MXPA06005633A - Hypochlorite bleach composition. - Google Patents

Abstract

The invention provides a thickened bleach composition comprising water, a hypochlorite bleaching agent, a surfactant and an electrolyte selected from the group consisting of alkali metal hydroxides, chlorides, sulphates, carbonates and mixtures thereof; wherein the composition comprises at least two different kinds of alkali metal ion. The compositions of the invention have a sufficient viscosity for application to a wide range of surfaces, including vertical or inclined surfaces, and are effectively thickened using materials that are inexpensive and easily available.

Description

COMPOSITION OF HYPOCHLORITE BLEACHER Field of the invention The present invention relates to thickened chlorine bleach compositions.

BACKGROUND AND PRIOR ART Cleaning compositions are used in daily life to clean a wide variety of substrates, such as hard surfaces, textiles and soft accessories. Many cleaning compositions contain bleaching agents, often in combination with surfactants. Such bleach-containing compositions are particularly intended for removing stains of color, such as textiles and hard surfaces, or for hygienic cleaning in particular from hard surfaces. Active chlorine bleach agents are very popular for this purpose. The normal materials that make up such hard surfaces include ceramics, metals (for example, stainless steel, platinum-plated materials), stone, wood, vitreous enamel, and polymeric surfaces. Frequently there has been the need to thicken cleaning compositions comprising bleaching agents. The thickened compositions are easier to dispense in a controlled manner. In addition, when the compositions are applied on the surfaces to be cleaned, it is desirable that they are in contact with the surface for a sufficiently long time to allow good cleaning. This is especially important when the compositions are applied below horizontal surfaces or vertical or inclined surfaces, such as edges of lavatories or cups. Methods for thickening these compositions include the use of polymers or the incorporation of surfactants in high amounts, both expensive options. US 4,839,077 discloses a thickened bleach composition comprising: (i) a halogen bleaching compound, (ii) a polymeric thickener having a molecular weight of 1,000 to 100,000 and comprising a charged monomer and an unfilled monomer, so that the resulting polymer has an 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 discloses 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 1,000,000,000, (iv) from 0.25 to 3% of a bleach-stable surfactant system comprising mainly anionic surfactants and (v) a sufficient amount of potassium or sodium hydroxide to provide a pH in the range of 1 .5 to 13.5. JP 10/251, 687 describes a liquid bleaching composition for hard surface cleaning comprising: (i) 0.1 to 8% alkali metal hypochlorite salt, (ii) 0.1 to 9% 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. US 6,100,228 discloses a bleach gel cleaner and method for preparing it, comprising: (i) an effective amount of a hypochlorite generating compound, (ii) a ternary thickener system comprising (a) alkali metal soap; (b) a hydrotrope consisting of trialkylamine oxides, betaines and mixtures thereof, (iii) solvent stable to bleaching, and (iv) a buffer / electrolyte to stabilize the composition, the remainder being water. Such prior art compositions are expensive because they involve mixtures of multiple components and / or expensive raw materials, such as polymers. Thus, there is a need for hypochlorite bleach compositions that are thickened using inexpensive readily available materials.

BRIEF DESCRIPTION OF THE INVENTION The present invention provides a thickened liquid hypochlorite bleaching 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. 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, sulfates, carbonates and mixtures thereof, and the compositions comprise at least two different classes of alkali metal ions.

Bleaching agent The bleaching agent in the thickened bleaching compositions of the invention is a hypochlorite salt. The cation in the hypochlorite salt can 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 manufacturing the alkali metal hypochlorite with chlorine gas to form the corresponding alkali metal hypochlorite and alkali metal chloride. These are often sold as such without further purification and are called "high-salt" bleaches. For example, if the alkali metal is sodium, the "high salt" sodium hypochlorite bleach solution also contains sodium chloride. It is also possible to have as a source alkali metal hypochlorites which are free of the corresponding chloride. Such products, often called "low-salt" or "high purity" bleaches, are prepared by reaction of the alkali metal hydroxide with hypochlorous acid. It is possible to prepare the thickened bleaching compositions of the present invention starting either with "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 preferred to use "high salt" sodium hypochlorite bleach in the present invention, since 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 varies 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 non-soap or soap surfactants. It is preferred to use non-soap surfactants. The anionic surfactants may have counterions of alkali metal or alkaline earth metal or alkanolamine, or a mixture thereof. A wide 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 mono-esters of organic sulfuric acid and sulfonic acids having in the molecular structure a chain alkyl group linear or branched containing 8-22 carbon atoms or an aryl or alkylaryl group containing 8-22 carbon atoms. Such suitable anionic surfactants include alkali metal salt of alkylbenzene sulphonates, alkyl glyceryl sulfates (especially ethers of alcohols derived from coconut oil and tallow), sulfonates of primary and secondary alkyls, olefin sulfonates, alkyl sulfates, monoglyceride sulfates of fatty acids and mixtures thereof. Particularly suitable anionic surfactants for use in the composition of the invention are sulfates of ethoxylated alcohols, such as SLES (sodium lauryl ether sulfate), primary and secondary alkyl sulfates and mixtures thereof. It is also possible to include additional 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. The electrolytes used in the thickened bleaching compositions of the invention are selected from the group consisting of hydroxides, halides, sulfates, alkali metal carbonates and mixtures thereof. Preferably, they are chosen from hydroxides, halides and sulfates, more preferably hydroxides and halides. Among the halides, the chlorides are the most preferred. The electrolyte is chosen so 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 satisfying this requirement will be apparent to the person skilled in the art. A preferred way is to combine an alkali metal hypochlorite with at least one alkali metal electrolyte with a different cation. An alternative way is to make a combination of different alkali metal hypochlorites with one or more electrolytes having one or more alkali metal ions. Preferably, the less frequent alkali metal ion in the composition is present in a molar amount of at least 10% of the total alkali metal ions. In preferred embodiments of the invention, all components of the composition are chosen such that the total cation content of the composition consists entirely of alkali metal cations. In a preferred embodiment, the cations comprise only sodium and potassium. In view of the various preferred embodiments discussed above, a more preferred embodiment of the invention comprises sodium hypochlorite and at least one electrolyte chosen from potassium hydroxide and potassium chloride in such amount as at least 10% of the total molar amount of ion of alkali metal is potassium ion. It is also preferred that the electrolyte includes agents that ensure that the pH of the thickened bleach composition is at least 11, preferably at least 12.5. As noted above, in the event 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 that accompanies the hypochlorite. The total amount of electrolyte in the composition of the invention ranges from 0.1 to 8%, more preferably from 0.1 to 5.0%. In addition to the hypochlorite, the surfactant and the electrolyte, the composition of the invention comprises water.

Optional ingredients The composition of the invention may contain other optional ingredients to enhance the performance and / or aesthetics of the composition, such as: solvents, abrasives, structurants, dyes, hydrotropes, bleaches, optical brighteners, soil suspending agents and perfumes. The compositions according to the invention generally do not require polymeric thickening agents for further thickening and therefore, such agents are 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 voidable liquids, thick liquids, gels, pastes and mousses. A preferred form is a readily or thickly pourable liquid or gel.

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

Comparative Example A 280 g of SLES (sodium lauryl ether sulfate (2.5EO)) were placed in a 3 liter vessel. To this was added a solution of 134 g of sodium hydroxide, 2 g of sodium silicate solution (50% solids) and 10 g of sodium chloride, dissolved in 1580 g of water with continuous stirring. 140 g of a "high salt" sodium hypochlorite solution (containing 30 g of sodium hypochlorite and 26 g of sodium chloride and the remainder of water) were added to the above mixture with constant stirring to prepare a bleaching composition. .

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

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

Example 1 A composition corresponding to the Comparative Example was prepared A, except that 10 g of potassium chloride was added instead of sodium chloride.

Example 2 A composition corresponding to the Comparative Example was prepared B, except that 16 g of potassium chloride was added instead of sodium chloride.

Example 3 A composition corresponding to the Comparative Example was prepared C, except that 20 g 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, together with the weight percentage 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 from the alkali metal cation associated with the alkali metal hypochlorite, there is a synergistic benefit in terms of increased viscosity of the composition.

In the comparative examples D, E and examples according to the invention 4 v 5, a mixture of anionic surfactants was used Comparative Example D A composition corresponding to Comparative Example B was prepared, except that 187 g of SLES and 93 g of secondary alkyl sulfate (SAS) were used instead of 280 g of SLES.

Comparative Example E A composition corresponding to the Comparative Example was prepared C, except that 187 g of SLES and 93 g of SAS were used instead of 280 g of SLES.

Example 4 A composition corresponding to Example 2 was prepared, except that 187 g of SLES and 93 g of SAS were used instead of 280 g of SLES.

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

Table 2 lists the compositions of Comparative Examples D and E and Examples 4 and 5, together with the viscosities of the compositions.

The data in Table 2 indicate that, for compositions according to the invention, the synergistic benefit in terms of increased viscosity is also obtained when mixtures of surfactants are used.

Table 2 Examples 6-1 These examples show thickened bleaching compositions according to the invention over a wide range of concentrations of hypochlorite, surfactants and electrolytes as indicated in Table 3. The table shows the thickened bleaching 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

Claims (7)

1. CLAIMS 1 . A thickened liquid bleaching composition comprising water, hypochlorite bleaching agent and surfactant characterized in that it comprises: 0.1-10% by weight of a hypochlorite salt, chosen from sodium and potassium hypochlorite; 0.5 - 20% by weight of surfactant; 0.1 - 8% by weight of an electrolyte selected from the group consisting of hydroxides, halides, sulfates, alkali metal carbonates and mixtures thereof; and wherein the composition comprises at least two different classes of alkali metal ions, the less frequent alkali metal ion being present in a molar amount of at least 10% of the total alkali metal ion content, and in which the Polymeric thickeners are absent in the composition. 2. A composition according to claim 2, wherein the hypochlorite salt is sodium hypochlorite. 3. A composition according to claims 1-3, wherein the surfactant comprises anionic surfactant chosen from water-soluble salts of mono-esters of organic sulfuric acid and sulfonic acids having in the molecular structure a straight or branched chain alkyl group containing 8-22 carbon atoms or an aryl or alkylaryl group containing 8-22 carbon atoms. 4. A composition according to any of claims 1 to 5, wherein the electrolyte is chosen from hydroxides, chlorides, sulfates of alkali metals and mixtures thereof. 5. A composition according to claim 6, wherein the hypochlorite salt and the electrolyte are chosen from sodium and potassium compounds. 6. A composition according to claim 7, wherein the hypochlorite salt is sodium hypochlorite and the electrolyte is a potassium compound. 7. A composition according to any of claims 1-8, wherein the total amount of electrolyte in the composition varies from 0. 1 to 5% by weight.