WO1999036501A1

WO1999036501A1 - Process for preparing detergent compositions

Info

Publication number: WO1999036501A1
Application number: PCT/EP1999/000248
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: AU2279899A; GB9801082D0; AR014416A1; BR9900074A; UY25360A1

Abstract

The invention concerns a process for the manufacture of detergent compositions which contain a UV absorber. The process comprises the steps of forming a premix of the UV absorber and one or more semipolar solvents and combining this premix with the remaining components of the detergent composition which includes at least one surfactant. The semipolar solvents comprise preferably glycol ethers and/or alkanols. The process is particularly suitable for preparing hard surface and window cleaning compositions containing a UV absorber to provide protection of the cleaned surface or items behind the cleaned window against damage by UV light.

Description

PROCESS FOR PREPARING DETERGENT COMPOSITIONS

Field of the Invention

The present invention relates to the manufacture of detergent 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.

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. Single phase or at least non-macro-emulsion liquid products are preferred to macro-emulsions for reasons of product stability and appearance.

Brief Description of the Invention

We have determined that the aforementioned difficulties can be overcome by incorporating the UV adsorbing agent as a pre-mix of at least a semi-polar solvent and the UV adsorbing agent.

Accordingly, the present invention provides a process for the manufacture of a detergent composition comprising a UV absorbing agent, said process comprising the steps of:

a) forming a premix of the UV absorbing agent and one or more semi-polar solvents, and,

b) combining the premix with the remaining components of the detergent composition including at least one surfactant . Detailed Description of the Invention

The process of the invention is suitable for making all kinds of detergent compositions containing a UV absorbing agent. It is particularly suitable for hard surface and window cleaning compositions.

comprised among the suitable solvents for forming the premix are such solvents which are also suitably added to detergent compositions in their own right e.g. because they will improve the cleaning or other properties of such compositions . Particularly suitable are glycol ether and 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, and n are independently 0-5, E stands for an ethylene group and P stands 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 di- ethylene 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 . Mixtures of both glycol ethers and alcohols can also be used, both for the premix as well as in the final composition. We have determined that a mixture of di- ethylene glycol mono-n-butyl ether and ethanol, or a mixture of di-ethylene glycol mono-n-butyl ether and iso-propanol is very suitable as a solvent mix and particularly suitable for the final composition. Typically, the weight ratio of the glycol ether to the alcohol in these mixtures is in the range 1:10 - 10:1

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%.

The glycol ether solvents are particularly suitable to form the pre-mix. Typically the pre-mix will comprise a mixture of the UV absorber material and the solvent in a weight ratio of 1:1 - 1:20 (absorber material : solvent), i.e. a 5-50%wt concentration of the UV absorber in the premix is suitable, preferably a concentration of 5-20%wt is used.

The UV absorber premix is particularly suitable for the manufacture of detergent compositions having a pH in the range 1.0-12 more preferably the pH is at least 2.0, most preferably at least 3.0. Above pH 8.5 the benefit of some UV-absorbers falls off although others are effective up to pH 12. Below pH 3.0 surface damage may occur with hard surface cleaners, especially of enamel surfaces. The most preferred pH is from 3.0 to 8.5. Acids such as citric acid and bases such as sodium hydroxide or ammonia are generally used to regulate the pH to the required level .

Other preferred components of formulations obtained according to the invention are described in greater detail below.

UV adsorbing agents:

the process according to the invention is effectively applied to UV-adsorbing agents effective in the UV-B range Typical UV-adsorbers are benzophenone derivatives, more specifically 2-hydroxy-4-methoxybenzophenone (benzophenone- 3) . Suitable materials are available in the marketplace from BASF and Haarmann & Reimer (H&R) .

Alternative UV absorbers 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 ' and UV absorber .

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%. Preferably the UV-adsorbing agent is water insoluble or substantially water insoluble.

Surfactants :

It is essential that the compositions manufactured according to 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/or 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 compositions 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 (especially as compared to amine-oxide) 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 is 0.1-10%wt, more preferably 0.5-8%wt, most preferably 0.5-4%wt.

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 GLUCOPON 425 CS ™ (ex HENKE ) .

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-S0₃ ^" 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 . Antimicrobials :

Optionally antimicrobial agents can be used in the compositions prepared according to 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 prepared 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, aminopolyphosphonates (such as those in the DEQUEST range) and phosphates and a wide variety of other poly-functional 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 minimized in view of their interaction with the polymers. Preferably the level of anionic is below 30%wt 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. For the purposes of this invention the aromatic sulphonate hydrotropes are non considered anionics.

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 corresponding levels of SCS will generally be in the range 0.6-0.8wt%, whereas for ethoxylated nonionic levels of around 14%wt corresponding levels of SCS will generally be in the range 1.0-1.2wt%.

Compositions prepared according to the invention can also contain, in addition to the ingredients already mentioned, various other optional ingredients such as, colourants, optical brighteners, soil suspending agents, viscosity modifiers, detersive enzymes, compatible bleaching agents, gel-control agents, freeze-thaw stabilisers, and perfumes. Preferred process and preferred Composition:

In a preferred process a pre-mix is prepared by dissolving at least one UV absorber, preferably a benzophenone derivative, in one or a mixture of C1-C6 alkanol solvent or glycol ether 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, to a concentration of 5-20%wt of the premix. This premix is thereafter mixed with the remaining components of the detergent composition to obtain a preferred compositions having a pH of 3-12 and comprising:

a) l-20%wt of the solvent or solvent mix mentioned above , b) 0.1-10%wt of at least one nonionic surfactant, preferably including at least one alkyl- polyglucoside, and/or at least one anionic surfactant, preferably including at least one alkyl sulphate or alkylether sulphate, c) 0.01-l%wt of the UV absorber or absorbers, d) water and minors .

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

In the examples below embodiments of the invention are demonstrated in the preparation of both window cleaning and in general purpose cleaning formulations.

Typical window cleaners (such as Vidrex [TM] ) available in the, for example, 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 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 with a pH of 7.

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

Table 1

In the example a pre-mixture of UV absorber/Butyl Digol at 10% concentration (0.5 g UV absorber in 5 g Butyl Digol) is prepared and the remaining components are admixed 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

Compatibility of the commercially available window cleaners and the compositions of the invention with the benzophenone UV-absorber 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 absorber will not absorb light in the UV-B range (280- 340 nm) , while a product with absorber will. In terms of stability, in a product is incompatible with the absorber, the light absorbance will be absent or inferior to a compatible combination of product and absorber. 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 absorber material in freshly prepared samples. Formulations as given in Table 1 are identified as " V (whether UV absorber 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 2 shows that if no absorber is present (le) there is no significant absorbance in the UV B wavelength.

The embodiments of the invention with UV absorber (examples lc-ld) all exhibit high absorbance, demonstrating compatibility of absorber and product. As soon as the pH of the product was increased by adding ammonia (to pH 12-13) , 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 UV adsorber 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 absorber to the high pH window cleaner the colour turned from transparent to yellow, indicating a chemical reaction had taken place.

Table 2 also show the absorbance of the UV absorber 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.

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 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.

In order to demonstrate the effectiveness of the present invention as applied to general purpose cleaning compositions, compositions prepared according to the invention were compared with products which were available in the Brazilian market. A typical heavy duty cleaners in this market is "Veja' (TM) , available from Reckitt & Colman. A further known product is "Domex¹ (TM) and is manufactured by Lever.

The compatibility of the benzophenone UV absorber of H&R with Veja was tested by simple mixture. Since the pH of this product is high, it was expected that the absorber will show a degree of incompatibility. The Lever product, Domex has a pH of around 4. It is therefore expected to be more compatible with the UV absorber. For comparative purposes a product (Comparative) was used as given in table 1 above .

The Domex product was formulated as follows (Table 3) : Table 3

In the example a pre-mixture of UV absorber/Butyl Digol at 10% concentration (0.5 g UV absorber in 5 g Butyl Digol is prepared and the remaining components are admixed before the UV absorber/solvent is added to give a final product concentration of 0.01-1%.

UV light absorbance was measured with a spectrophotometer . Table 4 shows the results.

Table 4

The measurements in Table 4 clearly show the effectiveness of the absorber in Domex, and a decrease in absorbance and hence less effectiveness for the Veja product (which does not contain polymer and has a higher pH) . In addition visual clues as to discoloration of the product indicated a degree of incompatibility of the absorber and the Vega product . It can be seen that the comparative product which did not contain the absorber material had little or no UV adsorbance.

Claims

A process for the manufacture of a detergent composition comprising a UV absorbing agent, said process comprising the steps of :

a) forming a premix of the UV absorbing agent and one or more semi -polar solvents, and,

b) combining the premix with the remaining components of the detergent composition including at least one surfactant .

2. A process according to claim 1 wherein the semipolar solvents comprise a glycol ether and/or alkanol solvent of the general formula:

Rl-0- (EO)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 stands for a propylene group.

3. A process according to claim 2 wherein the solvent is selected from methanol , ethanol, propanol , isopropanol, butanol, di-ethylene glycol mono-n- butyl ether, ethylene glycol mono-n-butyl ether, propylene glycol mono-n-butyl ether and mixtures thereof .

4. A process according to claims 1-3 which further comprises the step of adjusting the pH of the composition into the range 3.0-8.5.

5. A process according to claims 1-4 wherein the UV adsorbing agent is a benzophenone derivative or phenylbenzimidazole sulphonic acid

6. A process according to claim 2-4 wherein the components levels are selected such that the product of the process has a pH of 3.0-12 and comprises :

a) l-20%wt of at least one C1-C6 alkanol solvent or glycol ether solvent of the general formula:

Rl-0- (E0)m- (PO)n-R2,

wherein Rl and R2 are independently C2-6 alkyl or H, but not both hydrogen, m and n are independently 0-5 ;

b) 0.1-10%wt of at least one nonionic surfactant selected from the group consisting of alkoxylated alcohol, alkyl polyglucoside and mixtures thereof, and/or at least one anionic surfactant selected from the group consisting of alkyl sulphates and alkylether sulphates;

c) 0.01-l%wt of at least one UV adsorber;,

d) water and minors;

said at least one UV adsorber being combined with at least a part of the solvent to form a premix which is subsequently combined with the other components .