WO2004057088A1

WO2004057088A1 - Cleaning device

Info

Publication number: WO2004057088A1
Application number: PCT/EP2003/013821
Authority: WO
Inventors: Nilson Satoshi Arai; Claudio Roberto Grigolon
Original assignee: Unilever Plc; Unilever Nv; Hindustan Lever Limited
Priority date: 2002-12-19
Filing date: 2003-11-25
Publication date: 2004-07-08
Also published as: AU2003294802A1; AR042527A1; CL2003002681A1; BR0314208A; GB0229501D0

Abstract

A device (1) for cleaning a substrate such as a fabric comprising:(a) a reservoir (2) for s (3); (c) a corrugated surface formation (6) for scrubbing the substrate, (d) a shear-thinning detergent composition (4) in paste stored in said reservoir (2).

Description

CLEANING DEVICE

The present invention relates to a fabric cleaning device which has a scrubbing surface and a squeezable reservoir for containing a detergent composition in a paste form.

Hand-held devices which are specifically used for cleaning fabric are available, and typically include sponges, brushes, abrasive pads, intended for scrubbing the substrate.

Such devices can be used to pre-treat the substrate before a main wash (e.g. in an automatic washing machine) or as a main hand-washing operation.

Detergent compositions in paste form are known for use in hand washing, personal washing and laundry washing applications. Detergent products in the form of powders and bars are well known for use in the washing of fabrics and generally are employed far more widely than detergent pastes for this particular application. Pourable liquid detergent compositions are also known. However detergent pastes provide a suitable form of detergent product especially for washing applications in which the product is applied directly to the fabric to be washed. Furthermore detergent pastes may also be employed in which the detergent is dosed into a liquor to provide a solution wash as is the norm with detergent powders . Pastes therefore provide the consumer with a flexibility as regards the type of washing operation which may be employed. It is desirable to ensure that the viscosity of the composition is such that the composition is substantially not pourable, so that significant wastage is avoided in a direct application washing process and also that the composition is not so viscous that dispersibility and dissolution in a solution washing process become unacceptable if this flexibility of use is to be retained. Control of the viscosity of the composition to provide an optimum combination of characteristics is desirable.

It is also important that the composition is stable, i.e. it does not separate over time.

WO 95/09224A (Henkel) discloses a fabric washing detergent composition in paste form containing a mixture of nonionic and anionic surfactant of the sulphate and sulphonate type . The problem addressed in this disclosure is to minimise changes in viscosity due to an increasing or variable salt content from the surfactant raw materials. WO 95/09224 also discloses that a relatively modest level of salt, 0.5% in the case of a paste composition containing long chain alkyl sulphate as the only anionic surfactant, may lead to an unacceptable decrease in the viscosity of the paste composition; thus the level of salt may affect viscosity of the paste composition. This document discloses that 0.05 to 5 wt% of alkali metal and/or ammonium sulphate and/or chloride may be present in the composition together with the nonionic surfactant and alkyl benzene sulphonate and ether sulphate and/or alkyl sulphate surfactant. This approach can give problems if soluble or hydratable builder salts such as sodium tripolyphosphate are present . GB 2 308 128A (Unilever) discloses a shear-thinning detergent paste with a viscosity of 100 to 700 Pa.s at a shear rate of Is and a viscosity of from 400 to 5000 Pa.s at a shear rate of 0.1 s .

WO 01/68794A (Procter & Gamble) discloses a solid detergent composition comprising a surfactant and a thickener which may be made into a detergent paste having a viscosity of from 0.024 to 3 Pa.s at a shear rate of 20.2s.

It is known to formulate dish washing compositions as thick liquids, for example as described in EP-A-0365271. However, such compositions contain relatively small quantities of surfactant (typically less than 5 wt%) .

We have surprisingly found that the combination of a specific type of shear-thinning viscosity within a squeezable container having an orifice is particularly suitable for direct application to fabrics.

According to the present invention, there is provided a device for cleaning a substrate such as a fabric comprising:

(a) a reservoir for storing a detergent composition

(b) at least one dispensing orifice

(c) a corrugated surface formation for scrubbing the substrate

(d) a shear-thinning detergent composition in paste stored in the reservoir. THE DETERGENT COMPOSITION

Preferably the paste comprises :

(a) from 5 to 40 wt % of anionic surfactant

(b) from 5 to 60 wt% of a hydratable builder salt; and the paste has

(c) a viscosity of from 10 to 1000 Pa.s at a shear rate of Is at 25 °C; and (d) a viscosity of from 5 to 100 Pa.s at a shear rate of 10s at 25°C; and (e) the ratio of the viscosity at Is to the viscosity at 10s is from 2:1 to 10:1.

The composition of the present invention is preferably a paste, gel, semi-solid or highly viscous liquid.

It is not normal in the detergent art to formulate viscous detergent compositions having a viscosity in the range covered by the present invention, because compositions in this range can be sensitive to variables such as temperature, composition etc. Surprisingly, the present inventors have discovered that a detergent composition having the viscosity range specified gives acceptable rates of dissolution in wash water while being particularly suitable for direct application to fabrics. The Viscosity Profile

Viscosity is measured at 25 °C, as is standard in the art. Viscosity is preferably measured in a manner known in the art using a Haake VT 55.0 rotoviscometer using SV IIP cup and bob.

The composition of the present invention is shear thinning; that is, the viscosity decreases as the shear rate increases.

Preferably the detergent has a viscosity at a shear rate of Is at 25°C of from 15 to 700 Pa.s, preferably from 20 to 400, more preferably from 30 to 200 Pa.s, most preferably from 40 to 99 Pa.s. Preferably the detergent composition has a viscosity at a shear rate of 10s at 25 °C of from 7 to 60 Pa.s, preferably from 10 to 40, more preferably from 10 to 20 Pa.s. Preferably the ratio of the viscosity at Is to the viscosity at 10s is from 3:1 to 7:1. Preferably the viscosity is such that the paste is substantially not pourable from the container when the orifice is uncovered and the container is not squeezed.

The viscosity of the composition may be tailored according to local market requirements. Less viscous compositions may be provided by including water in the composition at a relatively high level such as at least 45 wt% and, according to the viscosity required up to 75 wt% of the composition. The precise level may be selected according to the other components in the composition. The viscosity according to the invention can be achieved by a number of techniques known to the skilled person. A filler or structurant may be included. For example, the balance of filler and surfactant may be adjusted. For example, the weight ratio of surfactant to filler may be in the region 2:1 to 1:2, preferably about 1:1. The quantity of water may be suitably controlled.

Viscosity may also be controlled by use of a thickening agent. A suitable thickening agent is a carbopol .

Detergent compositions according to the invention having a higher viscosity may be produced by incorporating a structurant or solid material for example a filler. Suitable fillers include conventional inorganic fillers such as kaolin, silica, starch, bentonite, talc, clay, silicate and especially calcite. The amount of inorganic material included as a filler will vary according to the desired viscosity but generally will not exceed 40%, and or preferably not exceed 30 wt% of the composition.

The Hydratable Builder Salt

Suitably any hydratable salt may be employed although it is preferred if the hydratable builder salt is selected from builders such as polyphosphates, orthophosphates, tripolyphosphates, phosphates, tetraphosphates, pyrophosphates , carbonates and bicarbonates and the alkali metal and ammonium salts of any of the foregoing. Silicates, preferably sodium silicates may be used, such as metasilicates, disilicates, alkaline silicates etc, or mixtures thereof .

The hydratable builder salt may be added in solution if necessary.

Pyrophosphates are preferably present at a level less than 5 wt%, preferably less than 1 wt%, as they can lead to instability of the composition.

Preferably the hydratable salt is present at a level of at least 10 wt% and desirably at least 15 wt% of the composition. Suitably the level of the hydratable salt does not exceed 60% and preferably does not exceed 50 wt% of the composition and a level of not more than 40 wt% is especially preferred.

In a particularly preferred embodiment, the hydratable salt comprises sodium tripolyphosphate and optionally sodium carbonate. Sodium tripolyphosphate is preferably present in an amount of 5 to 25% and preferably less than 30 wt% of the composition and, if present, the carbonate is suitably at a level of 1 to 15% especially 4 to 12 wt% of the composition.

Additional builder components may be included, such as calcite, aluminosilicates such as zeolite, organic builders, including organic polymeric builders, and mixtures thereof.

The compositions of the present invention can dissolve quickly in wash water. Preferably at least 30 wt%, more preferably at least 40 wt% of the composition dissolves in 30 seconds in the wash water at 25 °C.

The Anionic Surfactant

As regards the anionic surfactant, any conventional anionic surfactant may be employed including surfactant selected from linear or branched alkyl benzene sulphonate, alkyl sulphate, alkyl ether sulphate, alkane sulphonate, olefin sulphonate, fatty acid monoglyceride sulphate, alkyl glycerol ether sulphate, acyl sarcosinates, salts of Cg to

C₂₀ fatty acids and rosin acids and mixtures thereof.

Suitably the anionic surfactant is present as an alkaline metal, alkaline earth metal or an ammonium or substituted ammonium salt.

In another preferred embodiment, the anionic surfactant comprises linear alkyl benzene sulphonate. These surfactants suitably have a C₉ to C₁₅ alkyl chain.

The anionic surfactant may be incorporated as a pre- neutralised material or the acid form of the surfactant may be incorporated with a suitable quantity of alkaline material in order to effect the neutralisation of the acid.

Preferably the level of anionic surfactant in the composition is from 7 to 35 wt%, more preferably from 10 to 30 wt%. Other types of anionic surfactant may be present at a level of 1 to 35 wt%, more preferably 2 to 20 wt% of the composition.

The level of surfactant in the composition is selected according to the performance criteria required and having regard to cost .

Detergent compositions of this type may be formulated with the quantity of anionic surfactant exceeding that of builder salt or with the quantity of builder salt exceeding that of anionic surfactant, in weight percent terms. The choice of composition will depend upon factors such as the hardness of the water to be encountered, relative costs of the components, the effect of the components on the viscosity of the mixture and wash habit. Surfactants which are relatively tolerant towards hardness in water, such as olefin sulphonates and lauryl ether sulphates may be used in quantities exceeding the level of builder.

The form of the surfactant may be controlled. Preferably, the surfactant is in the lamellar or a viscous micellar phase. The surfactant can be fixed in these phases by controlling its dilution or, by structuring with suitable structuring agents such as electrolyte, e.g. NaCl, Na₂C0₃.

The filler may be used to stabilise the dispersion against separation. Other Detergent Ingredients

Other surfactants may be included in the composition as desired. Suitable other surfactants include other anionic surfactants, nonionic, a photeric and cationic surfactants which may be included in order to provide improved cleaning performance or other desirable properties.

If other surfactants are present, the detergent composition preferably contains nonionic surfactant, especially alcohol alkoxylates which desirably have a linear or branched alkyl chain having 9 to 15 carbon atoms and which have an average degree of ethoxylation of 1 to 15, preferably 1 to 10 for example 3 and 7. Nonionic surfactants may be employed in the composition in order to provide improved skin mildness characteristics .

However, nonionic surfactants are preferably present in low quantities, as they have a deleterious effect upon foaming. The level of foam produced is an important indicator to the user of effectiveness of the surfactant composition. Preferably, nonionic surfactant is present at a level of from 0.1 to 5 wt%, preferably from 0.5 to 3 wt%.

It is preferred not to use substantial quantities of fatty acid soap. However, as described below, fatty acid soap may be used as a structurant at a level of less than 3 wt% of the composition. Preferably the detergent composition is formulated so that in use as a paste in a direct washing application, it has a pH of 8 to 11.5, preferably 9 to 11.

A filler may be added, such as clay, kaolin, silica, starch, bentonite, talc, silicates of other metals such as calcium, calcite or mixtures thereof .

A small quantity of soap may be included as a structurant. Soap may be defined as alkali metal salts of long chain moncarboxylic acids. Preferably, the alkali metal salt of C16-C26 carboxylic acids or a mixture thereof may be used. Preferably, C18-24 soaps are used, most preferably C20-C24.

The structuring properties of soap vary with temperature.

The composition tends to become more liquid with increasing temperature. It has been found that long chain fatty acid soaps (C20-C24) retain their structuring properties up to temperatures in the region 40-50 °C.

The soap structurant is preferably present in an amount of approximately 0.2-3 wt%, most preferably 0.5-2.0 wt%, preferably about 1 wt%. Excess quantities of sodium soap have been found to suppress formation of foam.

Other structurants may be used. It is preferred that a cross-linked carboxylic polymer structurant is substantially absent, as it is believed to be less effective. Similarly, it is preferred that clay, such as natural or synthetic hectorite clay structurant is substantially absent. Non- structurant clay may be included. Manufacturing Methods of the Detergent Composition

Compositions according to the invention may be prepared by incorporating the components of the composition into a batch mixer with agitation in order to provide a substantially homogeneous composition. For high viscosity pastes, a Winkworth Z-blade mixer may suitably be employed and for lower viscosity compositions, for example below about lOOPa.s, a conventional batch mixer equipped with paddles may be employed.

An alternative process involves the use of two mixing stages . This involves firstly making a slurry from some of the powder ingredients plus water and a second main mixer tank with the remaining ingredients.

A further alternative process is to use a three stage process. This is where liquid acidic surfactant precursors are added with a neutralising agent in a reaction tank in order to produce the neutralised surfactant, prior to using the two-stage process as described above.

Care must be taken with the control of the temperature and the speed of agitation.

Compositions according to the invention may comprise other ingredients conventionally found in detergent compositions, including fluorescers lather control agents or lather boosters as appropriate, dyes, perfumes and the like. Antiredeposition agents such as sodium carboxy methyl cellulose (SC C) may be used at a level of 0.1 to 4% preferably 0.2 to 2 wt%. This list is not intended to be exhaustive. All amounts and proportions and by weight unless otherwise specified.

The Device

Preferably the dispensing orifice has an exit area of from 3 to 300 mm, preferably from 5 to 200 mm, more preferably from 10 to 150 mm, most preferably from 20 to 100 mm.

Thus the combination of the viscosity and the opening provide for a particularly effective delivery system for detergent pastes .

Preferably the container has a volume of from 50 to

1000 cm, more preferably from 200 to 700 cm, most preferably from 250 to 500 cm.

Additionally the ratio of the orifice area to the container volume can be important since larger containers advantageously have a larger orifice. In this respect it is preferred that the ratio of the volume to the orifice area is from 1 to 10 cm/mm, preferably from 2 to 8 cm/mm, more preferably from 4 to 7 cm/mm.

As used herein, the term corrugated' is intended to include an undulating formation, wherein the undulations may be curved and/or angular, and may have regular or irregular sections . The surface formation may comprise alternating smoothly curved convex (outer) and concave (inner) portions. Alternatively or additionally, the formation may comprise v- shaped inner portions and inverted v-shaped outer portions.

The smoothness/sharpness of the outer portions of the corrugated surface formation can be varied to increase or decrease its abrading capacity.

The corrugated surface formation may be configured such that at least two and preferably all its outer portions lie in a substantially common flat plane. In this way, the whole of the corrugated surface formation's outer portions can be made to contact a fabric supported on flat surface (kitchen worktop) for more effective scrubbing.

In one embodiment, the corrugated surface formation may be regular and formed along a generally flat portion of the device.

Alternatively or additionally the outer portions may also lie on a generally curved or undulating plane.

The corrugated surface formation may be rigid or include rigid portions, in order to provide a more effective scrubbing action.

The corrugated surface may comprise an elongate strip extending along the device. The strip may have a constant width or this may vary along the length, e.g. it may taper toward one end. In one embodiment, the corrugated surface formation is formed on an external portion of the reservoir. The corrugated surface formation may extend the whole length of a side or wall of the reservoir. In one embodiment the formation extends across one whole side of a reservoir.

The device may include at least a resilient portion. For example the reservoir may be resilient, at least in part. Such resilience may allow squeezing of the reservoir to aid egress of the cleaning composition from the at least one orifice and/or to allow the user to grip the device.

The device may comprise the following combination:

(a) a reservoir with resilient opposing side walls to allow squeezing so as to aid dispensing of cleaning product through the dispensing orifice,

(b) a rigid corrugated surface formation and

(c) one or more rigid dispensing orifices.

The rigid surface formation and one or more dispensing orifices may be part of the reservoir.

The device may have one or more recesses or indentations for ergonomic purposes, to ease the handling and gripping of the device .

The one or more recesses or indentations may be provided in a part of the device opposite the corrugated surface formation. For example the corrugated surface formation and recess (s) /indentation (s) may be located in respective opposing walls of the device. At least a portion of the device may be flattened in cross section, so that the cross section may have e.g. a flattened elliptical shape.

In one embodiment the device is a bottle including a hollow body forming the reservoir and a bottle finish including one or more outer locking surfaces configured for mutual engagement a bottle closure and forming the dispensing orifice .

In addition, according to a second aspect of the invention there is provided a method of cleaning a fabric using the device according to the first aspect of the invention, the method comprising the steps of:

(a) applying a fabric cleaning composition from the reservoir via the dispensing orifice to a fabric to be cleaned

(b) scrubbing said fabric using the corrugated surface formation.

The device may be supplied as a commercial package. Accordingly in a further aspect of the invention there is provided a commercial package for the cleaning of fabrics comprising a device of the first aspect of the invention in combination with instructions to direct the user in use of the device according to the method of the second aspect of the invention. Various non-limiting embodiments of the invention will now be more particularly described with reference to the following figures in which: Figure 1 is a front view of one embodiment according to one aspect of the invention;

Figure 2 is a side view of the embodiment shown in figure 1; and Figure 3 is a schematic perspective view of the embodiment of figure 1.

Figure 1 illustrates device 1 (shown orientated upright and viewed from the front) for cleaning a substrate such as a fabric (not shown) comprising:

(a) reservoir 2 for storing a cleaning composition indicated at 4,

(b) a single dispensing orifice 3 for dispensing said cleaning composition 4

(c) a corrugated surface formation 6 for scrubbing the substrate provided on a external surface of the reservoir 2.

The device is ideally moulded from any suitable plastic e.g. LDPE (low density polyethylene) .

The surface formation (when viewed from the side, as in figure 1) comprises alternating curved convex (outer) portions 8 and concave (inner) portions 10. The outer portions are tapered slightly toward the outermost part, to provide a sharper peak. The increase sharpness of the outer portions of the corrugated surface formation can be varied to increase or decrease its abrading capacity. The corrugated surface formation 6 is configured such that all its outer portions 8 lie in a substantially common flat plane. In this way, the whole of the corrugated surface formation's outer portions 8 can be made to contact a fabric supported on flat surface (kitchen worktop) for more effective scrubbing.

The corrugated surface formation 6 is regular and formed along a generally flat portion of the reservoir.

Referring to figure 2, the corrugated surface formation 6 comprises an elongate strip which comprises one side wall of the reservoir 2, whereby the corrugations provide lateral furrows on the reservoir. The strip tapers toward an upper end 2a of the reservoir 2.

The corrugated surface formation 6 is rigid to minimise flexing during use, in order to provide a more effective scrubbing action.

Opposing front and rear walls 12,10 of the reservoir 2 are, relative to the side walls 20 and its corrugated surface formation 6 and side wall 22, flexible to allow squeezing of the reservoir 2 to aid egress of the cleaning composition from the at least one orifice and/or to allow the user to grip the device 1.

The flexibility of the front walls 10,12 combined with the rigid corrugated sides 20 and 22 assist is ejecting the gel or paste from the bottle in a controlled manner. The device 1 has, as part of the reservoir 2, a smoothly undulating side 22 with a smoothly curved recess 18 for ergonomic purposes, to ease the handling and gripping of the device 1. The corrugated surface formation 6 and the recess 18 are located in respective opposing walls 20,22 of the device .

As can be seen in figures 2 and 3, the reservoir 2 is flattened in cross section. This makes for an easier grip which assist scrubbing, as do the pair of crescent shaped ribs 24 on the front 12 of the reservoir 2. A second pair of ribs may also be situated on the rear 10 of the reservoir 2, in the same sort of position as ribs 24 are on the front 12.

The device also comprises a threaded neck portion 3a for mutual engagement with internally threaded cap 3b.

The device 1 is supplied as a commercial package including with instructions (e.g. printed on the reservoir 2 or a label (not shown) applied to the reservoir 2) to direct the user to

(a) apply fabric cleaning composition from the reservoir 2 via the dispensing orifice 3 to a fabric to be cleaned, and

(b) scrubbing said fabric using the corrugated surface formation. Exemplary detergent compositions are given below;

The composition, indicated as weight percent, as detailed in Table 1 below was produced by dosing the components into a batch mixer. The process was conducted at about 40 °C and was carried out in a common Liquid Detergent (HDL) process plant :

The raw materials were sequentially added into a single stirrer tank.

Table 1

The composition produced according to Example 1 exhibited acceptable washing performance and desirable foaming and sensory properties when tested by manual application and washing of fabrics .

It is of course to be understood that the invention is not intended to be restricted to the details of the above embodiments which are described by way of example only.

r

Claims

1. A device for cleaning a substrate such as a fabric comprising a reservoir for storing a detergent composition at least one dispensing orifice a corrugated surface formation for scrubbing the substrate and a shear-thinning detergent composition in paste stored in said reservoir.

2. A device according to claim 1 wherein the corrugated surface formation comprises alternating convex (outer) and concave (inner) portions.

3. A device according to claim 2 wherein the convex (outer) and concave (inner) portions are curved and tapered in the direction of an outermost part.

4. A device according to claim 2 or 3 wherein the corrugated surface formation is configured such that at least two and preferably all its outer portions lie in a substantially common flat plane.

5. A device according to any preceding claim wherein the corrugated surface formation is rigid or includes rigid portions.

6. A device according to any preceding claim wherein the corrugated surface formation is an elongate strip extending along the device.

7. A device according to claim 6 wherein said strip is tapered.

8. A device according to any preceding claim wherein the corrugated surface formation is formed on an external portion of the reservoir.

9. A device according to any preceding claim wherein the corrugated surface formation extends the whole length of a side or wall of the reservoir.

10. A device according to any preceding claim wherein the corrugated surface formation extends across one whole side of a reservoir.

11. A device according to any preceding claim wherein the device comprises resilient portions.

12. A device according to claim 11 wherein the resilient portions are opposing walls of the reservoir.

13. A device according to any preceding claim wherein the device comprises rigid portions.

14. A device according to claim 13 wherein the corrugated surface formation is a rigid portion.

15. A device according to claim 13 or 14 wherein the device has opposing rigid portions, comprising a rigid corrugated surface portion and a opposing rigid wall.

16. A device according to any preceding claim wherein the device, and preferably the reservoir, has one or more recesses or indentations.

17. A device according to any preceding claim wherein the corrugated surface formation and the one or more recesses or indentations are provided in respective opposing walls.

18. A method of cleaning a fabric using the device according to the first aspect of the invention, the method comprising the steps of:

(b) scrubbing said fabric using the corrugated surface formation.

19. A device according to any of claims 1 - 19 wherein said shear-thinning detergent composition in paste form comprises

(a) from 5 to 40 wt% of anionic surfactant;

(b) from 5 to 60 wt% of a hydratable builder salt; and the paste has

(c) a viscosity of from 10 to 1000 Pa.s at a shear rate of Is at 25 °C; and (d) a viscosity of from 5 to 100 Pa.s at a shear rate of 10s at 25 °C; and (e) the ratio of the viscosity at Is to the viscosity at 10s is from 2:1 to 10:1.

20. A device according to claim 20 wherein said detergent composition has a viscosity of from 15 to 700 Pa.s at a shear rate of Is at 25 °C.

21. A device according to claim 21 wherein the detergent composition has a viscosity of from 20 to 400 Pa.s at a shear rate of Is at 25 °C.

22. A device according to claimed in any preceding claim, wherein the detergent composition has a viscosity of from 30 to 200 Pa.s at a shear rate of Is at 25 °C.

23. A device according to any preceding claim wherein the detergent composition has a viscosity of from 7 to 60 Pa.s at a shear rate of 10s at 25 °C.

24. A device according to any preceding claim wherein said detergent composition has a viscosity of from 10 to 40 Pa.s at a shear rate of 10s at 25°C.

25. A device according to any preceding claim wherein ratio of the viscosity at Is to the viscosity at 10s is from

3:1 to 7:1.

26. A device substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings .