GB2096162A

GB2096162A - Effervescent cleansing composition

Info

Publication number: GB2096162A
Application number: GB8209534A
Authority: GB
Original assignee: Warner Lambert Co LLC
Current assignee: Warner Lambert Co LLC
Priority date: 1981-04-03
Filing date: 1982-03-31
Publication date: 1982-10-13
Also published as: GB2096162B; ZA822235B; CA1183752A; AU8219782A; AU553406B2

Abstract

There is disclosed an effervescent cleansing composition comprising: (a) an oxidizing agent comprising a monopersulphate salt, in an amount of from 35 to 60% by weight; (b) a bleaching promoter selected from alkali metal and alkaline earth metal halides, and being present in an amount of up to 20% by weight; and (c) an effervescence promoting compound comprising a perborate salt, present in an amount of from 0.5 to 20% by weight; wherein the effervescent cleansing composition effervesces at an alkaline pH when placed in solution, and wherein the percentages by weight relate to the total weight of the composition. When the composition also contains a colourant, there may also be present a fade control agent, which is especially useful when the composition is to be used as a denture cleansing composition. The composition is effective and is easy to manufacture.

Description

SPECIFICATION Effervescent cleansing composition This invention relates generally to effervescent cleansing compositions and more particularly to those cleansing compositions that include oxidizing and bleaching agents.

Cleansing compositions have for some time used oxidizing agents and bleaching agents in concert to remove visible stains from hard surfaces, while at the same time effecting the removal of scale or plaque build-up on those surfaces. Thus, cleansing compositions, prepared with abrasive materials for use as scouring cleansers, or alone for the purpose of mild surface cleaning applications, have employed a variety of sulphate salts, e.g. bisulphates, monopersulphates and sulphates, as detergents, oxidizers and the like, and have utilized alkali metal and alkaline earth metal halides as bleaches.

Thus United States Patent No. 3,458,446 to Diaz discloses an abrasive cleansing composition which utilizes certain monopersulphate oxidizing agents in combination with a water-soluble bromide salt, in place of chlorine-liberating constituents conventionally employed in such compositions. The replacement of the chlorine constituents by the bromide constituents was found to eliminate the unpleasant odour of chlorine. The composition disclosed in Diaz was primarily intended for use in powdered form, and utilized a variety of additives, such as detergents and builders, in its formulation.

The preparation of cleansers to be utilized in a solution in which the articles to be cleaned are dipped or soaked, presents different problems from those that attend the preparation and use of cleansing compositions that are applied to the surface of the articles to be cleaned. Thus, whereas one may apply a composition, either in liquid or granular form, to a surface and may then agitate the surface to assist the cleaning operation, the employment of compositions that operate in a "passive" manner to serve as dipping solutions, gives no indication of their efficacy, and of the period of their activity.In particular, cleansers utilized for the preparation of dipping solutions for dentures and the like, have conventionally exhibited an effervescent action in solution that assists in stain and plaque removal by providing a desired amount of agitation in the solution to promote cleansing activity. Also, such compositions have conventionally included colourants such as dyes, incorporated into the composition to indicate the presence of the cleansing composition in the solution.

The effervescent activity of these solution-forming cleansing compositions has conventionally been provided by the inclusion in the composition of the ingredients sodium bicarbonate and citric acid.

Correspondingly, the reaction of these two ingredients has taken place at a pH that is weakly acidic or neutral, with a sacrifice in the efficiency and speed of cleaning, that would be achieved by the employment of a composition operable at a more basic pH.

The employment of the colourant in the composition as an indicator has been for the purpose of not only indicating the presence and activity of the cleansing composition, but serves to indicate by its disappearance the cessation of cleaning activity. For example, in the instance where denture cleansers are prepared, a dye component is included as an indicator to signify by colouration the presence of the cleansing composition and the commencement of its activity. In these applications, the actual period of activity is reasonably finite, and is predetermined by the manufacturer.

Accordingly, as the indicator or dye indicates to the user that the cleaning process has ended, attempts have been made to control the disappearance or fading of the dye, so that the disappearance of the dye will coincide with the completion of the cleaning cycle. Attempts to control the time span of the dye component have included the addition of limited quantities of dye, and the inclusion of additional amounts of bleaching agents to cause the dye to fade more quickly. The first approach has been generally unsuccessful, and the second approach proved uneconomical; the inclusion of additional bleach to fade the dye frequently required additional dye to be added to the composition to give the appropriate depth of initial colouration, and in turn required additional bleach to be added for fade control.

According to the present invention, there is provided an effervescent cleansing composition comprising: (a) an oxidizing agent comprising a monopersulphate salt, in an amount of from 35 to 60% by weight; (b) a bleaching promoter selected from alkali metal and alkaline earth metal halides, and being present in an amount of up to 20% by weight; and (c) an effervescence promoting compound comprising a perborate salt, present in an amount of from 0.5 to 20% by weight; wherein the effervescent cleansing composition effervesces at an alkaline pH when placed in solution, and wherein the percentages by weight relate to the total weight of the composition.

Preferably the oxidizing agent comprises an alkali metal monopersulphate salt.

The composition, upon dissolution, provides a solution which possesses a pH in the basic range.

The composition may include sodium carbonate in an amount that may range from 20 to 40%, and sodium hydroxide may also be present in an amount of up to 0.5% to assist in pH maintenance.

Thus, the present invention provides an effervescent cleansing composition comprising: (a) an oxidizing agent comprising a monopersulphate salt, in an amount of from 35 to 60% by weight; (b) a bleaching promoter comprising an alkali metal halide, in an amount of from 10% to 20% by weight; (c) an effervescence promoting compound comprising a perborate salt, in an amount of from 0.5% to 20% by weight; (d) sodium carbonate in an amount of from 20 to 40% by weight; and (e) sodium hydroxide in an amount of up to approximately 0.5% by weight; wherein the effervescent cleansing composition is operable to effervesce at an alkaline pH, and the percentages by weight relate to the total weight of the composition.

Preferably, the oxidizing agent comprises potassium monopersulphate, and is present in an amount ranging from 40% to 50%.

The bleaching promoter may comprise an alkali metal halide, preferably a chloride, bromide, iodide or mixture thereof, more preferably sodium chloride. The bleaching promoter is preferably present in an amount ranging from 10 to 20%.

The perborate compound may comprise an alkali metal perborate or alkaline earth metal perborate, e.g. potassium or sodium perborate and is present in an amount ranging from 0.5 to 20%, preferably from 0.7 to 1 5% by weight.

Solutions containing the present cleansing composition possess effervescing capability within an alkaline pH, owing to the presence of the perborate compound. The perborate is theorized to react with the oxidizing agent and the bleaching promoter to initiate effervescence. The ability of these solutions to achieve effervescence within a basic pH range yields improved cleaning efficiency at reduced cost.

The cleansing composition of the present invention may also include at least one material selected from builders, sequestrants, detergents, colourants, perfumes, flavourings, excipients, pH stabilizers, tableting agents, disintegrants, and mixtures thereof.

The cleansing composition may be prepared in tablet form, and may accordingly include tableting agents, excipients, disintegrants and the like. In this latter form, the cleansing composition is particularly useful as a denture cleanser.

Preferably the builders are selected from alkali metal carbonates, alkali metal phosphates, and mixtures thereof; the sequestrants comprise polyfunctional organic acids, and their alkali metal salts, the pH stabilizers comprise sodium hydroxide; and the colourants comprise at least one food, drug and cosmetic or drug and cosmetic grade dye or lake.

More preferably the builders comprise sodium carbonate and/or trisodium phosphate whose total amount is in the range from 20 to 40% by weight; the sequestrants comprise the alkali metal salts of ethylenediamine tetraacetic acid in an amount of from 0.33.5% by weight; and the colourants are selected from food, drug and cosmetic grade dyes or lakes having the individual colours blue, red and green, and mixtures thereof, in amounts of up to approximately 0.5% by weight.

Preferably, when at least one colourant is present, there is also present in the composition a fade control agent comprising a compound providing soluble halide ion, the fade control agent being present in an amount sufficient to promote the fading of the colourant within 18 minutes after the composition containing the colourant is placed in solution.

Alternatively, when at least one colourant is present, there is also present in the composition a fade control agent comprising a compound providing soluble halide ion, the fade control agent being present in an amount of from 0.04% to 0.3% by weight.

The fade control agent is preferably present as from 0.04 to 0.18% by weight and preferably comprises a compound selected from alkali metal bromides, chlorides and iodides, and mixtures thereof.

Thus, in accordance with one embodiment of the present invention, a cleansing composition is provided which comprises an oxidizing agent containing a monopersulphate salt, in an amount of from 35%60%, a bleaching promoter selected from alkali metal and alkaline earth metal halides, present in an amount of up to 20%, an effervescence promoting compound selected from alkaline earth metal and alkali metal perborates, present in an amount from 0.05 to 20%, a colourant selected from pigments and dyes, and preferably comprising non-toxic dyes, the colourant being present in an amount that may be as high as 1%, and a fade control agent comprising a compound capable of providing soluble halide ion. The halide component of the fade control agent may be selected from bromide, iodide and chloride ion, and is preferably selected from bromide and iodide.

The fade control agent is theorized to coact with the oxidizing agent in a catalytic manner that may abruptly accelerate the fading of the colourant. The fade control agent is particularly useful in the instance where the colourant comprises those dyes certified by the Food and Drug Administration as acceptable for use in foods, drugs and cosmetics, and known as F.D. s C. grade dyes. Also, D. s C.

grade dyes, and insoluble dyes, such as F. D. C. and D. 8 C. grade lakes may be utilized. C. grade may also be used.

The amount of fade control agent present in the cleansing composition of the present invention varies with the amount of dye and oxidizing agent present in the composition, and to a lesser extent, the amount of perborate salt included therein. In a preferred embodiment, the fade control agent may comprise potassium bromide, and may be present in an amount ranging from 0.04 to 0.3%.

The fade control agent appears to act in an unexpected catalytic manner and is particularly useful in the instance where the composition is prepared in tablet form as a denture cleanser. The dissolving tablet has been found to provide an initially strong, intensely coloured solution. This intense colour may be maintained for varying periods of time, depending on the desired quantities of colourant, perborate, oxidizing agent and fade control agent utilized.

By use of a particular quantity of the fade control agent, the colour intensity of the solution can be maintained for a predetermined period of time, after which the fading of the colour becomes noticeably accelerated, and a substantially colourless solution is thereafter rapidly obtained. For example, increments of as little as 0.1 milligram of the fade control agent have been found to vary the fade time of the dyes utilized in denture cleanser tablets prepared in accordance herewith, by as much as 1 minute; thus, the addition of 0.1 milligram of the fade control agent has been found to reduce the time it takes for the dyes to completely disappear by as much as 1 minute.

The foregoing compositions are useful in a variety of applications, apart from their preparation into denture cleanser tablets. Thus, for example, the compositions of the present invention may additionally be prepared as household cleansers, such as laundry bleaches and toilet bowl cleansers.

Depending upon the desired applications, the cleansing compositions including those having the fade control agent, may include additional ingredients, such as soaps, perfumes, flavorings, and the like that may range in total amount as high as 5-1 0%. Preferably, these additional ingredients are present in amounts of up to 5%.

As used throughout the present specification, all percentages are intended to be percent by weight.

The cleansing compositions of the present invention can be formulated so as to be capable of effervescing within a basic pH range.

The cleansing compositions of the present invention can include certain colourants and agents capable of controlling the colour reaction.

The cleansing compositions of the present invention may be particularly utilized as denture cleansers, and can be both inexpensively prepared and reliable in use.

In the effervescing cleansing compositions of the present invention, the oxidizing agent may be an alkali metal monopersulphate salt, present in an amount ranging from 35 to 60%, preferably from 40 to 50% by weight. The alkali metal monopersulphate salts are preferably the potassium or sodium salts, which are commercially available. The potassium salt is preferred, and may, if desired, be employed in the form of a triple salt with potassium bisulphate and potassium sulphate, e.g.

KHSOs.KHSO4.K2SO4. In the mole ratio of about 2:1:1, the foregoing triple salt is known commercially by the registered trademark "OXONE" and is sold by E.l. duPont DeNemours s Co., Inc.

The bleaching promoter or component may likewise be a well known one, and may be selected from alkali and alkaline earth metal halides, in an amount of up to 20%, preferably in the range from 10 to 20% by weight of the composition. The halide salt is preferably selected from alkaline metal halides such as the sodium and potassium salts. In a preferred embodiment, sodium chloride is utilized in an amount in the range from 10 to 20%.

The effervescence promoting compounds comprise the perborate salts, including the alkali metal and alkaline earth metal perborates. Preferably, the perborate salts are selected from the alkali metal salts, such as sodium and potassium, and in a preferred embodiment, sodium perborate monohydrate is utilized. The perborate compounds unexpectedly promote effervescence by their reaction with the halide component. The perborate compounds are theorized to react as reducing agents, thereby recycling the halide to react in turn with the oxidizing agent to promote greater effervescence.

The perborate compounds may be present in amounts ranging from 0.5 to 20%, preferably from 0.7 to 15%.

As noted earlier, solutions obtained from the cleansing compositions possess a pH in the basic or alkaline range, which results in improved stain and soil removing capabilities. In a preferred embodiment, the pH of solutions obtained from the present compositions may range as high as pH 11, and preferably resides within the pH range of 8 to 10. In the instance where the present compositions are formulated as denture cleansers, the preparation of compositions whose solutions will possess a pH within the aforementioned range facilitates the rapid removal of stains, with a reduction in the time that the dentures must reside in the cleansing solution, to as low as five minutes in some instances.

In addition to promoting effervescence in an alkaline or basic pH, the perborate compounds react favourably with the chloride bleaching promoters to reduce or eliminate the irritating odour and after taste caused by the presence of the hypochlorite resulting from the reaction of the chloride salt with the oxidizing agent. The elimination of the hypochlorite odour permits the compositions of the present invention to be modified by the addition of perfuming agents and flavours, in the instance where the present compositions are to be formulated for use as denture cleansers.

As noted earlier, the cleansing compositions described above may be prepared in various formulations, and, accordingly, may contain certain additional ingredients selected on the basis of desired end use. Thus, for example, the compositions may include additional detergent compounds, including organic and inorganic detergents, including non-ionic detergents such as the various polyoxyethylene ethers of aromatic and aliphatic alcohols, as wells as the polyoxyethylene ethers of hydrophobic propylene oxide polymers. These compounds assist in maintaining a foaming action, in the instance where the cleansing compositions are placed in aqueous solution.

Also, the compositions may contain other adjuvant materials, that may be inorganic or organic in structure. Thus, inorganic water-soluble alkaline builders such as alkali and alkaline earth metal carbonates, tetrapyrophosphates, tripolyphosphates, phosphates, metasilicates, and hydroxides, and mixtures of these may be added. Particularly, sodium carbonate may be present in an amount ranging from 20 to 40%, and preferably in an amount of from 25 to 30%, as it functions not only as a builder, but enhances effervescence and assists in stabilizing the pH of the solutions obtained from the composition. In this latter capacity, sodium hydroxide may be added to assist in pH stabilization and may be present in amounts of up to about 0.5%, and preferably 0.3% to 0.5%.

The present compositions may also contain sequestrants for the purpose of maintaining solution clarity, in the instance where the compositions are placed in solution. Sequestrants useful in the present invention include ethylene diamine tetraacetic acid (EDTA) and its corresponding alkali salts, as well as other polyfunctional organic acids, such as citric acid, maleic acid, and their corresponding salts. The sequestrants may be present in an amount of up to 3.5%, preferably from 0.3% to 3.5% by weight of the composition.

In the instance where the composition is to be prepared for use as a denture cleanser, other additives such as flavourings, colourants, perfumes and the like may be added in various amounts, as mentioned earlier. For example, the flavourings may include varieties of mint. These materials may be included and blended in various combinations within the scope of the present invention. The choice of the required amounts is likewise within the skill of the art.

In the instance where the present cleansing compositions are formulated for use as denture cleansers, the colourants useful herein are those known as F.D. s C. and D. 8 C. dyes and lakes. These materials are certified by the Federal Food and Drug Administration as acceptable for use in food, drug and cosmetic applications, and drug and cosmetic colourings. The materials acceptable for the foregoing spectrum of use are preferably water-soluble, and include indigold dye, known as F.D. s C.

Blue No. 2, which is the disodium salt of 5,5'-indigotindisulfonic acid. Similarly, the dye known as F.D.

8 C. Green No. 1, comprises a triphenylmethane dye and is the monosodium salt of 4-[4-(N-ethyl-psulphobenzylamino)diphenylmethylene]-[1 -(N-ethyl-N-p-sulphoniumbenzyl)-A2,5-cyclohexadienimine].

A full recitation of all F.D. s C. and D. & C. and their corresponding chemical structures may be found in the Kirk-Othmer Encyclopedia of Chemical Technology, at Volume 5, pages 857-884, which text is accordingly incorporated herein by reference. Dyes and colourants will fade at different rates and may be chosen to provide specific end points.

The foregoing colourants may be blended with each other in a variety of combinations. It is particularly desirable that the colourants be chosen so that the composition when initially dissolved will present a deep hue. This is important in the instance where the composition serves as a denture cleanser, as the fading phenomenon embodied in denture cleansers can be more easiiy observed by the end user.

As indicated above, the effervescent cleanser compositions may be prepared to include a fade control agent, in the instance where the compositions contain a colourant such as previously described, and are to be utilized in applications where cessation of composition activity is signified by disappearance of the colour. The fade control agent comprises a compound providing soluble halide ion. The halide component of the fade control agent may be selected from bromide, iodide and chloride ion, and is preferably selected from bromide and iodide ion.

The amount of fade control agent present in the composition may vary, depending upon the end utility of the composition, as the fade time of the colourants employed will vary with the colourants, and with the end use to which the composition is put. For example, in the instance where the composition is to be utilized as a denture cleanser, it is desirable that the fade control agent be present in an amount sufficient to cause the total disappearance of the colourant within 1 8 minutes after a composition containing the colourant is placed in solution. Naturally, the amount of fade control agent present may be adjusted to accelerate the fading reaction and correspondingly to reduce the fade time.

Thus the present invention provides an effervescent cleansing composition comprising: (a) an oxidizing agent comprising a monopersulphate salt, in an amount of from 35 to 60% by weight; (b) a bleaching promoter comprising an alkali metal halide, in an amount of from 10 to 20% by weight; (c) an effervescence promoting compound comprising a perborate salt, in an amount of from 0.5% to 20% by weight; (d) sodium carbonate in an amount of from 20 to 40%; (e) sodium hydroxide in an amount of up to approximately 0.5%; (f) a colourant comprising at least one food, drug and cosmetic grade, or drug and cosmetic grade, dye or lake, in an amount of from 0.15 to 0.5% by weight; and (g) a fade control agent comprising a compound providing soluble halide ion in an amount sufficient to permit the fading of the colourant within 1 8 minutes after the composition containing the colourant is placed in water.

One of the surprising aspects of the present invention, is that the fade control agents set forth herein operate in a catalytic manner, in that minute quantities of the fade control agents can achieve substantial and precise fade time control. For example, in the instance where a denture cleanser tablet is prepared having a weight of approximately 3.3 grams, with a content of about 4 milligrams of colourant, the addition of 1 milligram of the fade control agent can effect the reduction of the fade time of the colourant to within about 12 minutes. Moreover, the inclusion of an additional 0.1 milligram of the fade control agent to the denture cleanser tablet causes a reduction of 1 minute in the fade time.

The foregoing results are particularly advantageous in that the addition of the present fade control agent does not adversely effect the initial colour reaction of the composition when placed in an aqueous solution. Prior art attempts to control fade time by the addition of greater quantities of bleaches and the like, have adversely effected the initial colour reaction of the tablet, and have therefore been undesirable for use.

The particular fade control agents useful in the compositions of the present invention comprise those compounds selected from the group consisting of the alkali metal salts of bromine, chloride and iodine, individually or in mixtures with each other. The potassium salts of these compounds are generally preferred, and more particularly, the compounds potassium bromide and potassium iodide have been found to be most effective.

The fade control agents may be added to the cleansing compositions in an amount ranging from 0.04 to 0.3% by weight of the composition. Preferably, the fade control agents are present in an amount ranging from 0.04 to 0.18% by weight.

The compositions of the present invention are capable of preparation by a variety of techniques, depending upon the intended end use. In the instance where the present compositions are to serve as denture cleansers, it is desirable to prepare the compositions in tablet form. The use of the present compositions in tablet form is commercially preferred, as it is easier to achieve the uniformity of quantity and distribution of the ingredients of the compositions that is necessary to ensure the corresponding uniformity of performance of the denture cleanser. Thus, cleanser tablets have been found to exhibit uniformity of colour reaction, disintegration and fade time, and cleaning ability on a tablet-to-tablet basis.

To enable the present composition to be prepared in tablet form certain ingredients, including excipients, tableting agents and the like are added, and the resulting composition is then compressed to form the final tablet. The particular tableting additives utilized herein comprise conventional materials normally utilized for such purpose, and may be selected and employed in amounts determined within the skill of the art.

In the instance where the contemplated composition is to contain a halide such as sodium chloride, it is advisable to add the basic component such as sodium carbonate to the ingredients prior to adding the monopersulphate salt, in order to avoid undue or premature reactivity of the resulting mixture.

A fuller understanding of the present invention will be gained from a review of the following illustrative examples. Compositions representing both the alkaline effervescing system, and the fade control agent are included. Unless specified otherwise, all amounts expressed as percent are deemed to be percent by weight of the total composition.

Examples 1-9 A series of compositions were prepared for use as denture cleansers, and comprised the ingredients set forth in the following Table 1, below.

The compositions were prepared in tablet form, each tablet weighing approximately 3.3 grams.

The tablets were thereafter immersed in approximately 125 millilitres of water maintained at a temperature of about 450C. The colour reaction, disintegration time, pH and fade time were noted. Quantitles, Weight % Ingredients Example No. 1 2 3 4 5 6 7 8 9 1. Sodium Chloride 14.7 15 15 15 15 15 16 12.1 12.1 2. Sodium Hydroxide 50 % Solution .3 .3 .3 .45 .45 .45 - 3. Potassium bromide .04 .04 .04 .03 .04 .05 - - 4. Water, Potabel USP .17 .75 .75 .06 .06 .06 - - 5. Sodium Carbonate Anhydrous 29 28 28 29 29 29 2.5 25.8 26.3 6. Trisodium Phosphate, Anhydrous, .45 .9 .9 .45 .45 .45 - 2.5 .9 Food Grade, Granular 7. Potassium Monopersulphate Compound 48.3 50 48 49 49 49 49.4 48.7 49.6 8. Ethylenediaminetetraacetic Acid .75 .75 3.0 .75 .75 .75 .7 .7 .7 Tetrasodium salt dihydrate/Pure 9. Sodium Perborate Monohydrate 4.2 4.0 4.0 4.0 4.2 4.2 4.9 7.3 7.4 10.FD#C Blue Colours, mixed .23 .41 .4 .23 .23 .23 .08 .2 .2 11. Flavour and Fragrance .94 .92 .91 .94 .94 .94 .9 .99 .99 12. Detergent .18 .18 .18 .18 .18 .18 0.3 .1 .1 13. Tablet Lubricants .72 .28 .28 .72 .72 .72 - 0.5 0.5 Each of the tablets disintegrated within 5 minutes, and exhibited initially a strong colour reaction, generally bluish on the basis of the dyes included in the colourants.

Favourable effervescence was likewise observed, and the pH of the solutions of each of the compositions ranged between 9.0 and 9.6. In the instance where the compositions contained the fade control agent, fade time for the colourant ranged between 7 and 1 7 minutes.

Example 10 Using a composition similar to that of Example 1, incremental additions of potassium iodide were made, after tablets of the composition were placed in separate containers holding 1 25 millilitres of water, maintained at a temperature of 45 degrees C. Four such containers were prepared having the incremental additions of potassium iodide set forth in the following Table 2 below.

Table 2 Potassium lodide Sample No. Added(mg) Fade Time (min) 1 0 (Control) 1 2 2 0.5 10 3 1.0 9 4 1.5 8 5 2.0 7 It is apparent from a review of Table 2 above that 0.5 milligram incremental additions of potassium iodide effected substantial incremental reductions in the fade time, the most significant change being that of 2 minutes reduction upon the addition of the first .5 milligram increment. It is apparent from the above that substantial fade time reductions can be achieved with minimal incremental additions of the fade control agents.

Claims

1. An effervescent cleansing composition comprising: (a) an oxidising agent comprising a monopersulphate salt, in an amount of from 35 to 60% by weight; (b) a bleaching promoter selected from alkali metal and alkaline earth metal halides, and being present in an amount of up to 20% by weight; and (c) an effervescence promoting compound comprising a perborate salt, present in an amount of from 0.5 to 20% by weight; wherein the effervescent cleansing composition effervesces at an alkaline pH when placed in solution, and wherein the percentages by weight relate to the total weight of the composition.

2. A composition as claimed in Claim 1, wherein the oxidizing agent comprises an alkali metal monopersulphate salt.

3. A composition as claimed in Claim 2, wherein the alkali metal monopersulphate salt comprises potassium monopersulphate.

4. A composition as claimed in Claim 1, 2 or 3, wherein the monopersulphate salt is present in an amount of from 40 to 50% by weight of the total weight of the composition.

5. A composition as claimed in any preceding claim, wherein the bleaching promoter comprises an alkali metal halide.

6. A composition as claimed in Claim 5, wherein the alkali metal halide is selected from the chloride, bromide, iodide and mixtures thereof.

7. A composition as claimed in Claim 6, wherein the alkali metal halide of the bleaching promoter is sodium chloride.

8. A composition as claimed in any preceding claim, wherein the bleaching promoter is present in an amount of from 10 to 20% by weight of the total weight of the composition.

9. A composition as claimed in any preceding claim, wherein the effervescence promoting compound comprises a perborate salt selected from the alkali metal and alkaline earth metal perborates.

10. A composition as claimed in any preceding claim, wherein the effervescence promoting compound comprises an alkali metal perborate.

11. A composition as claimed in Claim 10, wherein the effervescence promoting compound comprises potassium perborate monohydrate.

1 2. A composition as claimed in any preceding claim, wherein the effervescence promoting compound is present in an amount of from 0.7 to 1 5% by weight of the total weight of the composition.

13. A composition as claimed in any preceding claim, which further includes at least one material selected from builders, sequestrants, detergents, colourants, perfumes, flavourings, excipients, pH stabilizers, tableting agents, disintegrants, and mixtures thereof.

14. A composition as claimed in Claim 13, wherein the builders are selected from alkali metal carbonates, alkali metal phosphates, and mixtures thereof; the sequestrants comprise polyfunctional organic acids, and their alkali metal salts; the pH stabilizers comprise sodium hydroxide; and the colourants comprise at least one food, drug and cosmetic or drug and cosmetic grade dye or lake.

1 5. A composition as claimed in Claim 14, wherein the builders comprise sodium carbonate and/or trisodium phosphate whose total amount is in the range from 20 to 40% by weight; the sequestrants comprise the alkali metal salts of ethylenediamine tetraacetic acid in an amount of from 0.33.5% by weight; and the colourants are selected from food, drug and cosmetic grade dyes or lakes having the individual colours blue, red and green, and mixtures thereof, in amounts of up to approximately 0.5% by weight.

1 6. A composition as claimed in Claim 1 3, 14 or 15, wherein, when at least one colourant is present, there is also present in the composition a fade control agent comprising a compound providing soluble halide ion, the fade control agent being present in an amount sufficient to promote the fading of the colourant within 1 8 minutes after the composition containing the colourant is placed in solution.

1 7. A composition as claimed in Claim 1 3, 14 or 15, wherein, when at least one colourant is present, there is also present in the composition a fade control agent comprising a compound providing soluble halide ion, the fade control agent being present in an amount of from 0.04% to 0.3% by weight.

1 8. A composition as claimed in Claim 17, wherein the fade control agent is present in an amount of from 0.04 to 0.18% by weight.

1 9. A composition as claimed in Claim 1 6, 1 7 or 1 8 wherein the fade control agent comprises a compound selected from alkali metal bromides, chlorides and odides, and mixtures thereof.

20. A composition as claimed in Claim 19, wherein the fade control agent is selected from potassium bromide, potassium iodide and mixtures thereof.

21. An effervescent cleansing composition comprising: (a) an oxidizing agent comprising a monopersulphate salt, in an amount of from 35 to 60% by weight; (b) a bleaching promoter comprising an alkali metal halide, in an amount of from 10% to 20% by weight; (c) an effervescence promoting compound comprising a perborate salt, in an amount of from 0.5% to 20% by weight; (d) sodium carbonate in an amount of from 20 to 40% by weight; and (e) sodium hydroxide in an amount of up to approximately 0.5% by weight; wherein the effervescent cleansing composition is operable to effervesce at an alkaline pH, and the percentages by weight relate to the total weight of the composition.

22. A composition as claimed in Claim 21, which is capable of providing a solution ranging in pH from 8.0 to 10.0.

23. A composition as claimed in Claim 21 or 22, wherein the monopersulphate salt comprises potassium monopersulphate and is present in an amount of from 40 to 50% by weight, and the bleaching promoter comprises sodium chloride.

24. A composition as claimed in Claim 21,22 or 23, wherein the perborate salt comprises an alkali metal perborate selected from sodium perborate and potassium perborate, and is present in an amount of from 0.7 to 15% by weight.

25. A composition as claimed in Claim 24, wherein the perborate salt comprises sodium perborate.

26. A composition as claimed in any one of Claims 21 to 25, which further includes at least one material selected from builders, detergents, sequestrants, colourants, perfumes, flavourings, excipients, tableting agents, disintegrants, and mixtures thereof.

27. A composition as claimed in Claim 26, wherein the builders comprise sodium carbonate and tri-sodium phosphate, the sequestrants comprise ethylene diamine tetracetic acid and its alkali metal salts, and the colourants are selected from food, drug and cosmetic and drug and cosmetic grade dyes and lakes.

28. A composition as claimed in Claim 27, wherein the builder is present in an amount of up to 4% by weight, the sequestrant is present in an amount of from 0.3 to 3.5% by weight, and the colourant is present in an amount of from 0.1 5 to 0.5% by weight.

29. An effervescent cleansing composition comprising: (a) an oxidizing agent comprising a monopersulphate salt, in an amount of from 35 to 60% by weight; (b) a bleaching promoter comprising an alkali metal halide, in an amount of from 10 to 20% by weight; (c) an effervescence promoting compound comprising a perborate salt, in an amount of from 0.5% to 20% by weight; (d) sodium carbonate in an amount of from 20 to 40%; (e) sodium hydroxide in an amount of up to approximately 0.5%; (f) a colourant comprising at least one food, drug and cosmetic grade, or drug and cosmetic grade, dye or lake, in an amount of from 0.15 to 0.5% by weight; and (g) a fade control agent comprising a compound providing soluble halide ion in an amount sufficient to permit the fading of the colourant within 1 8 minutes after the composition containing the colourant is placed in water.

30. An effervescent cleansing composition comprising: (a) an oxidizing agent comprising a monopersulphate salt, in an amount of from 35 to 60% by weight; (b) a bleaching promoter comprising an alkali metal halide, in an amount of from 10% to 20% by weight; (c) an effervescence promoting compound comprising a perborate salt, in an amount of from 0.5% to 20% by weight; (d) sodium carbonate in an amount of from 20 to 40%; (e) sodium hydroxide in an amount of up to about 0.5 iO; (f a colourant comprising at least one food, drug and cosmetic grade, or drug and cosmetic grade, dye or lake, in an amount of from 0.1 5 to 0.5% by weight; and (g) a fade control agent comprising a compound providing soluble halide ion, in an amount of from 0.04 to 0.3% by weight.

31. A composition as claimed in Claim 30, wherein the fade control agent is present in an amount of from 0.04 to 0.18% by weight.

32. A composition as claimed in Claim 29, 30 or 31, wherein the fade control agent is selected from alkali metal bromides, chlorides and iodides, and mixtures thereof.

33. A tablet suitable for use as a denture cleanser, comprising a composition as claimed in any preceding claim.

33. A composition as claimed in Claim 32, wherein the fade control agent is selected from potassium bromide, potassium iodide and mixtures thereof.

34. A composition as claimed in any one of Claims 29 to 33, which further includes at least one material selected from the group consisting of builders, detergents, lubricants, sequestrants, perfumes, flavourings, excipients, tableting agents, disintegrants and mixtures thereof.

35. A composition as claimed in Claim 34, wherein the builders comprise sodium carbonate and trisodium phosphate, and the sequestrants comprise ethylene diamine tetraacetic acid and its alkali metal salts.

36. A composition as claimed in Claim 35, wherein the builders are present in an amount of up to 40% by weight, and the sequestrant is present in an amount of from 0.3 to 3.5% by weight.

37. A tablet suitable for use as a denture cleanser, comprising a composition as claimed in Claim 13, 14or 15.

38. A tablet suitable for use as a denture cleanser, comprising a composition as claimed in Claim 16.

39. A tablet suitable for use as a denture cleanser, comprising the composition as claimed in Claim 17.

40. A tablet suitable for use as a denture cleanser, comprising a composition as claimed in Claim 18 or 19.

41. A tablet suitable for use as a denture cleanser, comprising a composifion as claimed in Claim 26, 27 or 28.

42. A tablet suitable for use as a denture cleanser, comprising a composition as claimed in Claim

34.

43. A tablet suitable for use as a denture cleanser, comprising a composition as claimed in Claim 31,32,35 or 36.

New Claims or Amendments to Claims filed on 6 July 1982 Superseded Claims 1, 14--17, 21,26--43.

New or Amended Claims:

1. An effervescent cleansing composition comprising: (a) an oxidising agent comprising a monopersulphate salt, in an amount of from 35 to 60% by weight; (b) a bleaching promoter selected from alkali metal and alkaline earth metal halides, and being present in an amount of up to 20% by weight; (c) an effervescence promoting compound comprising a perborate salt, present in an amount of from 0.5 to 20% by weight; (d) a colourant comprising at least one food, drug and cosmetic grade dye or lake in an amount of from 0.1 5 to 0.5% by weight; and (e) a fade control agent comprising a compound providing soluble halide ion in an amount sufficient to permit the fading of the colourant within 1 8 minutes after the composition containing the colourant is placed in water; wherein the effervescent cleansing composition effervesces at an alkaline pH when placed in solution, and wherein the percentages by weight relate to the total weight of the composition.

14. A composition as claimed in Claim 13, wherein the builders are selected from alkali metal carbonates, alkali metal phosphates, and mixtures thereof; the sequestrants comprise polyfunctional organic acids, and their alkali metal salts; and the pH stabilizers comprise sodium hydroxide.

15. A composition as claimed in Claim 14, wherein the builders comprise sodium carbonate and/or trisodium phosphate whose total amount is in the range from 20 to 40% by weight; and the sequestrants comprise the alkali metal salts of ethylenediamine tetraacetic acid in an amount of from 0.3-3.5% by weight.

16. A composition as claimed in any preceding claims, wherein the or each colourant is selected from food, drug and cosmetic grade dyes or lakes having the individual colours blue, red and green, and mixtures thereof.

1 7. A composition as claimed in any preceding claims, wherein the fade control agent is present in an amount of from 0.04% to 0.3% by weight.

21. An effervescent cleansing composition comprising: (a) an oxidising agent comprising a monopersulphate salt, in an amount of from 35 to 60% by weight; (b) a bleaching promoter comprising an alkali metal halide, in an amount of from 10% to 20% by weight; (c) an effervescence promoting compound comprising a perborate salt, in an amount of from 0.5% to 20% by weight; (d) a colourant comprising at least one food, drug and cosmetic grade dye or lake in an amount of from 0.15 to 0.5% by weight; (e) a fade control agent comprising a compound providing soluble halide ion in an amount sufficient to permit the fading of the colourant within 1 8 minutes after the composition containing the colourant is placed in water; (f) sodium carbonate in an amount of from 20 to 40% by weight; and (g) sodium hydroxide in an amount of up to approximately 0.5% by weight; wherein the effervescent cleansing composition is operable to effervesce at an alkaline pH, and the percentages by weight relate to the total weight of the composition.

26. A composition as claimed in any one of Claims 21 to 25, which further includes at least one material selected from builders, detergents, sequestrants, perfumes, flavourings, excipients, tableting agents, disintegrants, and mixtures thereof.

27. A composition as claimed in Claim 26, wherein the builders comprise sodium carbonate and trisodium phosphate, and the sequestrants comprise ethylene diamine tetracetic acid and its alkali metal salts.

28. A composition as claimed in Claim 27, wherein the builder is present in an amount of up to 40% by weight, and the sequestrant is present in an amount of from 0.3 to 3.5% by weight.

29. A composition as claimed in any one of Claims 21 to 28, wherein the fade control agent is present in an amount of from 0.04 to 0.3% by weight.

30. A composition as claimed in Claim 29, wherein the fade control agent is present in an amount of from 0.04 to 0.18% by weight.

31. A composition as claimed in any one of Claims 21 to 30, wherein the fade control agent is selected from alkali metal bromides, chlorides and iodides, and mixtures thereof.

32. A composition as claimed in Claim 31, wherein the fade control agent is selected from potassium bromide, potassium iodide and mixtures thereof.