fabric.
EXAMPLE 5:
[0035] A further product found to have beneficial effects, comprises the following ingredients:
COMPOUND |
WT% |
Lutensol A03 (a C₁₃₋₁₅ alcohol 3 mole ethoxylate) |
55 |
Stearyl alcohol |
9.9 |
Polyethylene Glycol 8000 |
18 |
TAED |
15 |
EDTMPA |
1 |
Enzyme |
1 |
Fragrance |
0.1 |
[0036] The first three components comprise the binder. The TAED had a particle size such
that 80% by weight of the particles had a size less than 20 microns. The product is
made by mixing the binder components at a temperature of between 60 and 64°C at which
the mixture is a melt. To the melt is added a premix of the TAED and phosphonate and
this causes the temperature to drop to about 53 to 56°C at which the mixture is still
sufficiently fluid to be mixed and poured. The fragrance and enzyme are then added
whilst maintaining the temperature at less than 58°C and the mixture is poured into
moulds as soon as possible thereafter and allowed to cool.
1. A laundry pre-treatment composition in stick form comprising a water-soluble surfactant
binder having a dropping point in the range of 30 to 100°C and bleach activator and
bleach stabiliser dispersed in the binder.
2. A composition according to claim 1 in which the activator is particulate.
3. A composition according to claim 2 in which the activator particles have sizes
in the range 50 to 500 microns preferably 50 to 250 microns.
4. A composition according to claim 2 in which the activator particles having sizes
less than 20 microns, preferably less than 10 microns, the average size of the particles
preferably being in the range 2 to 20 microns, more preferably 3 to 10 microns.
5. A composition according to any preceding claim in which the activator is a mono-
or di-functional acyl derivative, preferably an ester, imide or oxime.
6. A composition according to any preceding claim in which the activator comprises
tetracetyl ethylene diamine.
7. A composition according to any preceding claim in which the bleach stabiliser is
a sequestering agent or mixture of sequestering agents, preferably an amino carboxylic
acid or a phosphonic acid.
8. A composition according to any preceding claim in which the binder is non-ionic
binder, preferably comprising an ethoxylated alcohol, for instance an ethoxylated
derivative of C₁₂₋₁₈ alkanol.
9. A process for producing a composition as defined in any preceding claim comprising
: forming a dispersion of the solid components in the molten binder and mixing to
obtain an homogeneous dispersion and then moulding the composition and cooling it
to form a stick-shaped composition.
10. A process according to claim 9 in which the dispersion is moulded in an applicator.
11. A process in which a stick-form composition according to any of claims 1 to 8
is contacted with an article to be laundered to deposit a portion of the composition
onto the article and the article is laundered in a detergent solution containing a
peroxy bleach compound.