SK942000A3 - Use of electrolyte mixtures as sequestering agents - Google Patents

Abstract

The invention relates to the use of electrolyte mixtures containing a) lignin sulfonates and b) at least one other electrolyte salt from the group made up of polyacrylates, phosphonates, silicates, carbonates and citrates as sequestering agents for producing aqueous bleaching agents. According to the invention, preparations which reliably prevent fabric from yellowing, preferably chlorine bleaching solutions, can be obtained especially together with chlorine-resistant tensides.

Description

Use of electrolyte mixtures as sequestering agents

Technical field

The invention relates to the use of electrolyte mixtures as sequestering agents for the manufacture of aqueous bleaching compositions.

BACKGROUND OF THE INVENTION

While, in many European countries, washing of heavily soiled fabrics uses powder or liquid detergents that only achieve performance at higher temperatures, consumers in the US and Spain, for example, prefer cold washing where they are added to the wash to remove very difficult stains. and a bleaching agent, in particular based on hypochlorite.

Many liquid bleaching agents are known in the art. For example, EP-A-0274885 (ICI) recommends the use of a mixture of linear and branched amine oxides in the manufacture of viscous hypochlorite bleaching compositions. According to EP-A 0145084 (Unilever) mixtures of amine oxides with soaps, sarcosinates, taurides or sugar esters can also be used for this purpose. EP-A-0137551 and EP-A-0447261 (Unilever) disclose the use of amine oxides with a soap or sarcosinate and other anionic surfactants, for example alkyl sulfates, alkyl ether sulfates, secondary alkanesulfonates or alkyl benzene sulfonates as a thickening agent for the thickening agent. Further, EP-A1 0447261 discloses aqueous bleaching compositions containing sodium hypochlorite and anionic surfactants. However, the hypochlorite concentration in this composition is 0.1 to 8 wt. of active chlorine. DE-C1 4333100 describes chlorine bleaching liquors based on hypochlorite, fatty alcohol ether sulfates, amine oxides and amine oxide phosphonic acids. The use of silicates or carbonates as a buffer in chlorine bleaching liquids is disclosed, for example, in the publications.

-2US 4,623,476 (Procter & Gambia) as well as in EP-A1 0079102 and EP-A1 0137551 (Unilever).

Consumers place high demands on the bleaching agent of this kind: they must be compatible with textiles, i.e. j. treatment with aggressive hypochlorite chemicals must remove stains without breaking the fabric. Since skin contact with the bleaching agent is not excluded, the preparations must be as dermatologically compatible as possible. A particular problem is that hypochlorite solutions also attack metals and the dissolved traces of metals can settle on the fibers of the fabric during washing, which can subsequently cause the fabric to yellow. Although preparations on the market attempt to prevent such deposition by the common use of silicates, in practice this measure is not always satisfactory.

Consequently, the complex object of the present invention has been to counteract the yellowing of laundry by heavy metal ions and to provide a sequestering agent allowing the production of aqueous bleaching agents, in particular chlorine bleaching liquids, which are simultaneously chlorine stable, protect textiles and are sufficiently skin tolerant high viscosity and high stain removal capability reliably prevent metal traces from settling on the fabric.

SUMMARY OF THE INVENTION

The present invention provides the use of electrolyte mixtures comprising (a) lignin sulfonates and (b) at least one other electrolyte salt selected from the group consisting of polyacrylates, phosphonates, silicates, carbonates and citrates as sequestering agents in the manufacture of aqueous bleaching compositions.

Surprisingly, it has been found that the addition of a small amount of said electrolyte mixtures to an aqueous bleaching agent, in particular to a hypochlorite solution, significantly reduces the deposition of metals on the fabric during washing and counteracts the yellowing of the fibers. The invention includes the finding that the combined use of fine chlorine-stable surfactants such as, in particular, alkyl ether sulfates, amine oxides, alkyl- and / or alkenyloligoglycosides and fatty acid salts leads to further improvements

-3stabilization against yellowing, cleansing performance and dermatological tolerance. Finally, the compositions according to the invention have a sufficiently high viscosity due to the gel-forming effect of the lignin sulfonates, so that dosing by consumers is problem-free.

lignin

Lignin sulfonates are alkali metal salts, alkaline earth metal salts, ammonium, aluminum or zinc salts of ligninsulfonic acid, which are formed, for example, by the sulphite decomposition of wood as a reaction product of natural lignin and sulfur-containing acid. For the purposes of the invention, the ligninsulfonic acids to be used have an average molecular weight of from 500 to 200 000, preferably from 10 000 to 50 000 daltons, the number of sulfonic groups per unit of phenylpropane unit being from 1 to 5.

Alkaline hypochlorites

I

The aqueous bleaching compositions may contain hydrogen peroxide, but are preferably chlorine bleaching liquors containing alkali hypochlorite. Alkali hypochlorite is understood to mean lithium, potassium and especially sodium hypochlorite. The hypochlorites can be used in amounts of from 1.5 to 10, preferably from 2 to 8, and in particular from 4 to 6% by weight. relative to the device.

Salts of electrolytes

The lignin sulfonates are used together with at least one other electrolyte salt. These may be alkali metal and / or alkaline earth metal silicates, carbonates, citrates, or mixtures thereof; typical examples are sodium silicate, potassium silicate, sodium carbonate, potassium carbonate, sodium citrate, potassium citrate, magnesium citrate.

In a more preferred embodiment of the invention, polyelectrolytes of the polyacrylate type are used as electrolyte salts. These are not only homopolymers of acrylic acid, but also methacrylic acid and their esters of lower linear or branched alcohols having 1 to 8 carbon atoms. Generic term polyacrylates

It also includes copolymers of said substances. The average molecular weight of the polyacrylates can be dispersed over a wide range and is from 300 to 5,000,000, more preferably from 1,000 to 1,000,000, in particular from 50,000 to 500,000, and in particular from 100,000 to 250,000 daltons.

In another more preferred embodiment of the invention, phosphonates are used as electrolyte salts. Inorganic phosphonates (also known as secondary phosphonates) of formula (I),

HP (O) (OM ¹ ) ₂ (I) wherein M is an alkali metal, an alkaline earth metal, aluminum or zinc, especially sodium, and organic phosphonates of formula II,

R ¹ P (O) (OR ² ) ₂ (II) wherein R ¹ and R ² independently of one another represent hydrogen or a linear or branched hydrocarbon radical having 1 to 22, in particular 4 to 12, carbon atoms, optionally containing functional groups thereto R ¹ and R ² are not simultaneously hydrogen. Typical examples of inorganic phosphonates are sodium phosphite, calcium phosphite and zinc phosphite. Regarding the production and properties of these compounds, compare Holleman-Wiberg, Lehrbuch der Anorganischen Chemie, Walter de Gruyter, Berlin, 81-90th edition, 1976, page 458/459. Examples of organic phosphonates are methylphosphonate, ethylphosphonate, butylphosphonate, 2-ethylhexylphosphonate as well as amine group phosphonates such as aminomethylene phosphonate or aminoethylene phosphonate. Further suitable phosphonates are compounds which are linked to one another by functional groups such as nitrilotris (methylene phosphonate) or nitrilotris (ethylene phosphonate). Particularly preferred is the use of amino oxide phosphonic acids, such as those marketed under the name Sequion® from Bozetto / IT.

The electrolyte salts promote the sequestering effect of the lignin sulfonates and ensure that the compositions have a constant, highly alkaline pH in the range of from 10 to 14. The lignin sulfonates and electrolyte salts may be used in a weight ratio of 95: 5 to 5:95, more preferably 80:20 to 20 : 80 and especially 60:40 to 40:60. The amount of electrolyte mixtures containing lignin sulfonates and electrolyte salts used may be 0.01 to 5, more preferably 0.1 to 2 and in particular 0.5 to 1% by weight. relative to the device.

Chloride-stable surfactants

(a) Alkyl ether sulphates

Alkyl ether sulfates are known anionic surfactants which can be obtained by sulfating nonionic surfactants of the alkyl polyglycol ether type and subsequent neutralization. In the context of the composition according to the invention, suitable alkyl ether sulfates of the formula III are considered,

R ³ O- (CH ₂ CH ₂ O) _q SO ₃ X (III) wherein R ³ represents an alkyl radical having 12 to 18, more preferably 12 to 14 carbon atoms, q is a number from 2 to 5, in particular 2 to 3, and X is sodium or potassium. Typical examples are the sodium salts of the C _12/14 -cocoalcohol sulphates + 2, + 2,3- and + 3-EO adduct. The alkyl ether sulfates may have a conventional or narrow distribution of homologs. It is preferred to use alkyl ether sulfates in an amount of from 1 to 8, more preferably from 1.5 to 6, and in particular from 2 to 4% by weight. relative to the device.

I

(b) Amine oxides

Also, amine oxides are known substances which are occasionally ranked as cationic, but generally nonionic surfactants. They are prepared from tertiary fatty amines, which generally have either one long and two short or two long and one short alkyl radicals and are oxidized in the presence of hydrogen peroxide. The amine oxides of the formula IV are suitable for the purposes of the invention,

-6R ⁵

I

R ⁴ - N -> O (IV)

IR ⁶ in which R ⁴ represents a linear or branched alkyl radical having 12 to 18 carbon atoms as well as R ⁵ and R ® independently of one another denote R ⁴ or an alkyl radical having 1 to 4 carbon atoms optionally hydroxy-substituted. Preference is given to the use of amine oxides of the formula IV in which R ⁴ and R ⁵ represent C 12/14 or C 12/18 -cocoalkylalkyl and R ® is a methyl or hydroxyethyl radical. Equally preferred are amine oxides of formula IV wherein R ⁴ is a C 12/14- or C _12/18 -cycloalkyl radical and R ⁵ and R ⁶ are methyl or hydroxyethyl radicals. The amine oxides are generally used in an amount of from 0.5 to 5, preferably from 1 to 4% by weight. relative to the device.

c) Alkyl- and / or alkenyloligoglycosides

Alkyl- and alkenyloligoglycosides are known nonionic surfactants of the formula V,

R ⁷ O- [G] _P (V) wherein R ⁷ represents an alkyl and / or alkenyl radical having 4 to 22 carbon atoms, G is a sugar radical having 5 or 6 carbon atoms, and is a number from 1 to

10. They can be obtained by an appropriate preparative organic chemistry procedure. Representative for the extensive literature is referred to EP-A1 0301298 and WO 90/03977. The alkyl and / or alkenyl oligoglycosides can be derived from aldoses or ketoses having 5 or 6 carbon atoms, in particular glucose. Preferred alkyl and / or alkenyloligoglycosides are thus alkyl and / or alkenyloligoglucosides. The index number p in the general formula V indicates the degree of oligomerization (DP), i.e. the distribution of mono- and oligoglycosides and means a number from 1 to 10. While p in a given compound must be an integer and here in particular have a value of p = 1 to 6 p value for a certain alkyloligoglycoside is an analytically determined calculated quantity, which is usually a fraction. Preference is given to using alkyl- and / or alkenyloligoglycosides having a mean degree of oligomerization of p from 1.1 to 3.0. Preferred for the application are those alkyl- and / or alkenyloligoglycosides whose degree of oligomerization is less than 1.7 and in particular has a value of from 1.2 to 1.4. The alkyl or alkenyl radical R ⁷ may be derived from primary alcohols having 4 to 11, more preferably 8 to 10, carbon atoms. Typical examples are butanol, caproalcohol, caprylalcohol, caprinal alcohol and undecyl alcohol as well as technical mixtures thereof, such as can be obtained, for example, in the hydrogenation of industrial fatty acid methyl esters or during the hydrogenation of aldehydes in Roelen oxosynthesis. Preferred are alkyl chain oligoglucosides of Ce-C10 (DP = 1 to 3), which are formed by distillation of the technical C8-C18-coconut fatty alcohol and may be contaminated with less than 6 wt. C12-alcohols as well as alkyl oligo-glucosides based on industrial C8 / 11-oxoalcohols (DP = 1-3). The alkyl or alkenyl radical R ⁷ may further be derived from primary alcohols having 12 to 22, more preferably 12 to 14, carbon atoms. Typical examples are lauryl alcohol, myristyl alcohol, cetyl alcohol, palmoleyl alcohol, stearyl alcohol, isostearyl alcohol, oleyl alcohol, elaidyl alcohol, petrozelinyl alcohol, arachyl alcohol, gadoleyl alcohol, behenyl alcohol, erucyl alcohol, brassidyl alcohol as well as the above-described technical mixtures thereof. Preference is given to C12 / 14-cocoalcohol-based alkyl oligo-glucosides having a DP of from 1 to 3. It is preferred to use glycosides in amounts of from 1.5 to 6, more preferably from 2 to 4% by weight. relative to the device.

d) Salts of fatty acids

As further surfactants, the compositions of the invention may contain salts of fatty acids of formula VI,

R ⁸ CO-OX (VI) wherein R ⁸ CO is an acyl radical of 12 to 22 carbon atoms and X is an alkali metal. Typical examples are the sodium and / or potassium salts of lauric acid, myristic acid, palmitic acid, palmitoolic acid, stearic acid,

-8 isostearic acids, oleic acid, elaidic acid, petrozelinic acid, linoleic acid, linolenic acid, elaeostearic acid, arachic acid, gadoleic acid, behenic acid and erucic acid, as well as their technical mixtures resulting from the pressure cleavage of industrial fats and oils. Preference is given to the use of salts of technical coconut or tallow fatty acid. Since the formulations of the invention are strongly alkaline, it is also possible to use fatty acids instead of salts, which, when added to the mixture, are neutralized in situ. The compositions according to the invention in which particularly low foaming is desired preferably contain fatty acid salts as optional ingredients. Preference is given to the use of soaps in amounts of from 1.5 to 6, more preferably from 2 to 4% by weight. relative to the device.

Industrial usability

The bleaching compositions obtained using the electrolyte compositions of the invention generally have a non-aqueous proportion of from 5 to 35, and more preferably from 8 to 15 wt. and are suitable for the treatment of textile surfaces such as yarns, fabric belts and especially textiles. Usually their use at low temperatures, i. in the cold wash area (approx. 15 to 25 ° C). The compositions are not only excellent in stain removal, but also reliably prevent metal traces from settling on the fibers and thus prevent yellowing. Although the actual use of the compositions is to wash stains, they are also well suited for other purposes where hypochlorite solutions are used, for example, for cleaning and disinfecting hard surfaces.

Other auxiliaries and additives which may be used are, for example, other chlorine-stable surfactants or hydrotropes, such as alkyl sulfates, alkyl sulfonates, alkylbenzenesulfonates, xylolsulfonates, sarcosinates, taurides, isothionates, sulfosuccinates, betaines, sugar esters, fatty alcohol polyglycol ethers and fatty alcohol polyglycol ethers. It is preferred that the sum of all surfactants is at most 10-15% by weight. the total amount of ingredients in the recipe. The compositions according to the invention may contain alkali metal compounds, in particular sodium hydroxide or potassium hydroxide, by means of which the pH of the formulation can be adjusted to an optimum value of 10 to 14, more preferably 12.5 to 13.5.

In addition, the compositions may contain chlorine-active fragrances, optical brighteners, dyes and pigments in amounts from 0.01 to 0.5% by weight in total. relative to the device. Known active chlorine-stable fragrances include, for example, monocyclic and bicyclic monoterpene alcohols as well as their esters with acetic or propionic acid (e.g. isoborneal, dihydroterpene oil, isobornyl acetate, dihydroterpenylacetate). Other fragrances which are suitable for this purpose are mentioned, for example, in EP-A1 0622451 (Procter & Gambia) and JP-A Sho 62/89800 (Raison). Optical brighteners may be, for example, the potassium salt of 4,4'-bis- (1,2,3-triazolyl) - (2 -) - stilbine-2,2-sulfonic acid, which is distributed under the Phorwite® BHC 766 brand. colored pigments can be used among others green chlorophthalocyanines (Pigmosol® Green, Hostaphine® Green) or Solar Yellow BG 300 (Sandoz). The compositions are produced by mixing. Optionally, the product obtained for separating foreign particles and / or agglomerates can be decanted or filtered. The compositions have a viscosity greater than 100 mPas as measured at 20 ° C in a Brookfield viscometer.

DETAILED DESCRIPTION OF THE INVENTION

To determine the bleaching effect, the soiled fabric was treated with various chlorine bleaching liquors. The yellowing of the fabric was determined photometric, with the starting value of the soiled fabric serving as a standard (100%). The measurements were carried out in a bath containing metal ions of 300 ppb Fe and 100 ppb t

Mn; the water hardness was 1000 ppm CaCl ₂ , the bicarbonate content was 0.013 wt. The bath (fabric: water) ratio was 1:50, and the treatment time was 30 minutes at 40 ° C. The results are summarized in Table 1; the amount data is understood as% wt. Examples 1-8 are according to the invention, examples V1 and V2 are for comparison.

-10Table 1 Bleaching Effect

composition 1 2 3 4 5 6 7 8 V1 V2 sodium hypochlorite 5.0 sodium hydroxide 0.5 Lignin sulphonate sodium salt (M = 50 000) 0.1 0.1 0.1 0.1 0.2 lignin sulphonate calcium salt (M = 100 000) 0.1 0.1 0.1 0.1 polyacrylate * 0.1 - - - 0.1 - 0.1 0.1 - - 2-etylhexylfosfonát - 0.1 amine oxide phosphonic acid ** 0.1 0.1 0.1 0.1 0.1 sodium silicate *** - - - 0.1 - 0.1 0.1 0.1 0.2 - sodium carbonate - - - - - - - 0.1 - - yellowing [% rel.] 83 83 83 83 82 81 81 80 101 92 *) polyacrylic acid, ca. 15.0C 0 gave on **) Sequion® Bozetto ***) mode 2.0

f / W 2gm -11 -

Claims (11)

PATENT CLAIMS Use of a mixture of electrolytes containing (a) lignin sulfonates and (b) at least one other electrolyte salt selected from the group consisting of polyacrylates, phosphonates, silicates, carbonates and citrates as sequestering agents in the manufacture of hypochlorite-containing aqueous bleaching compositions. Use according to claim 1, characterized in that alkali salts, alkaline earth metal salts, ammonium, aluminum and / or zinc salts of lignin sulphonic acid are used. Use according to claim 1 or 2, characterized in that the lignin sulfonates have an average molecular weight in the range of 500 to 200 000 daltons. Use according to claims 1 to 3, characterized in that amino phosphide salts are used as phosphonate salts of electrolytes. • Use according to claims 1 to 4, characterized in that homo- or copolymers of acrylic acid, methacrylic acid and their esters with lower linear or branched alcohols having 1 to 8 carbon atoms are used as polyacrylate salts of electrolytes. and Use according to claim 5, characterized in that the polyacrylates have an average molecular weight of from 300 to 5,000,000 daltons. Use according to claims 1 to 6, characterized in that sodium silicate, potassium silicate, sodium carbonate, potassium carbonate, sodium citrate, potassium citrate, magnesium citrate and mixtures thereof are used as the electrolyte salts. Use according to claims 1 to 7, characterized in that the lignin sulphonates and electrolyte salts are used in a weight ratio of 95: 5 to 5:95. Use according to claims 1 to 8, characterized in that the electrolyte mixtures are used in an amount of 0.01 to 5% by weight. based on an aqueous bleaching composition. Use according to Claims 1 to 9, characterized in that the electrolyte mixtures are used together with chlorine-stable surfactants selected from the group consisting of alkyl ether sulfates, amine oxides, alkyl and / or alkenyloligoglycosides and / or fatty acid salts. Use according to claims 1 to 10, characterized in that chlorine-stable fragrances are used together with the electrolyte mixtures.