Classifications

• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D3/00—Other compounding ingredients of detergent compositions covered in group C11D1/00
  • C11D3/39—Organic or inorganic per-compounds
  • C11D3/3902—Organic or inorganic per-compounds combined with specific additives
  • C11D3/3905—Bleach activators or bleach catalysts
  • C11D3/3932—Inorganic compounds or complexes

Definitions

• the present invention relates to peroxide activation and in particular to the activation of compositions containing hydrogen peroxide or persalts which generate hydrogen peroxide under the conditions of use.
• one class of bleaching agents comprises hydrogen peroxide and persalts that generate it in use conditions.
• Such bleaching agents are comparatively ineffective at stain removal from fabrics or hard surfaces at low washing temperatures, such as ambient to 60°C. Accordingly, and especially in the wake of increased energy prices, considerable efforts have been devoted to activating the bleaching agents at those temperatures.
• transition metals One class of activators which have received intermittent attention comprise transition metals. It has long been recognised that first row transition metals such as iron or copper catalyse peroxide decomposition, but harnessing the reaction between the two components to enhance low temperature stain removal has proven to be rather elusive.
• manganese One transition metal that appears to be capable of activating hydrogen peroxide or persalts is manganese. Passing reference is made to it in US-A-3156654, but the patent asserts that it must be used in conjunction with chelating agents which meet certain criteria of which most examples fall under the heading aminocarboxylic acids. When the process was tested using a representative aminocarboxylate and hydrogen peroxide under buffered alkaline conditions, the system with a catalytic amount of manganese sulphate bleached no better than hydrogen peroxide alone at the same conditions. Clearly US-A-3156654 represented mere speculation in so far as it referred to manganese.
• US-A-3532634 also described compositions containing a transition metal and a persalt, but they demonstrated activation only in the presence of a range of weakly chelating agents, different from those in US-A-3156654 when an organic persalt activator was present as well. Stronger chelating agents such as aminocarboxylic acids were specifically excluded. In a comparative example no activation was apparent when manganous sulphate and picolinic acid was employed with a heavy duty detergent composition to which sodium perborate had been added.
• EP-A-72166 describes a multi-component activator system for persalts including two metal catalysts and a range of sequestrants of which one major specified class comprises amino(poly)carboxylates. It will be recognised that these sequestrants are the same as those referred to in US-A-3156654 and those specifically excluded from US-A-3532634. Consequently this specificatior provides no direct teaching upon the provision of a single metal catalyst system, when similar comments apply as for the repeat test described in the passage relating to US-A-3156654.
• a process for activating hydrogen peroxide in which hydrogen peroxide or a persalt that generates hydrogen peroxide is brought into contact with a catalytic amount of a manganous salt in the presence of a substantial excess of an organic complexing builder selected from alkali metal citrates and citric acid.
• the manganese used in the present invention can be derived from any manganese (II) salt, such as manganous sulphate and manganous chloride, or from any manganese compound or substrate which delivers manganese (II) ions in aqueous solution.
• the substrate can comprise an absorbent particulate or non particulate substrate which previously has absorbed a manganous salt.
• Non particulate substrates include fibres, foams, sponges and films often made from certain cellulose ethers, alginates, polyvinyl alcohols or polyvinyl pyrrolidene polymers.
• Particulate substrates include clays, including bentonites, and any of the general classes of zeolites that hitherto have been proposed for incorporation in washing compositions, in for example FR-A-2225568, DE-A-2422655 or BE-A-849382, which include manganous exchanged zeolites A, X and Y.
• the effect of increasing the concentration of soluble manganese salt in the washing solution first results in enhanced activation of hydrogen peroxide and further increase then results in a progressive reduction in the enhancement, possibly even in impairment of stain bleaching performance.
• the amount of manganous salt to employ represents a balance between enhanced activation of hydrogen peroxide and the deleterious effect possibly resulting from an increased propensity to deposit an insoluble salt upon the surface being bleached.
• Use of amounts of available manganese above the upper specified amount tend towards impaired bleaching. In practice, it is often convenient to select the available manganous concentration within the range of 1 to 5 mg/l.
• the concentration of the citrate/citric acid is desirably at least 10 times that of the manganous ion, and in particular at least 100 mg/l. It is convenient, often, to select the citrate/citric acid concentration in the range of 100 to 5000 mg/l since such a concentration range can readily be obtained by dissolution of citrate/citric acid built washing composition in the washing/bleaching bath at recommended dosages.
• the washing/bleaching bath also contains hydrogen peroxide at a concentration sufficient to provide normally at least 5 and preferably at least 20 mg/1 available oxygen (avox) in solution.
• avox is frequently selected in the range of 35 to 200 mg/l avox, for combined stain removal and disinfection often from 200 to 500 mg/l avox and for textile bleaching often from 1000 to 10,000 mg/l avox.
• the hydrogen peroxide can be added as such or introduced as any persalt including alkali metal perborates, especially sodium perborate tetrahydrate, trihydrate or monohydrate, urea peroxide, or as an adduct with sodium sulphate and sodium or potassium chloride.
• the presence of carbonate can be tolerated within the system according to the invention and thus sodium percarbonate may be employed.
• alkaline conditions particularly from about pH 8 to about pH 10.5, and for textile bleaching especially from about pH 10 to about pH 12-13.
• This can be achieved either by introduction of an alkali such as sodium hydroxide under automatic or manual control as is feasible within commercial laundry or industrial textile bleaching operations, or more conveniently in domestic washing/bleaching operations by the presence of an alkaline buffer or buffer combination.
• an alkali such as sodium hydroxide
• citrate builder especially when added as trisodium citrate
• a particulate activator composition comprising at least 0.5 and preferably 1-5 parts by weight of a manganous salt, calculated on the basis of the weight of the manganous ion part thereof, and from 100 to 5000, preferably 250 to 2000 parts by weight of the citric acid/alkali metal citrate complexing builder.
• a formulation can be provided as such or be aggregated to form tablets, granulates, pills or the like thereby permitting the unitary dosing of precalculated quantity of each component to a hydrogen peroxide solution.
• the aforementioned activator composition from 200 to 4000, preferably 500 to 2000 parts by weight of a persalt, thereby forming a bleach composition that can be employed by itself or as an adjuvant with a surfactant composition, particularly an unbuilt composition or alternatively as a component in a surfactant washing composition.
• washing compositions comprise a bleaching composition as outlined hereinabove in a weight amount of at least 5% and generally from 10 to 60%, especially 15 to 50% of the composition, a surfactant, in a weight amount of at least 2% to 70% and generally 5 to 50%, processing acids in a weight of 0 to 40%, and other detergent adjuvants in a total amount of 0 to 20%.
• the surfactants that can be employed in the present invention include anionic, nonionic, zwitterionic or cationic surfactants or mixtures thereof, which are suitable for incorporation in persalt-containing washing compositions. In practice they are selected to exhibit water solubility.
• the anionic surfactants are normally alkali metal or ammonium salts, especially sodium, though a proportion of alkaline earth metal salts can be tolerated.
• One or more anionic surfactants are often selected from linear alkyl benzene sulphonates, especially having C 9 -C 15 in the alkyl chain, alkyl sulphates, particularly C 10 -C 22 , olefin sulphonates, particularly C 10 -C 24 , alkane and/or hydroxyalkane sulphonates, often C 10 -C 24 , alkyl phenoxy ether sulphates, often with C 8 -C 12 alkyl chain and 1-10 ethylene oxide units, alkyl ether sulphates often with C 10 -C 20 alkyl chain and 1-10, preferably 2-4 ethylene oxide units and soaps, particularly C 12 -C 20 .
• anionic surfactants often provide at least part of the total added including sulphocarboxylates, alkyl glyceryl ether sulphonates, monoglyceride sulphates and sulphonates, and phosphated ethylene oxide-based nonionic surfactants.
• the nonionic surfactants for incorporation in invention washing compositions generally comprise condensation products of ethylene oxide and propylene oxide, typically 5-30 units, with an aliphatic or aromatic alcohol or an aliphatic acid amine or amide.
• the hydropholic aliphatic moiety often has a chain length of C 8 -C 22 ; and is C 6 -C 12 when present in an alkyl aromatic group.
• Other usable nonionic surfactants are condensates of glycerol and sorbitol.
• Semipolar surfactants are useable herein and include water-soluble amine oxides, phosphine oxides and sulphur oxides, each containing a C 10 -C 22 alkyl chain and often 2 C 1 -C 3 alkyl chains.
• Zwitterionic surfactants herein are often selected from water-soluble derivatives of aliphatic quternary ammonium, phosphonium and sulphonium cationic compounds in which the aliphatic moieties are straight or branched, and in which one substituent is Ca-C18 and one terminates in an anionic water-solubilizing group, especially a sulphonate group for example alkyl-hydroxy-propane-sulphonates and alkyl-dimethyl-ammonio-hydroxy- propane-sulphonates.
• the cationic surface active agents when employed are often selected from quaternary ammonium compounds having one or two C 8 -C 20 straight or branched hydrophobic groups, e.g. cetyl trimethyl ammonium bromide or chloride, dioctadecyl dimethyl ammonium chloride, and the fatty alkyl amines.
• washing compositions and processes of the present invention tolerate the presence of auxiliary builders selected from both water soluble or insoluble particulate builders.
• Such builders can include alkali metal polyphosphates, pyrophosphates, polymetaphosphates and alkali metal silicates as well as zeolites obeying the general formula (M 2 0) x .(AI 2 0 3 ).(Si0 3 )y in which M is a monovalent metal especially sodium, x is 0.7 to 1.5 and y is 1.3 to 4.0, including zeolites A and X and mixtures thereof.
• Auxiliary organic builders include nitrilotracetic acid, sodium salt and related amino carboxylic acid salts. The amount of auxiliary builder present depends upon the extent to which the user is willing to tolerate impaired performance in bleachable stains.
• auxiliary builder As a guide it is preferable for the weight of auxiliary builder to be less than the weight of citrate, lest some benefit is still retained even when the proportion of citrate falls to as low as 20% of the total builder weight. In practice this means that it is normally selected in the range of 0-30%, and often represents 5-20% of the total formulation. Indeed, in view of the quality of citrate as builder in its own right, the addition of such auxiliary builders is not necessary, and their inclusion may be primarily at low levels of e.g. up to 5-10% for other functions such as pH control etc, rather than for the normal function of overcoming hardness.
• the processing aid when present, is usually selected from sodium and/or magnesium sulphate.
• the detergent auxiliary agents present are normally selected from soil antiredeposition agents, dye transfer inhibitors, optical brightening agents, peroxy stabilisers, corrosion inhibitors, bactericides, foam enhancers, foam inhibitors, thickeners, absorbents, abrasives, diluents, dyes, perfumes and proteolytic enzymes.
• auxiliary agents carboxymethyl cellulose salts and polyvinylpyrrolidines
• SARDs the various aminocarboxylates, aminomethylenephosphonates, hydroxy quinolines and dipicolinic acid as peroxy stabilisers and/or dye transfer inhibitors, silicates for corrosion inhibition, quaternary ammonium or pyridinium halides as bactericides, alkanolamides and ethylene oxide/propylene oxide copolymers to regulate foaming.
• Derivatives of diaminostilbene sulphonic acid, diarylpyrazolines and aminocoumarins are examples of OBA's
• anhydrous sodium or magnesium sulphate are examples of absorbents and diluents
• silica or maleic modified cellulose polyethylene oxide, e.g. above MW of 10,000
• silica or kieselguhr as abrasives.
• compositions according to the present invention are particularly well suited to a process at which washing or bleaching is carried out by steeping at ambient or by heating the solution to a temperature from about 25° to 60°.
• the washing and bleaching processes may be effected by heating up a cold washing solution.
• a combination of processes can be used, such as cold steeping followed by a wash at 30, 40 or 50 o C.
• the rate of removal of stains is enhanced by employing a higher temperature and by higher Avox. concentrations, but by virtue of the rate at which the invention washing compositions dissolve or are dispersed in the wash solution, the contact period between solution and fabric can conveniently be as short as 5 minutes. Longer periods of for example typically 10 to 30 minutes and up to 1 hour tend to provide greater soil removal. In cold washing or steeping even longer periods can be employed, such as steeping overnight.
• the stain removal gain shown is the difference attributable to adding the builder manganese to the bleach solution.
• the activaator composition corresponding to the process in Example 1 comprise 8 parts by weight manganese sulphate tetrahydrate per 1000 parts by weight of trisodium citrate.
• Example 1 The washing procedure and testing of Example 1 was repeated except that the washing solutions were allowed to attain their natural pH and the peroxide in solution was provided by sodium perborate tetrahydrate added at 1.15 g/1 and in Example 7 and Comparison 10, 4 times the weight of manganous salt was added.
• the bleach composition corresponding to the Example 6 or 7 processes comprises 8 respectfully or 32 parts by weight manganese sulphate tetrahydrate, 1000 parts by weight trisodium citrate and 1150 parts by weight sodium perborate tetrahydrate.
• Example 6 and Comparison 8 washing solutions according to Example 6 and Comparison 8 were made, but employing additionally a phosphate-free detergent composition called US Tide (Trademark) at a concentration of 6 g/1 having a composition analysed as approximately
• Example 11 there was a stain removal of 49% whereas in Comparison 12 the stain removal was only 41%. This indicates that it is beneficial to employ a manganous salt in the presence of trisodium citrate and sodium perborate in the presence of a substantial concentration of a detergent composition, which provides auxiliary builders and surfactants.

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Cited By (7)

Citations (3)

• 1984
  • 1984-02-28 GB GB848405189A patent/GB8405189D0/en active Pending
• 1985
  • 1985-02-19 EP EP85301075A patent/EP0157483A1/de not_active Withdrawn
  • 1985-02-20 ZA ZA851282A patent/ZA851282B/xx unknown
  • 1985-02-26 AU AU39154/85A patent/AU3915485A/en not_active Abandoned
  • 1985-02-26 JP JP60037348A patent/JPS60210698A/ja active Pending
  • 1985-02-27 ES ES540757A patent/ES8705516A1/es not_active Expired
  • 1985-02-27 BR BR8500864A patent/BR8500864A/pt unknown
  • 1985-02-28 PT PT80029A patent/PT80029B/pt unknown

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