ZA200602877B

ZA200602877B - Hypochlorite bleach composition

Info

Publication number: ZA200602877B
Application number: ZA200602877A
Authority: ZA
Inventors: Dave Parthiv Ripudaman; Mukherjee Nikhileshwar
Original assignee: Unilever Plc
Priority date: 2003-11-19
Filing date: 2004-10-29
Publication date: 2007-06-27
Also published as: PL1685228T3; EP1685228B8; MY142747A; AU2004291627B2; EP1685228B1; ES2317063T3; RU2006121450A; CA2544330A1; RU2360955C2; ATE414133T1; AU2004291627A1; WO2005049779A1; BRPI0416020A; AR046636A1; JP2007511648A; MXPA06005633A; EP1685228A1; DE602004017774D1

Description

HYPOCHLORITE BLEACH COMPOSITION

Field of the Invention

The present invention relates to thickened chlorine bleach compositions.

Background and Prior Art

Cleaning compositions are used in everyday life for cleaning a large variety of substrates, such as hard surfaces, textiles and soft furnishings. Many cleaning compositions contain bleaching agents, often in combination with surfactants. Such bleach containing compositions are particularly intended for removing coloured stains such as from textiles or hard surfaces, or for hygienic cleaning of particularly hard surfaces. Active chlorine bleaching agents are very popular for this purpose. :

Typical materials constituting such hard surfaces include ceramic, metals (e.g. stainless steel, chrome-plated materials), stone, wood, vitreous enamel, and polymeric surfaces.

There has often been a need to thicken cleaning compositions comprising bleaching agents. Thickened compositions are easier to dispense in a controlled manner. Also, when the compositions are applied on to surfaces to be cleaned, it is .. desirable that they are in contact with the surface for a sufficiently long time to enable good cleaning. This is especially important when the compositions are applied

' underneath horizontal surfaces or to vertical or inclined surfaces such as lavatory rims or bowls. Methods to thicken these compositions include the use of polymers or the incorporation of surfactants in high quantities, both of which are expensive options.

US 4,839,077 describes a thickened bleach composition comprising: (i) a bleaching halogen compound, (ii) a polymeric thickener having a molecular weight of 1,000 to 100,000 and comprising a charged monomer and an uncharged monomer such'that the resulting polymer has a acid number . between 80 to 400 mg KOH/g polymer and (iii) a surfactant system including a bleach-resistant nonionic surfactant and a bleach-resistant anionic surfactant.

US 5,821,214 describes a cleaning composition comprising: (i) from 0.5 to 10% of soft abrasive particles, (ii) from 0.5 to 2.5% of a chlorine bleach, (iii) from 0.2 to 3% of a thickening system comprising a crosslinked polyacrylate resin having a molecular weight in the range of 1,000,000 to 10,000,000, (iv) from 0.25 to 3% of a bleach stable surfactant system comprising mainly anionic surfactants and (v) sufficient amount of potassium or sodium hydroxide to provide a pH in the range of 11.5 to 13. 5."

JP 10/251, 687 describes a liquid bleach composition for hard surface cleaning that comprises: (i) 0.1 to 8% of alkali metal hypochlorite salt, (ii) 0.1 to 9% of alkali metal hydroxide, (iii) 0.1 to 5% of anionic surfactant and (iv) 0.1 to 5% of a buffer which is preferably phosphoric acid or its salts or soluble silicic acid salts.

~ 3 =

US 6,100,228 describes a bleaching gel cleaner and a method of preparing it comprising: (i) an effective amount of a hypochlorite generating compound, (ii) a ternary thickening - 5 system.comprising (a) alkali metal soap; (b) a hydrotrope consisting of trialkylamine oxides, betaines and mixtures thereof, iii) bleach stable solvent, and (iv) a buffer/electrolyte to stabilize the composition, the balance being water.

The above prior art compositions are expensive since they. involve complex multi-component mixtures and/or expensive raw materials such as polymers. Thus, there is a need for hypochlorite bleaching compositions that are thickened using inexpensive and easily available materials.

Summary of the Invention

The present invention provides a thickened liquid hypochlorite bleach composition comprising surfactant and alkali metal electrolyte which has sufficient viscosity to be useful for application to a wide range of surfaces, - including vertical or inclined surfaces.

Detailed Description of the Invention : . All percentages herein are by weight based on the total } weight of the composition, unless specifically indicated otherwise. :

The thickened liquid bleach compositions comprise water, from 0.1 to 10% of a hypochlorite salt; from 0.5 to 20% of a surfactant; from 0.1 to 8% of an electrolyte selected from the group consisting of alkali metal hydroxides, halides, sulphates, carbonates and mixtures thereof, and the compositions comprise at least two different kinds of alkali metal ions.

Bleaching agent : :

The bleaching agent in the thickened bleach compositions of the invention is a hypochlorite salt. The cation in the hypochlorite salt may be chosen from alkali metal and alkaline earth metal, preferably alkali metal, more preferably sodium and potassium, most preferably sodium.

Many commercially available solutions of alkali metal hypochlorites in water also include the corresponding alkali metal chloride. This is due to the method of manufacture of the alkali metal hypochlorite that involves reacting an alkali metal hydroxide with chlorine gas to form the corresponding alkali metal hypochlorite and alkali metal chloride. These are often sold as such without further purification and called ‘high salt’ bleach... For example, if the alkali metal is sodium, the ‘high salt’ sodium hypochlorite bleach solution also contains sodium chloride.

It is also possible to source alkali metal hypochlorites which are free of the corresponding chloride. Such products, often termed ‘low salt’ or ‘high purity’ bleaches, are

-5 =

Prepared by reaction of alkali metal hydroxide with hypochlorous acid.

It is possible to prepare the thickened bleach compositions ~ 5 of the present invention starting with either ‘high salt’ or ‘low-salt’ bleach. However, a preferred bleaching agent of the present invention is sodium hypochlorite, due to its wide availability and low cost. It is also préferred to use ‘high salt’ sodium hypochlorite bleach in the present invention as it is more widely and cheaply available compared to the corresponding ‘low-salt’ solutions. }

The total amount of alkali metal hypochlorite in the compositions of the invention ranges up to 10%, preferably from 0.1 to 8%, more preferably from 1 to 5%.

Surfactant : :

A surfactant that is compatible with hypochlorite is used in the thickened bleach composition of the invention.

It is preferred to use anionic surfactants for the invention, which may be soap or a non-scap surfactants. It is preferred to use non-soap surfactants. The anionic surfactants may have alkali metal or alkaline earth metal or ammonium or alkanolamine counter ions, or a mixture thereof.

A large variety of anionic surfactants have been named in the prior art to be suitable for use in hypochlorite solutions, including the water-soluble salts of organic sulphuric acid mono-esters and sulphonic acids having in the

- 6 = : molecular structure a branched or straight chain alkyl group containing 8-22 C atoms or an aryl or alkylaryl group containing 8-22 C atoms. Such suitable anionic surfactants include alkali metal salt of alkylbenzene-sulphonates, 5S alkyl-glycerylether sulphates (especially ethers of the alcohols derived from coconut oil and tallow), primary and secondary alkyl sulphonates, olefin sulphonates, alkyl sulphates, fatty acid monoglyceride sulphates and mixtures thereof.

Particularly suitable anionic surfactants for use in the composition of the invention are ethoxylated alcohol sulphates such as SLES (sodium laurylether sulphate), primary and secondary alkyl sulphates, and mixtures thereof.

It is also possible to include further surfactants such as nonionic, cationic, amphoteric, or zwitterionic surfactants in the compositions of the invention.

The total amount of surfactant in the compositions of the invention ranges from 0.5 to 20%, preferably from 0.5 to 10%. Preferably at least 50% by weight of total surfactant, more preferably at least 70%, is anionic surfactant.

Electrolyte }

For the purposes of this invention the word “electrolyte” as ++ used herein does not comprise hypochlorite salt and ionic surfactant. Electrolytes used in the thickened bleach compositions of the invention are selected from the group consisting of alkali metal hydroxides, halides, sulphates,

- 7 = carbonates and mixtures thereof. Preferably they are chosen from hydroxides, halides and sulphates, more preferably hydroxides and halides. Among the halides the chlorides are most preferred.

The electrolyte is chosen such that in combination with the hypochlorite the total alkali metal ion content of the composition comprises at least two different alkali metals.

Various alternative ways of meeting this requirement will be apparent to the person skilled in the art. One preferred way is to combine one alkali metal hypochlorite with least one alkali metal electrolyte with a different cation. An alternatively way is to combine a combination of different alkali metal hypochlorites with one or more electrolytes having one or more alkali metal ions.

Preferably the least prevalent alkali metal ion in the composition is present in a molar amount of at least 10% of total alkali metal ions.

In preferred embodiments of the invention all the components of the composition are chosen such that the total cation content of the composition consists entirely of alkali metal cations. In a more preferred embodiment the cations comprise only sodium and potassium

In view of the various preferred embodiments discussed above, a most preferred embodiment of the invention comprises sodium hypochlorite and at least one electrolyte chosen from potassium hydroxide and potassium chloride in such an amount that at least 10% of total molar amount of alkali metal ion is potassium ion. :

It is also preferred that the electrolyte includes agents 5S that ensure that the PH of the thickened bleach composition is at least 11, preferably at least 12.5.

As outlined above, in the case that “high salt” alkali metal hypochlorite is used, part of the total amount of electrolyte in the composition will necessarily be the alkali metal chloride which accompanies the hypochlorite.

The total amount of electrolyte in the composition of the invention ranges from of 0.1 to 8%, more preferably from 0.1 to 5.0%.

In addition to hypochlorite, surfactant and electrolyte, the composition of the invention comprises water.

Optional Ingredients

The composition of the invention may contain other optional ingredients for enhancing performance and/or aesthetics of the composition such as: solvents, abrasives, structurants, colourants, hydrotropes, whiteners, optical brighteners, soil suspending agents and perfumes.

The compositions according to the invention do generally not require polymeric thickening agents for further thickening and such agents are therefore preferably absent in the compositions.

Product Form

The composition of the invention is a thickened liquid, which for the purposes of this invention includes easily pourable liquids, thick liquids, gels, pastes and mousses.

A preferred form is an easily or thick pourable liquid or a gel. :

EXAMPLES

In the comparative examples the compositions comprise only one alkali metal ion.

Comparative Example A 280g of SLES (sodium laurylether sulphate (2.5E0)) were placed in a 3-litre vessel. To this was added a solution of 134g of sodium hydroxide, 2g of sodium silicate solution (50% solids), and 10g of sodium chloride, dissolved in 1580g of water with continuous stirring. 140g of a ‘high-salt’ sodium hypochlorite solution (containing 30g sodium hypochlorite and 26g sodium chloride and the balance water) was added to the above mixture with constant stirring to prepare a bleach composition.

Comparative Example B .. A composition corresponding to Comparative Example A was ; prepared except that 16g of sodium chloride was used instead of the 10g of sodium chloride in the pre-prepared solution.

Comparative Example C

A composition corresponding to Comparative Example A was prepared except that 20g of sodium chloride was used instead of the 10g of sodium chloride in the pre-prepared solution.

Example 1

A composition corresponding to Comparative Example A was prepared except that 10g of potassium chloride was added instead of sodium chloride.

Example 2

A composition corresponding to Comparative Example B was prepared except that 16g of potassium chloride was added instead of sodium chloride.

Example 3

A composition corresponding to Comparative Example C was prepared except that 20g of potassium chloride was added instead of sodium chloride.

Table 1 lists the compositions of Comparative Examples A,B,C and Examples 1,2,3 along with the weight percent of the . ingredients. Table 1 also lists the viscosities of the compositions. The data in Table 1 indicate that for the same total electrolyte concentration, when the alkali metal cation associated with the electrolyte is different to the alkali metal cation associated with the alkali metal " hypochlorite, there is a synergistic benefit in terms of increased viscosity of the composition.

Table 1 :

Re EN EA EI CN ER SA

EY C0 KC KC ra I

EE EE EEE CE ESC EEN Er

Ei SS 2 GN LC

Total 2.47 2.47 2.77 2.77 3.07 3.07 electrolyte

Ri I EXE NN ECC LO

ZO EC EC LC

In comparative examples D, E and examples according to the "invention 4 and 5 a mixture of anionic surfactants was used. — Can 9 2 TaXture of anionic surfactants was used.

Comparative Example D

A composition was prepared corresponding to Comparative

Example B except that 187g of SLES and 93g of secondary alkyl sulphate (SAS) were used instead of 280g of SLES.

Comparative Example E

A composition was prepared corresponding to Comparative

Example C except that 187g of SLES and 93g of SAS were used instead of 280g of SLES.

CC -12 -

Example 4

A composition was prepared corresponding to Example 2 except that 187g of SLES and 93g of SAS were used instead of 280g of SLES.

Example 5 ‘A composition was prepared corresponding to Example 3 except that 187g of SLES and 93g of SAS were used instead of 280g of SLES.

Table 2 lists the compositions of Comparative Examples D and

E and Examples 4 and 5 along with the viscosities of the compositions. The data in Table 2 indicates that, for compositions according to the invention, the synergistic Dbenefit in terms of increased viscosity is also obtained when mixtures of surfactants are used.

Table 2

EC LI a LL

ECR LAN La a ca cc CN CL LEC LC a CE CC CN LILA

RS GN CAEN CI

Examples 6-11

These examples show thickened bleach compositions according to the invention over a wide range of concentrations of hypochlorite, surfactants, and electrolytes as outlined in

Table 3. The table shows that thickened bleach compositions according to the invention (with viscosities of 90 mPas and above) can be obtained over a wide range of concentrations of hypochlorite, surfactants and electrolytes.

Table 3

Ee a LC EE a

KSC GS EG Ch Ea

Fe Silicate [0°05 [0.05 [0:65 aos [a5 [005

Total 5.1 5.1 4.3 4.3 3.1 3.3 se 7 ELC EL CI CL EL

Claims

1. A thickened liquid bleach composition comprising water, hypochlorite bleaching agent and surfactant characterised in that it comprises: :

0.1 - 10% of a hypochlorite salt;

0.5 - 20% of a surfactant;

0.1 - 8% of an electrolyte selected from the group consisting of alkali metal hydroxides, halides, sulphates, carbonates and mixtures thereof; and wherein the composition comprises at least two different kinds of alkali metal ions.

2. A composition according to claim 1 wherein the hypochlorite salt is an alkali metal salt.

3. A composition according to claim 2 wherein the hypochlorite salt is sodium hypochlorite

4. A composition according to claims 1-3 wherein the surfactant comprises anionic surfactant chosen from water-soluble salts of organic sulphuric acid mono- esters and sulphonic acids having in the molecular structure a branched or straight chain.alkyl group containing 8-22 C atoms or an aryl or alkylaryl group containing 8-22 C atoms.

= 5. - A composition according to claims 1-4 wherein the least prevalent alkali metal ion in the composition is present in a molar amount of at least 10% of total alkali metal ions.

6. A composition according to any one of claims 1 to 5 wherein the electrolyte is chosen from alkali metal hydroxides, chlorides, sulphates and mixtures thereof.

7. A composition according to claim 6 wherein. the hypochlorite salt and the electrolyte are chosen from sodium and potassium compounds.

8. A composition according to claim 7 wherein the hypochlorite salt is sodium hypochlorite and the electrolyte is a potassium compound.

9. A composition according to any one of claims 1-8 wherein the total amount of electrolyte in the composition ranges from 0.1 to 5%.