GB1573143A - Process for activation peroxide-based bleaches and bleaching/washing compositions - Google Patents

Description

(54) PROCESS FOR ACTIVATING PEROXIDE-BASED BLEACHES AND BLEACHING/WASHING COMPOSITIONS (71) We, SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ B.V., a company organised under the laws of The Netherlands, of 30 Carel van Bylandtlaan, The Hague, The Netherlands, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to an improved process for activating peroxide-based bleaches and to bleaching/washing compositions.The specification of our co-pending Patent Application No. 24655/79 Serial No. 1573144, which has been divided out of the present application relates to stable bleaching compositions which alone or in combination with other ingredients can be added to aqueous media to form activated peroxide-based bleach media which can be used to effect the bleaching of fibrous materials and other bleachable substances over a wide range of temperatures.

Peroxide-based bleaches, such as hydrogen peroxide and perborates, are well known in the art and have been used for a number of years for bleaching textiles, and more recently, in home laundering applications for the bleaching of fabrics which cannot safely be bleached with chlorine-based bleaches because of problems with fibre and colour damage. However, for home laundering use such bleaching agents generally have the disadvantage, as compared to chlorine-based bleaches, that their bleaching effectiveness falls off rapidly as the temperature decreases. For example, peroxide-based bleaches are relatively ineffective at 15-720C, which are typical temperatures for home laundering in certain countries, e.g., the United States.

Considerable effort has been devoted over the years to improve the effectiveness of peroxide-based bleaches at lower temperatures. One approach involves catalytic activation with the use of transition metals which decompose hydrogen peroxide to more reactive moieties which accelerate bleaching at lower temperatures. These activators generally must be used in the presence of compounds having suitable sequestering properties to prevent useless decomposition of the hydrogen peroxide. U.S. 2,975,139 and U.S. 3,156,654 are representative of this approach. However, despite its technical feasibility, catalytic activation has not found lasting commercial application because of the difficulty in controlling the activation phenomenon under practical conditions, and interference by other chemical substances commonly found in bleach/detergent compositions.

A different approach to activation involves the use of "organic activators" which react with hydrogen peroxide to form peracids, which are relatively strong bleaching agents. A great number of these so-called "organic activators" are described in the prior art and generally comprise compounds having one or more acyl groups. U.S. 2,898,181, for example, discloses certain carboxylic acid amides as activators for perborate bleaching agents. U.S. 3,163,606 discloses a variety of diacylated nitrogen containing compounds as activators for active oxygen releasing bleaches. Among the compounds specifically disclosed in this patent are N, N-diacetylcyanamide and the N-diacyldicyanodiamides. U.S. 3,583,924 discloses a four component cleaning composition including a mineral persalt, an organic activator therefore, a water-soluble cupric salt and a copper complexing agent.N, N-diacetylcyanamide and the N-diacyldicyanodiamides are also among the activators for the persalts specifically disclosed in this patent. U.S. 2,927,840 also discloses that certain organic nitriles are likewise activators for peroxidic compounds. The patent teaches that the best results are obtained with organic nitriles containing a plurality of nitrile groups which are not separated too far from each other.

U.S. 3,756,774 also discloses that organic nitriles will react with hydrogen peroxide under acidic conditions to form stable peroxy carboximides which can be employed in the bleaching of cellulosic textile materials in place of alkaline hydrogen peroxide solutions stabilized with sodium silicate. Among the various organic nitriles disclosed as being suitable for this purpose are cyanamide and dicyanodiamide. Other patents directed to methods of stabilizing hydrogen peroxide bleach baths without the use of sodium silicate include U.S. 2,820,690 and U.S. 3,437,599. The former patent discloses the use of magnesium and calcium orthophosphate salts as stabilizers in place of sodium silicate, while the latter patent discloses the use of alkaline earth metal carbonates for this purpose.

Despite the extensive efforts devoted by those skilled in the art to finding suitable activators for peroxide-based bleaches, there is little practical application of this technology.

There are a number of reasons for this. One is that organic activators generally must be used in equimolar proportions with the active oxygen releasing component of the bleach package. Since most organic activators are relatively expensive, this results in the activator contributing significantly to the cost of the bleach formulation, and in many cases makes the product prohibitively expensive relative to competitive hypochlorite bleaches. Also, many prior art organic activators are relatively toxic or have unpleasant odours which render them unsuitable for use in applications such as home laundering.

A further drawback of many known organic activators is that they are unstable in storage and, hence, are not suitable for use in commercial bleach products which are stored over extended periods of time in warehouses or on the supermarket shelf before consumer use.

The present invention provides a bleach activation process and related compositions based on an activator which when employed under alkaline conditions not only provides substantially improved bleaching action at relatively low temperatures, but, in addition, is inexpensive and does not suffer from the drawbacks of most of the prior art organic activators, or at least to a substantially lesser degree.

It has now been found, and forms the basis of the present invention, that cyanamide (H2NCN) and/or metal cyanamides when employed under alkaline conditions are extremely effective activators for peroxide-based bleaches over a wide range of temperatures, including low temperatures, such as those encountered in home laundering.

It has also been found that the unique effectiveness of cyanamide and metal cyanamides as activators for peroxide-based bleaches can be further enhanced by the use of Group IIA metals in combination with the cyanamide-activated bleach composition. In addition, it has also been found that still greater levels of bleaching can be attained, if in addition to the Group IIA metal, certain compounds commonly employed as detergent builders, are also present in the alkaline aqueous bleaching/washing medium.

Accordingly, the present invention is concerned with a process for activating a peroxidebased bleach which comprises conjointly incorporating into an aqueous medium a(a) a peroxide-based bleach, (b) cyanamide and/or a metal cyanamide, and optionally (c) a Group IIA metal compound, and wherein the aqueous medium is maintained under alkaline conditions, optionally by the incorporation of a buffering agent therein, with the proviso that if component (b) is cyanamide and component (c) is absent then the aqueous medium is maintained at a pH of above 7.5.

In a preferred embodiment of the invention detergent builders such as alkali metal phosphates, e.g., sodium tripolyphosphate (STPP) and trisodium phosphate (TSP), and alkali metal carbonates and silicates are additionally incorporated into the aqueous medium.

The peroxide-based bleach, cyanamide or metal cyanamide activator and, optionally, Group IIA metal compound may be added separately to an aqueous medium, with sufficient buffering agent, if necessary, to maintain the aqueous medium under alkaline conditions. If a metal cyanamide is used, or cyanamide is used together with a Group IIA metal compound (component C), an activated peroxide-based bleach can be formed by adding to an aqueous medium a composition comprising less than 2.5 % by weight, calculated as hydrogen peroxide, of peroxide-based bleach, together with component (b) and optionally component (c) as appropriate.

In addition to discovering the effectiveness of cyanamide under alkaline conditions as a peroxide bleach activator over a relatively broad range of concentrations, it has been further found that when cyanamide and the bleach component are present in certain specific proportions, an unexpected improvement in formulation stability results even at relatively high temperatures. If still further stability is desired, various stabilizers can be incorporated into the compositions of the invention, such as stannates, pyrophosphates, ethylenediamine tetra-acetic acid and its salts and higher homologues, citric acid, acetic acid, gluconic acid and sodium tripolyphosphate.

It has also been found that not only do cyanamide and metal cyanamides under alkaline conditions enhance the bleaching effectiveness of peroxide-based bleaches, but in addition cyanamide-activated peroxide based bleaches appear to substantially improve the detergency of many conventional detergents, which makes the present compositions particularly attractive for use in laundry applications.

"Cyanamide-activated bleach or bleach composition" as used in this specification is intended to include either solid or liquid peroxide-based bleach compositions containing either cyanamide or metal cyanamides as an activator therefor.

A preferred process for activating a peroxide-based bleach comprises conjointly incorporating into an aqueous medium effective amounts of (a) a peroxide-based bleach, (b) cyanamide and (c) a buffering agent to maintain the pH of the aqueous medium above 7.5.

Another preferred process for activating a peroxide-based bleach comprises conjointly incorporating into an aqueous medium effective amounts of (a) a peroxide-based bleach, (b) a metal cyanamide and (c) a buffering agent to maintain the aqueous medium under alkaline conditions.

A further preferred process for activating a peroxide-based bleach comprises conjointly incorporating into an aqueous medium effective amounts of (a) a peroxide-based bleach, (b) cyanamide or metal cyanamide, (c) a Group IIA metal compound and (d) a buffering agent to maintain the aqueous medium under alkaline conditions.

By "peroxide-based bleaches" as this term is used in this specification and claims, is meant hydrogen peroxide and any compound which releases hydrogen peroxide in aqueous solution. Such compounds include, for example, perborates, percarbonates, urea peroxides and ketone peroxides. Peroxy compounds of this type and their manner of preparation are well known in the art, and are described, for example, in Kirk-Othmer, Encyclopedia of Chemical Technology, 2nd ed., Vol. 14, pp. 757-760. Of the various peroxide-based bleaches which can be suitably employed in accordance with the invention, hydrogen peroxide, perborates and percarbonates are preferred. Particularly preferred among the perborates are the sodium perborates, especially sodium perborate tetrahydrate (NaBO3,4H20) because of its commercial availability.However, sodium perborate trihydrate (NaBO3.3H20) and sodium perborate monohydrate (NaBO3.H20) can also be suitably employed. The peroxide-based bleach may be added to the aqueous medium as a separate component or as a component of a concentrated bleach composition.

Fundamental to this invention is the discovery that cyanamide and certain relatively inexpensive metal cyanamides when employed under alkaline conditions are surprisingly effective activators for peroxide-based bleaches.

Metal cyanamides which can be suitably employed in the activated bleach compositions of the invention include any metal cyanamide which is at least partially water-soluble or water-dispersible to provide reactive sites. Preferred metal cyanamides include Groups IA and IIA metal salts of cyanamide, in particular calcium cyanamide (CaNCN), disodium cyanamide (Na2NCN) and sodium acid cyanamide (NaHNCN). Dipotassium c anamide (K2NCN), potassium acid cyanamide (KHNCN), dilithium cyanamide (Li2NCN , lithium acid cyanamide (LiHNCN), magnesium cyanamide (MgNCN), barium cyanamide (BaNCN) and strontium cyanamide (SrNCN) can also be employed. Disodium cyanamide and sodium acid cyanamide are especially preferred because of their availability and in cases where rapid solubility in an aqueous medium is desired.

The aforementioned metal cyanamides and their manner of preparation are known in the art, and are described for example in Kirk-Othmer, Encyclopedia of Chemical Technology, 2nd ed., Vol. 6, pp. 553-559. Calcium cyanamide can be employed in the present compositions in its crude form, which contains about 65 per cent by weight (vow) calcium cyanamide, but preferably is employed in its purified form.

The cyanamide or metal cyanamide may be added to the aqueous medium as a separate component or as a component of a concentrated bleach composition other than a bleaching composition as described and claimed in our co-pending Application No. 24655/79 Serial No. 1573144. The form of cyanamide for introduction into the bleach system is not critical, and such introduction can be accomplished by employing cyanamide as such in solid or aqueous solution form, or by the use of a cyanamide-releasing compound.

Insofar as the proportions of the cyanamide or metal cyanamide to the peroxide-based bleach are concerned, all that is required for purposes of the present invention is that sufficient cyanamide or metal cyanamide be present to activate the peroxide-based bleach upon addition to an aqueous bleaching/washing medium under alkaline conditions. Gener ally, the molar ratio of cyanamide or metal cyanamide to the peroxide-based bleach will be on the order of from 1:20 to 20:1, with preferred ratios being from about 1:1 to about 1:10.

It has also been found that Group IIA metals, such as magnesium, calcium, barium and strontium, when employed in a cyanamide-activated peroxide-based bleach system, boost the bleaching activity of the system to a substantial degree. Similar results are not attained when Group IIA metal salts are employed in conjunction with many known peroxide bleach activators and other metal salts such as Group IA metal salts appeaar to have no appreciable effect on the bleaching activity of the cyanamide-activated system. In the case of transition metals and many other variable valence metals, significantly diminished bleaching performance is observed.

The group IIA metals are normally incorporated into the cyanamide activated peroxidebased system as metal oxides or metal salts, although any compounds which generate such metal ions can be employed. A wide range of metal salts can be suitably employed to introduce the Group IIA metal into the bleach system including metal hydroxides, chlorides, sulphates, nitrates, citrates and the like. Group IIA metal salts of ethylenediamine tetraacetic acid and its homologues are also very suitable. Because of its commercial availability, magnesium sulphate is an especially preferred Group IIA metal salt.

The Group IIA metal can be incorporated into the cyanamide-activated peroxide bleach system as part of the concentrated bleach formulation (either liquid or solid), or it may be added as a separate component to the aqueous bleaching/washing medium. Alternatively, the Group IIA metal can be provided by means of the metal cyanamide activator, which is a metal salt (e.g., calcium cyanamide, generates calcium ions upon dissolution in an aqueous medium, and thus can serve as both the activator and source of the Group IIA metal).

The concentration of Group IIA metals can vary over a relatively broad range. However, in general, the molar ratio of Group IIA metal to the peroxide-based bleach will range from about 1:60 to about 25:1. Preferred Group IIA metal to peroxide-based bleach molar ratios are from about 1:1 to about 1:10.

Neither the mechanism by which cyanamide or metal cyanamides effect activation of peroxide-based bleaches nor the mechanism by which Group IIA metals act to boost the bleaching effectiveness of cyanamide-activated peroxide-based bleaches is known; moreover, is it not known why the addition of certain detergent builders serves to further increase bleaching effectiveness of the overall system. It is known, however, that in order to obtain enhanced bleaching activity and satisfactory activation, it is generally necessary that the pH of the aqueous medium in which the bleaching or washing is accomplished (e.g., a washing machine in the case of home laundering) be maintained under alkaline conditions, e.g., at a pH of at least 7.5, preferably from 7.5 to about 13, or higher. Preferably, the pH of the washing/bleaching medium will be from about 8.0 to 8.5 to about 11.5.

The aqueous medium may be maintained under alkaline conditions by any suitable means such as by incorporating therein an alkali and/or alkaline buffering agent. However, the addition of a separate buffering agent is not essential since certain peroxides, e.g. perborates and percarbonates, metal cyanamides and Group IIA metal compounds, if present, contribute to the alkalinity of the aqueous bleaching medium. This is an advantage of using metal cyanamides, as compared to cyanamide per se, since many metal cyanamides in the aqueous bleaching/washing medium produce hydroxyl groups. Hence, normally lesser amounts or no additional alkaline buffering agents are required in bleach compositions containing metal cyanamides and the aforementioned peroxide-based bleaches.If additional alkaline buffering agents are employed, they can be conveniently incorporated into dry bleach formulations or added to the aqueous bleaching/washing medium. Suitable alkaline buffering agents of this type include carbonates, phosphates, silicates, citrates, polycarboxylates and borates. A convenient means of accomplishing buffering in the case of laundering compositions is by the use of detergents which commonly contain alkaline buffering agents.

Stable bleaching compositions prepared in either liquid or solid form are described and claimed in the aforesaid divisional Application No. 24655/79 (Serial No. 1573144). In this connection the cyanamide or metal cyanamide and peroxide bleach components can be suitably incorporated into a substantially non-aqueous liquid organic carrier material, or prepared as an aqueous solution, e.g., an aqueous hydrogen peroxide solution. However, in this latter case, the pH of the aqueous liquid formulation should be maintained at a relatively low pH of from about 2 to 5, more preferably at a pH of about 4) until the product is ready for use to prevent premature reaction and/or decomposition of the cyanamide and peroxide components (e.g., cyanamide undergoes various addition reactions under alkaline conditions, sometimes accompanied by a further increase in pH. Hydrogen peroxide may decompose by either free radical or ionic reactions, which in general proceed more rapidly at higher pH values). In this manner a stable, i.e., inactive or non-reactive bleach composition is provided, which can be readily activated upon use by adjusting the pH level to the alkaline conditions required for effective activation of the peroxide-based bleach. Such pH adjust ment can be conveniently accomplished by the use of an alkaline buffering agent and/or detergent which commonly contain alkaline buffering agents. Particularly preferred stable aqueous bleaching compositions comprise hydrogen peroxide and cyanamide.

In addition to maintaining the pH at low levels during storage, e.g., at a pH' of about 4, a further means of enhancing the stability of the preferred liquid hydrogen peroxide/cyanamide bleach compositions is based on the discovery that the stability of such compositions especially at high temperatures is beneficially affected by the use of less than stoichiometric proportions of cyanamide to peroxide bleach in the composition. Specifically, it has been found that substantially improved stability is obtained if the molar ratio of cyanamide to hydrogen peroxide in the bleach composition is from 1:2 to about 1:10, preferably from about 1:2 to 1:4.

It is to be understood that while the afore-mentioned molar ratios are beneficial from a standpoint of storage stability, especially at higher temperatures, a broader range of ratios can be employed when high temperature stability is not a factor, or when other means of stabilizing the composition are employed, or if the hydrogen peroxide and cyanamide are added to the bleaching/washing medium as separate ingredients and, in accordance with the present invention, compositions are formed in situ in the bleaching/washing medium. Hence, to practise the present invention all that is required is that an activating amount of cyanamide be present in the aqueous bleaching/washing medium containing a peroxide-based bleach and buffered to the appropriate pH.

Stable solid bleach compositions as described and claimed in Application No. 24655/79 (Serial No. 1573144) can be prepared from cyanamide or metal cyanamides, e.g. sodium cyanamide or sodium acid cyanamide, and a solid peroxide-based bleach (e.g., sodium perborate or percarbonate), optionally a Group IIA metal salt (e.g., MgSO4) or suitable, alkaline buffering agents, fillers and/or desiccants, without the need for pH adjustment to below 5 level required for stable liquid bleach compositions. To ensure the stability of the solid-based bleach compositions, all that is required is that the compositions be maintained free from contaminating amounts of moisture. This can be conveniently accomplished by use of desiccants, if desired, and/or by encapsulating the cyanamide or metal cyanamide activator and/or the solid peroxide-based bleach as hereinafter discussed.To convert the stable solid bleach compositions to their reactive state, all that is required is that they be added to the aqueous bleaching/washing medium which is then maintained under alkaline conditions. Since solid peroxide-based bleaches, such as sodium perborate and percarbonate, are typically alkaline-forming substances, the necessary alkaline conditions in the aqueous bleaching/washing medium can normally be obtained without further alkaline buffering agent addition, especially if metal cyanamides, which are also alkaline-forming substances, are also present. However, additional alkaline buffering agents can be (and usually are) employed if higher pH levels are desired.

From the foregoing it can be seen that the term "stable" as employed in connection with the solid and liquid bleach compositions as described and claimed in the specification of" Patent Application No. 24655/79 (Serial No. 1573144) means the compositions are in an essentially inactive or non-reactive state (thereby facilitating their storage and handling), but can be readily converted to a reactive state at their time of use. In the case of liquid bleach compositions this is accomplished by pH adjustment from the below 5 level in storage, to an about 7.5 level in the aqueous bleaching/washing medium, while in the case of solid bleach compositions all that will normally be required is that the cyanamide-activated peroxidebased bleach be added to an aqueous bleaching/washing medium.

A method of practising the present invention with regard to bleach compositions is to package the peroxide-based bleach and cyanamide or metal cyanamide (in solid or liquid form) in separate containers, optionally together with alkaline buffering agents as required to achieve the desired pH level, and add them to the aqueous bleaching/washing medium just prior to use, thereby forming the activated bleaching composition in situ. Even if packaged separately it is generally desirable that the pH of aqueous solutions of hydrogen peroxide and cyanamide or metal cyanamide be kept at low pH values previously mentioned, in order to avoid decomposition thereof. The stability of cyanamide can be enhanced, if desired, by the addition of trace amounts of phosphoric, acetic, sulphuric or boric acid or salts thereof.

Preferably, in accordance with the present invention, especially from a storage stability standpoint, cyanamide, disodium cyanamide or sodium acid cyanamide is used as component (b), with sodium perborate monohydrate as the peroxide-based bleach component (a). The advantage of utilizing the monohydrate form of sodium perborate is that any moisture absorbed during storage will first act to convert the sodium perborate monohydrate to its higher hydrate forms (e.g., sodium perborate tetrahydrate), thereby making the bleach component more stable to moisture contamination.

Disodium cyanamide also can serve to minimize the adverse effects of moisture, in that in the presence of moisture it merely converts to sodium acid cyanamide. By having to go through this intermediate step to make cyanamide, the use of disodium cyanamide increases the "shelf-life" of component (b).

The amount of peroxide-based bleach employed will vary widely depending on the material to be bleach the extent of bleaching desired, and the bleaching conditions. In cases where the peroxide-based bleach and cyanamide activator are incorporated into a conventional detergent composition prior to the addition thereof to an aqueous medium, lower concentrations of peroxide-based bleach (e.g., from 0.1 to 2Sow, calculated as hydrogen peroxide) can be employed. However, in this case generally lower levels of bleaching will be obtained than if the aforementioned concentrated metal cyanamide-activated peroxidebased bleach compositions were employed.

The cyanamide-activated bleaching compositions of the present invention can be emp loyed to bleach any of a wide variety of bleachable substances including textiles, wood and wood products, surfactants, leather, hair and any other substance commonly bleached with peroxide-based bleaches. The present cyanamide-activated peroxide-based bleach compositions are especially suitable for use in home and commercial laundering applications, in which unactivated peroxide-based bleaches are largely ineffectual because of the relatively short wash cycles and lower temperatures involved. The compositions of the invention are effective in bleaching stains from a wide variety of fabrics, including those manufactured from natural as well as synthetic fibres.They are particularly effective for washing cotton goods and goods produced from synthetic fibres, and are advantageous over chlorine-based bleaches in that they will not cause yellowing of fabrics even after repeated washings. In addition, the compositions of the present invention would be expected to cause considerably less loss in strength of fibres than do chlorine-based bleaches, and are also safer to use on coloured materials. The present compositions can be safely employed in their concentrated or dilute forms, and may be used for pre-soaking as well as during washing.

To effect bleaching, the components (a) and (b), and optionally (c), are generally added to an aqueous medium in an amount that will result in 2 to 600 millimoles/litre (mmoles/l) of the peroxide-based bleach, calculated as hydrogen peroxide, being present in the aqueous medium. The precise peroxide-based bleach concentration selected will vary depending on the nature of the substance being bleached and the degree of bleaching desired.

For home and commercial laundry applications, the concentration of peroxide-based bleach, calculated as hydrogen peroxide, in the wash water will be about 2 to 12 mmoles/l. As would be apparent to those skilled in the art, the foregoing concentrations could be varied if greater or lesser bleaching is desired.

The present invention is also concerned with a method of bleaching a bleachable substance comprising contacting the bleachable substance with an alkaline bleaching bath as described above.

A preferred method comprises contacting the bleachable substance with an aqueous medium containing from about 2 to about 600 millimoles/litre of hydrogen peroxide, cyanamide and a buffering agent to maintain the pH of the aqueous medium within the range of 7.5 to about 13.

Another preferred method comprises contacting the bleachable substance with an aqueous medium containing from about 2 to about 600 millimoles/litre of a peroxide-based bleach, calculated as hydrogen peroxide, a metal cyanamide and a buffering agent to maintain the pH of the aqueous medium within the range of 7.5 to about 13.

A further preferred method comprises contacting the bleachable substance with an aqueous medium containing (a) from 2 to about 600 millimoles/litre of a peroxide-based bleach, (b) cyanamide or a metal cyanamide, (c) a Group IIA metal compound, and (d) an alkaline buffering agent to maintain the aqueous medium under alkaline conditions, the molar ratio of the Group IIA metal compound to the peroxide-based bleach being from 1;60 to 25:1.

The present process and compositions can be employed over a relatively wide range of temperatures, e.g., from about 7"C up to the boiling point of water (100"C). However it can most advantageously be employed at temperatures of 15 to 72"C, which encompasses typical temperatures of home laundering, especially in the United States. As previously stated, a substantial improvement in bleaching effectiveness is obtained by use of the present invention as compared to the use of peroxide-based bleaches alone, or peroxide-based bleaches activated with many of the prior art activators.

In the case of home or commercial laundering, the components (a) and (b), and optionally (c), will normally be employed in conjunction with a soap or detergent, which may be provided in admixture with one of these components, or may be added separately to the wash liquor. In general, any commonly used soap may be employed for this purpose, for example, alkali metal salts of fatty acids, such as stearic and/or palmitic acids, or of rosin acids.

Synthetic detergents which can be used with or without such soaps include the anionic, cationic, zwitterionic, ampholytic, non-ionic and semi-polar organic surface-active agents.

Typical anionic detergents which can be employed in the practice of the present invention include various sulphates and sulphonates, such as alkyl aryl sulphonates, alkyl sulphonates, sulphates of fatty acid-monoglycerides, olefin sulphonates, sulphonated fatty acids and esters, alkyl glyceryl ether sulphonates, fatty isethionates, fatty acid oxyethylamide sulphates, oleylmethyltauride, and the like having aliphatic hydrocarbon chains of about 10 to about 20 carbon atoms, and alkyl sulphate, alkyl polyether sulphate and alkyl phenol polyether sulphate salts, such as sodium lauryl sulphate, sodium alkyl phenol polyether sulphates and mixed secondary alkyl sulphate alkali metal salts of 8 to 18 carbon atoms per molecule.Examples of non-ionic surface-active agents which can be used in the practice of the invention are the saponines, fatty alkanolamides, amine oxides and ethylene oxide condensation products with fatty acids, alcohols, polypropylene glycols, alkyl phenols, esters, and the like, especially those with alkyl chains of 8 to 20 carbon atoms and 3 to 20 glycol units per molecule. Examples of typically suitable cationic surface-active agents include those based on diamines, e.g., N-aminoethylstearyl amine and N-aminoethyl myristyl amine; amide-linked amines, e.g., N-aminoethyl-stearyl amide and N-aminoethyl-myristyl amide, quaternary ammonium compounds containing at least one long chain alkyl group attached to the nitrogen atom, e.g., ethyl-dimethyl-stearyl ammonium chloride and dimethyl-propylmyristyl ammonium chloride; and the like.

Any of the builders or other additives conventionally employed in bleach or detergent products can be used in the bleaching media of the invention. These include, for example, alkaline materials such as alkali metal hydroxides, phosphates (including orthophosphates, tripolyphosphates and pyrophosphates), carbonates, bicarbonates, citrates, polycarboxylates, borates and silicates, also alkanolamines and ammonia Inert compounds such as alkali metal sulphates or chlorides can also be employed.

It has been found that the presence of sodium tripolyphosphate (STPP) and trisodium phosphate (TSP) in the aqueous bleaching/washing medium further enhances the bleaching action of the metal cyanamide-activated peroxide-based bleach. Hence, in a preferred embodiment of the present invention, STPP or TSP (or a detergent containing either of these compounds) is added to the aqueous bleaching/washing medium in addition to the peroxide-based bleach and metal cyanamide activator.

It has also been found that one or more alkali metal phosphates, carbobates or silicates enhance the bleaching of an aqueous bleaching/washing medium containing Group II metal compounds.

Other additives which may optionally be incorporated in or used in conjunction with the instant compositions include fabric softeners, germicides, fungicides, enzymes, antiredeposition agents, flocculents, optical brighteners, colorants, perfumes, thickeners, stabilizers, suds-builders or suds-depressants, anti-corrosion agents and fluorescent agents.

The activated bleaching media of the invention may generally also be used for their germicidal properties in various applications, for example, as a disinfectant for use in the home, e.g., in kitchens, bathrooms, etc.; for institutional use, for water treatment and the treatment of swimming pools, etc.

The invention will now be further described with reference to the following Examples, of which Examples 5, 11, 15, and 21 are included for reference only, being examples illustrating compositions as described and claimed in the specification of Application No. 24655/79 (Serial No. 1573144).

EXAMPLE 1 The following experiments demonstrate the improved bleaching action obtainable, using cyanamide as the peroxide activator. The general procedure employed in these tests was as follows: Five hundred (500) ml of de-ionized water were added to a U.S. Testing, Inc. Terg-O Tometer bath maintained at the temperatures shown in Table 1 and the hardness level of the water adjusted to 150 ppm as CaCO3 (Ca/Mg = 3/2 on a molar basis). The pH of the water in the bath was adjusted to the values shown in Table I by the addition of Na2 CO3 or NaOH.

The peroxide-based bleach and/or cyanamide activator and detergent were then added to the wash water in the concentrations shown in Table I, and the water agitated to avoid localized concentrations of any one additive. Finally, eight swatches, measuring 4" x 4", of EMPA 115 cloth (a standard cotton bleach test cloth soiled with sulphur black dye) were introduced into the wash water and the agitator run for 10, 20, 30 or 60 minutes at 100 rpm.

At the conclusion of each wash period, two swatches were removed and rinsed by squeezing under a tap. The test cloths were then dried and the reflectance values measured on a Gardner Reflectometer, Model UX-2, utilizing a G-filter. The change that occurred as a result of the bleach/wash cycle was reported as the change in per cent reflectance value (AR), which equals the difference between the reflectance of the swatch after bleaching and the reflectance of the same swatch before bleaching. Thus, the larger the AR value, the more effective the bleaching action.

The compositions tested and the results obtained are presented in the following Table. TABLE I Cyan- Deter- pH #R Exp. Bleach, a) amide, gent, b) Temp., Wash cycle No. mmol./l mmol./l g/l Initial Final C 10 min. 20 min. 30 min. 60 min.

1 8 0 1.5 9.8 9.5 85 4.3 7.5 9.7 2 8 8 1.5 9.2 8.9 85 26.4 31.9 33.6 3 8 0 1.5 9.7 9.6 49 0.8 1.5 1.9 4 8 8 1.5 9.1 8.8 49 17.3 25.1 29.0 5 8 0.8 1.5 9.6 9.5 49 7.7 11.7 12.5 6 8 0.4 1.5 9.7 9.5 49 4.9 7.3 8.5 7 8 0 1.5 9.6 9.2 24 0.1 0.9 0.7 8 8 8 1.5 9.1 8.8 24 6.1 11.5 16.5 9 8 0 1.5 9.3 9.0 7 - - 0.8 0.5 10 8 8 1.5 8.9 8.8 7 - - 3.7 7.2 11 8 8 1.5 11.5 11.3 85 24.9 27.9 30.1 12 8 8 1.5 11.7 11.6 85 19.5 24.5 27.2 a) Hydrogen peroxide (introduced as a stabilized, commercial grade 50% aqueous solution).

b) Tide containing 6.1% phosphorus (Tide, 6.1% P). Tide is a powdered detergent manufactured by Procter & Gamble Company. Tide is a registered Trade Mark.

The following tests indicate that the compositions of the invention containing cyanamide and hydrogen peroxide in various proportions provide excellent bleaching action over a wide range of temperatures and concentrations.

EXAMPLE 2 In this example a series of experiments was conducted at 490C to further demonstrate the effect of concentration and pH on the bleaching effectiveness of the present compositions.

The test procedure employed was essentially the same as in Examplle I unless otherwise indicated. The compositions tested and the results obtained are summarized in Table II. TABLE II Cyan- Deter- pH #R Exp. Bleach, a) amide gent, b) Temp., Wash cycle No. mmol./l mmol./l Initial Final C 10 min. 20 min. 30 min.

13 16 0 1.5 9.8 9.5 49 1.1 1.6 2.3 14 0 16 1.5 9.8 9.7 49 0.5 0.8 0.9 15 8 8 1.5 9.3 8.8 49 18.1 26.0 30.3 16 8 80 1.5 9.8 9.8 49 13.3 14.7 15.8 17 8 160 1.5 9.6 9.7 49 11.4 12.5 13.5 18 8 8 - 2.9 2.8 49 0 0 0.2 19 8 8 - 7.0 7.2 49 0.3 1.4 3.8 20 8 8 - 11.4 11.5 49 21.1 27.7 30.4 21 8 8 - 12.6 12.6 49 4.0 8.6 11.7 a) Hydrogen peroxide (introduced as a stabilized, commercial grade 50% aqueous solution).

b) Tide, 6.1%P.

The foregoing data indicate that the combination of cyanamide with a peroxide-based bleach gives substantially greater bleaching action than the use of equivalent amounts of these components individually. The results also reflect that the bleaching effectiveness is pH-dependent, with little or no activation occurring under the test conditions at pH-values of 7 and below.

EXAMPLE 3 In this Example a series of experiments was conducted utilizing the test procedures outlined in Example 1, except as otherwise noted, to compare the bleaching effectiveness of several commercially available peroxide-based bleaches when used alone, to the same bleaches containing cyanamide as an activator. The commercial peroxide-based bleaches employed in these experiments are listed in Table III, while the results of the experiments are tabulated in Table IV.

TABLE III Product Type W2 2 c) Bleach A Liquid a) 5.9 Bleach B Liquid a) 3.2 Bleach C Solid b) 4.9 Bleach D Solid b) 8.0 Bleach E Solid b) 7.5 Bleach F Solid b) 4.9 a) Aqueous hydrogen peroxide.

b) Contains sodium perborate which dissolves in wash water to form hydrogen peroxide.

c) Determined by iodometric titration.

TABLE IV Exp. Product only Product plus cyanamide c) No. Product a) %H2O2 utilized b) #R %H2O2 utilized b) #R 22 Bleach A 0 3.1 95 17 23 Bleach B 0 3.2 90 17 24 Bleach C 0 3.5 89 14 25 Bleach D 0 4.1 91 8 26 Bleach E 0 2.5 94 11 27 Bleach F 0 2.4 83 11 a) Added to wash water at pH 9.6-10 to provide initial H2O2 concentration of 8.8 mmol./l Washing conditions other than those shown in Example 1: Detergent concentration 1.5 g/l Tide, 6.1% P, temperature of all runs 49 C, wash cycle 10 mins.

b) Determined by iodometric titration on 50-100 ml of wash liquor immediately (within one minute) after wash.

c) H2NCN concentration 8.8 mmol./l.

The foregoing test results indicate that while the commercial peroxide-based bleaches are virtually ineffective in bleaching the test cloth under the conditions shown, the addition of cyanamide as an activator substantially improves their performance and results in utilization of virtually all of the hydrogen peroxide.

EXAMPLE 4 A series of experiments was conducted to compare the bleaching effectiveness of the cyanamide activated peroxide-based bleach compositions of the present invention to peroxide-based bleaches activated with various organic nitrile activators disclosed in the prior art. The test procedure employed was essentially the same as that utilized in Example 3. The compositions tested and results obtained are presented in Table V.

TABLE V Activator H2O2 pH Exp.

Compound mmol./l mmol./l Added as Wash water #R No.

28 None - 8.8 50%H2O2 9.6 2.4 29 Dicyanodiamide 9.5 8.8 50% H202 9.6 1.7 30 Dicyanodiamide 17.6 17.6 50% H2O2 10.1 3.3 31 Acetonitrile 9.3 9.1 SPB-4a) 10.1 1.4 32 Malononitrile 9.1 9.1 SPB-4 9.2 1.2 33 Malononitrile 9.1 9.1 SPB-4 9.7 1.8 34 Benzonitrile 9.1 9.1 SPB-4 10.1 3.3 35 p-Nitrobenzonitrile 9.5 8.8 50% H202 9.7 7.2 36 Phthalonitrile 9.1 9.1 SPB-4 10.0 14.8@) 37 Phthalonitrile 9.1 9.1 50%H2O2 9.7 10.0b) 38 Cyanamide 9.1 9.1 SPB-4 9.6 20.1b) 39 Cyanamide 9.1 9.1 50% H202 9.7 19.4C) a) SPB-4 = sodium perborate tetrahydrate; b) Average of triplicate runs; c) Average of quadruplicate runs The foregoing results indicate that hydrogen peroxide alone does not provide appreciable bleaching at the test temperature (49 C).However, in combination with cyanamide, hydrogen peroxide added in the form of a stabilized, commercial grade of 50% aqueous solution, or as sodium perborate tetrahydrate, exhibits significant bleaching action, far superior to low molecular weight organic nitriles, such as acetonitrile and malononitrile, and significantly superior to higher molecular weight organic nitriles, such as p-nitrobenzonitrile and phthalonitrile.

EXAMPLE 5 A series of experiments was conducted to demonstrate the effect of concentration on high temperature stability of liquid cyanamide/peroxide-based bleach formulations. One of the compositions employed in these tests contained approximately stoichiometric amounts of cyanamide and hydrogen peroxide, while the remaining compositions contained reduced ratios of cyanamide to hydrogen peroxide as shown in Table VI.

The formulations utilized in this series of experiments were prepared from a stabilized, commercial grade 50% aqueous hydrogen peroxide and solid cyanamide, which were added to de-ionized water in the concentrations shown in the Table, and the pH adjusted to about 4 using dilute sulphuric acid.

The percentage of hydrogen peroxide, pH and the bleaching effectiveness of each of the formulations was determined upon preparation, and after 5 and 7 days' storage in a loosely capped bottle in an oven at 500 C. The hydrogen peroxide concentration was determined by iodometric titration.

The results of the tests were as follows: TABLE VI Stability at 50 C at Exp. Concentration (%w) Day 0 Day 5 Day 7 No.

H2O2 H2NCN %H2O2 pH #Ra) %H2O2 pH #Ra) %H2O2 pH #Ra) 40 6 7.7 6.1 4.0 14 0 8.1 1.5 - - 41 6 3.8 6.0 4.0 17 5.5 3.5 14 2.7 7.9 1.8 42 12 7.7 12.0 4.0 - 9.3 4.0 25 2.4 80 1.2 a) For each test 2.5g offormulation were added to the wash water. The same test procedure employed as in Example 3, except that 2.0 g/l of Tide, 6.1% P were added to the wash water to obtain the proper pH.

EXAMPLE 6 A series of experiments was conducted to determine the effect, if any, of commonly employed detergent builders on the bleaching action of the present cyanamide-activated peroxide-based bleach system. The test procedure employed was similar to that described in Example 1, except that de-ionized water with no added hardness or detergent was employed in the Terg-O-Tometer bath. In addition to the test runs with various detergent builders, a number of the experiments presented in Example 4 were repeated in the absence of added harness and detergent at various pH-levels. The compositions tested and the results obtained are shown in the following Table. The temperature of the Terg-O-Tometer bath in all of these tests was 49"C.

TABLE VII Exp. #R No. Activator H2O2 Builder pH Wash cycle * Compound mmol./l mmol./l Type mmol./l Initial Final 10 min. 20 min. 30 min.

43 None - 8 None - 9.7 9.2 1.0 1.3 1.6 44 Cyanamide 8 8 None - 9.4 9.3 6.7 9.6 11.0 45 Cyanamide 8 8 STPP 1 9.5 9.4 16.8 20.6 22.9 46 Cyanamide 8 8 TSP 3 9.5 9.4 11.5 16.0 18.8 47 Cyanamide 8 8 Na2SiO3 4 9.7 9.8 5.7 7.9 9.0 48 Cyanamide 8 8 Na2CO3 4 9.5 9.5 6.8 8.5 9.5 49 Cyanamide 8 8 Na2B4O7 4 9.2 9.2 6.0 9.2 10.8 50 Benzo- 8 8 None - 9.6 9.4 0.9 1.7 3.1 nitrile 51 p-Nitro- 8 8 None - 9.7 9.4 2.5 3.1 4.2 benzonitrile 52 Phthalo- 8 8 None - 7.5 7.1 1.3 2.6 2.9 nitrile 53 Phthalo- 8 8 None - 8.5a) 7.9 1.9 3.5 4.1 nitrile 54 Phthalo- 8 8 None - 9.5 7.5 4.2 5.4 6.1 nitrile 55 Phthalo- 8 8 None - 9.5a) 8.9 7.1 8.4 9.5 nitrile TABLE VII (cont'd) Exp. #R No. Activator H2O2 Builder pH Wash cycle Compound mmol./l mmol./l Type mmol./l Initial Final 10 min. 20 min. 30 min.

56 Phthalo- 8 8 None - 10.2 10.1 5.7 5.3 6.5 nitrile 57 Cyan- 8 8 None - 7.5 7.3 5.9 11.7 18.4 amide 58 Cyan- 8 8 None - 8.0 7.5 10.0 20.2 26.9 amide 59 Cyan- 8 8 None - 8.5 8.0 9.9 17.0 22.9 amide 60 Cyan- 8 8 None - 9.2 9.0 8.2 11.3 13.4 amide 61 Cyan- 8 8 None - 10.3 10.2 6.4 7.7 8.2 amide a) Phthalonitrile in this pH-range appears to hydrolyze rapidly to phthalic acid. Sodium hydroxide was added continually during these experiments in an attempt to maintain the initial pH.

The foregoing test results indicate that while silicates, carbonates and borates have no appreciable effect on the bleaching activity of the cyanamide-activated bleach system, sodium tripolyphosphate and trisodium phosphate synergistically interact with the cyanamide-actlvated peroxide-based bleach to give even further bleach enhancement. The tests, comparing cyanamide to prior art nitriles again indicate that cyanamide is far superior to benzonitrile and p-nitrobenzonitrile as a peroxide activator. Likewise cyanamide is superior to phthalonitrile at each of the pH-levels tested, and exhibits particularly pronounced advantages over phthalonitrile at longer wash cycles, and is not subject to the pH adjustment problems of phthalonitrile.

EXAMPLE 7 In this Example Philippine mahogany was bleached employing a cyanamide-activated peroxide-bleaching composition in accordance with the invention. Hydrogen peroxide and cyanamide were made up separately as 20% aqueous solutions. The peroxide solution was adjusted to a pH of 9-10 with sodium hydroxide.

Separate pieces of Philippine mahogany were then treated at room temperature with a blend of the aforementioned cyanamide and hydrogen peroxide solutions in stoichiometric proportions, and with the cyanamide solution first, followed by treatment with the alkaline peroxide solution, and vice versa. A piece of mahogany was also treated with unactivated alkaline hydrogen peroxide for comparison purposes.

The results of these tests indicate that the pieces of mahogany treated with both cyanamide and hydrogen peroxide were bleached more rapidly than those treated with alkaline hydrogen peroxide alone. The most effective procedure was first to contact the dry wood with the cyanamide solution, followed by applications of the alkaline hydrogen peroxide solution.

While the unactivated alkaline hydrogen peroxide solution ultimately bleached the mahogany substrate, it required more applications and longer contact time to achieve the same degree of bleaching.

EXAMPLE 8 To demonstrate the effectiveness of cyanamide in activating a peroxide-based bleach of the percarbonate-type, a test similar to that used in Example 4 was conducted in a Terg-O Tometer bath maintained at 490C containing 8.8 mmoles/l of hydrogen peroxide derived from sodium percarbonate (3Na2CO3,2H202),9.1 mmoles/l of cyanamide activator and 1.0 g/l of detergent. The pH of the wash water was 9.8. The AR value obtained for the cyanamide/percarbonate combination was 18.

EXAMPLE 9 In addition to the cotton bleach test clothes utilized in the tests reported in the previous examples, cyanamide-activated bleaching compositions were tested at full scale home laun dry conditions and were found to be effective in bleaching a variety of cotton materials as well as other fabrics, with and without finishes, including nylon, silk, Orlon, Dacron/cotton blends and linens. Among the stains "bleached-out" during regular and extended wash cycles were bacon grease, grape juice, tea, caffee, dried blood and cooking oils. "Orlon" and "Dacron" are registered Trade Marks.

EXAMPLE 10 The following tests evidence the substantial benefits which can be realized by use of compositions of the present invention, even under higher-temperature European-type laun dry conditions, especially if short wash cycles are employed. In these tests the wash cycles were conducted at a temperature of 87"C with increased concentrations of detergent (Tide, 8.7% P). The compositions tested and results obtained were as follows: TABLE VIII Exp. H202 Cyanamide Detergent AR No. mmol. /I mmol. /1 g/l Wash cycle 10 min. 20 min. 30 min. 60 min.

62 8 0 5 8 11 15 18 63 8 8 5 16 17 19 20 EXAMPLE 11 In this Example an encapsulated solid bleaching composition was prepared and subjected to a high temperature storage stability test. In this test an encapsulated bleaching composition containing 3.9%w cyanamide (solid), 18.6Sow sodium perborate monohydrate, 10.6Sow magnesium sulphate tetra-acetate and 66.9%w sodium sulphate, was placed in an open beaker in an oven at 500C and the bleaching effectiveness of the composition determined at the outset of the test and at random intervals by removing a portion of the sample from the oven and bleaching a test fabric with it to determine its AR potential.The bleach composition was encapsulated by blending 100 parts by weight of the aforementioned ingredients with 35 parts by weight of Neodol 45-50 (a C14 - 15 linear, primary alcohol ethoxylate) which had been liquefied by heating to facilitate encapsulation. The test results on the encapsulated composition showed that after four weeks of continuous storage at 500C the bleaching effectiveness of the composition remained at 90% of its original value.

EXAMPLE 12 The following experiments demonstrate the improved bleaching action obtainable using a metal cyanamide as the peroxide activator. The general procedures employed in these tests were as follows: Five hundred (500) ml of de-ionized water were added to a U.S. Testing, Inc. Terg-O Tometer bath maintained at a temperature of 49"C and the hardness level of the water adjusted to 150 ppm as CaCO3 (Ca/Mg = 3/2 on a molar basis). The peroxide-based bleach (sodium perborate tetrahydrate) and metal cyanamide activator (crude calcium cyanamide) were then added to the wash water in the concentrations shown in Table I, and the water agitated to avoid localized concentrations of any one additive. The pH of the water in the bath was maintained in the general range of 10-11.5 throughout the test.Although sodium perborate and calcium cyanamide give alkaline solutions, a detergent was used to simulate home laundry conditions. In this example Tide containing 12.3 per cent phosphorus (Tide, 12.3 % P) was employed as the detergent. Finally, four swatches, as described in Example 1, were introduced into the wash water and the agitator run for 10 minutes at 100 rpm. At the conclusion of the wash cycle, the swatches were removed, rinsed by squeezing under a tap and examined by the technique described in Example 1.

The compositions tested and the results obtained are presented in the following Table: TABLE IX Exp. Bleach (SPB-4)a) CaNCNb) Detergent c) pH Temp. AR No. mmol./l mmol./l g/l (final) 0C 64 8 - 1.5 10.2 49 2.0 65 8 8 1.5 11.2 49 21.0 66 8 4 1.5 10.7 49 9.1 67 16 16 1.5 11.3 49 25.8 68 16 8 1.5 10.9 49 27.0 69 24 24 1.5 11.3 49 31.3 70 24 12 1.5 10.9 49 34.9 71 8 16 1.5 11.3 49 16.1 72 24 8 1.5 10.7 49 21.1 a) SPB-4 = sodium perborate tetrahydrate.

b) Introduced as crude CaNCN (typical assay approximately 65% CaNCN).

c) Tide, 12.3% P (Tide is a powdered detergent manufactured by Procter & Gamble Company).

The foregoing test results indicate that the bleaching action of sodium perborate tetrahydrate is substantially enhanced when activated with various proportions of crude calcium cyanamide.

EXAMPLE 13 In this Example a series of experiments was conducted employing the preferred purified form of calcium cyanamide instead of the crude form employed in Example 12. Except as noted, essentially the same test procedure was employed as in Example 12. The compositions tested and test results are reproduced below.

TABLE X Exp. Bleach, CaNCNb) Deter- pH #R No. (SPB-4)a) mmol./l gent, c) Temp., Wash cycle mmol./l g/l Initial Final C 10 min. 20 min. 30 min.

73 8 0 1.5 9.4 9.3 85 8.1 11.4 14.2 74 8 8 1.5 9.7 10.0 85 33.0 38.9 41.6 75 8 0 1.5 10.3 10.2 49 1.9 2.8 3.8 76 8 8 1.5 10.7 11.4 49 23.8 24.3 33.4 77 8 8d) 1.5 11.3 11.2 49 30.1 31.0 33.3 78 8 0.8d) 1.5 10.4 10.3 49 5.8 7.9 9.7 79 8 0 1.5 9.9 9.7 7 - - 0.5 1.1 80 8 8 1.5 10.9 11.0 7 - - 2.8 8.5 a) SPB-4 = sodium perborate tetrahydrate.

b) Introduced as pharmaceutical grade CaNCN (typical assay approximately 96% CaNCN).

c) Tide, 6.1%P.

d) CaNCN activator dissolved in hot water prior to addition to Terg-O-Tometer.

From the foregoing results it is apparent that CaNCN effectively activates sodium perborate over a wide range of temperatures, with the very substantial bleach enhancement benefits being achieved at a temperature of 49"C, which is representative of home laundering conditions in the United States.

EXAMPLE 14 In this example a series of experiments was conducted to demonstrate the effectiveness of sodium acid cyanamide as a peroxide-based bleach activator. The peroxide-based bleach employed in these tests was either sodium perborate monohydrate or sodium perborate tetrahydrate. The test procedure employed was essentially the same as in Example 13 except as indicated.

The compositions tested and results obtained are summarized in the following table. TABLE XI Exp. Bleach NaHNCN Detergenta) pH Temp., #R No. mmol./l mol./l Type g/l Initial C Wash Cycle 10 min. 20 min. 30 min. 60 min.

81 8b) - - - 10.5 48 2.4 3.4 3.8 82 8b) 8 - - 10.7 48 26.2 28.8 31.9 33.6 83 8b) 8 A 1.5 10.4 48 28.2 34.6 38.0 42.2 84 8b) 8 B 1.5 10.8 48 13.1 15.3 17.2 19.2 85 8c) 0.8 B 1.5 10.1 48 6.8 8.9 10.7 86 8c) 80 B 1.5 10.9 48 6.2 7.2 8.3 a) Detergent A - Cheer, 0%P (Cheer is a powdered detergent manufactured by Procter & Gamble Company).

Detergent B - Tide 6.1%P.

b) Sodium perborate monohydrate.

c) Sodium perborate tetrahydrate.

From the above data it can be seen that sodium acid cyanamide materially enhances the bleaching activity of sodium perborate bleach in the presence or absence of detergents.

EXAMPLE 15 In this example a solid bleaching composition was subjected to a high temperature storage stability test. In this test the composition was placed in a loosely capped bottle in an oven at 50"C and the bleaching effectiveness of the composition (AR) determined at the outset of the test, after 10 days storage and after encapsulation and an additional 27 days storage. The composition tested and the results obtained were as follows: Composition 5.9%w Sodium acid cyanamide 18.6Sow Sodium perborate monohydrate 10.6tow Magnesium sulphate, anhydrous 64.9Sow Sodium carbonate, anhydrous Stability at 50"C ARa) Days in Wash Cycle Storage 10 min. 20 min. 30 min. 60 min.

0 29 38 41 44 10b) 28 36 40 43 37 26 34 36 39 a) Determined under essentially the same conditions as in Example 12, except that 1.5 g/l of Cheer, 0%P, was employed as the detergent.

b) After 10 days the composition was removed from the oven and encapsulated with 12 parts of Neodol 25-9 (a C12-C15 linear, primary alcohol ethoxylate) per hundred parts of the composition. Encapsulation was effected by blending the composition with the encapsulating agent with mechanical agitation. After encapsulation, the composition was returned to the oven and the test continued.

The foregoing results indicate the encapsulated test composition retained approximately 90% of its bleaching effectiveness after 37 days storage at 50toy.

EXAMPLE 16 The following experiments demonstrate the improved bleaching action obtainable by the use of a Group IIA metal compound. The general procedures employed in these tests were as follows: Five hundred (500) ml of de-ionized water was added to a U.S. Testing, Inc. Terg-O Tometer bath maintained at the temperatures indicated in Table I and the hardness level of the water adjusted to 150 ppm as CaCO3 (Ca/Mg = 3/2 on a molar basis). The pH of the water in the bath was adjusted to the values shorn in Table I by the addition of the detergent and NaOH as required, as the alkaline buffering agents. The peroxide-based bleach, cyanamide activator, Group IIA metal compound and detergent were added to the wash water in the concentrations shown in Table XII and the water agitated to avoid localized concentrations of any one additive. Finally, eight swatches, as described in Example 1 were tested and examined by the technique described therein.

The compositions tested and the results obtained are presented in Table XII.

TABLE XII Group IIA b) Deter- pH #R Exp. Bleacha) H2NCN Metal gent,c) Temp., Wash Cycle No. mmol./l mmol./l mmol./l g/l Init. Final C 10 min. 20 min. 30 min. 60 min.

87 8 0 0 1.5 9.8 9.5 85 4.3 7.5 9.7 88 8 8 0 1.5 9.2 8.9 85 26.4 31.9 33.6 89 8 8 8 1.5 - - 85 36.1 43.2 47.1 90 8 0 - 1.5 9.7 9.6 49 0.8 1.5 1.9 91 8 8 0 1.5 9.3 8.8 49 18.1 26.0 30.3 92 8 8 4 1.5 9.1 8.5 49 21.1 31.2 36.8 93 8 8 8 1.5 9.0 8.5 49 19.3 30.0 36.2 94 8 8 16 1.5 8.9 8.4 49 18.0 28.3 33.9 95 8 0 0 1.5 9.3 8.8 7 - - 0.8 0.5 96 8 8 0 1.5 8.9 8.7 7 - - 3.7 7.2 97 8 8 1 1.5 8.9 8.6 7 - - 3.2 7.1 98 8 8 0 1.5 9.8 9.7 7 - - 5.7 9.1 99 8 8 1 1.5 9.3 9.1 7 - - 6.6 10.6 100 8 8 8 1.5 9.7 9.4 7 - - 6.4 12.2 a) Hydrogen peroxide (introduced as a stabilized, commercial grade 50% aqueous solution).

b) Introduced as magnesium sulphate (MgSO4.7H2O).

c) Tide containing 6.1% phosphorus (Tide, 6.1% P). Tide is a powdered detergent manufactured by Procter & Gamble Company.

The foregoing tests indicate that the compositions of the invention containing hydrogen peroxide, cyanamide and a Group II metal compound in various proportions provide significantly enhanced bleaching action over a wide range of temperatures.

EXAMPLE 17 In this Example a series of experiments was conducted with various Group IIA metal salts and oxides as well as salts of other metals for comparison purposes. Unless otherwise noted the test procedure employed was the same as that used in Example 16. The compositions tested and results obtained are tabulated below.

TABLE XIII #R Exp. Bleacha) H2NCN Metal Salt or Oxide Detergent f) pH Temp. Wash Cycle No. mmoles/l mmoles/l Compound mmoles/l g/l Initial C 10 mins.

101 8.8 8.8 - - 1.5 9.8 49 14 102 8.8b) 0 CanCNc) 8.8 1.5 9.8 49 20 103 8.8 8.8 MgOd) 10.5 1.5 9.8 49 22 104 8.8 8.8 MgCl2.6H2O 4.9 1.5 9.8 49 28 105 8.8 8.8 MgSO4.7H2O 3.3 1.5 9.8 49 23 106 8.8 8.8 Mg(NO3)2.6H2O 3.9 1.5 9.8 49 26 107 8.8 8.8 Ca(NO3)2.4H2O 4.2 1.5 9.8 49 24 108 8.8 8.8 BaCl2.2H2O 4.1 1.5 9.8 49 25 109 8.8 8.8 SrCl2.2H2O 5.1 1.5 9.8 49 25 110 8.8 8.8 Al(CH3COO)e3) 7.1 1.5 9.8 49 11 111 8.8 8.8 LiOH 37.0 1.5 9.8 49 15 112 8.8 8.8 RbCl 8.3 1.5 9.8 49 16 113 8.8 8.8 NiCl2.6H20 4.2 1.5 9.8 49 1.9 114 8.8 8.8 MnSO4.H2O 6.0 1.5 9.8 49 0 115 8.8 8.8 CuCl2.2H2O 1.2 1.5 9.8 49 -2.2 116 8.8 8.8 Fe(NO3)3.9H2O 2.5 1.5 9.8 49 3.0 117 8.8 8.8 HgCl2 7.4 1.5 9.8 49 5.4 118 8.8 8.8 NH4VO3 8.6 1.5 9.8 49 0.6 119 8.8 8.8 Ti(i-C3H7O)4 7.0 1.5 9.8 49 1.4 120 8.8 8.8 SnCl2 5.3 1.5 9.8 49 12.0 a) Hydrogen peroxide (introduced as a stabilized, commercial grade 50% aqueous solution), except as noted.

b) Sodium perborate tetrahydrate added in place of hydrogen peroxide.

c) CaNCN was employed in place of cyanamide in this experiment and served as both the activator and the source of Group IIA metal ions.

d) Added as 4MgCO3.Mg(OH)2.n H2O (42.4% MgO).

e) Added as Al(OH)2(CH3COO).1/3H3BO3.

f) Tide, 6.1%P.

The foregoing results indicate that various Group IIA metal salts and oxides can be effectively employed in further increasing the bleaching effectiveness of cyanamide activated peroxide-based bleaches, and that bleach enhancement is not critically affected by the anion with which the Group IIA metal is introduced. The data further indicate that Group IA metals such as lithium or rubidium are not effective in enhancing the bleaching activity of the cyanamide/peroxide system, nor is aluminium acetate, a Group IIIA metal salt. The variable valance metals tested, except for tin which showed no appreciable effect, considerably depressed the bleaching action of the cyanamide/peroxide system.

EXAMPLE 18 In this Example a series of experiments was conducted utilizing the test procedures outlined in Example 16, except as otherwise noted, to compare the bleaching effectiveness of several commercially available peroxide-based bleaches (identified in Table XIV) when used alone, to the same bleaches containing cyanamide as an activator or a combination of cyanamide with a Group IIA metal salt. The commercial peroxide-based bleaches employed in these experiments are tabulated in Table XV.

TABLE XIV Product Type SaM202C) Bleach A Liquid a) 5.9 Bleach B Liquid a) 3.2 Bleach C Solid b) 4.9 Bleach D Solid b) 8.0 Bleach E Solid b) 7.5 Bleach F Solid b) 4.9 a) Aqueous hydrogen peroxide.

b) Contains sodium perborate which dissolves in wash water to form hydrogen peroxide.

c) Determined by iodometric titration.

TABLE XV Exp. Producta) Product only Product plus H2N(CNc) Product plus H2NCNc) plus Mg d) No. %H2O2 %H2O2 %H2O2 utilizedb) #R utilizedb) #R utilizedb) #R 121 Bleach A 0 3.1 95 17 73 26 122 Bleach B 0 3.2 90 17 71 24 123 Bleach C 0 3.5 89 14 65 12 124 Bleach D 0 4.1 91 8 76 19 125 Bleach E 0 2.5 94 11 78 19 126 Bleach F 0 2.4 83 11 77 23 a) Added to wash water to provided initial H2O2 concentration of 8.8 mmol./l.

Washing conditions in addition to or other than those shown in Example. 16: Detergent concentration 1.5 g/l Tide, 6.1% P, temperature of all runs 49 C, wash cycle 10 mins., pH adjusted to 9.6-10.

b) Determined by iodometric titration on 50-100 ml of wash liquor immediately (within one minute) after wash c) H2NCN concentration 8.8 mmol./l.

d) Added as MgSO4.7H2O at 3.3 mmol./l.

The foregoing test results indicate that while the commercial peroxide-based bleaches are virtually ineffective in bleaching the test cloth under the conditions shown, the addition of cyanamide as an activator, or a combination of cyanamide plus a Group IIA metal compound substantially improves their performance and results in more effective utilization of the hydrogen peroxide.

EXAMPLE 19 The effectiveness of Group IIA metals in further enhancing the bleaching action of a solid cyanamide-activated peroxide bleach system was demonstrated in a series of experiments in which various amounts of magnesium and calcium salts were employed in conjunction with a sodium acid cyanamide activated peroxide-based bleach (sodium perborate monohydrate).

The test procedure employed in this series of tests was the same as that of Example 16, except as noted. The compositions employed and the results of the tests are presented in the following Table.

TABLE XVI #R Bleach Group IIA pH Wash Cycle Exp. SPB-1 NaHNCN Metalb) Detergentc) Temp 10 20 30 60 No. mmoles/l mmoles/l mmoles/l Type g/l Initial Final C mins mins mins mins 127 8 8 0 - 0 10.7 - 48 26 29 32 34 128 8 8 0 A 1.5 10.4 10.0 48 28 35 38 42 129 8 8 4(Mg) A 1.5 9.9 9.5 48 30 38 42 45 130 8 8 8(Mg) A 1.5 9.7 9.3 48 32 38 41 45 131 8 8 4(Ca) A 1.5 10.3 10.0 48 27 34 38 42 132 8 8 0 B 1.5 10.8 - 48 13 15 17 19 133 8 8 4(Mg) B 1.5 10.5 - 48 31 39 41 45 134 8 8 4(Ca) B 1.5 10.7 - 48 19 25 29 43 135 8 4 2(Mg) B 1.5 10.1 9.9 48 30 36 39 41 136 8 4 4(Mg) B 1.5 10.0 9.8 48 32 39 42 45 137 8 4 4(Mg) C 1.5 9.9 9.5 48 31 38 41 43 138 8 4 8(Mg) C 1.5 9.7 9.3 48 31 38 41 44 a) SPB-1 = sodium perborate monohydrate.

b) Added as MgSO4.7H2O or CaCl2.2H2O.

c) Detergent A - Cheer, 0%P (Cheer is a powdered detergent sold by Procter & Gamble Company).

Detergent B - Tide, 6.1%P.

Detergent C - Tide, 12.3%P.

From the above data it can be seen that the inclusion of Group IIA metals in the cyanamide-activated peroxide-based bleach system results in high levels of bleaching being achieved in the presence of various detergents. In addition, the results indicate that enhanced bleaching can be achieved with lower levels of cyanamide activator when Group IIA metals are also present in the system.

EXAMPLE 20 A series of experiments was conducted to determine the effect of commonly employed detergent builders on the bleaching action of the present Group IIA metal-containing, cyanamide-activated, peroxide-based bleach compositions. The test procedure employed was similar to that described in Example 16, except that de-ionized water with no added hardness or detergent was employed in the Terg-O-Tometer bath. The compositions tested and the results obtained are presented in the following table. The temperature of the Torg-O-Tometer bath in all of these tests was 49"C.

TABLE XVII #R Exp. H2NCN H2O2 MgSO4 Builder pH Wash Cycle No. mmoles/l mmoles/l mmoles/l Type mmoles/l Initial Final 10 mins. 20 mins. 30 mins.

139 0 8 0 None - 9.7 9.2 1.0 1.3 1.6 140 0 8 4 None - 9.4 8.9 0.8 1.2 1.8 141 8 8 4 None - 9.5 9.3 25.8 32.2 34.9 142 8 8 4 STPPa) 2 9.6 9.4 31.7 38.7 41.2 143 8 8 4 TSPb) 3 9.3 9.0 33.6 42.6 46.4 144 8 8 4 Na2SiO3 4 9.4 9.0 35.4 42.6 45.9 145 8 8 4 Na2CO3 4 9.5 9.4 31.2 35.7 37.9 146 8 8 4 Na2B4O7 4 9.3 9.2 27.4 32.5 34.3 a) STPP = Sodium tripolyphosphate b) TSP = trisodium phosphate The foregoing test results indicate that hydrogen peroxide alone, or in combination with magnesium sulphate in the absence oc cyanamide, exhibits virtually no bleaching activity at 49"C. However, when the magnesium salt and hydrogen peroxide are employed in combination with cyanamide activator, very substantial levels of bleaching activity are obtained, which activity is even further enhanced by the presence of alkali metal phosphates (STPP and TSP), silicates and carbonates, and to a lesser extent borates.

EXAMPLE 21 In this example an encapsulated solid bleaching composition was prepared and subjected to a high temperature storage stability test. In this test an encapsulated bleaching composition containing 5.9%w sodium acid cyanamide, 18.6%w sodium perborate monohydrate, 10.6low di-magnesium ethylenediamine tetra-acetate and 64.9Sow sodium sulphate, was placed in an open beaker in an oven at 500C and the bleaching effectiveness of the composition determined at the outset of the test and at random intervals by removing a portion of the sample from the oven and bleaching a test fabric with it to determine its AR potential.The bleach composition was encapsulated by blending 100 parts by weight of the aforementioned ingredients with 12 parts by weight of Neodol 25-9 (a C12-15 linear, primary alcohol ethoxylate) which had been liquefied by heating to facilitate encapsulation. The word "Neodol" is a Registered Trade Mark. The test results on the encapsulated composition showed that after four weeks of continuous storage at 50"C the bleaching effectiveness of the composition remained at 84% of its original value.

EXAMPLE 22 A series of experiments was conducted to compare the effect of magnesium relative to other Group IIA metals on the bleaching action of the cyanamide-activated peroxide bleach compositions. The test procedure employed in these experiments was similar to that described in Example 16, except that de-ionized water with no added hardness or detergent was employed in the Terg-O-Tometer bath. The temperature of the Terg-O-Tometer bath in all of these tests was 49"C. The compositions tested and results obtained are presented in the following Table.

TABLE XVIII Exp. Act- H2O2b) Metal ion pH #R No. ivatora) Wash cycle mmol./l mmol./l Type mmol./l Initial Final 10 mins. 20 mins. 30 mins.

147 4 8 - 0 10.0 10.2 5.1 7.1 8.8 148 4 8 Cac) 4 10.0 10.2 3.6 5.3 6.3 149 4 8 Cad) 4 10.0 10.1 5.4 6.8 8.3 150 4 8 Bae) 4 9.8 10.2 4.5 6.2 7.6 151 4 8 Srf) 4 9.8 10.2 3.7 5.3 6.6 152 4 8 - 0 10.0 10.2 5.1 7.0 8.7 153 4 8 Mgg) 0.1 10.0 10.2 10.2 16.7 20.7 154 4 8 Mgg) 0.2 10.0 10.2 17.4 28.3 33.3 155 4 8 Mgg) 0.4 10.0 10.1 27.2 37.3 41.0 156 4 8 Mgg) 0.6 10.0 9.9 31.1 39.6 42.9 157 4 8 Mgg) 2.0 10.0 9.8 32.0 39.4 41.8 158 4 8 Mgg) 4.0 10.0 10.0 29.8 38.1 49.9 a) sodium acid cyanamide (NaHNCN); b) Added as NaBO3.H2O; c) Added as Ca(NO3)2.4H2O; d) Added as Ca(CH3COO)2.H2O; e) Added as BaCl2.2H2O; f) Added as SrCl2.6H2O; g) Added as MgSO4.7H2O.

Claims (22)

WHAT WE CLAIM IS:

1. A process fo, activating a peroxide-based bleach comprising incorporating into an aqueous medium: (a) a peroxide-basec' bleach, b) cyanamide and/ -i metal cyanamide, and optionally e) a Group IIA metal compound, and wherein the aqueous medium is maintained under alkaline conditions, optionally by the incorporation of a buffering agent therein, with the proviso that if component (b) is cyanamide and component (c) is absent then the aqueous medium is maintained at a pH of above 7.5.

2. A process as claimed in claim 1, wherein component (a) is hydrogen peroxide, sodium perborate or sodium percarbonate.

3. A process as claimed in claim 1 or claim 2, wherein component (a), component (b), in the case of a metal cyanamide, or component (c) in the case of a Group IIA metal salt or oxide, also serve, at least in part, as the buffering agent.

4. A process as claimed in any one of claims 1 to 3, wherein an additional buffering agent is incorporated into the aqueous medium.

5. A process as claimed in any one of claims 1 to 4, wherein component (c) is a magnesium or calcium salt or oxide.

6. A process as claimed in claim 5, wherein component (c) is magnesium hydroxide, magnesium sulphate, magnesium chloride, magnesium nitrate, dimagnesium ethylenediamine tetra-acetate, calcium chloride or calcium nitrate.

7. A process as claimed in any one of claims 1 to 6, wherein component (b) is a group IA or Group IIA metal cyanamide.

8. A process as claimed in claim 7, wherein component (b) is calcium cyanamide, disodium cyanamide or sodium acid cyanamide.

9. A process as claimed in claim 7 or claim 8, wherein component (b) is sodium acid cyanamide and component (a) is sodium perborate monohydrate.

10. A process as claimed in any one of claims 1 to 6, wherein component (b) is cyanamide and the aqueous medium is maintained at a pH of above 7.5.

11. A process as claimed in any one of claims 1 to 10, wherein a detergent is additionally incorporated into the aqueous medium.

12. A process as claimed in any one of claims 1 to 11, wherein an alkali metal phosphate, carbonate or silicate is additionally incorporated into the aqueous medium.

13. A process as claimed in claim 12, wherein the alkali metal phosphate is sodium tripolyphosphate or trisodium phosphate.

14. A process as claimed in any one of claims 1 to 13, wherein the aqueous medium is maintained at a pH within the range 7.5 to 13, preferably within the range 8.0 to 11.5.

15. A process as claimed in any one of claims 1 to 14, wherein the temperature of the aqueous medium is from 15 to 72"C.

16. A process as claimed in claim 1, substantially as hereinbefore described with particular reference to the Examples.

17. A process as claimed in any one of claims 1 to 16, wherein the amount of peroxidebased bleach is such that the aqueous medium comprises from 2 to 600 millimoles/litre of peroxide-based bleach, calculated as hydrogen peroxide.

18. A process as claimed in claim 1, wherein component (b) is a metal cyanamide and component (c) is absent or component (b) is cyanamide and component (c) is present and wherein the activated peroxide-based bleach is formed by adding to the aqueous medium a composition comprising less than 2.5% by weight, calculated on hydrogen peroxide, of peroxide-based bleach, together with component (b) and optionally component (c) as appropriate.

19. An aqueous alkaline bleach composition whenever produced by the process claimed in any one of claims 1 to 18.

20. A method of bleaching a bleachable substance comprising contacting the bleachable substance with an aqueous alkaline bleach composition as claimed in claim 19.

21. A method as claimed in claim 20, substantially hereinbefore described with reference to the Examples.

22. A bleached substance whenever prepared by the process claimed in claim 20 or claim 21.