GB2400379A - Two-component stain treating composition - Google Patents

Abstract

A process for stain removal at a surface, comprising the application to that surface an aqueous composition (pH of 7 or more) which comprises a mixture of two components of (a) an aqueous acidic source of active oxygen and (b) an aqueous alkali. The composition may comprise an enzyme, a surfactant, preferably non-ionic or a water-soluble polymer, preferably a polycarboxylate. The alkaline component may contain a pH buffer. In another aspect, a two-compartment container containing a first compartment comprising an aqueous acidic source of active oxygen, and a second compartment containing an aqueous alkali. The container comprises dispensing means to deliver the contents of the two compartments sequentially or simultaneously to form a mixture thereof.

Description

112l6P6GB 2400379 Stain Treating Composition This invention relates to an

improved process for the removal of stains from surfaces, preferably from fabric, and to compositions used in such processes.

The use of oxygen bleaches with or without enzymes in compositions for stain removal has been known for a long time and many such compositions are available.

However a common difficulty in formulating such a composition is to ensure that the bleach remains stable during storage but is sufficiently active on use. This is particularly difficult to achieve in liquid compositions.

One solution has been to formulate liquid peroxygen bleaches at pHs between about 3 and 7 to produce a stable composition, but such compositions do not provide sufficient bleaching power to be useful for many household situations. Attempts have therefore also been made to formulate liquid peroxygen bleach compositions at pus above this range to improve their performance.

However these generally require expensive stabilizing compounds to prevent loss of activity after manufacture. 3()

The present invention provides a peroxide or peracid bleach product which has acceptable stability of the peroxide or peracid after manufacture, but which is capable of providing effective stain removal power when used by the consumer.

We have found that providing two separate compositions, in which the pH changes upon mixing, that are mixed during, before or after application have excellent stability and performance.

Enzymes are a common component of cleaning compositions. It is usually believed that enzymes lose their cleaning performance in the presence of a strong oxidant, such as hydrogen peroxide at alkaline pH.

Surprisingly, we have found that by the inclusion of a surfactant or a water-soluble polymer in either or both of the separate compositions, but preferably present in at least the enzyme composition, excellent cleaning performance is achieved. Whilst not wishing to be bound by theory it is believed that the activity of the enzyme is maintained for a longer period after the peroxide is applied to the stained surface and mixed with the enzyme by the protective effects of the micelles formed in the solution.

According to the invention there is provided a process for stain removal at a surface, comprising applying to that surface an aqueous composition comprising a source of active oxygen, preferably of hydrogen peroxide or a source thereof, which composition has a pH of 7 or more and comprises a mixture of: (a) an aqueous composition comprising a source of active oxygen having a pH of greater than O but less than 6 [hereinafter component (a)] and (b) an aqueous composition [hereinafter component (b)] comprising an alkalising agent.

Preferably component(a) and/or component (b) additionally comprise at least one surfactant or water-soluble polymer and are mixed not more than two hours before being applied to the surface requiring stain removal.

Preferably component (b) also contains at least one enzvme.

Sources of Active Oxygen An essential ingredient is a source of active oxygen. A preferred source according to the present invention is hydrogen peroxide or sources thereof. As used herein a hydrogen peroxide source refers to any water-soluble sources of hydrogen peroxide. Suitable watersoluble sources of hydrogen peroxide for use herein include percarbonates, organic or inorganic peroxides and perforates.

Ideally, the pH of component (a) is less than 5, ideally less than 4, preferably less than 3. Preferably the pH of component (a) is greater than 1, greater than 2 or greater than 2.5.

Hydrogen peroxide or sources thereof provide from 0.1% to 15%, preferably from 0.5% to 10%, most preferably from 1% to 5% by weight of the total composition of active oxygen in component (a).

As used herein active oxygen concentration refers to the percentage concentration of elemental oxygen, with an oxidation number zero, that being reduced to water would be stoichiometrically equivalent to a given percentage concentration of a given peroxide compound, when the peroxide functionality of the peroxide compound is completely reduced to oxides. The active oxygen sources 3s according to the present invention increase the ability of the compositions to remove oxidizable stains, to destroy malodourous molecules and to kill germs.

The concentration of available oxygen can be determined by methods known in the art, such as the iodimetric method, the permanganometric method and the cerimetric method. Said methods and the criteria for the choice of the appropriate method are described for example in "Hydrogen Peroxide", W. C. Schumo, C. N. Satterfield and R. L. Wentworth, Reinhold Publishing Corporation, New York, 1955 and "Organic Peroxides", Daniel Swern, Editor Riley Int. Science, 1970.

Suitable organic and inorganic peroxides for use in the compositions according to the present invention include diacyl and dialkyl peroxides such as dibenzoyl peroxide, dilauroyl peroxide, dicumyl peroxide, persulphuric acid and mixtures thereof. The component (a) according to the present invention comprise from 0% to 15%, preferably from 0.005% to 10%, by weight of the total composition of said organic or inorganic peroxides.

Suitable preformed peroxyacids for use in the compositions according to the present invention include diperoxydodecandioic acid DPDA, magnesium perphthalatic acid, perlauric acid, perbenzoic acid, diperoxyazelaic acid and mixtures thereof. The compositions according to the present invention comprise from 0% to 15%, preferably from 0.005% to 10%, by weight of the total composition of said preformed peroxyacids.

Optionally, component (a) or component (b) or both components (a) and (b) may additionally comprise from 0% to 30%, preferably from 2% to 20%, by weight of peracid precursors, i.e. compounds that upon reaction with hydrogen peroxide product peroxyacids. Examples of peracid precursors suitable for use in the present invention can be found among the classes of anhydrides, amides, imides and esters such as acetyl triethyl citrate(ATC) described for instance in EP 91 87 0207, tetra acetyl ethylene diamine(TAED), succinic or maleic

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anhydrides.

Alkalising Agent As an essential element the compositions according to the present invention comprise an alkalising agent. The alkalising agent must be sufficient to raise the pH of the [a] and [b] mixture to pH of greater than 8, ideally greater than 9, 10, 11 or 12. Ideally the pH is raised up to 14, 13 or 12. Suitable alkalising agents are caustic alkalis such as sodium hydroxide, potassium hydroxide and/or lithium hydroxide and/or the alkali metal oxides such as sodium and/or potassium oxide. A preferred source of alkalinity is a caustic alkali, more preferably sodium hydroxide and/or potassium hydroxide.

Ideally, an alkaline buffering means is also present. An alkaline buffering means at a level of from 0.1% to 10% by weight of component (b). Preferably, component (b) herein comprise from 0.2% to 8% by weight of the total composition of a pH buffering means or a mixture thereof, preferably from 0.3% to 5%, more preferably from 0.3% to 3% and most preferably from 0.3% to 2%.

By "alkaline buffering means", it is meant herein any compound which when mixed with component (a) makes the resulting solution able to resist an increase in hydrogen ion concentration.

Preferred alkaline buffering means for use herein comprise an acid having its pK (if only one) or at least one of its pKs in the range from 7.5 to 12.5, preferably from 8 to 10, and its conjugated base.

pK is defined according to the following equation: pK = - log K s where K is the Dissocation Constant of the weak acid in water and corresponds to the following equation: [A] [H] / [ HA] =K where HA is the acid and A is the conjugated base.

The weak acid (HA) and its conjugate base (A) are in equilibrium in the compositions of the present according to the equation: HA A + H (hydrogen ions).

Preferably the alkaline buffering means herein consists of the weak acid as defined herein and its conjugate base at a weight ratio of the weak acid to its conjugate base of preferably 0.1:1 to 10:1, more preferably 0. 2:1 to 5:1. Highly preferred ratio of the weak acid to its conjugate base is 1 since this is the best combination to achieve optimum buffering capacity.

Preferably a given pH buffering means herein will be used to buffer compositions having a pH between pH = pK - 1 and pH = pK +1 of each of its pK.

Surfactant Preferably, the surfactant is found at levels of 0.1 to 25%wt, ideally from 1 to 10%wt.

Preferably non-ionic surfactants are used. Examples of non-ionic surfactants are fatty acid alkoxylates, such as fatty acid ethoxylates, especially those of formula: R(C2H4O)nOH wherein R is a straight or branched C8-Cl6 alkyl group, preferably a Cg-Cl5, for example C1O-Cl4, alkyl group and n is at least 1, for example from 1 to 16, preferably 2 to 12, more preferably 3 to 10.

The alkoxylated fatty alcohol non-ionic surfactant will frequently have a hydrophilic-lipophilic balance (HLB) which ranges from 3 to 17, more preferably from 6 to 15, most preferably from 7 to 13.

Examples of fatty alcohol ethoxylates are those made from alcohols of 12 to 15 carbon atoms and which contain about 7 moles of ethylene oxide. Such materials are commercially marketed under the trademarks Neodol 25-7 and Neodol 23-6.5 by Shell Chemical Company. Other useful Neodols include Neodol 1-5, an ethoxylated fatty alcohol averaging 11 carbon atoms in its alkyl chain with about 5 moles of ethylene oxide; Neodol 23-9, an ethoxylated primary C12-Cl3 alcohol having about 9 moles of ethylene oxide; and Neodol 91-10, an ethoxylated Cg-C primary alcohol having about 10 moles of ethylene oxide.

Alcohol ethoxylated of this type have also been marketed by Shell Chemical Company under the Dobanol trademark.

Dobanol 91-5 is an ethoxylated Cg-Cll fatty alcohol with an average of 5 moles ethylene oxide and Dobanol 25-7 is an ethoxylated Cl2-Cl5 fatty alcohol with an average of 7 moles of ethylene oxide per mole of fatty alcohol.

Other examples of suitable ethoxylated alcohol non- ionic surfactants include Tergitol 15-S-7 and Tergitol 15-S-9, both of which are linear secondary alcohol ethoxylated available from Union Carbide Corporation.

Tergitol 15-S-7 is a mixed ethoxylated product of a C1l C15 linear secondary alkanol with 7 moles of ethylene oxide and Tergitol 15-S-9 is the same but with 9 moles of ethylene oxide.

Other suitable alcohol ethoxylated non-ionic surfactants are Neodol 45-11, which is a similar ethylene oxide condensation products of a fatty alcohol having 14- carbon atoms and the number of ethylene oxide groups per mole being about 11. Such products are also available from Shell Chemical Company.

Further non-ionic surfactants are, for example, C10- C1 alkyl polyglycosides, such s C12-Cl6 alkyl polyglycosides, especially the polyglucosides. These are especially useful when high foaming compositions are desired. Further surfactants are polyhydroxy fatty acid amides, such as C10-Cl N-(3-methoxypropyl) glycamides and ethylene oxide- propylene oxide block polymers of the Pluronic type.

The surfactant can also be an anionic surfactant.

Such anionic surface active agents are frequently provided in a salt form, such as alkali metal salts, ammonium salts, amine salts, amincalcohol salts or magnesium salts. Contemplated as useful are one or more sulfate or sulfonate compounds including: alkyl sulfates, alkyl ether sulfates, alkylamidoether sulfates, alkylaryl polyether sulfates, monoglyceride sulfates, alkyleulfonates, alkylamide sulfonates, alkylaryleulfonates, olefinsulfonates, paraffin sulfonates, alkyl sulfosuccinates, alkyl ether sulfosuccinates, alkylamide sulfosuccinates, alkyl / sulfosuccinamate, alkyl sulfoacetates, alkyl phosphates, alkyl ether phosphates, acyl sarconsinates, acyl isethionates, and N-acyl taurates. Generally, the alkyl or acyl radical in these various compounds comprise a carbon chain containing 12 to 20 carbon atoms.

Particularly preferred are alkyl sulfate anionic surfactants. Most preferred are the non-ethoxylated C12-15 primary and secondary alkyl sulfates, especially sodium lauryl sulfate.

In a further feature of the invention a surfactant is chosen to be present in either (a), (b) or both (a) and (b) that is capable of forming a stable foam. Such systems are described in EP0745665.

Polymer Suitable polymers are those that are water-soluble and include polycarboxylate polymer (such as those that can be purchased by Rohm and Haas under the Acusol 445N name) and polycarboxylic acid copolymers (such as can be purchased under the Sokalan CP9 name by BASF) Compositions suitable for carrying out the invention may be provided as separate components suitable for mixing by the consumer. Where the compositions are suitable for mixing they may be mixed either directly at the surface or remote from the surface before application. i

Component (a) preferably comprises hydrogen peroxide or peracetic acid.

In accordance with the invention the two components (a) and (b) may be mixed in any suitable proportions, depending upon their initial concentrations, suitably such that the finally applied mixture comprises 0.01-30%, by weight of hydrogen peroxide or an organic peracid.

Preferably, the ratio of component (a) to component (b) is from 10:1 to 1:10, most preferably from 2:1 to 1:2.

When component (a) and (b) are mixed it is preferred that the pH of the mixture is greater than 7, ideally greater than 8, 9, 10, 11 or 12.

It is preferred that the two components (a) and (b) are mixed no more than 10 minutes before application to the surface requiring stain removal.

It is most preferred that the two components (a) and (b) are mixed at the surface requiring stain removal, so that the improved stain removal effect may occur immediately.

In this aspect component (a) may be applied to the surface followed by component (b) or vice versa.

Alternatively (and preferably) components (a) and (b) are applied to the surface substantially simultaneously within 30 seconds.

According to a preferred embodiment of the presentation invention, the concentration of hydrogen peroxide or organic peracid in the composition immediately after mixing is from 0.01 to 10% w/w. This would mean for example in a 1:1 mix of component (a) and ) (b) that component (a) prior to the mixing would contain from 0.02 to 20% w/w of hydrogen peroxide or an organic peracid.

Where component (a) comprises hydrogen peroxide it is most preferred that the concentration of hydrogen peroxide in the mixture immediately after mixing should be from 1.5 to 5% w/w. For example, if a 1:1 mixture of components (a) and (b) is to be mixed, then component (a) should comprise from 3 to 10% w/w hydrogen peroxide.

The concentration of the enzyme in component (b) will be less than 1% wt.

The process of the present invention alleviates the need to use further stabilising components for the hydrogen peroxide/organic peracid or enzyme when preparing commercial products.

The components suitable for use in the process according to the invention may further include any other conventional additives known to the art. Examples of these include fragrances, dyes, sequesterants, chelating agents, germicides, preservatives, corrosion inhibitors or antioxidants.

The above auxiliary components may be included in the compositions suitable for use in the process of the present invention at concentrations of from 0.01% w/w to 10% w/w. These auxiliary ingredients may be included in either component (a), or component (b) or both if appropriate.

Compositions suitable for use in the process according to the present invention may be stored in any appropriate containers known to the art. For example, i the two components may be stored in two-compartment packs suitable for sequential or simultaneous dispensing.

Where both components (a) and (b) are liquids, most preferably they may be stored in a two-compartment dispenser, one compartment containing each component and the dispenser being adapted to dispense each component on to a surface, either sequentially or, preferably, simultaneously.

According to a further aspect of the invention, there is provided a twocompartment dispenser comprising a first compartment containing an aqueous composition comprising hydrogen peroxide or an organic peracid and having a pH of greater than O but less than 7: a second compartment containing an aqueous composition comprising an alkalising agent and; dispensing means adapted to dispense the contents (or part thereof) of the compartments on to a surface either sequentially or simultaneously to form a mixture thereof.

Preferably wherein the first compartment and/or the second compartment additionally comprise at least one surfactant or water-soluble polymer.

Preferably, the first compartment contains an aqueous composition comprising 3 to 10% w/w hydrogen peroxide; and the second compartment contains an aqueous composition comprising less than 1% w/w of an enzyme.

The invention will now be illustrated by the

following Examples.

Comoartment 1 % Hydrogen Peroxide 7.3 Oxo Alcohol C12-C15 5EO 7.0 HEDP 0 12 Water up to 100 pH (100%) 3 8 Comnartment 2 % Sodium Bicarbonate 10.0 Water up to 100 pH 8.5 Conditions of test 1 ml of product was placed on the soil, scrubbed five times by hand and left to react for 5 minutes. The materials were then washed in a US top loading washing-machine (Whirlpool Imperial) on the cycle for medium load at 30C temp with water of 12 F hardness and a 1.5/1 Ca/Mg ratio. The materials were evaluated by measuring the reflectance (Y value) using a Ultrascan XE Spectrophotometer. )

Claims (8)

1. Claims 1. A process for stain removal at a surface, comprising applying to

   that surface an aqueous composition, which composition has a pH of 7 or more and comprises a mixture of: (a) an aqueous composition comprising a source of active oxygen and having a pH of greater than O but less than 6 and (b) an aqueous composition comprising an alkalising agent.
2. 2. A process as claimed in claim 1 wherein components (a) and/or (b) additionally comprise at least one surfactant or water- soluble polymer.
3. 3. A process as claimed in claim 2 wherein component (b) additionally comprises at least one enzyme.
4. 4. A process as claimed in claim 1 or claim 2 wherein the surfactant is a non-ionic surfactant.
5. 5. A process as claimed in claim 4 wherein (a) or (b) additionally contains a polycarboxylate.
6. 6. A process as claimed in any claim from 1 to 4 wherein the pH of component (b) is greater than 9.
7. 7. A process as claimed in any preceding claim wherein component (b) contains a pH buffer.
8. 8. A two-compartment dispenser comprising a first compartment containing an aqueous

   J

   composition comprising a source of active oxygen and having a pa of greater than O but less than 7; a second compartment containing an aqueous composition comprising an alkalising agent; and dispensing means adapted to dispense the contents (or part thereof) of the compartments on to a surface either sequentially or simultaneously to form a mixture thereof.