EP3191573B1

EP3191573B1 - Paste composition for cleaning hard surfaces

Info

Publication number: EP3191573B1
Application number: EP15756909.6A
Authority: EP
Inventors: Sumanth Kumar ARNIPALLY; Manoj Vilas Dagaonkar; Suresh Murigeppa Nadakatti
Original assignee: Unilever PLC; Unilever NV
Current assignee: Unilever PLC; Unilever NV
Priority date: 2014-09-11
Filing date: 2015-08-31
Publication date: 2018-08-22
Anticipated expiration: 2035-08-31
Also published as: BR112017004467A2; AR101790A1; EP3191573A1; TR201815131T4; EA031894B1; WO2016037884A1; EA201790596A1; PL3191573T3

Description

Field of the invention

The invention relates to a composition for removing deposits of encrusted oily or greasy stains from a hard surface.

Background of the invention

Hard surface cleansing compositions are meant for cleaning surfaces such as kitchen tiles, sinks, hobs, chimney, platforms and soiled articles like utensils, cutlery and crockery.
Such surfaces are prone to heavy soiling as they often come in contact with oily or greasy substances like cooking media. Over a period of time, such deposits tend to harden or get encrusted. Oily stains and grease are usually easy to remove when they are not hardened or encrusted, however once encrusted, e.g., by aging or baking, the stains become particularly difficult to be removed. Cleaning is easier so long as the stain has not encrusted. If not cleaned promptly, the encrusted oil or grease can bind firmly to the hard surface. US 5849105 discloses a liquid crystal detergent composition for cleaning hard surfaces by removing greasy stains comprising a nonionic surfactant, a magnesium salt of an alkyl benzene sulphonic acid, an amorphous silica abrasive, a cosurfactant, a water-insoluble organic compound and water. Compositions for cleansing hard surfaces usually have high pH. However, low pH formats are also known. The high pH compositions are better at stain removal owing largely due to the highly alkaline nature. However, such compositions are harsh. On the other hand, the compositions having neutral to slightly acidic pH are not as harsh but they are not as effective either. Therefore, such compositions often contain more of hard abrasive particles, typically the ones having Moh's index above 3.5.
IN204326 discloses compositions in the form of detergent bars having about 14 % anionic surfactant which is formed by reacting linear alkyl benzene sulphonic acid (LAS acid) with stoichiometric excess of dolomite. The reaction leads to a mixture of calcium LAS and magnesium LAS leaving a significant part of free dolomite to serve as an abrasive. In view of the specific format of the product that is exemplified, the composition contains over 70% total abrasives. Usually the bars are used with an implement or scrubber made of nylon. Such an implement augments the inherent abrasive action of the composition and at levels in the range of 70%, the composition inherently has high abrasive action.
WO2015/078679 A1 (Unilever) discloses a paste composition suitable for cleaning dishes. The composition aids removal of tough stains like burnt-on soot and/or burnt-on food and grease at perceivably lesser efforts and time in comparison to at least some of the known products. The paste has inorganic alkaline material with pH greater than 11 and reserve alkalinity greater than 45 in 1% solution; and an abrasive having Mohs' index greater than 3.5. The strong alkaline nature of the composition augments the cleaning action of the abrasive.
WO2015/067438 A1 (Unilever) discloses cleaning paste where the primary surfactant is Ca/Mg LAS obtained by reaction of LAS acid with dolomite. The composition also contains fatty acids or esters which gives non-gritty feel and superior soil removal. The compositions contain abrasive material.
In WO2004013268 A1 (Unilever) is disclosed a synergistic cleaning composition having 0.1 to 40 wt% surfactant and 0.1 to 40 wt% shape selective particulate abrasive having roundness factor of 0.6 to 1.0. Dolomite is used for neutralization of linear alkyl benzene sulphonic (LAS) acid leading to a mixture of linear alkyl benzene sulphonate having a mixture of calcium and magnesium as counterions.
Therefore, as far as state of the art pertaining to hard surface cleansing compositions in paste form is concerned; on the one hand there are highly alkaline compositions containing high level of sodium salt of linear alkyl benzene sulphonate as the anionic surfactant, and on the other hand, there are neutral or slightly acidic compositions, containing calcium-LAS and/or magnesium-LAS, which either contain high levels of strong abrasives or no abrasive at all.
Thus there is an unmet need for cleaning compositions in paste or cream format with neutral to slightly acidic pH and have optimum level and type of abrasive, but which still are highly effective against deposits of encrusted oily/greasy stains on hard surfaces.

Summary of the invention

It has now been determined that neutral to slightly acidic paste or cream compositions can be made more effective against deposits of encrusted oily/greasy stains on a hard surface through a combination of abrasive with Moh's index more than 2.5 and a mineral oil.
According to a first aspect of the present invention is disclosed a cream composition for cleaning hard surfaces:

(i) 0.5 wt% to 15 wt% anionic surfactant of which at least 90 parts is calcium or magnesium salt of linear alkyl benzene sulphonic acid, or a mixture of the two; and,
(ii) 10 wt% to 50 wt% of an abrasive having Moh's index in the range of 2.5 to 6,

According to a second aspect is disclosed is a process for preparing a cream composition for cleaning hard surfaces, comprising the steps of:

(i) neutralising at least 90 parts by weight of linear alkyl benzene sulphonic acid with a mineral of dolomites group;
(ii) adding 0.5 to 4 parts by weight mineral oil and 10 to 50 parts by weight of an abrasive having Moh's index in the range of 2.5 to 6 to the neutralised mass.

According to a third aspect is disclosed use of a cream composition of the first aspect for removing deposits of encrusted oily or greasy stains from a hard surface.
According to a fourth aspect is disclosed a method of removing deposits of encrusted oily or greasy stains from a hard surface, the method comprising the steps of applying thereon a composition of the first aspect and scrubbing the stained part with a scrubber or a cloth and wiping with a wet cloth.

Detailed description of the invention

Disclosed cream composition for cleaning hard surfaces has:

Hard surface

The compositions disclosed herein are generally suited for cleaning hard surfaces. The hard surface could be any household or industrial surface, but household surfaces are specifically considered and the invention will be explained further with reference to this application. Typical hard surfaces include glass, wood, tiles and other ceramic materials, metal surfaces, polished stones and polished concrete; more preferably stone or concrete kitchen tops, hobs, chimneys, platforms, sink, glass windows and cooker tops and tiles.

The composition

Disclosed composition is in a cream form. The term cream, as used herein, also includes the closely related "paste format" and all references to the term cream should be interpreted to include the equivalent format of paste.
Such products are generally packaged in collapsible tubes, plastic bottles, sachets and even jars as well as other forms of packaging.

Anionic and other surfactants:

The composition essentially includes 0.5 wt% to 15 wt% anionic surfactant which is primarily responsible for cleaning action. Excess anionic surfactant often results in too much foam leading to more water being used for rinsing. At least 90% of the total anionic surfactant is calcium or magnesium salt of linear alkyl benzene sulphonic acid or a mixture of the two. This can be obtained by neutralisation of a suitable precursor of the anionic surfactant, like linear alkyl benzene sulphonic acid with an alkaline salt of calcium or magnesium, e.g., carbonate. A preferred method of obtaining a mixture of calcium and magnesium salts is by neutralisation of an acid precursor of the surfactant (linear alkyl benzene sulphonic acid) with a mineral from the dolomites group. When stoichiometric excess of the mineral is used, a part of it is utilised for neutralisation and the unreacted part usually remains in the neutralised mass which subsequently gets incorporated into the cleansing composition to serve as a hard abrasive.
Preferred compositions have total anionic surfactant content of 2 wt% to 12 wt%, more preferably 3 wt% to 8 wt%. In further preferred compositions, all of the anionic surfactant content is made of calcium or magnesium salt of linear alkyl benzene sulphonic acid or a mixture of the two.
The term "dolomite group or generally dolomites" refers to minerals with an unusual trigonal symmetry and with the general formula AB(CO₃)₂, where A is calcium and B is magnesium. Dolomites can be selected from the naturally occurring materials such as Ankerite Ca(Fe, Mg, Mn) (CO₃)₂, Benstonite (Ba, Sr)₆(Ca, Mn)₆Mg(CO₃)₁₃, Dolomite CaMg(CO₃)₂ and Huntite CaMg₃(CO₃)₄. The term "dolomite" refers to a particular mineral from the class "dolomites" and its molecular formula is as given earlier. The basic anionic (negatively charged) unit of this class consists of a triangle where at the centre resides a carbon atom. At every corner of the triangle is an oxygen atom. The threefold symmetry of the triangle explains the trigonal symmetry that many members of this class possess. The structure of the dolomites group of minerals is layered in such a way that the "A" metal ions occupy one layer which is followed by a carbonate layer which is followed by the "B" metal ion layer followed by another carbonate layer.
Balance of the anionic surfactant, may be any suitable surfactant such as water soluble salt of organic sulphuric reaction products having an alkyl radical containing from 8 to 22 carbon atoms, and sulphuric acid ester. Non-limiting examples of the anionic surfactants include alkylpoly(ethoxylates), sodium lauryl ether sulphates and methyl ester sulphonates.
The composition may also contain other surfactants, (other than anionic). These include nonionic, cationic, amphoteric and zwitterionic surfactants. However, their role is limited to providing secondary benefits, such as foam reduction, or to augment the cleaning action of anionic surfactants. Accordingly, it is preferred that, when present, their aggregate wt% is less than 15 wt%, more preferably less than 10 wt% and most preferably in the range of 1.5 wt% to 5 wt%.
Preferred compositions have 0.5 wt% to 5 wt% non-ionic surfactant. Suitable non-ionic surfactants can be broadly described as compounds produced by the condensation of alkylene oxide groups, which are hydrophilic in nature, with an organic hydrophobic compound which may be aliphatic or alkyl aromatic in nature. The length of the hydrophilic or polyoxyalkylene radical 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.
Particular examples include the condensation product of aliphatic alcohols having from 8 to 22 carbon atoms in either straight or branched chain configuration with ethylene oxide, such as a coconut oil ethylene oxide condensate having from 2 to 15 moles of ethylene oxide per mole of coconut alcohol; condensates of alkylphenols whose alkyl group contains from 6 to 12 carbon atoms with 5 to 25 moles of ethylene oxide per mole of alkylphenol; condensates of the reaction product of ethylenediamine and propylene oxide with ethylene oxide, the condensate containing from 40 to 80% of polyoxyethylene radicals by weight and having a molecular weight of from 5,000 to 11,000; tertiary amine oxides of structure R₃NO, where one group R is an alkyl group of 8 to 18 carbon atoms and the others are each methyl, ethyl or hydroxyethyl groups, for instance dimethyldodecylamine oxide; tertiary phosphine oxides of structure R₃PO, where one group R is an alkyl group of from 10 to 18 carbon atoms, and the others are each alkyl or hydroxyalkyl groups of 1 to 3 carbon atoms, for instance dimethyldodecylphosphine oxide; and dialkyl sulphoxides of structure R₂SO where the group R is an alkyl group of from 10 to 18 carbon atoms and the other is methyl or ethyl, for instance methyltetradecyl sulphoxide; fatty acid alkylolamides; alkylene oxide condensates of fatty acid alkylolamides and alkyl mercaptans. The nonionic surfactants can also be selected from a range of alkyl poly glucosides.
Suitable amphoteric surfactants are derivatives of aliphatic secondary and tertiary amines containing an alkyl group of 8 to 18 carbon atoms and an aliphatic radical substituted by an anionic water-solubilizing group, for instance sodium 3-dodecylamino-propionate, sodium 3-dodecylaminopropane sulphonate and sodium N-2-hydroxydodecyl-N-methyltaurate. Suitable cationic detergent-surfactant compounds are quaternary ammonium salts having aliphatic radical of from 8 to 18 carbon atoms, for instance cetyltrimethyl ammonium bromide.
Suitable zwitterionic surfactants that may be used are derivatives of aliphatic quaternary ammonium, sulphonium and phosphonium compounds having an aliphatic radical of from 8 to 18 carbon atoms and an aliphatic radical substituted by an anionic water-solubilising group, for instance 3-(N-N-dimethyl-N-hexadecylammonium) propane-1-sulphonate betaine, 3-(dodecylmethyl sulphonium) propane-1-sulphonate betaine and 3-(cetylmethylphosphonium) ethane sulphonate betaine.
Further examples of suitable surfactants are given in the well-known textbooks "Surface Active Agents" Vol. 1, by Schwartz & Perry, Interscience 1949, Vol. 2 by Schwartz, Perry & Berch, Interscience 1958, and/or the current edition of "McCutcheon's Emulsifiers and Detergents" published by Manufacturing Confectioners Company or in "Tenside-Taschenbuch", H. Stache, 2nd Edn., Carl Hauser Verlag, 1981.

Abrasives

The hard surface cleaning cream composition includes 10 wt% to 50 wt% of an abrasive. The abrasive, which is a particulate material, may be soluble or insoluble in water. Water soluble abrasives when used may be present in such excess to any water present in the composition so that the solubility of the abrasive in the aqueous phase is exceeded and consequently the abrasive exists in the composition.
Preferred compositions contain 30 wt% to 50 wt% abrasive, which may be one abrasive or a mixture of different abrasives.
Moh's index of the abrasive is in the range of 2.5 to 6.0. In preferred compositions the abrasive is clay, calcite, dolomite, feldspar, apatite, fluorite and hematite, kyanite, magnetite orthoclase or pumice.
More preferred abrasives are clay, calcite, dolomite and feldspar, and optimally a combination of calcite and dolomite.
In preferred compositions, the average particle size of each abrasive is 0.5 µm to 400 µm, more preferably 10 µm to 200 µm.
The viscosity of preferred cream compositions is in the range of 600 cps to 1200 cps. The viscosity can be measured by any known means/procedure. It is preferred that viscosity is measured by a Controlled-stress Rheometer, Ex. TA Instruments AR 1000 series. Parallel flat plate geometry having diameter of 4 cm is used. The gap between the plate and the base is set to 1000 mm. Data is analyzed by the TA data analysis software. A sample of the paste is placed on the base and the plate is brought to the set geometry gap. The viscosity is measured at shear rates varying from 10 to 25 s^-1 and reported at 20 s^-1.
The pH of the compositions is in the range of 6 to 7.5, more preferably 6 to 7. The pH is measured at 25 °C of a neat (undiluted) sample.

Water

The paste/cream compositions further include 20 to 60 wt% water, preferably 30 to 65 wt% and more preferably 40 to 65 wt%.

Mineral oil

Disclosed compositions include 0.5 wt% to 4 wt% mineral oil. Preferably the composition includes 2 wt% to 4 wt% of mineral oil. It is preferred that the mineral oil is a hydrocarbon having 14 to 40 carbon atoms.
Preferably light or heavy mineral oil or mixtures are employed. Examples of alkanes are tetra-decane, penta-decane, hexadecane, octa-decane, nonadecane, icosane and henicosane and examples of mixtures of alkanes are light liquid paraffin/light mineral oil (14 to 16 carbon atoms), heavy liquid paraffin/heavy mineral oil (more than 20 carbon atoms). Other mineral oils include white oil, liquid paraffin, pariffinum liquidum, liquid petroleum and perfumed mineral oil. The hydrocarbons may have linear, branched at any carbon atom or cyclic structures. The preferred mineral oil is light liquid paraffin oil with 14 to 16 carbon atoms.
Without wishing to be bound by theory, it is believed that mineral oil acts synergistically with the abrasive and provides higher degree of encrusted oil/grease removal.

Optional ingredients

The composition according may contain other ingredients that aid the cleaning performance. For example, the composition may contain builders such as citrates, dicarboxylic acids, water-soluble phosphates especially polyphosphates, mixtures of ortho- and pyrophosphates, zeolites, sodium carbonate, sodium silicate, disodium silicate, sodium meta silicate and mixtures thereof. Such builders can additionally function as abrasives if present in an amount in excess of their solubility in water. In addition to the ingredients already mentioned, various other optional ingredients such as structurants, colourants, soil suspending agents, detersive enzymes, perfume and preservatives may be included for their respectively known benefits.
In accordance with a second aspect is disclosed a process for preparing a cream composition for cleaning hard surfaces, comprising the steps of:

(i) neutralizing at least 90 parts by weight of linear alkyl benzene sulphonic acid with a mineral of dolomites group;
(ii) adding 0.5 to 4 parts by weight mineral oil and 10 to 50 parts by weight of an abrasive having Moh's index in the range of 2.5 to 6 to the neutralised mass.

In accordance with a third aspect is disclosed use of a cream composition of the first aspect for removing deposits of encrusted oily or greasy stains from a hard surface.
In accordance with a fourth aspect is disclosed a method of removing deposits of encrusted oily or greasy stains from a hard surface, the method comprising the steps of applying thereon a composition of the first aspect, scrubbing the stained part with a scrubber or a cloth and wiping with a wet cloth.
The composition is spread uniformly over the surface. The paste is left on the surface for some time, scrubbed with a scrubber and then rinsed or wiped with a tissue paper/cloth till completely dry. The dried treated surface is observed to show superior soil removal.
The invention will now be illustrated by means of the following non-limiting examples.

Examples

Example 1: Preparation of a control composition

A premix was prepared by mixing 5 g commercial grade sodium carbonate in 92 g de-mineralised water at 50 °C. To this premix was added 32 g of LAS acid (Linear alkyl benzene sulphonic acid, (Reliance Industries, India)) and the contents were further mixed for five minutes for neutralization. Completion of the reaction was confirmed by checking pH of the mix; and pH of 8 or more indicates complete neutralisation. To this neutralised mass, 5 g methyl laurate was added and mixed, which was followed by addition of 18 g of C12-3EO non-ionic surfactant. Mixing continued for two more minutes. This premix was stored in an oven maintained at 50 °C.
In a separate vessel, 0.06 g of an antifoam silicone emulsion was mixed with 358 g demineralised water at 50 °C. To this aqueous mixture, 35 g sodium carbonate was added and mixed, followed by addition of 450 g calcite. To this mix, 153 g of the premix described earlier was added mixing continued for five minutes. The composition was allowed to cool for one hour. Subsequently, other ingredients like colorants and perfume were added to the composition.

Example 2: Preparation of a cream composition according to the invention

A premix was prepared by mixing 10 g dolomite with 91 g de-mineralised water at 50 °C. To this, 32 g of LAS acid (as mentioned above) was added and mixed further for 5 minutes in order to achieve complete neutralisation. Completion of the reaction was confirmed by ensuring that pH of the mix was in the range of 6 to 7.5. To this neutralized mass, 5 g of methyl laurate ester was added and mixed further, followed by addition and mixing of 17 g non-ionic surfactant (as above). This premix (245 g) was stored in an oven maintained at 50 °C.
In a separate vessel, 350 g of calcite was added to 360 g of demineralised water at 50 °C and mixed for two minutes. To this mix, 285 g of the above premix was added and mixed for five minutes. The composition was allowed to cool for 1 hour. Subsequently, other ingredients like colorants and perfume were added to the composition.

Preparation of model encrusted stain and method of cleaning

The compositions described above were tested on steel tile (the hard surface) on which castor oil was deposited. The oil (0.05 - 0.07 g) was deposited on to a stainless steel tile (pre-weighed) using a pipette. The oil was spread on the plate which was left in horizontal position at room temperature for 12 hours in order to allow the oil to form a regular even film. Tiles were then placed in an oven for one hour and the oven was maintained at 100 °C. Tiles were removed, left to cool for one hour and were weighed again to know the precise weight of the encrusted oily/greasy stain.
The soiled tile was placed in the sample holding area of an Effort Testing Machine (ETM). A cotton cloth was attached to the head of the ETM. A predetermined weight was fixed to the top of the head and the machine was allowed to run for fixed number of rotations. The tile was then removed from the machine, rinsed under tap water, followed by de-mineralised water and then dried in an oven at 50 °C for about thirty minutes. The plate was weighed. The % soil removal was calculated using the difference in the weights.
Some more control compositions and compositions according to the invention were prepared by making suitable changes to the procedure described earlier.

Details of all such compositions and the cleaning data is summarised in table 1.

Table 1

Ingredient	wt%/Control					wt%/Compositions according to invention
	1	2	3	4	5	1	2	3
Water	45.0	45.0	45.0	45.0	45.0	45.0	45.0	45.0
Do-LAS*	-	-	-	3.2	3.2	3.2	3.2	3.2
Na-LAS*	3.2	3.2	3.2	-	-	-	-	-
Dolomite (free)	-	-	-	9.7	9.7	9.7	9.7	9.7
Sodium carbonate	3.5	3.5	-	-	-	-	-	-
Non ionic surfactant	1.8	1.8	1.8	1.8	1.8	1.8	1.8	1.8
Calcite	45.0	45.0	45.0	35.0	35.0	35.0	35.0	35.0
Mineral oil	-	5.0	-	-	5.0	3.0	4.0	2.0
Perfume, colour, methyl laurate, an tifoam and other minors to	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0
pH	10.5	10.5	7.0	6.5	6.5	6.5	6.5	6.5
Grease removal/%	69	-	68	60	72	83	89	74
Phase separation	No	Yes	No	No	Yes	No	No	No

Note:

Do-LAS indicates a mixture of calcium and magnesium salt of linear alkyl benzene sulphonic acid obtained by neutralisation of linear alkyl benzene sulphonic acid with stoichiometric excess of "dolomite", thereby leaving significant quantity of unreacted (free) dolomite for abrasive action.
Na-LAS is sodium salt of alkyl benzene sulphonic acid obtained by the usual neutralisation reaction.

Table 1 has a set of control compositions and a set of compositions in accordance with the invention.
In the case of all the control compositions, either the grease removal is low, or the compositions tend to phase-separate even at room temperature. No such phase separation was observed in the case of any of the composition according to the invention and these compositions also provided high grease removal.
The illustrated examples clearly indicate how the need for cleaning compositions in paste or cream format with neutral to slightly acidic pH and having optimum level of mineral oil but which still are highly effective against deposits of encrusted oily/greasy stains on a hard surface is met.

Claims

A cream or paste composition for cleaning hard surfaces, comprising:
(i) 0.5 wt% to 15 wt% anionic surfactant of which at least 90 parts is calcium or magnesium salt of linear alkyl benzene sulphonic acid, or a mixture of the two; and,

(ii) 10 wt% to 50 wt% of an abrasive having Moh's index in the range of 2.5 to 6,
wherein said composition comprises 0.5 wt% to 4 wt% mineral oil and wherein pH of said composition is in the range of 6 to 7.5, measured at 25 °C of a neat sample.
A composition as claimed in claim 1 comprising 2 wt% to 4 wt% mineral oil.
A composition as claimed in claim 1 or 2 wherein said mineral oil is a hydrocarbon having 14 to 40 carbon atoms.
A composition as claimed in any one of the preceding claims 1, 2 or 3 wherein the abrasive is clay, calcite, dolomite, feldspar, apatite, fluorite, hematite, kyanite, magnetite, orthoclase, and pumice.
A composition as claimed in any one of the preceding claims 1,2, 3 or 4 wherein the anionic surfactant is obtained by neutralisation of linear alkyl benzene sulphonic acid with a mineral of dolomites group.
A composition as claimed in claim 5 wherein the mineral is dolomite.
A composition according to any one of the preceding claims 1, 2, 3, 4 or 5 comprises a non-ionic surfactant.
A process for preparing a hard surface cleaning composition as claimed in any one of the preceding claims comprising the steps of:
(i) neutralizing at least 90 parts by weight of linear alkyl benzene sulphonic acid with a mineral of dolomites group;

(ii) adding 0.5 to 4 parts by weight mineral oil and 10 to 50 parts by weight of an abrasive having Moh's index in the range of 2.5 to 6 to the neutralised mass.
Use of a cream or paste composition as claimed in claim 1 for removing deposits of encrusted oily or greasy stains from a hard surface.
A method of removing deposits of encrusted oily or greasy stains from a hard surface, the method comprising the steps of applying thereon a composition as claimed in claim 1, scrubbing the stained part with a scrubber or a cloth and wiping with a wet cloth.