GB1573144A - Stable bleaching compositions for forming activated peroxide-based bleach media - Google Patents

Description

PATENT SPECIFICATION ( 11) 1 573 144

11 ( 21) Application No 24655/79 ( 22) Filed 7 Feb 1977 ( 19) t ( 62) Divided out of No 1573143 ( 31) Convention Application Nos 656456 ( 32) Filed 9 Feb 1976 in i 656464 656457 ( 33) United States of America (US) ^ ( 44) Complete Specification Published 13 Aug 1980 ( 51) INT CL 3 D 06 L 3/02 ( 52) Index at Acceptance Di P 1113 FC ( 72) Inventors: LOUIS KRAVETZ EUGENE FREDERICK LUTZ HANS ERNEST KUBITSCHEK ( 54) STABLE BLEACHING COMPOSITIONS FOR FORMING ACTIVATED PEROXIDE-BASED BLEACH MEDIA ( 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 specification of our co-pending Patent Application No 4907/77, (Serial No.

1573143), from which this application has been divided, relates to an improved process for activating peroxide-based bleaches and to bleaching/washing compositions The present invention relates to stable bleaching compositions which alone or in combination with other ingredients can be added to aqueous media to form activated peroxidebased bleach media 1 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 be safely bleached 1 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 15-720 C, which are typical temperatures for home laundering in certain countries, e g, the United 20 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 25 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 30 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, 40 2 1,573,144 2 a water-soluble cupric salt and a copper complexing agent N,Ndiacetylcyanamide 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 5 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 10 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 15 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 20 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 25 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 inexpen 30 sive 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 (H 2 NCN) and/or metal cyanamides when employed under alkaline conditions are extremely effective activators for peroxide-based bleaches over a wide range of temperatures, including 35 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 40 Group HA metal, certain compounds commonly employed as detergent builders, are also present in the alkaline aqueous bleaching/washing medium.

The specification of the aforesaid Patent Application No 4907/77 (Serial No 1573143) claims a process for activating a peroxide-based bleach which comprises conjointly incorporating into an aqueous medium 45 a) a peroxide-based bleach, ) 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 50 cyanamide and component (c) is absent then the aqueous medium is maintained at a p H of above 7 5.

In a preferred embodiment 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 55 The present invention provides stable concentrated solid (dry) or liquid peroxide-based bleach compositions which can be used for bleaching as such or as a component of a soap or detergent formulation.

According to the present invention a stable bleaching composition comprises:

(a) from 2 5 to 35 % by weight, calculated as hydrogen peroxide, of a peroxide-based 60 bleach, {b) cyanamide and/or a metal cyanamide, and optionally c) a Group IIA metal compound.

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 be further 65 1,573,144 3 1,573,144 3 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 5 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 particu 10 larly 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.

According to the specification of Patent Application No 4907/77 (Serial No 1573143), a 15 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 p H 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 20 cyanamide and (c) a buffering agent to maintain the aqueous medium under alkaline conditions; and a further preferred process for activating a peroxidebased 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 25 The present invention also includes an alkaline bleach medium comprising an aqueous medium to which has been added a stable bleaching composition as defined above, the aqueous medium containing said composition being maintained under alkaline conditions, optionally by the presence of a buffering agent.

By "peroxide-based bleaches" as this term is used in this specification and claims, is meant 30 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 35 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 (Na BO 3 4 H 20) because of its commercial availability However, sodium perborate trihydrate (Na BO 3 H 20) and sodium perborate monohydrate (Na BO 3 H 20) can also be suitably employed The peroxide-based 40 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 45 Metal cyanamides which can be suitably employed in forming the stable bleaching compositions of the present 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 (Ca NCN), disodium cyanamide (Na 2 NCN) and sodium acid cyanamide (Na HNCN) 50 Dipotassium cyanamide (K 2 NCN), potassium acid cyanamide (KHNCN), dilithium cyanamide (Li 2 NCN), lithium acid cyanamide (Li HNCN), magnesium cyanamide (Mg NCN), barium cyanamide (Ba NCN) and strontium cyanamide (Sr NCN) 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 55 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 (%ow) calcium cyanamide, but preferably is employed in its purified form 60 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 65 1,573,144 4 1,573,144 4 sufficient cyanamide metal cyanamide be present to activate the peroxidebased bleach upon addition to an aqueous bleaching/washing medium under alkaline conditions Generally, the molar ratio of 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 5 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 appear to have no appreciable effect on the bleaching activity of the cyanamide-activated system In the case of transition 10 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 15 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 20 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) 25 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 30 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 35 the p H 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 p H of at least 7 5, preferably from 7 5 to about 13, or higher Preferably, the p H of the washing/bleaching medium will be from about 8 0 or 8 5 to about 11 5.

The aqueous medium may be maintained under alkaline conditions by any suitable means 40 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 compound, 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 45 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 50 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.

The stable bleaching compositions may be prepared in either liquid or solid form In this connection the cyanamide or metal cyanamide and peroxide bleach components can be 55 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 p H of the aqueous liquid formulation should be maintained at a relatively low p H (e g, at a p H below about 5, preferably at a p H of from about 2 to 5, more preferably at a p H of about 4) until the product is ready for use to prevent premature reaction and/or 60 decomposition of the cyanamide and peroxide components (e g, cyanamide undergoes various addition reactions under alkaline conditions, sometimes accompanied by a further increase in p H Hydrogen peroxide may decompose by either free radical or ionic reactions, which in general proceed more rapidly at higher p H values) In this manner a stable, i e, inactive or non-reactive bleach composition is provided, which can be readily activated upon 65 1,573,144 1,573,144 5 use by adjusting the p H level to the alkaline conditions required for effective activation of the peroxide-base bleach Such p H adjustment 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 5 peroxide and cyanamide.

In addition to maintaining the p H at low levels during storage, e g, at a p H 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, 10 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 The effect of using such low cyanamide to hydrogen peroxide ratios on the stability of aqueous formulations of cyanamide/hydrogen peroxide is is shown in the Examples.

Stable solid bleach compositions in accordance with the invention 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, Mg SO 4) or suitable alkaline buffering agents, fillers and/or desiccants, without the need for p H adjustment to below 5 level required for stable liquid bleach 20 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 of the 25 present invention 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 30 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 p H levels are desired.

From the foregoing it can be seen that the term "stable" as employed in connection with the solid and liquid bleaching compositions in accordance with the invention, means the 35 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 bleaching compositions this is accomplished by p H 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 bleaching compositions all that will normally be required is that the 40 cyanamide-activated peroxide-based bleach be added to an aqueous bleaching/washing medium.

As mentioned above, a useful technique for obtaining stability of solid cyanamideactivated peroxide-based bleaching compositions of the invention is by use of the well-known technique of encapsulation In general, any encapsulating technique which provides a cover 45 ing for the cyanamide activator and/or peroxide-based bleach particles to prevent their coming into direct contact until they are added to the aqueous bleaching medium can be suitably employed in the practice of the present invention Thus, the function of the covering material (encapsulating agent) is to prevent premature reaction or decomposition of the cyanamide activator and peroxide-based bleach while in storage, yet effectively release the 50 activator and/or peroxide-based bleach upon addition to the aqueous bleaching medium.

Suitable encapsulating agents include both water-soluble and waterdispersible substances, such as stearic acid, polyethylene glycols, condensation products of ethylene oxide and propylene oxide (e g, alcohol ethoxylates), polyvinyl alcohol, carboxymethyl cellulose, cetyl alcohol and fatty acid alkanolamides Encapsulation may be conveniently accomplished 55 by dissolving the encapsulating agent in a volatile organic solvent and spraying the finely divided particles of cyanamide activator and/or peroxide-activated bleach with the solution after which the sprayed particles are dried Such a procedure is described, for example, in U.S 3,163,606 Other suitable encapsulation techniques are described in U K 1,395,006.

A preferred peroxide-based bleaching (or bleach) composition in accordance with the 60 invention, especially from a storage stability standpoint, is a dry bleach formulation based on a combination of cyanamide, disodium cyanamide or sodium acid cyanamide with sodium perborate monohydrate as the peroxide-based bleach component The advantage of utilizing the monohydrate form of sodium perborate is that any moisture absorbed by the dry bleach formulation during storage, will first act to convert the sodium perborate monohydrate to its 65 1,573,144 higher hydrate forms (e g, sodium perborate tetrahydrate), thereby making the package more stable to moisture contamination.

Disodium cyanamide also can serve to minimize the adverse effects of moisture on product stability, 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 5 cyanamide increases the "shelf-life" of the total bleach.

The amount of peroxide-based bleach employed in the bleaching compositions of the present invention will vary widely depending on the material to be bleached, the extent of bleaching desired, and the bleaching conditions In general, the amounts of peroxide-based bleach, calculated as hydrogen peroxide, in the stable bleach compositions of the invention 10 will range preferably from 2 to 15 % by weight Peroxide concentrations higher than 35 % by weight, calculated as hydrogen peroxide, are excluded because of the reactivity of highly concentrated peroxide with organic material, which could form detonable mixtures.

The preferred molar ratios of the cyanamide or metal cyanamide to the peroxide-based 15 bleach and of the Group IIA metal compound to the peroxide-based bleach, present in the stable concentrates are as described above.

A preferred stable liquid bleaching composition comprises an aqueous solution of from 2 5 to 35 % by weight, calculated as hydrogen peroxide, of a peroxide-based bleach, cyanamide and a buffering agent to maintain the p H of the aqueous solution from about 2 to 5 20 A preferred stable concentrated solid bleaching composition consists essentially of a solid mixture of from 2 5 to 35 % by weight, calculated as hydrogen peroxide, of peroxide-based bleach and a cyanamide as an activator therefor.

Another preferred stable bleaching composition comprises (a) from 2 5 to 35 %by weight, calculated as hydrogen peroxide, of the total composition of a peroxidebased bleach, (b) 25 cyanamide or a metal cyanamide and (c) a Group IIA metal compound, the molar ratio of Group IIA metal compound to the peroxide-based bleach being from 1:60 to 25:1.

In use the cyanamide-activated bleaching compositions of the present invention can be employed 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 peroxidebased bleach 30 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 In use the compositions of the inventionare 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 activated peroxide-based bleach compositions of the invention are generally added to an aqueous medium in an amount that will result in 2 to 600 millimoles/litre (mmoles/1) 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 so bleach present should suitably be such that the concentration of peroxide-based bleach, O 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.

Stable bleaching compositions in accordance with the present invention can be used for bleaching/washing as described in the specification of Application 4907/77 When so used a preferred bleaching/washing composition comprises an aqueous medium containing from 55 about 2 to about 600 millimoles/litre of hydrogen peroxide, cyanamide, a buffering agent to maintain the p H of the aqueous medium within the range of 7 5 to about 13, and a bleachable substance.

Another preferred bleaching/washing composition comprises an aqueous medium containing from about 2 to about 600 millimoles/litre of a peroxide-based bleach, calculated as 60 hydrogen peroxide, a metal cyanamide, a buffering agent to maintain the p H of the aqueous medium within the range of 7 5 to about 13 and a bleachable substance.

A further preferred bleaching/washing composition comprises 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 11 A metal compound, (d) an alkaline buffering agent to 65 7 1,573,144 7 maintain the aqueous medium under alkaline conditions and (e) a bleachable substance, the molar ratio of the Group IIA metal compound to the peroxide-based bleach being from 1:60 to 25:1.

The present compositions can be employed over a relatively wide range of temperatures, e g, from about 70 C up to the boiling point of water ( 1000 C) However it can most 5 advantageously be employed at temperatures of 15 to 720 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 compositions as compared to the use of peroxide-based bleaches alone, or peroxide-based bleaches activated with many of the prior art activators 10

In the case of home or commercial laundering, the compositions of the present invention will normally be employed in conjunction with a soap or detergent, which may be provided as a part of the composition, 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 15 can be used with or without such soaps include the anionic, cationic, switterionic, ampholytic, non-ionic and semi-polar organic surface-active agents Typical anionic detergents which can be employed 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 20 sulphates, oleylmethyltauride, the compounds referred to generically having aliphatic hydrocarbon chains of abut 10 to abiut 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 25 used 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 30 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 dimethylpropylmyristyl ammonium chloride; and the like.

Any of the builders or other additives conventionally employed in bleach or detergent 35 products can be present in the bleaching compositions 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 40 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, preferably when using the compositions of the invention STPP or TSP (or a detergent containing either of these compounds) is present in the aqueous bleaching/washing medium in addition to the 45 peroxide-based bleach and cyanamide or a metal cyanamide activator, which are essential components of the stable bleaching compositions of the present invention.

It has also been found that one or more alkali metal phosphates, carbonates or silicates enhance the bleaching of an aqueous bleaching/washing medium containing Group II metal compounds 50 Other additives which may be optionally incorporated in or used in conjunction with the stable bleaching compositions of the present invention include fabric softeners, germicides, fungicides, enzymes, anti-redeposition agents, flocculents, optical brighteners, colorants, perfumes, thickeners, stabilizers, suds-builders or suds-depressants, anti-corrosion agents and fluorescent agents 55 The bleaching compositions 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 and bathrooms; for institutional use; for water treatment; and the treatment of swimming pools.

The present invention will now be illustrated by reference to the following Examples in 60 which Examples 5, 11, 15 and 21 provide specific examples of compositions in accordance with the invention:

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 65 8 1,573,144 8 follows:

Five hundred ( 500) ml of de-ionized water were added to a U S Testing, Inc Terg-OTometer bath maintained at the temperatures shown in Table I and the hardness level of the water adjusted to 150 ppm as Ca CO 3 (Ca/Mg = 3/2 on a molar basis) The p H of the water in the bath was adjusted to the values shown in Table I by the addition of Na CO 1 or Na OH 5 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 10 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 15 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

Exp Bleach, a) No mmol /1 Cyanamide, mmol /1 Detergent, b) g/l p H Initial Final Temp, DC OR Wash cycle min 20 min 30 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 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 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.

min.

t A -j) LA I1,573,144 The foregoing tests indicate that compositions 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 49 C to further demonstrate the effect of concentration and p H on the bleaching effectiveness The test procedure employed was essentially the same as in Example I unless otherwise indicated The compositions tested and the results obtained are summarized in Table II.

I OO, -( 4 E c S twoo 4 m to cq cq C't tn -rn s d dt) -4 -4 4 U 2N.1 I C-.

Z 1 O V) O m W O o m N i \ C 00 00 C^ 00 C C -4 O -0 0 \ C\ O \ i\ O \ Co C 4 cl Ad Ad 4 I I I I 00 \ O 0 000 o O oO O OO W O -4 Wrn U, U, c 0 U :i o.

, c) 0 Cdl R 0 0 o, Cds U -.4 1,573,144 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 p H-dependent, with little or no activation occurring under test conditions at p H-values of 7 and below 5 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 peroxidebased bleaches 10 employed in these experiments are listed in Table III, while the results of the experiments are tabulated in Table IV.

TABLE IX

Product Type % H 202 c) Bleach A Liquid a) 5 9 Bleach B Liquid a) 3 2 Bleach C Solid b) 49 Bleach D Solid b) 8 0 Bleach E Solid b) 75 Bleach F Solid b) 49 a) Aqueous hydrogen peroxide.

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

c) Determined by iodometric titration.

I-.

TABLE IV

Exp Product only Product plus cyanamide c) No Product a) R % H 202 utilized b) AAR 22 Bleach A 0 3 1 95 17 23 Bleach B 0 3 2 90 17 24 Bleach C 0 3 5 89 14 Bleach D 0 4 1 91 8 26 Bleach E 0 2 5 94 11 27 Bleach F 0 2 4 83 11 -.o i4 x a) Added to wash water at p H 9 6-10 to provide initial H 202 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) H 2 NCN concentration 8 8 mmol /l.

t'J 13 1,573,144 13 The foregoing test results indicate that while the commercial peroxidebased 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 5

A series of experiments was conducted to compare the bleaching effectiveness of cyanamide activated peroxide-based bleach compositions 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 10 TABLE V S 15

Ep. Activator H 202 p H No.p Compound mmol / mmol /l Added as Wash water AR No.

28 None 8 8 50 % H 202 9 6 2 4 29 Dicyanodiamide 9 5 8 8 50 % H 202 9 6 1 7 Dicyanodiamide 17 6 17 6 50 % H 02 10 1 3 3 31 Acetonitrile 9 3 9 1 SPB-4 a) 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 p-Nitrobenzonitrile 9 5 8 8 50 % H 202 9 7 7 2 36 Phthalonitrile 9 1 9 1 SPB-4 10 0 14 8 b) 37 Phthalonitrile 9 1 9 1 50 % H 202 9 7 10 0 b) 38 Cyanamide 9 1 9 1 SPB-4 9 6 20 1 b) 39 Cyanamide 9 1 9 1 50 % H 202 9 7 19 4 c) 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 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 pnitrobenzonitrile 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 in accordance with the invention 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 p H adjusted to about 4 using dilute sulphuric acid.

The percentage of hydrogen peroxide, p H 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 50 C The hydrogen peroxide concentration was determined by iodometric titration.

The results of the tests were as follows:

1,573,144 XTABLE VI

Day 0 H 2 NCN %H 202 p H Stability at 50 C at Day 5 L Ra) %H 202 p H Ma) o 1 4:.

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 8 0 1 2 a) For each test 2 5 g of formulation 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 p H.

Exp.

No.

Concentration (% w) H 202 Day 7 %H 202 p H A Ra) b 1,573,144 15 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 cyanamideactivated peroxidebased 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 5 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 hardness and detergent at various p H-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 490 C 10 C\ TABLE VII

Activator H 202 Compound mmol /Il mmol /l Builder Type mmol /l AR p H Wash cycle Initial Final 10 min 20 min.

43 None 44 Cyanamide Cyanamide 46 Cyanamide 47 Cyanamide 48 Cyanamide 49 Cyanamide Benzonitrile 51 p-Nitrobenzonitrile 52 Phthalonitrile 53 Phthalonitrile 8 8 8 8 8 8 8 None 8 None 8 STPP 8 TSP 8 Na 25 i O 3 8 Na 2 CO 3 8 Na 2 B 407 8 None 8 None None None 1 3 4 4 9.7 9.4 9.5 9.5 9.7 9.5 9.2 9.6 9.2 9.3 9.4 9.4 9.8 9.5 9.2 9.4 1.0 6.7 16.8 11.5 5.7 6.8 6.0 0.9 1.3 9.6 20.6 16.0 7.9 8.5 9.2 1.7 1.6 11.0 22.9 18.8 9.0 9.5 10.8 3.1 9.7 9 4 2 5 3 1 4 2 7.5 7 1 1 3 2 6 2 9 7.9 1 9 3 5 4 1 Exp.

No.

min.

8.5 a) TABLE VII (cont'd) Exp.

No.

54 Phthalonitrile Phthalonitrile 56 Phthalonitrile 57 Cyanamide 58 Cyanamide 59 Cyanamide Cyanamide 61 Cyanamide 8 None 8 None 8 None 8 None 8 None 8 None 8 None 8 None 9 5 9 5 a) 2 7 5 8 0 8 5 9 2 3 a) Phthalonitrile in this p H-range appears to hydrolyze rapidly to phthalic acid Sodium hydroxide was added continually during these experiments in an attempt to maintain the initial p H.

b-4 Activator H 202 Compound mmol /1 mmol /1 Builder Type mmol /1 OR p H Wash cycle Initial Final 10 min 20 min.

7.5 8.9 10.1 7.3 7.5 8.0 9.0 10.2 4.2 7.1 5.7 5.9 10.0 9.9 8.2 6.4 min.

6.1 9.5 6.5 18.4 26.9 22.9 13.4 8.2 5.4 8.4 5.3 11.7 20.2 17.0 11.3 7.7 itl Jw z 18 181,573,144 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-activated peroxide-based bleach to give even further bleach enhancement The tests, comparing cyanamide to prior art nitriles again indicate that cyanamide is far superior 5 to benzonitrile and p-nitrobenzonitrile as a peroxide activator Likewise cyanamide is superior to phthalonitrile at each of the p H-levels tested, and exhibits particularly pronounced advantages over phthalonitrile at longer wash cycles, and is not subject to the p H adjustment problems of phthalonitrile.

EXAMPLE 7 10

In this Example Philippine mahogany was bleached employing a cyanamideactivated peroxide-bleaching bath Hydrogen peroxide and cyanamide were made up separately as % aqueous solutions The peroxide solution was adjusted to a p H of 9-10 with sodium hydroxide.

Separate pieces of Philippine mahogany were then treated at room temperature with a 15 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 20 and hydrogen peroxide were bleached more rapidly than those treated with alkaline hydrogen peroxide alone The most effective procedure was to first 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 25 same degree of bleaching.

EXAMPLE 8

To demonstrate the effectiveness of cyanamide in activating a peroxidebased bleach of the percarbonate-type, a test similar to that used in Example 4 was conducted in a Terg-OTometer bath maintained at 490 C containing 8 8 mmoles/l of hydrogen peroxide derived 30 from sodium percarbonate ( 3 Na 2 CO 3 2 H 202), 9 1 mmoles/l of cyanamide activator and 1 0 g/l of detergent The p H 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 35 examples, cyanamide-activated bleaching compositions in accordance with the invention were tested in aqueous media at full scale home laundry 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 (The words "Orlon" and "Dacron" are Registered Trade Marks) Among the stains "bleached-out" 40 during regular and extended wash cycles were bacon grease, grape juice, tea, coffee, dried blood and cooking oils.

EXAMPLE 10

The following tests evidence the substantial benefits which can be realized by the use of the cyanamide-activated bleach system, even under higher-temperature Europeantype laundry 45 conditions, especially if short wash cycles are employed In these tests the wash cycles were conducted at a temperature of 870 C with increased concentrations of detergent (Tide, 8 7 % P) The compositions tested and results obtained were as follows:

50 TABLE VIII

55 Exp H 202 Cyanamide Detergent AR No mmol /i mmol /i gil Wash cycle min 20 min 30 min 60 min.

62 8 0 5 8 11 15 18 63 8 8 5 16 17 19 20 1,573,144 1,573,144 EXAMPLE 11

In this Example an encapsulated solid bleaching composition in accordance with the invention was prepared and subjected to a high temperature storage stability test In this test an encapsulated bleaching composition containing 3 9 %ow cyanamide (solid) , 18 6 %ow s 1 sodium perborate monohydrate, 106 %ow magnesium sulphate tetraacetate and 669 %/ow 5 sodium sulphate, was placed in an open beaker in an oven at 500 C 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 10 C 14-15 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 50 WC the bleaching effectiveness of the composition remained at % of its original value.

EXAMPLE 12 15

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-OTometer bath maintained at a temperature of 490 C and the hardness level of the water 20 adjusted to 150 ppm as Ca CO 3 (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 p H of the water in the bath was maintained in the general range of 10-11 5 throughout the test Although sodium 25 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 30 examined by the technique described in Example 1.

The compositions tested and the results obtained are presented in the following Table:

35 TABLE IX

40 Exp Bleach (SPB-4) a) Ca NC Nb) Detergent c) p H Temp AR No mmol /l mmol /l g/l (final) O C 64 8 1 5 10 2 49 2 0 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 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 Ca NCN (typical assay approximately 65 % Ca NCN).

c) Tide, 12 3 % P (Tide is a powdered detergent manufactured by Procter & Gamble Company).

1,573,144 20 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 5 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.

Exp Bleach No (SPB-4)a) mmol /1 Ca NC Nb) mmol /1 Detergent, c) g/l TABLE X p H Initial Final Temp, o C AR Wash cycle 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 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 8 d) 1 5 11 3 11 2 49 30 1 31 0 33 3 78 8 0 8 d) 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 8 8 1 5 10 9 11 0 7 2 8 8 5 a) SPB-4 = sodium perborate tetrahydrate.

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

c) Tide, 6 1 %P.

d) Ca NCN activator dissolved in hot water prior to addition to Terg-OTometer.

min.

22 1,573,144 22 From the foregoing results it is apparent that Ca NCN effectively activates sodium perborate over a wide range of temperatures, with the very substantial bleach enhancement benefits being achieved at a temperature of 490 C, which is representative of home laundering conditions in the United States.

EXAMPLE 14 5

In this example a series of experiments was conducted to demonstrate the effectiveness of sodium acid cyanamide as a peroxide-based bleach activator The peroxidebased 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 10 The compositions tested and results obtained are summarized in the following table.

TABLE XI

Exp Bleach Na HNCN Detergent a) p H Temp, AR No mmol /l mol /l Type g/l Initial C Wash Cycle min 20 min 30 min 60 min.

81 8 b) 10 5 48 2 4 3 4 3 8 82 8 b) 8 10 7 48 26 2 28 8 31 9 33 6 83 8 b) 8 A 1 5 10 4 48 28 2 34 6 38 0 42 2 84 8 b) 8 B 1 5 10 8 48 13 1 15 3 17 2 19 2 8 c) 0 8 B 1 5 10 1 48 6 8 8 9 10 7 86 8 c) 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.

-J w' 24 1,573,144 24 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 in accordance with the

invention was subjected to a high temperature storage stability test In this test the composition was placed 5 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:

10 Composition 5.9 %ow Sodium acid cyanamide 18.6 %ow Sodium perborate monohydrate 10.6 %ow Magnesium sulphate, anhydrous 64 90 ow Sodium carbonate, anhydrous 15 Stability at 500 C 20 Ma) Days in Wash Cycle Storage 10 min 20 min 30 min 60 min.

0 29 38 41 44 25 b) 28 36 40 43 37 26 34 36 39 30 a) Determined under essentially the same conditions as in Example 12, except that 1 5 g/l of Cheer, 00 o 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 C 12-C 15 linear, primary alcohol ethoxylate) per hundred parts of the composition Encapsulation was effected by blending the composition with the encap 35 sulating 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 % of its bleaching effectiveness after 37 days storage at 500 C.

EXAMPLE 16 40

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 deionized water was added to a U S Testing, Inc Terg-OTometer bath maintained at the temperatures indicated in Table I and the hardness level of 45 the water adjusted to 150 ppm as Ca CO 3 (Ca/Mg = 3/2 on a molar basis) The p H of the water in the bath was adjusted to the values shown in Table I by the addition of the detergent and Na OH as required, as the alkaline buffering agents The peroxidebased 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 50 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.

l 1,573,144 TABLE XII

Group IIA b) Deter p H ALR Exp Bleacha) H 2 NCN 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 8 0 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 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 8 8 8 1 5 9 7 9 4 7 6 4 12 2 E" 74 a) Hydrogen peroxide (introduced as a stabilized, commercial grade 50 % aqueous solution).

b) Introduced as magnesium sulphate (Mg SO 4 7 H 20).

c) Tide containing 6 1 % phosphorus (Tide, 6 1 % P) Tide is a powdered detergent manufactured by Procter & Gamble Company.

t Li ul 26 1,573,144 26 The foregoing tests indicate that the compositions 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 5 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

AR Exp Bleacha) H 2 NCN Metal Salt or Oxide Detergent 1) p H 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 8 b) 0 Ca NC Nc) 8 8 1 5 9 8 49 20 103 8 8 8 8 Mg Od) 10 5 1 5 9 8 49 22 104 8 8 8 8 Mg C 12 6 H 20 4 9 1 5 9 8 49 28 8 8 8 8 Mg SO 4 7 H 20 3 3 1 5 9 8 49 23 106 8 8 8 8 Mg(N 03)2 6 H 20 3 9 1 5 9 8 49 26 107 8 8 8 8 Ca(NO 3)2 4 H 20 4 2 1 5 9 8 49 24 108 8 8 8 8 Ba C 12 2 H 20 4 1 1 5 9 8 49 25 109 8 8 8 8 Sr CI 2 2 H 20 5 1 1 5 9 8 49 25 8 8 8 8 Al(CH 3 COO)e 3) 7 1 1 5 9 8 49 11 111 8 8 8 8 Li OH 37 0 1 5 9 8 49 15 112 8 8 8 8 Rb Cl 8 3 1 5 9 8 49 16 113 8 8 8 8 Ni C 12 6 H 20 4 2 1 5 9 8 49 1 9 114 8 8 8 8 Mn SO 4 H 20 6 0 1 5 9 8 49 0 8 8 8 8 Cu C 12 2 H 20 1 2 1 5 9 8 49 -2 2 116 8 8 8 8 Fe(NO 3)3 9 H 20 2 5 1 5 9 8 49 3 0 117 8 8 8 8 Hg C 12 7 4 1 5 9 8 49 5 4 118 8 8 8 8 NH 4 VO 3 8 6 1 5 9 8 49 0 6 119 8 8 8 8 Ti(i-C 3 H 70)4 7 0 1 5 9 8 49 1 4 8 8 8 8 Sn CI 2 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) Ca NCN 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 4 Mg CO 3 Mg(OH)2 N H 20 ( 42 4 % Mg O).

e) Added as Al(OH)2 (CH 3 COO) 1/3 H 3 BO 3.

f) Tide, 6 1 %P.

hi j ls 28 1,573,144 28 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 5 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 10

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 15 in these experiments are tabulated in Table XV.

20 TABLE XIV

Product Type % H 202 C) Bleach A Liquid a) 5 9 Bleach B Liquid a) 3 2 25 Bleach C Solid b) 4 9 Bleach D Solid b) 8 0 Bleach E Solid b? 75 Bleach F Solid b) 4 9 30 a) Aqueous hydrogen peroxide.

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

c) Determined by iodometric titration 35 l 1,573,144 TABLE XV

Product only %H 202 utilizedb) AR Product plus H 2 NCNC) %H 202 utilizedb) AR Product plus H 2 NC Nc) plus Mg d) % H 202 utilizedb) m 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 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 H 202 concentration of 8 8 mmol /1.

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, p H adjusted to 9 6-10.

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

c) H 2 NCN concentration 8 8 mmol /l.

d) Added as Mg SO 4 7 H 20 at 3 3 mmol /l.

Exp.

No.

Producta) -P.

1,573,144 30 The foregoing test results indicate that while the commercial peroxidebased 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 5 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) 10 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

AR Bleach Group IIA p H Wash Cycle Exp SPB-1 Na HNCN Metalb) Detergent c) 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 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 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 Mg SO 4 7 H 20 or Ca C 12 2 H 20.

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.

32 1,573,144 32 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 5 EXAMPLE 20

A series of experiments was conducted to determine the effect of commonly employed detergent builders on the bleaching action of Group HA metal-containing, cyanamideactivated, peroxide-based bleach compositions The test procedure employed was similar to 10 that described in Example 16, except that deionized 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 Terg-OTometer bath in all of these tests was 490 C.

TABLE XVII

Exp H 2 NCN H 202 Mg 504 No mmoles/l mmoles/l mmoles/l Type Builder mmoles/l Initial p H OR Wash Cycle Final 10 mins 20 mins 30 mins.

139 0 8 0 None 9 7 9 2 1 0 1 3 1 6 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 STP Pa) 2 9 6 9 4 31 7 38 7 41 2 143 8 8 4 TS Pb) 3 9 3 9 0 33 6 42 6 46 4 144 8 8 4 Na 2 Si O 3 4 9 4 9 0 35 4 42 6 45 9 8 8 4 Na 2 CO 3 4 9 5 9 4 31 2 35 7 37 9 146 8 8 4 Na 2 B 407 4 9 3 9 2 27 4 32 5 34 3 a) STPP = Sodium tripolyphosphate b) TSP = trisodium phosphate win L Pl 34 1,573,144 34 The foregoing test results indicate that hydrogen peroxide alone, or in combination with magnesium sulphate in the absence of cyanamide, exhibits virtually no bleaching activity at 490 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 5 TSP), silicates and carbonates, and to a lesser extent borates.

EXAMPLE 21

In this example an encapsulated solid bleaching composition in accordance with the invention was prepared and subjected to a high temperature storage stability test In this test an encapsulated bleaching composition containing 5 9 %/Ow sodium acid cyanamide, 18 6 %w 10 sodium perborate monohydrate, 10 6 %w di-magnesium ethylenediamine tetraacetate and 64.9 %w sodium sulphate, was placed in an open beaker in an oven at 50 C 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 15 by weight of the aforementioned ingredients with 12 parts by weight of Neodol 25-9 (a C,2-15 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 WC the bleaching effectiveness of the composition remained at 84 % of its original value 20 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 25 was employed in the Terg-O-Tometer bath The temperature of the Terg-OTometer bath in all of these tests was 49 CC The compositions tested and results obtained are presented in the following Table.

I 1,573,144 Lu W/ TABLE XVIII

Exp Act H 202 b) Metal ion p H LAR 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 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 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 40 9 -3 -P a) sodium acid cyanamide (Na HNCN); b) Aqded as Na BO 3 H 20; c) Added as Ca(NO 3)2 4 H 20; Ca(CH 3 COO)2 H 20; e) Added as Ba CI 2 2 H 20;) Added as Sr CI 2 6 H 20; g) Added as Mg SO 4 7 H 20.

d) Added as 1,573,144

Claims (19)

WHAT WE CLAIM IS:

1 A stable bleaching composition comprising:

(a) from 2 5 to 35 % by weight, calculated as hydrogen peroxide, of a peroxide-based bleach, (b) cyanamide and/or a metal cyanamide, and optionally 5 c) a Group IIA metal compound.

2 A composition as claimed in claim 1, wherein the amount of component (a) is from 3 to % by weight, calculated as hydrogen peroxide, of the total composition.

3 A composition as claimed in claim 1 or claim 2, wherein the molar ratio of component (b) to component (a) is in the range 1:20 to 20:1 10

4.A composition as claimed in claim 3, wherein said range is 1:1 to 1:10.

A composition as claimed in any one of the claims 1 to 4, wherein the molar ratio of component (c) to component (a) is in the range 1:60 to 25:1.

6 A composition as claimed in any one of claims 1 to 5, wherein component (b) is a Group IA or Group IIA metal cyanamide, in particular calcium cyanamide, disodium 15 cyanamide or sodium acid cyanamide.

7 A composition as claimed in any one of claims 1 to 6, wherein component (c) is a calcium or magnesium salt or oxide, in particular magnesium sulphate, magnesium chloride, magnesium nitrate, dimagnesium ethylenediamine tetraacetate, calcium chloride or calcium nitrate 20

8 A composition as claimed in any one of claims 1 to 7, wherein component (a) is an aqueous solution of a peroxide-based bleach and a buffering agent is also present to maintain the p H of the composition in the range 2 to 5.

9 A composition as claimed in claim 8, wherein component (a) is hydrogen peroxide.

10 A composition as claimed in claim 8 or claim 9, wherein component (b) is cyanamide 25

11 A composition as claimed in any one of claims 1 to 7, wherein the composition is a solid mixture of component (a), component (b) and optionally component (c) .

12 A composition as claimed in claim 11, wherein component (a) is sodium perborate, preferably sodium perborate monohydrate, or sodium percarbonate.

13 A composition as claimed in claim 11 or claim 12, wherein a desiccantis also present 30

14 A composition as claimed in any one of claims 11 to 13, wherein component (a) and/or component (b) is encapsulated.

A composition as claimed in any one of claims 1 to 14, wherein a soap or detergent is also present.

16 A stable bleaching composition as claimed in claim 1 and substantially as hereinbe 35 fore described.

17 A stable bleaching composition as claimed in claim 1, and substantially as hereinbefore described with reference to any one of Examples 5, 11, 15 and 21.

18 A built laundry detergent composition comprising a synthetic detergent and an alkaline detergent builder, and which has been formed by mixing with said detergent and said 40 builder sufficient of a stable bleaching composition as claimed in claim 1 in an amount to provide from 0 1 to 2 0 %w, calculated as hydrogen peroxide, of a peroxide-based bleach in said built composition.

19 An alkaline bleach medium comprising an aqueous medium to which has been added a stable bleaching composition as claimed in any one of claims 1 to 17 or a built composition 45 as claimed in claim 18, the aqueous medium containing the composition being maintained under alkaline conditions, optionally by the presence of a buffering agent.

R.C ROGERS chartered Patent Agent Shell Centre London SE 1 7 NA Agent for the Applicants Printed tor Her Majesty' Stationers Ottice by Croydon Printing Company Limited Croydon Surrey 1980.

Published bs The Patent Ottice 25 Southampton Buildings London WC 2 A l AY from which copies ma be obtained.

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