EP1434844B1

EP1434844B1 - Cleaning wipe

Info

Publication number: EP1434844B1
Application number: EP02732672A
Authority: EP
Inventors: Alexander Unilever Research Port Sunlight ALLAN; Carlo Johannes Van Den Bergh; Helen Burgess; Martin Unilever Research Port Sunlight SHARPLES
Original assignee: Unilever PLC; Unilever NV
Current assignee: Unilever PLC; Unilever NV
Priority date: 2001-05-08
Filing date: 2002-04-25
Publication date: 2007-03-07
Anticipated expiration: 2022-04-25
Also published as: ATE356193T1; DE60218716T2; AR033714A1; EP1434844A2; HUP0400012A3; HUP0400012A2; WO2002090483A3; GB0111175D0; WO2002090483A2; DE60218716D1; ZA200307519B

Description

TECHNICAL FIELD

The present invention relates to a cleaning wipe which is designed in particular for the cleaning of hard surfaces such as are found in the household, or in institutional or hospital environments. The wipe has a textured abrasive surface on one side and is impregnated with a hard surface cleaning formulation.

BACKGROUND AND PRIOR ART

Liquid all purpose hard surface cleaning compositions have historically been generally comprised of two types.
The first type is a particulate aqueous suspension containing suspended water-insoluble abrasive particles.
Several disadvantages may be encountered with cleaners of this type. Some suffer a stability problem, since it is difficult to suspend the insoluble abrasive particles in the composition. Others have received poor acceptance by consumers because of their "gritty" feel. This may cause people to be reluctant to use them for fear of scratching the surface to be cleaned. In addition, they may leave abrasive insoluble particles behind on the treated surface that are difficult to remove and require rinsing or wiping as part of the cleaning process.
The second type is a liquid detergent without suspended abrasive, which is often preferred by consumers over the first type.
However, liquid detergents of this second type generally contain a high level of non-volatile active ingredients such as surfactant and/or detergent builder salts, in order to improve cleaning in the absence of added abrasive. This high level of non-volatiles tends to leave films, spots or streaks on cleaned unrinsed surfaces, particularly shiny surfaces such as glass or stainless steel. Thus, such liquids require thorough rinsing of the cleaned surfaces which is time-consuming and inconvenient for the user.
It is an object of the present invention to provide both excellent cleaning and superior "end-results" (i.e. no significant residues, streaks or spotting left behind after use).

SUMMARY OF THE INVENTION

The present invention provides an impregnated wipe suitable for the cleaning of hard surfaces, which wipe comprises an absorbent substrate having on one side a textured abrasive surface formed from nodules and/or striations of abrasive material applied thereon, the abrasive material having a hardness ranging from 40 to 100 Shore D units, and the substrate incorporating an aqueous hard surface cleaning composition comprising:

(i) from 0.01 to 2% by weight, based on total weight of the composition, of surfactant, and
(ii) from 0 to 15% by weight, based on total weight of the composition, of organic solvent having the general formula (I) :

R₁-O-(EO)_m-(PO)_n-R₂ (I)

wherein R₁ and R₂ are independently C_2-6 alkyl or hydrogen, but not both hydrogen, m and n are independently 0-5, EO represents an ethoxy group and PO represents a propoxy group.

Wipes according to the invention show both excellent cleaning and superior "end-results" (i.e. no significant residues, streaks or spotting left behind after use). It has been found that these properties are apparent even at very low levels of active ingredient and, surprisingly, when the textured surface is of relatively low abrasivity. This is particularly advantageous in the context of delicate, easily-damaged surfaces in the household such as plastics.

DETAILED DESCRIPTION OF THE INVENTION

Wipes of the invention are especially suitable for the cleaning of hard surfaces. By "hard surfaces" is meant those surfaces which are typically found in the household, or in institutional or hospital environments, and which are prone to contamination. Examples include lavatory fixtures, lavatory appliances (toilets, bidets, shower stalls, bathtubs and bathing appliances), wall and flooring surfaces and those surfaces associated with kitchen environments and other environments associated with food preparation.
By "wipe" it is meant a disposable substrate such as a sheet or cloth which has been pre-treated with the aqueous composition comprising ingredients (i) and (ii) as defined above (hereinafter referred to as "the composition of the invention") so as to incorporate the composition of the invention into or onto the substrate prior to its use by the consumer.
This product form is particularly advantageous since it allows for safe and convenient one-step cleaning of surfaces by the user, without the need for dilution or spraying.
Typically the wipe is formed by absorbing the composition of the invention onto the substrate to form a moist wipe. A batch of wipes can then be placed in a container which can be opened when needed and when closed, sufficiently seals to prevent evaporation of any components from the composition. The composition of the invention is impregnated at the desired weight into the substrate which may be formed from any woven or nonwoven fibre, fibre mixture or foam of sufficient wet strength and absorbency to hold an effective amount of the composition.

Wipe

Wipes of the invention comprise an absorbent substrate having on one side a textured abrasive surface as described above.
Preferred materials used to form the wipe include in general all nonwoven materials with sufficient wet strength and liquid absorption capacity to contain the aqueous composition of the invention and to deliver it in use.
Illustrative examples of suitable nonwoven materials include fibres from natural sources such as viscose, cellulose, or from synthetic origin such as polypropylene or polyester. Especially suitable are mixtures of these materials such as viscose/polyester, viscose/polypropylene, and cellulose/polyester.
Optionally one or more latex binders can be added. These latex binders can typically include one or more monomers selected from styrene-2-ethyl hexyl acrylate, butyl acrylate, methyl methacrylate, ethyl acrylate, methyl acrylate, acrylonitrile and vinyl acetate.
The materials can be formed into webs using technologies generally known in the art such as carding, drylaid, wetlaid, airlaid and extrusion.
Webs can be bonded using technologies known in the art such as needlepunch, stitchbond, hydroentangling, chemical bonding, thermal bonding, spunbinding, spunlacing and meltblowing. A preferred method is spunlacing.
The wipe may be a single layer structure or a multilayer structure formed from layers of materials of the above general type, which may be the same or different.
Prior to impregnation with the composition of the invention, the wipe typically has an average thickness ranging from 0.1 to 3.0mm, preferably from 0.2 to 1.0mm, more preferably from 0.3 to 0.6mm.
Prior to impregnation with the composition of the invention, the wipe typically has a maximum absorbency of from 2 to 12g/g (grams water per gram of wipe), preferably from 3 to 10g/g, more preferably from 4 to 8g/g.
Prior to impregnation with the composition of the invention, the wipe typically has a baseweight of from 30 to 100 g/sq m, preferably from 40 to 90 g/sq m, more preferably from 50 to 80 g/sq m.

Textured Abrasive Surface

The wipe of the invention has on one side a textured abrasive surface formed from nodules and/or striations of abrasive material applied thereon, the abrasive material having a hardness ranging from 40 to 100 Shore D units.
As used herein, the term "abrasive" refers to a surface texture that enables the wipe to produce a mild scouring or abrading action to effectively break up and remove dirt or other contaminants. Such dirt or contaminants are frequently embedded in a surface.
Shore D hardness is measured at 20°C using the procedures explained in ISO R 868. A suitable instrument is the Bareiss HHP 2000 Shore Hardness tester.
Synthetic polymeric abrasive materials are especially useful. Most preferred are those having a hardness ranging from 40 to 100 Shore D units, preferably from 50 to 95 Shore D units, more preferably from 70 to 90 Shore D units.
Suitable synthetic polymeric abrasive materials of the appropriate Shore D hardness range as defined above include polyolefins, polyesters, polyvinyl chlorides, and polyamides. Copolymers or mixtures of any of these may also be suitable. Specific examples include polyethylene, polypropylene, polybutylene, polyethylene terephthalate, poly (ethylene) vinyl acetate, polystyrene, polyamide, polymethyl methacrylate, and polyvinyl chloride.
The nodules and/or striations of abrasive material may be distributed on the wipe substrate in a uniform pattern (such as polka dots) or an irregular distribution (such as speckles or streaks), depending on the method used to apply the abrasive to the wipe.
The abrasive material may suitably be dyed or pigmented. Preferably it is in a different colour to the wipe substrate on which it is present, so as to provide a visual indicator of its presence. In this way the user can readily distinguish between the non-abrasive and abrasive sides of the wipe.
The extent of surface coverage per unit area of the wipe substrate by the abrasive material typically ranges from 10 to 50%, preferably from 15 to 45%, more preferably from 20 to 40%, when measured by image analysis of the wipe.
The abrasive material may be applied to the wipe in a number of different ways known to those skilled in the art.
For example, for melt-blown wipes the abrasive material may be applied directly following extrusion of the fibres used to form the wipe. The abrasive material is then embedded in the molten surface and becomes locked in place as the fibres cool.
For pre-formed wipe webs based on entangled fibres, such as spunlace wipes, the abrasive material is typically held in place on the substrate by means of an adhesive. The adhesive and abrasive material may be applied to the wipe substrate by any suitable method. Roller coating and screen printing both give good results. Alternatively a solution or dispersion of the adhesive containing dispersed abrasive particles may be sprayed onto the wipe substrate and subsequently heat-cured.
If desired, abrasive particles may be formed in situ on the wipe substrate by spraying or sputtering molten or dissolved polymer onto the substrate. Another suitable method is described in WO97/21865, according to which an abrasive nonwoven fibrous web material is produced by firstly forming a nonabrasive precursor web of nonwoven fibrous material. The precursor web carries on one surface a uniform distribution of attenuated meltable thermoplastic fibres, such as polypropylene fibres. The precursor web is then heated sufficiently to cause the attenuated thermoplastic fibres to shrink and form nodulated fibre remnants that impart a roughened abrasive character to the planar surface of the resultant web material. Because the fibres nodulate in situ, after being integrated within the web, this permits the formation of a single layer structure.

Hard Surface Cleaning Composition

Wipes according to the invention incorporate an aqueous hard surface cleaning composition as defined above and referred to herein as "the composition of the invention".
In an impregnated wipe according to the invention, the weight ratio of composition of the invention to wipe suitably ranges from 1:1 to 6:1, and is preferably from 1:1 to 4:1, more preferably from 2:1 to 3:1.
The ingredients of the compositions of the invention will be further described as follows:

Water

Compositions of the invention are aqueous compositions which preferably contain relatively low levels of actives.
Typically the principal ingredient is water, which is normally present at a level of at least 50%, preferably at least 80%, by weight based on total weight. The use of distilled or demineralised water is preferred, but not essential to the invention.

Surfactant

Compositions of the invention contain from 0.01 to 2% by weight, based on total weight of the composition, of surfactant.
Preferred surfactants for inclusion in compositions of the invention are anionic surfactants, amphoteric surfactants, nonionic surfactants, and mixtures thereof.
Suitable anionic surfactants for use herein include alkyl sulphates, alkyl sulphonates, alkyl aryl sulphonates, alkyl alkoxylated sulphates, or mixtures thereof.
Alkyl sulphates and alkyl alkoxylated sulphates are particularly preferred.
Suitable alkyl sulphate surfactants for use herein are represented by the formula RSO₄ M wherein R represents a hydrocarbon group which may suitably be a linear or branched alkyl group containing from 6 to 20 carbon atoms, or an alkyl phenyl group containing from 6 to 18 carbon atoms in the alkyl group.
Preferably R is a linear or branched alkyl group containing from 6 to 20 carbon atoms, more preferably from 8 to 18 carbon atoms, most preferably from 10 to 16 carbon atoms.
M is hydrogen or a cation such as an alkali metal cation (e.g., sodium, potassium, lithium, calcium, and magnesium) or ammonium or substituted ammonium (e.g., methyl-, dimethyl-, and trimethyl ammonium cations and quaternary ammonium cations, such as tetramethyl-ammonium and dimethyl piperidinium cations and quaternary ammonium cations derived from alkylamines such as ethylamine, diethylamine, triethylamine, and mixtures thereof).
An example of a commercially available branched alkyl sulphate is DACPON 27-23 AL, ex CONDEA. This material can be described as a branched, essentially C₁₂/C₁₃ sodium alkyl sulphate of formula (R₁)CH(R₂)-OSO₃Na where R₁ is C_1-4 alkyl and R₂ is C_8-11 alkyl.
An example of a commercially available linear alkyl sulphate is EMPICOL LX28, ex Albright & Wilson. This material can be described as R-OSO₃Na where R is C_10-16 alkyl, mainly C_12-14 alkyl.
Suitable alkyl sulphonates for use herein include water-soluble salts or acids of the formula RSO₃M wherein R is a linear or branched, saturated or unsaturated alkyl group containing from 6 to 20 carbon atoms, more preferably from 8 to 18 carbon atoms, most preferably from 10 to 16 carbon atoms, and M is hydrogen or a cation such as those listed above for alkyl sulphate surfactants. An example of a commercially available C₁₄-C₁₆ alkyl sulphonate is HOSTAPUR SAS ex Hoechst.
Suitable alkyl aryl sulphonates for use herein include water-soluble salts or acids of the formula RSO₃M wherein R is an aryl group, preferably a benzyl group, substituted by a linear or branched saturated or unsaturated alkyl group containing from 6 to 20 carbon atoms, more preferably from 8 to 18 carbon atoms, most preferably from 10 to 16 carbon atoms, and M is hydrogen or a cation such as those listed above for alkyl sulphate surfactants.
Examples of commercially available alkyl aryl sulphonates are the alkyl benzene sulphonates available from Albright & Wilson under the trade name NANSA.
Suitable alkyl alkoxylated sulphate surfactants for use herein are according to the formula RO(A)mSO₃M wherein R is an unsubstituted alkyl or hydroxyalkyl group having an alkyl component containing from 6 to 20 carbon atoms, more preferably from 8 to 18 carbon atoms, most preferably from 10 to 16 carbon atoms, A is an ethoxy or propoxy unit, m is greater than zero, typically between 0.5 and 6, more preferably between 0.5 and 3, and M is H or a cation such as those listed above for alkyl sulphate surfactants.
R is most preferably an alkyl group having from 12 to 14 carbon atoms. R can be linear, branched or mixed linear/branched, and is preferably linear.
An example of a commercially available alkyl alkoxylated sulphate surfactant is EMPICOL ESA 70, ex Albright & Wilson. This material can be described as RO-(CH₂CH₂O)SO₃Na where R is C_10-16 alkyl, mainly C_12-14 alkyl. A further examples is COSMACOL® AES 70-3-24, ex Condea. This material can be described as RO-(CH₂CH₂O)₃SO₃Na where R is linear C_12-14 alkyl.
Suitable amphoteric surfactants for use herein include betaines. Typical examples are the alkyl amidoalkyl betaines, particularly the alkyl amidopropyl betaines, preferably having an aliphatic alkyl group of from 8 to 18 carbon atoms and preferably having a straight chain, such as cocamidopropylbetaine. Other betaines, such as alkyl betaines, are also suitable.
Particularly preferred for disinfectancy benefits are antimicrobially-active amphoteric surfactants such as the alkyl(polyaminoalkyl)glycines sold by Goldschmidt under the tradename TEGO^®.
Materials of this type are described in US 5,160,666, and their structures correspond to the following general formulae (a), (b) or (c):

R-(NH-(CH₂)_n)_m-NH-CH₂-COOH (a)

[(R-(NH-(CH₂)_n)_m]₂-N-CH₂-COOH (b)

(R)(R¹)-N-(CH₂)_n-NH)_m-CH₂-COOH (c)

wherein

R represents C₈ to C₁₈ alkyl,
R¹ represents ((CH₂)_n-NH)_m-(CH₂)_n-NH₂,
n is an integer ranging from 2 to 4 and
m is an integer ranging from 1 to 5.

Mixtures of compounds of any of the above general formulae can also be used, as can their respective salts with acids such as mineral acids.
Specific examples are dodecyl-di-(aminoethyl) glycine; dodecyl aminopropylglycine; N-(N'-[C_8-18 alkyl]-3-aminopropyl)-glycine; N-(N'-(N"-[C_8-18 alkyl]-2-aminoethyl) -2-aminoethyl)-glycine; N,N-bis (N'-[C_8-18 alkyl]-2-aminoethyl)-glycine, and salts and mixtures thereof.
The alkyl(polyaminoalkyl)glycines of the formulae (a), (b) and (c) and salts and mixtures thereof are commercially available from Goldschmidt under the tradename TEGO^®, in the form of aqueous solutions.
Especially preferred are those alkyl(polyaminoalkyl)glycines of formula (a), where n = 3 and m = 1. A commercially available example of such a material is TEGO^® 2000, ex Goldschmidt.
Suitable nonionic surfactants for use herein include nonionic alkoxylates, nonionic alkylphenol polyethers, alcohol alkoxylates (e.g. alcohol ethoxylates and alcohol propoxylates and mixed ethoxylates/propoxylates), nonionic condensates of branched chain primary or secondary alcohols and alkylene (especially ethylene) oxides, alkoxylated amines, amine oxides, and nonionic condensates of fatty acids and alkylene oxides.
Preferred classes of nonionic surfactant are alkylpolysaccharides, alkyl pyrrolidones and mixtures thereof.
Suitable alkylpolysaccharides for use herein have a hydrophobic group containing from 6 to 30 carbon atoms, preferably from about 10 to about 16 carbon atoms, and a polysaccharide hydrophilic group such as a polyglycoside. Optionally there can be a polyalkyleneoxide (typically polyethylene oxide) chain joining the hydrophobic group and the polysaccharide group. Typical hydrophobic groups include alkyl groups, either saturated or unsaturated, branched or unbranched containing from 8 to 18 carbon atoms. Preferably, the alkyl group is a straight-chain saturated alkyl group. The alkyl group can contain up to about 3 hydroxyl groups and/or the polyalkyleneoxide chain can contain up to about 10, preferably less than 5, alkyleneoxide groups.
In the alkyl polysaccharides, the alkyl groups can be derived from the usual sources like fats, oils or chemically produced alcohols while their sugar units are created from hydrolyzed polysaccharides. Alkyl polyglycosides are the condensation product of fatty alcohol and sugars like glucose, which can be alkoxylated either before or after reaction with the fatty alcohols.
Alkyl polysaccharides are generally not molecularly uniform products, but represent mixtures of alkyl groups and mixtures of monosaccharides and different oligosaccharides. Preferred materials are alkyl polyglycosides (also sometimes referred to as "APGs"). The glycoside units are preferably formed from glucose and the alkyl substituent is preferably a saturated or unsaturated alkyl group containing from 8 to 18 carbon atoms, preferably from 8 to 10 carbon atoms. A commercially available example of such a material is GLUCOPON ^® 215 CS available from Henkel.
Suitable alkyl pyrrolidones are N-alkyl pyrrolidone derivatives which are N-(n-alkyl) pyrrolidones where the alkyl group has from 6 to 20, preferably from 8 to 14 carbon atoms.
Preferred N-alkyl pyrrolidone derivatives are N-(n-octyl)-2-pyrrolidone, N-(n-decyl)-2-pyrrolidone, N-(n-dodecyl)-2-pyrrolidone and N-(n-tetradecyl)-2-pyrrolidone.
Particularly preferred is N-(n-octyl)-2-pyrrolidone, available commercially as SURFADONE LP-100 ex International Speciality Products, Inc.
Mixtures of any of the above described surfactants are also suitable for use in compositions of the invention. Particularly preferred are blends of N-alkylpyrrolidone derivatives with anionic surfactants and/or other nonionic surfactants such as alkyl polyglycosides as described above.
Compositions of the present invention are prepared with relatively low levels of active materials. Typically, the total level of surfactant in compositions of the invention ranges from 0.05% to 1.5%, more preferably from 0.1 to 0.9%, by total weight of surfactant based on total weight of the composition. It has been found that use of low, rather than high levels of surfactant are advantageous to overall end result performance.

Organic Solvent

Compositions of the invention optionally contain an organic solvent having the general formula (I):

R₁-O-(EO)_m-(PO)_n-R₂ (I)

wherein R₁ and R₂ are independently C_2-6 alkyl or hydrogen, but not both hydrogen, m and n are independently 0-5, EO represents an ethoxy group and PO represents a propoxy group.
Such organic solvents assist the surfactant to remove soils such as those commonly encountered on hard surfaces such as in the kitchen or bathroom. The organic solvent can also increase the stability of the composition by helping to solubilise hydrophobic components.
Preferred organic solvents of the formula (I) above include ethanol; isopropanol; mono-propylene glycol mono-propyl ether; di-propylene glycol mono-propyl ether; mono-propylene glycol mono-butyl ether; di-propylene glycol mono-propyl ether; di-propylene glycol mono-butyl ether; tri-propylene glycol mono-butyl ether; ethylene glycol mono-butyl ether; di-ethylene glycol mono-butyl ether; ethylene glycol mono-hexyl ether; di-ethylene glycol mono-hexyl ether; and mixtures thereof. "Butyl" includes both n-butyl, iso-butyl and tert-butyl groups.
Particularly preferred examples are propylene glycol n-butyl ether, sold by Dow Chemical Company as Dowanol PnB. Other suitable materials include Dowanol PM (mono-propylene glycol mono-n-butyl ether) and Dowanol DPnB (di-propylene glycol mono-n-butyl ether), both also commercially available from Dow Chemical Company.
The amount of optional organic solvent can vary depending on the other ingredients present in the composition of the invention and the desired end use. The organic solvent is normally helpful in providing good cleaning, without impairing end results, and may present at levels of up to 15% by total weight of organic solvent based on total weight of the composition.
For other applications such as cleaning in enclosed spaces, too much organic solvent may be undesirable due to vapour formation, so in such cases it is preferable to have a lower level of organic solvent, such as 5% or less, by total weight of organic solvent based on total weight of the composition.

pH

Compositions of the invention can be made at pH values suitably ranging from 2 to 10, preferably from 3 to 8.
An acidic pH, such as from 2 to 5, more preferably 3 to 4, is not essential for compositions of the invention, which may also be neutral or alkaline.
However, lower pH and use of one or more suitable acids has been found to be particularly advantageous for disinfectancy benefits, especially when anionic surfactants as described above are present.
Accordingly, compositions of the invention may optionally contain an acid which is preferably organic in nature.

Organic Acid

Suitable organic acids for use herein include carboxylic acids and mixtures thereof.
The carboxylic acids and mixtures thereof may suitably be selected from aliphatic, cycloaliphatic or aromatic mono-, di-, tri- or polycarboxylic acids which generally contain 2 to 10 carbon atoms, preferably 3 to 6 carbon atoms in the molecule. Hydroxycarboxylic acids may also be used.
Examples of suitable carboxylic acids include caprylic acid, propionic acid, azelaic acid, caproic acid, hydroxybenzoic acid, salicylic acid, malic acid, maleic acid, fumaric acid, succinic acid, glutaric acid, adipic acid, tartaric acid, citric acid and mixtures thereof.
Especially preferred are mixtures of dicarboxylic acids, in particular mixtures including adipic, glutaric and succinic acid. These mixtures are preferred as they are commercially available. Typical commercially available mixtures comprise 30-35% adipic acid, 45-50% glutaric acid and 10-18% succinic acid. Such a mixture is available as SOKALAN DCS ex BASF. Another suitable mixture is available as RADIMIX ex Radici.
The amount of organic acid in compositions of the invention can vary depending on the other ingredients present in the composition. It suitably ranges from 0 to 1%, more preferably from 0.001% to 0.5%, by weight based on total weight of the composition.
One preferred composition of the invention comprises ingredients and amounts (by weight based on total weight) as specified below:

Anionic surfactant: from 0.1 to 0.5%, preferably from 0.2 to 0.4%
Nonionic surfactant: from 0.05 to 1%, preferably from 0.2 to 0.8%
Organic solvent: from 0.05 to 5%, preferably from 0.1 to 3%, more preferably from 0.2 to 5%.
Water: at least 80%, preferably from 90 to 98%.

A particularly preferred composition of this type comprises ingredients and amounts (by weight based on total weight) as specified below:

Alkyl sulphate anionic surfactant: from 0.1 to 0.5%, preferably about 0.3%
Organic carboxylic acid: from 0.1 to 0.8%, preferably about 0.4%.
N-alkylpyrrolidone derivative nonionic surfactant: from 0.05 to 1%, preferably about 0.5%.
Organic solvent: from 0.05 to 5%, preferably from 0.1 to 3%, more preferably from 0.2 to 5%.
Water: at least 80%, preferably about 95%

The above composition gives excellent hygienic cleaning benefits and low residue when incorporated into a wipe according to the invention.
Another preferred composition of the invention comprises ingredients and amounts (by weight based on total weight) as specified below:

Nonionic surfactant: from 0.01 to 1.0%, preferably from 0.1 to 0.2%
Organic solvent: from 10 to 15%
Water: at least 70%, preferably from 80 to 88%

Alkylpolyglycoside nonionic surfactant: from 0.01 to 0.5%, preferably about 0.1%
N-alkylpyrrolidone derivative nonionic surfactant: from 0.001 to 0.5%, preferably about 0.05%.
Organic solvent: from 10 to 15%, preferably about 12%
Water: at least 70%, preferably about 85%

The above composition gives excellent cleaning benefits and exceptionally low residue when incorporated into a wipe according to the invention.
Compositions of the invention can contain other optional ingredients which aid in their cleaning performance and maintain the physical and chemical stability of the product.
Examples include: preservatives, perfumes, colours and dyes, foam-control agents, viscosity modifying agents, hygiene agents, and mixtures thereof.
However, as far as the inclusion of further ingredients is concerned, since there is usually no rinsing step in the context of a general purpose pre-moistened wipe, it is highly preferred that the non-volatile content be kept to a minimum to avoid film/streak residue. Low levels of non-volatiles can advantageously be incorporated for their functional benefit, but it is highly desirable to keep the total level of non-volatiles (by weight based on total weight of the composition) no higher than 3%, most preferably no higher than 1.5%.
The invention will now be illustrated by the following nonlimiting Examples, in which all percentages are by weight based on total weight, unless otherwise indicated.

EXAMPLE

The cleaning performance of various combinations of wipes and formulations was evaluated by using a reciprocating linear scrubbing device to clean a model kitchen soil from white Decamel^® (ex Formica) sheets.
The composition of the soil was as follows:

wt%

Glycerol tripalmitate 1.0

Triolein 0.5

Kaolin 0.5

Liquid paraffin 0.2

Palmitic acid 0.1

Carbon black 0.02

Methylated spirit 97.68
The model kitchen soil dispersion was sheared for 30mins using a Silverson Mixer at half speed prior to application to the Decamel^® sheets.
The model soil was sprayed onto clean white Decamel^® (ex Formica) sheets in the form of a strip 5cm wide along the length of the sheet, with a surface coverage of 0.06mgs/sq cm (based on involatiles) using a gravity feed paint spray gun connected to a compressor.
The soiled sheets were aged overnight prior to cleaning to allow complete removal of the solvent and to ensure good adhesion of the soil.

Test formulations are detailed below:
Control: Water
Comparative A: Commercially available general purpose cleaner
Comparative B: Commercially available liquid abrasive cleaner
Example: Formulation according to the invention having ingredients as shown in the following Table:

INGREDIENT	wt%
Demineralised Water	to 100
Isopropyl alcohol	1.800
Propylene glycol mono-n-butyl ether (Dowanol PnB, ex Dow)	0.300
N-(n-octyl)-2-pyrrolidone (Surfadone LP100, ex ISP)	0.400
Primary alkyl sulphate 28% active (Dacpon 27-23 AL, ex Condea)	0.536
Mix of acids (Sokalan DCS, ex BASF)	0.600
Sodium hydroxide 50% active	0.050

The above test formulations were each used to impregnate test wipes. Test wipes are detailed below:

Wipe 1 was a spunlace substrate without abrasive
Wipe 2 was a wipe according to the invention with a spunlace substrate having an abrasive layer formed from synthetic polymeric material with hardness of 80 to 85 Shore D units.

Test wipes were cut to fit the head of the linear reciprocating scrubbing device and impregnated to a level of 2.5 grams of test formulation per gram of test wipe. The test wipes as fitted into the head of the device were then used to clean the model kitchen soil from the treated Decamel^® sheets as described above, using a standard cleaning pressure of 80g/cm² and a cleaning head with an area of 8cm x 2.5cm.
The cleaned sheets were assessed for degree of soil removal using a Dr Lange Micro Colour colorimeter, as follows.
Reflectance readings were taken for each of the following:

(i) the unsoiled sheet
(ii) the soiled sheet cleaned with the control wipe/control formulation combination (i.e. Wipe 1 impregnated with water)
(iii) the soiled sheet cleaned with the relevant test wipe/test formulation combination

Three readings for each of (i), (ii) and (iii) were averaged to give an L* value according to the LAB colour scale.
The % Soil Removal was determined as: $Soil Removal = \frac{L * (iii) - L * (ii)}{L * (i) - L * (ii)} \times 100 %$
The control value L*(ii) effectively sets the zero soil removal baseline taking into account the effects of mechanical action and the water, allowing differences between test wipe/formulation combinations to be determined. Cleaning performance results (% Soil Removal) were as follows:

Wipe 1 + Control 0

Wipe 1 + Comparative A 72

Wipe 1 + Comparative B 82

Wipe 2 + Control 13

Wipe 2 + Example 70
These results show that an impregnated wipe according to the invention (i.e. Wipe 2 + Example) gives similar cleaning performance to the comparative examples, even though the active ingredient level of the formulation and the abrasivity level of the wipe are both relatively low.

Claims

An impregnated wipe suitable for the cleaning of hard surfaces, which wipe comprises an absorbent substrate having on one side a textured abrasive surface formed from nodules and/or striations of abrasive material applied thereon, the abrasive material having a hardness ranging from 40 to 100 Shore D units, and the substrate incorporating an aqueous low-active hard surface cleaning composition comprising:
(i) from 0.01 to 2% by weight, based on total weight of the composition, of surfactant, and

(ii) from 0 to 15% by weight, based on total weight of the composition, of organic solvent having the general formula (I) :

R₁-O-(EO)_m-(PO)_n-R₂ (I)

wherein R₁ and R₂ are independently C_2-6 alkyl or hydrogen, but not both hydrogen, m and n are independently 0-5, EO represents an ethoxy group and PO represents a propoxy group.
A wipe according to claim 1, in which the abrasive material is a synthetic polymeric abrasive material having a hardness ranging from 40 to 100 Shore D units, preferably from 50 to 95 Shore D units, more preferably from 70 to 90 Shore D units.
A wipe according to claim 1 or 2, in which the wipe substrate has an average thickness ranging from 0.1 to 3.0mm, preferably from 0.2 to 1.0mm, more preferably from 0.3 to 0.6mm.
A wipe according to any one of claims 1 to 3, in which the aqueous hard surface cleaning composition comprises ingredients in the following percentages (by weight based on total weight of the aqueous composition):
Anionic surfactant: from 0.1 to 0.5%, preferably from 0.2 to 0.4%

Nonionic surfactant: from 0.05 to 1%, preferably from 0.2 to 0.8%

organic solvent: from 0.05 to 5%, preferably from 0.1 to 3%, more preferably from 0.2 to 5%.

Water: at least 80%, preferably from 90 to 98%.
A wipe according to claim 3, in which the aqueous hard surface cleaning composition comprises ingredients in the following percentages (by weight based on total weight of the aqueous composition):
Nonionic surfactant: from 0.01 to 1.0%, preferably from 0.1 to 0.2%

Organic solvent: from 10 to 15%

Water: at least 70%, preferably from 80 to 88%
A method of cleaning hard surfaces comprising wiping the hard surface with a wipe according to any one of claims 1 to 5.
Use of a wipe according to any one of claims 1 to 5 for cleaning hard surfaces.