GB2527347A

GB2527347A - Cleaning formulation

Info

Publication number: GB2527347A
Application number: GB1410949.0A
Authority: GB
Inventors: Samantha Heys; Nicole Thompson; Colin Litten-Brown
Original assignee: Robert McBride Ltd
Current assignee: Robert McBride Ltd
Priority date: 2014-06-19
Filing date: 2014-06-19
Publication date: 2015-12-23
Also published as: GB201410949D0

Abstract

An aqueous formulation for the chemical removal of foreign matter from solid surfaces, comprises: (i) a primary surfactant in the form of a linear C9-CI I alcohol ethoxylate 8E0, (ii) at least one water-soluble solvent, and (iii) at least one secondary surfactant. wherein the at least one secondary surfactant comprises a branched C10 alcohol ethoxylate 8E0 and/or a cationic surfactant of the formula I: In which: R1 is a C1-4 alkyl group; R2 is a C1-4 alkyl group; R3 is a C1-4 alkylene group; R4 is a C12-20 alkyl group; and X- is a counter-ion. Also shown is the use of the formulation and method of cleaning a substrate using the formulation.

Description

CLEANING FORMULATION

Field of the invention

The present invention relates to aqueous formulations for the chemical removal of foreign matter from solid surfaces. The invention relates more particularly to aqueous formulations having low Ieves of active components so as to minimise contamination of water-sources with excess chemicals.

There are many incidences in both household and industrial environments where it is desirable to remove foreign matter from a rigid surface. Such contaminations can render the surface unsuitable for use. For example, in many manufacturing processes for the conversion of metals, plastics, vitreous enamelled surfaces, glazed ceramics and processed materials containing a binder such as melamine-formaldehyde resin, contamination can occur at any point of the process either by the introduction of machine oils or other substances as part of the industrial process or associated machinery or through manual handling of the components during use.

Following conversion the surfaces can also become contaminated during use with a wide range of proteinaceous, lipidic, lime soap, of calcium or magnesium sterate, petrochemical or other generally water-insoluble substances, depending on the intended end-use of the substrate.

Where the substrate or component is intended for use in an environment in which it is in regular contact with water and associated with sanitary activities such as personal washing or machine washing there is the potential for lime soap accumulation which is exacerbated when the water has a significant level of dissolved inorganic salts or hardness". The accumulated lime soap can impair the mechanical use of components and substrates and also lead to bacterial contamination by providing a source for the accumulation of a bio-film.

For situations where the substrate or component is used in relation to medical procedures, food preparation or other situations handling biological material there is the potential for the contamination of the surface with proteinaceous and lipidic substances which again can impair the mechanical use of components or allow the accumulation of bacterial or other microbiological organisms within a bio-film.

Where the substrate or component is used in an industrial or mechanical situation oils and other petrochemical-based substances can contaminate the surface for example lubricating oils leaking from other components in the processing equipment.

In all cases of substance contamination, there the substrate is a rigid surface the presence of contamination and the potential of bio-tilm accumulation means that the surface has the potential to contaminate any materials or persons that come into contact with the substrate.

In the case of mechanical components the presence of contamination can result in moving parts becoming stuck together or having reduced mobility or, in the case of oils, the opposite may be true where the friction or adherence between two components is adversely reduced.

In all of these scenarios it is desirable to have a method for the removal of contamination in such a form that the method is non-specific to a particular contamination type. Methods that are specific to a particular contamination type would require clear identification of the contamnation and under most situations this may not be possible or the contamination may be a combination of materials with different propertes.

Methods for the decontamination of surfaces to counteract all of the above contaminant materials are well known but domestic and industrial decontaminants tend to contain high levels of aromatic or aliphatic solvents and non-ionic, anionic and cationic surfactants designed to remove contaminants by either pure solvency or by emulsification. Alternatively, acidic or alkaline formulations are used to chemically alter the contaminant, either rendering it soluble in water or another suitable surface or breaking it into solid particles which are easily removed.

In all cases the formulation are designed to have no chemical impact on the substrates or components on which they are to be used and are therefore non-reactive with respect to commonly used metals, vitreous enamel surfaces, glazed ceramic surfaces, common plastics or surfaces bonded with melamine-formaldehyde resins or other similar constructional binders.

Under typical usage conditions the decontaminant formulation is applied either neat or dilute by a pressurised spray from, for example, an aerosol, mechanical pressurised sprayer or manual trigger sprayer. It is also possible to supply the formulation as a liquid which is used in neat or diluted form and either applied directly to the substrate or component or is used as a soaking medium into which the contaminated material is immersed.

In some cases it is also practice to formulate the decontaminant using aliphatic solvents as the bulk solvent rather than water.

Contaminant removal is in all cases boosted by applying manual action, for example with a pad, sponge, cloth, brush or other implement to promote the action of the solvent and surfactant on the contaminant. For some contaminants the application of heat can also boost performance. In many applications, however, it is difficult to apply heat, for instance in the removal of contaminants from domestic surfaces and the application of excessive manual agitation may also be difficult or undesired as it may in time cause damage to the substrate.

A key issue with decontaminant formulations is the need for significant levels of surfactant and solvent to promote effective chemical removal of contaminants without the need for heat or significant manual agitation. This leads to formulations which are potentially expensive to use, hazardous to the user in the form of skin irritancy or de-fatting of skin and harmful to the aquatic environment when entering the waste water system.

In large-scale decontamination situations such as industrial cleaning processes or in situations where the formulation is used on a regular basis such as domestic cleaning it is desirable to have a formulation that is inexpensive, of low hazard to the user or the environment but at the same time has a suitable level of decontamination efficacy based on the solvency and emulsification capabilities of the surfactant system present. Such a formulation should therefore have a low level of active material but balanced to have optimum broad-spectrum contaminant removal properties.

There are other factors that can impact on decontaminant formulations of this type. For compositions intended for domestic use the odour of the formulation is important and it is desirable for the base odour not to be too strong or of an unpleasant "chemical" or "solvent" odour. Fragrances are commonly added to formulations to provide a pleasant scent during use but excessive levels of decontaminant raw materials would potentially still be detectable over the added fragrance.

The cloud point of the formulation is also critical as lowering the active levels can result in some of the components precipitating out at lower temperatures so it is essential that any low active system is still stable at normal working conditions of temperature and pressure.

It is an object of the present invention to obviate or mitigate the abovementioned disadvantages.

Summary of the Invention:

According to a first aspect of the present invention there is provided an aqueous formulation for the chemical removal of foreign matter from solid surfaces, the formulation comprising: (i) a primary surfactant in the form of a linear 09-Cu alcohol ethoxylate 8E0, (ii) at least one water-soluble volatile solvent, and (iii) at least one secondary surfactant, wherein the at least one secondary surfactant comprises a branched ClO alcohol ethoxylate and/or a cationic surfactant of the formula I: HOR3-N---R4 12 X® in which: R1 is a C1-4 alkyl group; R2 is a C1-4 alkyl group; ft is a C1-4 alkylene group; A4 is a Cl 2-20 alkyl group; and X is a counter-ion.

Preferably the linear 09-Cl 1 alcohol ethoxylate SEQ is present at a level of 1.0 to 2.60 wt%; and/or the solvent is present at a level of 0.01 to 0.6 wt% based on the total weight of the formulation.

It is preferred that at least one of R1 and R2 in the cationic surfactant is a methyl group (preferably both R1 and R2 are methyl groups). In some embodiments R3 of the cationic surfactant is an ethyleneyl group. The cationic surfactant may be present as a mixture of compounds of the formula I in which R4 comprises a mixture of 012-18 alkyl groups. Preferably, R4 comprises a mixture of 012-14 alkyl groups and more preferably R4 predominantly comprises a mixture of C12 and 014 alkyl groups. The cationic surfactant preferably comprises a hydroxyethyl laurdimonium cation, such as hydroxyethyl laurdimonium chloride.

If present, the cationic surfactant is preferably present at a level of 0.1 to 0.6 wt% based on the total weight of the formulation. Similarly, if present, the 010 alcohol ethoxylate SEQ is preferably present at a level of 0.5 to 2.0 wt% based on the total weight of the formulation.

The formulation may include one or more foam boosters (preferably cocoamine oxide), builders (preferably sodium carbonate and/or sodium bicarbonate), chelating agents (preferably EDTA), aromatic sovents, zwitterionic surfactants, preservatives, fragrances, dyes, thickeners, and/or biocidal agents.

The formulation may include sodium carbonate at a level of 0.2 to 0.5 wt%; sodium bicarbonate at a level of 0.1 to 0.5 wt%; EDTA at a level of 0.01 to 0.25 wt%; and/or sodium carbonate and sodium bicarbonate at a combined level of 0.35 to 1.00 wt% based on the total weight of the formulation.

The formulation preferably comprises at least 90 wt% (preferably at least wt%) water based on the total weight of the formulation.

The water-soluble solvent may be an aliphatic solvent, and is preferably selected from the group consisting of propylene glycol monobutyl ether, propylene glycol phenyl ether, dipropylene glycol n-butyl ether and 1-dodecyl-2-pyrrolidone.

According to a second aspect of the present invention there is provided an aqueous formulation for the chemical removal of foreign matter from solid surfaces, the formulation comprising: (i) a primary surfactant in the form of a linear C9-C11 alcohol ethoxylate 8E0; (ii) at least one water-soluble solvent; (Ui) at least one secondary surfactant; (iv) sodium carbonate; (v) sodium bicarbonate; and (vi) at least 90 wt% water based on the total weight of the formulation; wherein the at least one secondary surfactant comprises a branched ClO alcohol ethoxylate SF0 and/or a cationic surfactant of the formula I: HOR3-N--R4

X

in which: ft is a C1-4 alkyl group; R2 is a C1-4 alkyl group; R3 is a Cl -4 alkylene group; R4 is a Cl 2-20 alkyl group; and X is a counter-ion.

According to a third aspect of the present invention there is provided a method of cleaning a substrate comprising applying to a substrate a formulation according to the first or second aspect of the present invention.

According to a fourth aspect of the present invention there is provded a use of a formulation according to the first or second aspect of the present invention for cleaning a substrate.

Preferred features described above in relation to the first aspect of the present invention also represent preferred features of the other aspects of the present invention subject to a technical incompatibility that would prevent such a combination of preferred features. Furthermore, it will be evident to the skilled person that advantages set out in respect of the first aspect of the present invention are also offered by the other aspects of the present invention.

The present invention relates to a formulation intended to be used both undiluted and diluted in which the level of total active material in the undiluted formula is less than 5% where the active material is defined as all components within the system which have a demonstrable effect on contaminant removal. The present invention also relates to a formulation in which the non-volatile content (dry matter) is less than the amount of total active matter i.e. that at least a portion of the total active matter is formed of a volatile solvent.

Total active material is, in this case, defined as materials which have the function of pH adjustment, for example building alkalinity to promote contaminant removal, chelation to remove metal ions from solution to assist in the removal of lime soap, aromatic or aliphatic solvent for the chemical dissolution of contaminants and non-ionic, anionic, cationic or zwitterionic surfactants for the emulsification of contaminants.

Also present in the formulation may be ancillary materials such as preservative, fragrance, dye, thickener, and biocidal agents each of which has a function within the formulation that does not specifically affect the level of decontaminant performance and can optionally be added depending on the intended end-use of the formulation. For example, fragrance and dye would not necessarily be added to an industrial decontaminant but may be added to one intended for domestic use.

Foam booster may also be added depending on the end application of the formulation. In cases where the formula is to be sprayed industrially excessive foam generation may not be desirable whereas in a domestic cleaning scenario the generation of foam may be seen as beneficial. If foam boosting is required a suitable foam booster such as cocoamine oxide or other suitable material can be added as required. It is recognised that while included at a low level this material may also have a beneficial effect with respect to contaminant removal.

In a preferred embodiment of the invention, a formulation has been identified that contains active materials for the building of alkalinity, chelation of metal ions, an aliphatic solvent for the chemical dissolution of contaminants and a combination of a non-ionic and cationic surfactant for the emulsification of contaminants. The preferred inclusion levels of the materials are shown on Table 1 below: Table 1 -Preferred Formulation Range (Note: All ingredients refer to 100% of each respective component).

Material Percentage wiw Water Include up to 100 total; Sodium Carbonate 0.20-0.50; Sodium Bicarbonate 0.10-0.50; Ethylenediaminetetraacetic acid (EDTA) 0.05-0.20; CO-i 1 Alcohol Ethoxylate 8E0 1.00-2.60; Solvent (see list below in Table 3) 0.01 -0.60; Preservative as required; and Cl 0 Alcohol Ethoxylate 8E0 0.50-2.00; and/or Hydroxyethyl laurdimonium chloride 0.10-0.60*.

* Hydroxyethyl laurdimonium chloride is supplied as a 40 wt% solution.

Further features of the invention are defined in the appended claims and appendix.

The invention will now be described in more detail with reference to examples.

ExamDles: To demonstrate the relative performances of different decontaminant raw materials within a formulation, a base formulation was proposed in which an alkali builder system was selected and fixed along with a chelating agent to eliminate any issues deriving from the hardness of the water used and a preservative to ensure no biological growth or contamination that might impair the testing.

It is well known that for optimum contaminant removal a non-ionic surf actant is beneficial so this was added with the aim of identifying a further surfactant, solvent or other active material or combination of active materials that would provide the optimum decontamination performance at low active matter levels.

The amount of 09-011 alcohol ethoxylate added was varied depending on the other active material added to ensure low total active matter.

The base formulae used are shown in Table 2 below.

Table 2 -Base Formulations For Active Material Comparison Base formula #1 Material Percentage w/w Water Include to make up to 100 Sodium Carbonate 0.29 Sodium Bicarbonate 0.20 EDTA 0.08 Preservative Acticide MBS 0.20 09-Cl 1 Alcohol Ethoxylate 8E0 2.52 Solvent (see table 3 below) 0.60 Base formula #2 Material Percentage wlw Water Include to make up to 100 Sodium Carbonate 0.29 Sodium Bicarbonate 0.20 EDTA 0.08 Preservative Acticide MBS 0.20 09-Cl 1 Alcohol Ethoxylate 8E0 2.52 Hydroxyethyl laurdimonium chloride O.56 Solvent (see table 3 below) 0.20 Hydroxyethyl laurdimonium chloride is supplied as a 40 wt% solution.

Base formula #3 Material Percentage w/w Water Include to make up to 100 Sodium Carbonate 0.29 Sodium Bicarbonate 0.20 EDTA 0.08 Preservative Acticide MBS 0.20 C9-C1 1 Alcohol Ethoxylate 8E0 1.50 Cl 0 Alcohol Ethoxylate 8E0 1.00 Solvent (see table 3 below) 0.20 Base formula #4 Material Percentage wlw Water Include to make up to 100 Sodium Carbonate 0.29 Sodium Bicarbonate 0.20 EDTA 0.08 Preservative Acticide MBS 0.20 C9-C1 1 Alcohol Ethoxylate 8E0 1.50 Cl 0 Alcohol Ethoxylate 8E0 1.30 Hydroxyethyl laurdimonium chloride O.56 Solvent (see table 3 below) 0.20 tHydroxyethyl laurdimonium chloride is supplied as a 40 wt% solution.

A series of formulations were prepared by adding the following (Table 3) solvents to the base formulae detailed above. The percentage in each case refers to the percentage of active material present in the raw material as supplied (the bulk being made up of water, solvents or other materials that are deemed for the purpose of this disclosure to have no contaminant-removal efficacy).

Table 3 -Potential Decontaminant Active Materials Evaluated Solvents: Propylene Glycol Monobutyl Ether (95%) Propylene Glycol Phenyl Ether (99%) Dipropylene Glycol n-Butyl Ether (99%) 1 -Dodecyl-2-Pyrrolidone (99%) Experimentally, a number of variations were considered and tested using different combinations of solvent and surfactant.

In order to evaluate the contamination removal performance of the different formulations, specific cleaning methods and contaminant compositions were utilised: Contamination removal with mechanical action was performed using a wet abrasion scrub testing machine which uses a motorised pulley to draw a sponge or other form of pad back and forth across a treated surface. This type of device can be used to test a variety of soils on different surfaces with the only restriction being that the surface must be of a sufficient size to allow testing and be flat so that the linear tester can run freely.

Typical surfaces that are tested in such a device would include a metal sheet onto which a mixture of protein and lipid is baked at high temperature to form a solid layer. An example of a soil for such use would be one consisting of a standard commercially-available gravy powder, lard, gelatine and water.

The test can also be carried out on white acrylic sheets using a soil consisting of soap, grease, colloidal graphite, water and anhydrous calcium chloride (greasy soil).

Low cloud point was tested by lowering the temperature with propylene glycol and the inverse cloud point was also measured by heating a test tube of material in a beaker of water on a hot plate. Ideally a cloud point of >55°C was achieved but >50°C

was acceptable.

Base odour was evaluated using an expert panel of respondents who rated the level of base odour of the product under normal usage conditions.

Figures 1 -4 below show the scrub test scores using a greasy soil for the different base formulations using the four test solvents. Figure 5 shows the results for cloud point and base odour.

With reference to the scrub test results, a score between 5-7 would be equivalent to a standard domestic commercially available decontaminant spray product when tested against a mixed lipid / protein-based soil.

For base formulation 1, only the variant with 1-dodecyl-2-pyrrolidone provided adequate cleaning test results.

For base formulations 2, 3 and 4 (Figures 2, 3 & 4) the scrub testing results are all within the desired range so all of these formulations are acceptable in terms of contaminant removal performance.

With reference to Figure 5 it can be seen that the base odour of solvent is excessive when included at 0.6 results and in the case of the 1-dodecyl-1-pyrrolidone the high cloud point is lower than for the other formulations.

For base formulation 1 the single non-ionic surfactant does not give adequate contaminant removal performance as can be seen with the equivalent formulations 2, 3 and 4 in which there is either a mixed non-ionic or non-ionic! cationic blend. Of these systems the base formulations 2 & 4 are the preferred systems i.e. those with the non-ionic! cationic blend and the slightly higher active levels of the mixed nonHonic blend.

Between base formulations 2 & 4 there is a difference in cloud pcint with base formula 2 having a generally greater high cloud point than formula 4.

Appendix Emboctments of the invention will now be described in the following paragraphs.

1. Decontaminant formulations in which there is present at least one non-ionic surfactant which is a CS-Cl 1 Alcohol Ethoxylate 8E0, at least one volatile solvent and a secondary surfactant which is either a non-ionic or a cationic surfactant.

2. Formulations as described in embodiment 1 where the solvent is propylene glycol monobutyl ether, propylene glycol phenyl ether, dipropylene glycol n-butyl ether, or 1 -dodecyl-2-pyrrolidone.

3. Formulations as described in embodiment 1 in which the total solids content of the formulation is 5% or less.

4. Formulations as described in embodiment 1 where the solvent content is between 0.01 and 0.60% by mass of the total formulation.

S. Formulations as described in embodiment 1 where the CS-Cl 1 Alcohol Ethoxylate SF0 is present at 1.00-2.60% by mass in the total formulation.

6. Formulations as described in embodiment 1 where the secondary surfactant is a ClO Alcohol Ethoxylate SF0 and is present at 0.50-1.50% by mass in the total formulation.

7. Formulations as described in embodiment 1 where the secondary surfactant is hydroxyethyl laurdimonium chloride and is present at 0.10-0.60% by mass in the total formulation.

5. Formulations as described in embodiment 1 where alkaline builders sodium carbonate and sodium bicarbonate are present in a combined amount of 0.35 - 1.00% by mass in the total formulation.

9. Formulations as described in embodiment 1 with EDTA present at a level of 0.01 - 0.25% by mass in the total formulation.

10. Formulations as described in embodiment 1 in which optional preservative, fragrance and foam boosters may be added.

11. Low active content surface decontaminant formulations in which the total solids content are 5% or less by mass and which contain 1.00-2.60% of a C9-C1 1 Alcohol Ethoxylate SEQ as a primary surfactant, either 0.50-1.50% of a Gb Alcohol ethoxylate 8E0 or 0.10-0.60% of hydroxyethyl laurdimonium chloride as a secondary surfactant and 0.01-0.6% of a solvent from the group propylene glycol monobutyl ether, propylene glycol phenyl ether, dipropylene glycol n-butyl ether or 1 -Dodecyl-2-Pyrrolidone.

Claims

CLAIMS: 1. An aqueous formulation for the chemical removal of foreign matter from solid surfaces, the formulation comprisng: (i) a primary surfactant in the form of a linear C9-C11 alcohol ethoxylate 8E0, (ii) at least one water-soluble solvent, and (Ui) at least one secondary surfactant, wherein the at least one secondary surfactant comprises a branched ClO alcohol ethoxylate 8E0 and/or a cationic surfactant of the formula I: P1 HOR3-N---R4Xin which: ft is a C1-4 alkyl group; R2 is a C1-4 alkyl group; R3 is a Cl -4 alkylene group; R4 is a Cl 2-20 alkyl group; and X is a counter-ion.
2. The formulation as claimed in claim 1 wherein the linear C9-C11 alcohol ethoxylate 8E0 is present at a level of 1.0 to 2.60 wt% based on the total weight of the formulation.
3. The formulation as claimed in claims 1 or 2 wherein the formulation comprises said cationic surfactant.
4. The formulation as claimed in claim 3 wherein at least one of ft and R2 in the cationic surfactant is a methyl group.
5. The formulation as claimed in claim 4 wherein both R1 and R2 in the cationic surfactant are methyl groups.
6. The formulation as claimed in any one of claims 3 to 5 wherein R3 in the cationic surfactant is an ethyleneyl group.
7. The formulation as claimed in any one of claims 3 to 6 wherein the cationic surfactant is present as a mixture of compounds of the formula I in which Fl4 comprises a mixture of C12-18 alkyl groups.
8. The formulation as claimed in claim 7 wherein R4 comprises a mixture of C12- 14 alkyl groups.
9. The formulation as claimed in claim 8 wherein R4 predominantly comprises a mixture of C12 and C14 alkyl groups.
10. The formulation as claimed in any one of claims 3 to 9 wherein the cationic surfactant comprises a hydroxyethyl laurdimonium cation.
11. The formulation as claimed in claim 10 wherein the cationic surfactant is hydroxyethyl laurdimonium chloride.
12. The formulation as claimed in any one of claims 3 to 11 wherein the cationic surfactant is present at a level of 0.1 to 0.6 wt% based on the total weight of the formulation.
13. The formulation as claimed in any preceding claim wherein the formulation comprises said Cl 0 alcohol ethoxylate 8E0 at a level of 0.5 to 2.0 wt% based on the total weight of the formulation.
14. The formulation as claimed in any preceding claim further comprising a foam booster.
15. The formulation as claimed in claim 14 wherein the foam booster s cocoamine oxide.
16. The formulation as claimed in any preceding claim further comprising one or more builders (preferably sodium carbonate and/or sodium bicarbonate), chelating agents (preferably EDIA), aromatic solvents and/or zwitterionic surfactants.
17. The formulation as claimed in claim 16 wherein the formulation comprises sodium carbonate at a level of 0.2 to 0.5wt% based on the total weight of the formulation.
18. The formulation as claimed in claim 16 or 17 wherein formulation comprises sodium bicarbonate at a level of 0.1 to 0.5 wt% based on the total weight of the formulation.
19. The formulation as claimed in any one of claims 16 to 18 comprising sodium carbonate and sodium bicarbonate at a combined level of 0.35 to 1.00 wt% based on the total weight of the formulation.
20. The formulation as claimed in any one of claims 16 to 19 wherein the formulation comprises EDTA at a level of 0.01 to 0.25 wt% based on the total weight of the formulation.
21. The formulation as claimed in any one of claims 1 to 20 wherein the formulation comprises at least 90 wt% water based on the total weight of the formulation.
22. The formulation as claimed in claim 21 wherein the formulation comprises at least 95 wt% water based on the total weight of the formulation.
23. The formulation as claimed in any one of claims 1 to 22 further comprising one or more preservatives, fragrances, dyes, thickeners, and/or biocidal agents.
24. The formulation as claimed in any one of claims 1 to 23 wherein the solvent is present at a level of 0.01 to 0.6 wt% based on the total weight of the formulation.
25. The formulation as claimed in any one of claims 1 to 24 wherein the solvent is an aliphatic solvent.
26. The formulation as claimed in claim 25 wherein the aliphatic solvent is selected from the group consisting of propylene glycol monobutyl ether, propylene glycol phenyl ether, dipropylene glycol n-butyl ether and 1-dodecyl-2-pyrrolidone.
27. An aqueous formulation for the chemical removal of foreign matter from solid surfaces, the formulation comprisng: (i) a primary surfactant in the form of a linear 09-Cu alcohol ethoxylate 8E0; (ii) at least one water-soluble solvent; (iii) at least one secondary surfactant; (iv) sodium carbonate; (v) sodium bicarbonate; and (vi) at least 90 wt% water based on the total weight of the formulation; wherein the at least one secondary surfactant comprises a branched ClO alcohol ethoxylate SF0 and/or a cationic surfactant of the formula I: HOR3-N---R4 Xe in which: ft is a C1-4 alkyl group; R2 is a C1-4 alkyl group; R3 is a Cl -4 alkylene group; R4 is a Cl 2-20 alkyl group; and X is a counter-ion.
28. The formulation as claimed in claim 27 wherein the formulation comprises at least 95 wt% water based on the total weight of the formulation.
29. A method of cleaning a substrate comprising applying to a substrate a formulation as claimed in any one of claims 1 to 28.
30. The use of a formulation as claimed in any one of claims 1 to 28 for cleaning a substrate.