WO1999036500A1

WO1999036500A1 - Hard surface cleaners

Info

Publication number: WO1999036500A1
Application number: PCT/EP1999/000247
Authority: WO
Inventors: Marcia Regina Domingues Mobaier; Robert Jan Reinier Uhlhorn
Original assignee: Unilever N.V.; Unilever Plc
Priority date: 1998-01-19
Filing date: 1999-01-08
Publication date: 1999-07-22
Also published as: AR014415A1; BR9900076A; UY25361A1; GB9801079D0; AU2618199A

Abstract

The invention concerns a window cleaning composition comprising a UV absorber and a surfactant. The compositions leave sufficient UV absorber on the windows to reduce the extend of UV damage to the contents of the room. The compositions preferably comprise at least a nonionic surfactant e.g. chosen from alkoxylated alcohols and alkylpolyglucosides or an alkylether sulphate. The compositions preferably also comprise a glycol ether and/or alkanol solvent.

Description

HARD δURFACE CLEANERδ

Field of the Invention

The present invention relates to hard surface cleaning compositions which contain a UV absorbing agent.

Background to the Invention

Many household fittings fixtures and furnishings suffer from the harmful effects of the suns rays. This can, for example lead to discoloration of curtains, furniture (leather and wooden) and wooden floors. It is believed that a significant part of this damage is caused by the UV components of the sunlight, particularly in the UV-B region (280-320 nm) range. Similar problems are encountered in office and institutional environments although the present invention will be described with particular reference to household environments .

It is known to protect textiles from UV radiation by treating them with a UV adsorbing agent. For example,

EP697481 (CIBA-GEIGY: 1995) concerns textile treatment with a composition comprising UV-A compound, emulsifying agent, water and polysiloxane (i.e. silicone) in an otherwise aqueous textile treatment composition which comprises:

a) a non-reactive UVA compound

b) an emulsifying or dispersing agent for the UVA compound c) _ water d) optionally, a polysiloxane based product.

One problem with this general class of formulation is that formulations for household cleaning comprise a vast range of substances, are formulated at a broad range of generally neutral and alkaline pH's and comprise a range of product forms (gels, liquids, powders etc.). In addition, broad- spectrum UV adsorbing agents, such as benzophenone derivatives, can be difficult to incorporate in compositions due to their insolubility, cross-reaction with other components etc. As noted above it is known to overcome this problem by putting UV adsorbing agents into products which are in the form of oily emulsions. However putting a broad- spectrum UV adsorbing agent into the whole range of possible household cleaners without sacrificing formulation properties and flexibility is a difficult task and there is a need to find a simple solution to this problem.

Brief Description of the Invention

We have determined that the aforementioned difficulties can be overcome by incorporating the UV adsorbing agent in a window-cleaning composition. It is believed that the use of such a composition will leave sufficient UV-absorbed on the windows to reduce the transmission of UV therethrough and consequently reduce the extent of UV damage to the contents of the room, e.g. decorations, furnishing, fixtures and fittings, lit by the window. A further advantage of this invention is the need only to reformulate a single product to protect a wide range of materials.

Accordingly, a first aspect of the present invention relates to a window cleaning composition comprising a surfactant and a UV-adsorbing agent.

A second aspect of the present invention relates to a method of reducing UV damage to the contents of a room having at least one window which comprises the step of treating the window with a cleaning composition comprising a surfactant and at least one UV adsorbing agent .

Detailed Description of the Invention

Preferably, the UV-adsorbing agent is a UV-B absorber. Typical examples thereof are benzophenone derivatives. More preferably the UV adsorbing agent is 2-hydroxy-4- methoxybenzophenone (benzophenone-3) . Suitable materials are available in the marketplace from BASF and Haarmann & Reimer (H&R) .

Alternative UV-B absorbing agents believed suitable for use in the compositions of the present invention include phenyl- benzimidazole sulfonic acid and methoxycinnamic acid esters such as octyl methoxycinnamate.

Many laundry detergent compositions comprise so called optical whiteners or brighteners, i.e. fluorescent compounds which absorb UV light and re-emit this as visible, particularly blue, light. Such compounds have no use in the hard surface cleaning compositions of the present invention and are therefore not comprised in the term "UV absorbing agent ' .

Suitable levels of UV adsorbing agents are from 0.01%wt upwards, preferably at least 0.05%, more preferably at least 0.08%. The maximum amount is generally 5%wt. Higher amounts than 2%wt rarely serve a useful purpose and the amounts are preferably at most 1%, more preferably at most 0.5%. While the pH of the composition can fall in the range 1.0- 12, it is preferable that the pH of the composition is at least 2.0, most preferably at least 3.0. Above pH 8.5 the benefit of some absorbers, such as the benzophenone derivatives, falls off although others, such as phenylbenzimidazole sulphonic acid, are effective until pH 12. Below pH 3.0 surface damage may occur, especially of enamel surfaces . The most preferred pH is from around 3.0 to 8.5. A base such as sodium hydroxide or ammonia and/or an acid such as citric acid are generally used to bring the pH to the required level .

Advantageously, the compositions of the invention are aqueous and are preferably not macroscopic emulsions. Other preferred components of formulations according to the invention are described in greater detail below.

Surfactants :

It is essential that the compositions of the present invention comprise at least one surfactant component. Surfactants are selected from the nonionic, anionic, cationic or amphoteric surfactant materials.

The surfactant preferably comprises one or more of non- ionic and anionic surfactant components. Nonionic surfactants show particular efficacy on fatty soils and are most preferred.

Cationic surfactants can be included in the compositions of the invention as hygiene agents .

Optionally, the composition can include one or more amphoteric surfactants, preferably betaines, or other surfactants such as amine-oxide and alkyl-amino-glycinates. Betaines are preferred for reasons of cost, low toxicity and wide availability. It is believed that amphoteric surfactants show a slight synergy with some organic acids (when present) as regards antimicrobial effects.

Preferably the overall level of surfactant in the compositions of the invention is at least 0.05%wt, more preferably at least 0.1, most preferably 0.5 or more. Also preferably the overall level of surfactant is at most 10%wt, more preferably at most 8%wt, most preferably 4%wt or less.

Of the nonionic surfactants alkoxylated alcohols, alkoxylated phenols, alkyl-polyglucoside (APG) and amine oxides are very suitable for use in the compositions of the present invention e.g. in amounts of 0.1-5%wt.

In certain compositions according to the invention APG is preferred for its non-streaking and good foaming properties. Preferred levels of APG are such that the composition comprises 0.1-5%wt of APG, preferably 0.1-3 %wt, most preferably 0.2-2 %wt . Preferred APGs contain C8-C16 alkyl chains and it is preferred that more than 50%wt of the APG present in the compositions of the invention comprises C12- C14 alkyl APG and that the majority of the remaining APG contains C8-C16. The preferred degree of polymerization is

1.1-1.6, more preferably 1.3-1.5. Suitable materials include

TM

GLUCOPON 425 CS (ex HENKEL) .

Other suitable nonionics, as mentioned above, are alkoxylated alcohols, alkoxylated alkyl -phenols or amine oxides. Of these, alkoxylated alcohols are preferred as surfactants. Suitable nonionic detergent active compounds 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. Ethoxylated aliphatic alcohols are particularly preferred.

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 alcohol ethylene oxide condensate having from 1 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 1 to 25 moles of ethylene oxide per mole of alkylphenol .

Particularly preferred nonionic surfactants include the condensation products of C8-C18 alcohols with 2-12 moles of ethylene oxide. The most preferred alkoxylated alcohol nonionic surfactants are ethoxylated alcohols having a chain length of C9-C11 and an EO value of at least 5 but less than 10. Particularly preferred nonionic surfactants include the condensation products of CIO alcohols with 5-8 moles of ethylene oxide.

The preferred ethoxylated alcohols have a calculated HLB of 10-16. While mixtures of nonionic surfactants can be used it is preferred to use a single commercially available surfactant.

Anionic surfactants are also suitable. Of the anionic surfactants primary alkyl sulphates and/or alkyl ether sulphates are preferred components of compositions according to the invention. Preferably the alkyl ether sulphates (AES) are materials of the general formula:

+

Rl- (OCH₂CH₂)_m-Sθ₃ M

wherein Rl is linear or branched, C8-C18 alkyl and m is 1- 10. M is a sodium, potassium or ammonium counterion. More preferably the alkyl chain length of the AES falls in the range C8-C16. Preferably the AES has a C12-C13 average alkyl chain length. Preferably the AES alkyl chain is linear. Suitable materials include DOBANOL-23-3S (RTM, ex SHELL) and sodium laurylether sulphate .

Solvents :

One or more solvents may be present in the compositions of the invention. The presence of solvents is preferred.

It is preferred that the compositions of the present invention comprise not more than 25%wt of glycol ether or alkanol solvents of the general formula:

Rl-0- (E0)_m-(PO)_n-R2,

wherein Rl and R2 are independently Cl-6 alkyl or H, but not both hydrogen, m and n are independently 0-5. E stands for an ethylene group and P for a propylene group

The alcohol solvents are selected from the C1-C6 branched or straight chain alkanols, more preferably one or more of methanol, ethanol, propanols or butanols. Ethanol and iso-propanol are particularly preferred.

Preferably, the solvent comprises at least one glycol ether solvent selected from the group comprising diethylene glycol mono-n-butyl ether (available in the marketplace as Butyl

Digol TM) , ethylene glycol mono-n-butyl ether and propylene glycol mono-n-butyl ether and mixtures thereof.

The total level of these solvents in the detergent compositions prepared according to the invention is preferably not more than 25% by weight, more preferably 20% or less, most preferably 10% or less. On the other hand the compositions preferably contain at least l%wt of these solvents, more preferably at least 2% and most preferably at least 5%.

Antimicrobials:

Optionally antimicrobial agents can be used in the compositions of the present invention. The preferred antimicrobials are quaternary ammonium compounds and/or phenolic compounds.

Typical levels of the antimicrobial agent in formulations range from 0.01 to 8%, with levels of 0.05-4wt%, particularly around 2% being preferred for normal compositions and up to two or four times that concentration being present in so called, 'concentrated' products. Although both the normal and concentrated products can be used neat it will be commonplace for these to be diluted by the user before use. For sprayable products, which are seldom diluted prior to use, the concentration of the antimicrobial agent will be in the range 0.05-0.5%wt.

In general, whatever the strength of the product the ratio of the nonionic surfactant to the antimicrobial agent will preferably be in the range 50:1 to >1:1, more preferably 30:1 to >1:1 i.e. an excess of nonionic will be present relative to the antimicrobial .

Where antimicrobial agents are not present at significant levels it is advantageous that the compositions comprise a preservative. A suitable preservative is PROXEL LV TM or FORMOL™.

Minors and Optional Components:

The compositions according to the invention can contain other minor ingredients which are not essential, but aid in their cleaning performance and in maintaining the physical and chemical stability of the product.

For example, the composition can contain detergent builders. In general, a builder, when employed, preferably will form from 0.1 to 25% by weight of the composition.

Metal ion sequestrants, including ethylenediamine- tetraacetates, aminopolyphosp onates (such as those in the

DEQUEST range) and phosphates and a wide variety of other polyfunctional organic acids and salts, can also optionally be employed. It is believed that the hygiene performance of a composition is improved by the presence of a metal ion sequesterant .

Hydrotropes, are useful optional components. It is believed that the use of hydrotropes enables the cloud point of the compositions to be raised without requiring the addition of anionic surfactants. The presence of both anionic surfactants and betaine at the same time is believed to be less desirable as these surfactants interact and form a complex which inhibits the synergistic hygiene activity of the amphoterics with the organic acid. Preferably the formations according to the invention are free of anionic surfactants when betaine is present, or contain low levels of anionic surfactants, i.e. less than 50% of the total weight of surfactant present and preferably less than 50% of the weight of the betaine in the product. Anionics are compatible with the solely alcohol ethoxylate based compositions of the present invention when the level is below 50%wt of the total surfactant present, but their level should be minimised in view of their interactions with the polymers. Preferably the level of anionic is below 30% of the total surfactant content of the composition and more preferably below 10% of the surfactant content. It is possible to make compositions which contain little or no anionic surfactant .

Suitable hydrotropes include, alkali metal toluene sulphonates, urea, alkali metal xylene and cumene sulphonates, polyglycols, >20EO ethoxylated alcohols, short chain, preferably C2-C5 alcohols and glycols. Preferred amongst these hydrotropes are the sulphonates, particularly the cumene, xylene and toluene sulphonates.

Typical levels of hydrotrope range from 0-5% for the sulphonates . Correspondingly higher levels of urea and alcohols are required. Hydrotropes are not always required for dilute, sprayable products, but may be required if lower EO or longer alkyl ethoxylates are used or the cloud point needs to be raised considerably. Typically, the cloud point of the final composition should preferably be in the range 45-50 °C. The cumene sulphonate is the most preferred hydrotrope. For ethoxylated nonionic levels of around 7%wt on product levels of SCS will generally be in the range 0.6- 0.8wt% for ethoxylated nonionic levels of around 14%wt levels of SCS will generally be in the range 1.0-1.2wt%.

Compositions according to the invention can also contain, in addition to the ingredients already mentioned, various other optional ingredients such as, colourants, soil suspending agents, viscosity modifiers, detersive enzymes, gel-control agents, freeze-thaw stabilisers, and perfumes.

Bleaching compounds generally serve no useful purpose in cleaning compositions of the present invention and will therefore normally be absent. Also, the presence of abrasives is difficultly reconcilable with the purposes of the present invention. Moreover such components and other water-insoluble solid inorganic compounds tend to leave difficultly removable traces on a surface. They will, therefore, normally be absent as well.

Preferred Composition:

Preferred compositions according to the present invention comprise e.g.:

A a) l-25%wt of at least one glycol ether solvent, preferably di-ethylene glycol mono n-butyl ether, b) l-25%wt of at least one C1-C6 alkanol solvent, preferably ethanol, propanol or isopropanol, c) 0.1-5%wt of at least one nonionic surfactant, preferably alkylpolyglucoside, d) 0.05-l%wt of at least one UV-absorber, preferably a benzophenone derivative or phenylbenzimidazole sulphonic acid, e) water and minors. B a) l-25%wt of at least one glycol ether solvent, preferably di-ethylene glycol mono n-butyl ether, b) l-25%wt of at least one C1-C6 alkanol solvent, preferably ethanol, propanol or isopropanol, c) 0.1-8%wt of at least one anionic surfactant, preferably. AES, d) 0.05-l%wt of at least one UV-absorber, preferably a benzophenone derivative or benzimidazole sulphonic acid, e) water and minors.

In order that the present invention may be further understood it will be described hereinafter by way of examples :

Examples

TM

Typical window cleaners (such as Vidrex ) available in the Brazilian market contain ammonia and are of high pH, typically around 12-13. As will be described in more detail below, at these pH's the benzophenone UV absorbers are unstable in the commercially available products. For comparative purposes the present invention was also therefore compared below with a window cleaner available in

Brazil as Vidrex Crystal TM, which is formulated without ammonia and has pH 7.

In order to illustrate the present invention a composition according to the present invention was formulated as follows (Table 1) : Table 1

In the above exemplary formulation the order of addition is important, since the UV absorber material is difficult to dissolve in water. In the example a pre-mixture of the UV absorber in a part of the solvent is prepared and the remaining components are mixed before the UV absorber/solvent is added. In the case of the formulation above the order of addition is water, Butyl Digol, ethanol, APG and then the pre-mixture of UV absorber/Butyl Digol at 10% concentration (0.5 g UV absorber in 5 g Butyl Digol) .

Example 1: UV absorbance:

Compatibility of the commercially available window cleaners and the compositions of the invention with the UV absorbing material from both BASF and H&R was tested as described below. The method used involved measurement of UV light absorbance with a spectrophotometer. In principle, a product without a UV absorbing material will not absorb light in the UV-B range (280-340 nm) , while a product with such material will. In terms of stability, if a product is incompatible with the absorbing material, the light absorbance will be absent or inferior to a compatible combination of product and absorbing material. All products contained 0.05% UV absorber when present and were diluted to 0.5% concentration before measuring the absorbance.

Table 2 demonstrates the results for the BASF and H&R UV absorbing material in freshly prepared samples. Formulations as given in Table 1 are identified as "LV

(whether UV absorbing material is present or not) . The high pH (12) Vidrex product is identified as VR12 and the low pH

(7) Vidrex product as VR7. The UV-B region is identified by bold text, and the figures given are

Table 1 shows that if no UV absorber is present (le) there is no significant absorbance in the UV-B wavelength.

The embodiments of the invention with benzophenone UV- absorber (examples lc-ld) all exhibit high absorbance, demonstrating compatibility of UV-absorber and product. As soon as the pH of the product was increased to 12 by adding ammonia (examples la-lb) , the absorbance decreases, demonstrating the preference for the lower pH formulations. A typical window cleaner from the market (Vidrex pH 12 : examples lf-lg) to which the benzophenone UV-absorber had been added shows the same behaviour especially at a wavelength of around 320nm: relatively low absorbance is seen at this high pH . In addition it was noted that immediately upon addition of the UV absorber to the high pH window cleaner the colour turned from transparent to yellow, indicating that a chemical reaction had taken place.

Table 1 also show the absorbance of the UV-absorbing material in the low pH commercially available window cleaner (Vidrex pH 7) . With this sample precipitation occurred upon addition of the UV absorber, resulting in a white "cotton like" sediment and low absorbance.

The measurements clearly show good compatibility of the absorber with preferred window cleaner formulations according to the present invention. With all other formulations performance of the benzophenone absorber is inferior. Additionally, the formation of a precipitate or discoloration of the solution indicate at least partial incompatibility of the absorber and the known formulations.

Part of the incompatibility can be explained by the pH: as it is believed that a pH above 8 degenerates the absorber.

Example 2: Performance on glass

The performance of the benzophenone UV absorber was tested in a so-called weather-o-meter TM . This equipment simulates in an accelerated way the influence of the sun on discoloration of articles: 8 hours of experimental time being equivalent to around 1 month outside under typical conditions. Samples for this weather-o-meter were prepared using a coloured textile of inferior quality, i.e. material which was easy to discolour. All samples but one were then covered with a piece of normal glass, which subsequently was treated with various window cleaning products.

The results of these experiments are given in Table 3. Lower scores indicate less fading of colour.

Table 3

The sample without glass (2.1) served as reference to determine the maximum discoloration possible. A second reference (2.2) determined the influence of the glass only by using a sample with untreated glass. "Mini-windows ' (2.5) and (2.4) were treated with product with and without absorber and with high concentrations of absorber (up to 10% as in 2.3) to quantify the influence of the absorber on the discoloration of the textile.

Comparison of the discoloration of the textile without glass (2.1), with untreated glass (2.2) and with glass treated with a high concentration UV absorber solution (2.3) shows that the absorber slows down discoloration of the textile. Comparing the textile discoloration of a product according to Table 1 without (2.4) and with (2.5) UV absorber shows that the absorber in the product is contributing to preventing discoloration, even at the relatively low concentration in the window cleaning product

Example 3 : Cleaning Performance :

TM

The cleaning performance was measured with the Sheen apparatus. This equipment cleans a surface for a predetermined time, applying a constant force. Ten plates which had been treated with a fatty soil are cleaned with each product, the cleaning is visually assessed in each case (on a scale of 1 to 5) and a mean is statistically determined. The mean values for various products are then compared to see whether there is a statistically relevant difference (lower scores are better) .

Results are given in Table 4 both for embodiments of the invention and for commercial products. From this table it is clear that the cleaning performance of the window cleaner according to the invention is superior. The differences are statistically significant.

Table 4

From the above results it can be seen that the window cleaner according to the present invention (3.1) has a superior cleaning performance against comparable window cleaning formulations and the UV absorber is shown to be effective in slowing down discoloration of textiles caused by means of light falling on the textiles after passing through the glass.

Claims

1. A window cleaning composition comprising a surfactant and a UV-adsorbing agent.

2. Composition according to claim 1 wherein the amount of UV-adsorbing agent in the composition is 0.01-5%wt.

3. Composition according to claims 1 or 2 wherein the UV absorbing agent is a benzophenone derivative.

4. Composition according to claim 3 wherein the benzophenone derivative is 2-hydroxy-4-methoxy- benzophenone .

5. Composition according to any one of claims 1-4 having a pH of 3.0-12.

6. Compositions according to any one of claims 1-5 wherein the overall level of surfactant is 0.1-10%wt.

7. Composition according to any one of claims 1-6 wherein the surfactant is selected from the group consisting of anionic surfactants, nonionic surfactants or mixtures thereof

8. Composition according to claims 7 wherein the nonionic surfactant is selected from the group consisting of alkoxylated alcohols, alkoxylated phenols, amine oxides, alkyl-polyglucosides and mixtures thereof.

9. Composition according to any one of claims 1-8 which comprises a glycol ether or alkanol solvent of the general formula:

Rl-0- (E0)_m- (PO)_n-R2, wherein Rl and R2 are independently Cl-6 alkyl or H, but not both hydrogen, m and n are independently 0-5.

10. Composition according to claim 1 which comprises: a) l-25%wt of at least one glycol ether solvent, preferably di-ethylene glycol mono n-butyl ether, b) l-25%wt of at least one C1-C6 alkanol solvent, preferably ethanol, c) 0.1-5%wt of at least one nonionic surfactant, preferably alkylpolyglucoside, d) 0.05-l%wt of at least one UV-absorbed e) water and minors.

11. Composition according to claim 1 which comprises: a) l-25%wt of at least one glycol ether solvent, preferably di-ethylene glycol mono n-butyl ether, b) l-25%wt of at least one C1-C6 alkanol solvent, preferably ethanol, propanol or isopropanol, c) 0.1-8%wt of at least one anionic surfactant, preferably AES, d) 0.05-l%wt of at least one UV-absorber, e) water and minors.

11. A method of reducing UV damage to the contents of a room having at least one window which comprises the step of treating the window with a cleaning composition according to any of claims 1-11.