CA1306923C - Aqueous alkali metal halogenite compositions containing a colorant - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

Aqueous cleaner compositions containing an alkali metal halogenite, for example, NaClO2; a stabilizable colorant; and a stabilizing amount of a stabilizer compound selected from the group consisting of alkali metal carbonates, borates and mix-tures thereof. The preferred embodiment further includes an anionic or anionic fluorocarbon surfactant.

Description

~3~ 3 AQUEOUS AL~ALI METAL Hi~LOGENITE
COMPOSITIONS CONTAINING A CO~ORANT
by Richard S. Hutchings Field of Invention The present invention relates to aqueous, alkaline cleaner compositions containing an alkali metal halogenite, for example, sodium chlorite, NaC102, and a ~tabilizable colorant normally incompatible with said halogenite in aqueous media, the colorant being compatible therewith in view of the~inclusion within said composition of a stabilizing amount o~ a stabilizer selected from the group con6is~ing of alkali metal carbonates, alkali metal borates, and mixtures thereof.
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Backqround of Invention Aqueous alkali metal halogenite compositions are well known for use in the textile industry wherein the halogenite, es-pecially sodium chlorite, is a source of chlorine dioxide gas, a strong bleachan~. Below about pH 9.0, there is a sufficient .

~3~6~23 concentration of H+ ions to commence conversion of the chlorite ion to chlorine dioxide, especially at elevated temperatures. As the concentration of chlorine dioxide in the aqueous solution increases, aqueous alkali metal halogenite compositions become more acidic and the rate of conversion increases.

In the paper industry, sodium chlorite has been used to prevent mold and slime growth in paper mill "white" water, as disclosed in U.S. Patent 3,046,185 to Buonanno.

Applicant has found that alkali metal halogenite solutions, especially sodium chlorite solutions, are suitable for use in household and janitorial cleaning chores, for example, cleaning of tiles, porcelain surfaces, and drains.

For such compositions, especially for compositions for household use, the inclusion of a colorant is preferred. The colorant provides a pleasing hue to the consumer, and makes the composition visible when applied to the work surface being cleaned. In some instances the colorant is an indicator that the product composition has been exhausted.

~3~6'~23 It has been observed, however, that many colorants, in-cluding those often used in household cleaning products, are not stable in the alkali ~etal halogenite compo6itions herein dis-closed. Instability of the colorant is manifest by the formation of chlorine dioxide gas within the composition, by loss of tinctorial value of the colorant, and lowering of composition pH. Concomitant with the production of chlorine dioxide is the loss of the alkali metal halogenite. Moreover, chlorine dioxide odor ls unpleasant and is detectable by the user of the composition when present even in trace concentrations.

It has been found that for many colorants that are otherwise unsta~le in aqueous alkali metal halogenite compositions, inclu-sion can be successfully achieved by successfully stabilizing the system with alkali metal salts of carbonates, borates, and mixtures thereof.

Accordingly, it is an object of the present invention to provide a cleaning composition comprising an aqueous alkali metal halogenite solution containing therein a colorant that retains its tinctorial value.

~L306923 It is a ~urther and prlmary ob~ect of the present invention to provide such compositions wherein the included colorant does not react appreciably with the sodium chlorlke to release in excess of trace amounts of chlorine dioxide gas, at the pH of the composition.

These and other objects and advantages of the present invention will be more readily understood upon reading the detailed disclosure of the invention, a summary of which follows.

Summary of Invention ~' .
The aqueous, alkaline compositions of the present invention comprise an alkali metal halogenite, for example, ~odium chlorite, NaC102; a stabilizable colorant that is normally chemically incompatible with the halogenite in aqueous media, and a stabilizer present in the composition in an amount effective to stabilize not only the colorant hut also the composition, as evidenced by the substantial absence of chlorine dioxide in the composition. The stabilizer is selected from the group consisting of the alkali metal, preferably sodium and potassium, salts of carbonates, borates, and mixtures thereof.

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~L3(~6~;2 3 Optionally, ~ surfactant may be included in the composition to provide detergency thereto and to enhance its cleanlng efficacy.

The alkali metal halogenite :is typically present in an amount of about 5% or less by we:ight of the composition, sodium chlorite being the preferred species thereof. The colorant is selected from the group consisting of dyes, lakes, and pigment, dyes b~ing preferred in view of their great~r water solubility, the colorant generally being present in an amount of ~rom about 0.01 to about 3% (active colorant basis), preferably from about 0.1 to about 2%, by weight of the composition.

The ætabilizer is present in an amount effective ~o prevent interaction of the colorant with halogenite ions formed by dissociation of the alkali metal halogenite in aqueous media.
Preferably, the stabiliæer is present in an amount of from 0.5 to about 3% by weight of the composition.

Many otherwise unstable colorants may be stabilized by the practice of the present invention. It has been found, however, that for some colorants better stability is obtained if the colorant is first treated by neutralizing the colorant with base, to remove potential reaction sites or acidic contaminants from the colorant.

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~3~6~3Z3 The stable compositions of the present inventlon are ~lkaline, with 6tability increasing generally with increa~ing pH. For be6t stabilization the compositions exhibit a pH of about 9 and above, preferably from about 3.0 to about 10.5.

It has additionally been found khat stability of th~ com-position is fu~ther enhanced when the composition contains an anionic surfactant. Conver6ely, it has been found that the presence of a nonionic surfactant reduces stability, although stability is superior in such nonionic surfactant-containing compositions incorporating the stabilizer constituent in effective amount than without same, in the presence of the colorant.

Preferred colorants are Colour Index Dye Nos. 42,090 and 52,035.

Detailed Description of the Invention and Preferred Embodiment In attempting to prepare aqueous cleaning compositions com-prising sodium chlorite and including a colorant, it was found that the resulting compositions contained generally unacceptable amounts of chlorine dioxide gas. Such chlorine dioxide gas is unacceptable because of its unpleasant odor. Further, dye con-tained in the composition was dapleted, resulting in los~ of tinctorial value.

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~36~ 3 What was 6urprising about the formation of the chlorine dioxide in compositions containing the ~odium chlorite and the colorant, typically a dye, is that it occurred in compositions having a pH of 9 and above, such compos~tions generally being regarded as unable to form chlorine dioxide. Such appearance of chlorine dioxide occurred even when the colorant under investigation was neutralized wit:h base.

It is believed that the interaction between the colorant and the sodium chlorite was not a conventional acid-based neutralization reaction, as in the case of, say, hydrochloric acid and sodium hydroxide. Rather, it is believed that a chromophore site on the colorant molecule is conducive for converting the chlorite ion, C102 , to chlorine dioxide and H+ ions, the chlorine dioxide and the H~ ions then participating in the conversion of additional chlorite ion to chlorine dioxide. In any event, as the concentration of chlorine dioxide increased, a resulting decrease in system pH
was observed, the system pH falling to below 7.0 at completion.
The rate of chlorine dioxide formation accelerated as syskem pH
decreased towards the acid range.

Various materials were used in trying to prevent the chlorine dioxide from forming in the aforementioned 6~23 60dium chlorite-colorant systems. It was found that the alkali metal 6alts of carbon~tes and borates and mixtures thereof greatly improved the stab~llty of the composition, while alkali metal ~alt6 of HC03 , CH2C00 , P03 were unsuitable, surprising in view of their use as buffers at the pH 8 to 10 range. Also unsuitable was a mixture of NH40H and NaCl in co~position~ having a pH of 13.

Accordingly, the compositions of the present invention are aqueous, alkaline cleaning compositions comprising on a weight basis about 5% or less of an alkali metal halogenite, from about : 0.01 to about 3% on an active basis o~ a ~tabilizablP colorant selected from the group consisting of dyes, lakes, and pigments, said colorant normally chemically incompatible with said halo-genite in aqueous, alkaline media, and a stabili~er selected frc,m the group consisting of alkali metal carbonate and borate salts and mixtures thereof, said colorant stabilizer being present in the composition in an amount effective to stabilize the composition as evidenced by a substantial absence of chlorine dioxide thereinO

By the practice of the present invention, sodium chlorite co~positions containing the otherwise incompatible colorant, which compositions do not produce in excess of a trace .. . .
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' . . ' : , . : :' ' , g concentration of chlorine dioxide within about one month of preparation, preferably three month~, most prefer~bly ~ix monthe, can be made. ~y krace concentration i~ meant a level of chlorine dioxide detectable by conventional analytical ~eans and~or by olefactory sensory evaluation, usually less than about 10 ppm, preferably less than about 5 ppm, in said composition.

Sodium chlorite i~ preferably preeent in an am~unt of from about 0.5 to about 5%, most preferably ~rom about 1 to about 3%, by weight of the composition. Above about 5% of the chlorite generally provides a composition having too high an ionic strength for successful stabilization, although with proper selection of dye, stabilizer, and optionally anionic surfactant, higher sodium chlorite levels ~ay be suitable.

The incompatible colorants include many different classes of colorants. Thus, it has bsen found that of the dyes, stable compositions have been obtained in accordance with the present invention with Acid Blue 185 (Cibacro1in Blue 8G), and Colour Index Dye Nos. 22,610 (Direct Blue 6), 42,090 (Hidacid Azure Blue), 52035 (Hidacid Aqua Blue), and 74,18~ (Direct Blue 86), which includes phthalocyanine, diazo, thiazine, and triaryl-methane dyes. With regard to colorants not specifically referred to herein, stabilization potential both may easily be ascertained by routine experimentation, as described in greater detail in the examples below.

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In general, it 16 preferred that the composition pH have a value of about 9 and above, preferably between about 9.0 and 10.5. At such pH level, each of the afore~entioned dyes are stable in said co~po~itions ~nd siaid composition~ are stable, chlorire dioxide not being releas~ed.

In order to ensure that the compositions of the present invention are initially stable and that stability i8 maintained for reasonably long time periods, it is pre~erred to prepare an aqueous premix composition containing the chlorite and the stabilizer and to thereafter incorporate the dye component.

The compositions of the present invention may also include a surfactant, to improve detergency and enhance cleaning efficacy.
It has been found that many of the common classes of anionic surfactants are stablP in the subject composition, and that the composition remains stable when said effective amount of the stabilizer has been incorporated to stabilize the colorant.

Broadly, the anionic surfactants are water-soluble alkyl or alkylaryl compounds~ the alkyl having from about 8 to about 22 carbons, including a sulfate or sulfonate substituent group that has been base-neutralized, typically to provide an alkali metal, e.g., sodium or potassium, or an ammonium anion, including, for example: (1) alkyl and alkylaryl sulfates and sulfonates having - , ~. ' ' - ~, . - ' ,-' ~ , , , '' ' :
.

preferably 10 to 18 carbons in the alXyl group, which may be straight or branched chaln, e.g., ~odiu~ lauryl sulfate and sodium dodccylbenzene ~ulfonate; (2) alpha-olefin ~ryl ~ul-fonates pre~erably having from about 10 to 18 carb~ns in the olefin, e.g., sodium C14~16 olefin sulfonate, which i~ a mixture of long-chain sulfonate salts prepared by sulfonation of C14_16 alpha-ole~ins and chiefly compri~ing sodium alkene ~ul-fonates and sodium hydroxyalkane sulfonates: (3) sulfated and sulfonated monoglycerides, especially those derived from coconut oil fatty acids; (4) 6ulfate esters of ethoxylated fatty alco-hols having 1-10 mols ethylene oxide, e.g., sodium polyoxyethy-lene (7 ~ol E0) lauryl ether sulfate, and ethoxylated alkyl phenols having 10 mols ethylene oxide and 3 to 12 carbons in the alkyl, e.g., ammonium polyoxyethylene ~4 mol E0) nonyl phonyl ether sulfate; (5) base-neutralized esters of fatty acids and isethionic acid, e.g., sodium lauroyl isethionate; (6) fatty acid amides of a methyl tauride, e.g., sodium methyl cocoyl taurate, (7) beta-acetoxy- or beta-acetamido-alXane sulfonates where the alkane has from 8 to 22 carbons, and (8) acyl sar-cosinates having 8 to 18 carbons in the acyl moiety, e.g., sodium lauroyl sarcosinate.

Preferred anionics are the alkyl and alXylaryl sulfates and the alpha-olefin aryl sulfonates.

- r 3l3~ 2,3 The anionlc surfactant6 may be inclucled in an amount of from 0 to about 20%, pre~erably from about 0.5 to about 10%, most preferably from about 2 to about 8%, by weight of the composition.

It has been found that the an:ionic surfactants have a further stabilizing effect on the composition, the composition containing the chlorite, colorantv and stabilizer agents forming even less chlorine dioxide when the anionic surfactant is included than whPn it is omitted. It is beli~ved that this further stabilization is attri~uta~le to micellular interaction between the colorant and the surfactant anion.

It has been found that anionic fluorocarbon surfactants hav~
the same stability enhancement benefit as the anionic surfact-tants, in the compositions of the present invention, but at a much reduced concentration level. Examples of suitable anionic fluorosurfactants are the Zonyl series manufactured by E.I.
duPont de Nemours and Co., especially Zonyls FSA, FSJ and RP, and the Flourad series manufactured by 3M Company, especially Flourads 120 and 128. A further general discussion of fluorosurfactants is provided in U.S. Patent 4,511,489 to Requejo et al.

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~3g~23 The flourocarbon surfactant6 are includable in the com-positions of the pressnt invention in an amount of up to about 1%, preferably from about 0.005 to about 0.1~, by weight of the compos~tion. Mixtures of anionlc and anionic fluorocarbon ~ur-factants may be included in the compositions o~ the present invention.

Nonionic surfactants might also be included in the com-positions of the present invention. The presencs of the stabilizer provides a stabilizing benefit to such nonionic surfactant-containing ~olutions. Although greater stability is shown of such compositions as compared to compositions con-taining the nonionic surfactant and the colorant but without the stabilizer, the stability of the compositions of the present invention is generally lessened by the inclusion of the nonionic surfactant. For t~i6 reason, it is preferred not to include them, although they may be includable in an amount of less than about 3%, preferably less than 1%, by weight of the composition. Accordingly, adjuvants may be incorporated wherein the adjuvant is solubilized by minor amounts of a nonionic surfactant. The stability of compositions containing both an anionic and a nonionic surfactant is relatively proportional to the concentrations of each therein.

~3~6923 Cationic surfactants may also be included herein, although should not be ~ncluded w~th composition~ containing the anionic surfactant in view of their inherent incompatibility. Similar-ly, quaternary surfactants may be included. The cationic and quaternary surfactant6 generally would be included in low amounts, to achieve a particular activity. For example, these surfactants are known germicides.

Optionally, other adjuvants may be included in the com positions of the present invention, provided that such included adjuvants do not exhibit incompatibility. For example, per-fumes, chelating agents, sequestering agents, builders, and the like, may be included. With regard to perfumes, in view of the presence of substituent groups reactive with the chlorite ion, care must be taken to properly screen the perfume used.

The present invention is illustrated by the examples below.

General In the examples, a sample composition was deemed stable if chlorine dioxide gas is not formed within about one month of sample preparation and the dye half-life was about two weeks or longer.

~3~6~23 In some instances, chlorine dioxide gas is easily detected by its characteristic odor. Where such sensory evalu~tions did not indicate the presence of C10;2, ona o~ several analytical methods were used: ~1) spectrophometric measurement of a sample, chlorine dioxide having a peak absorbance oP 356 mm, unique among the oxychloro Bpecie~s; (2) titration of an alkaline sample with sodium thiosulfate in the presence of potassium iodide, and (3) purging C102(g) from the 6ample with inert gas and passing the purge gas through a potassium iodide solution.

For samples not forming C102 (g), dye concentration may be measured by spectrophometric measurement of the characteristic absorbance peak for the dye.

In the examples all concentrations are reported on an active ingredient basis, unless otherwise indicated.

Example 1 Constituent Concentration,_Wt. %
A B C D

Sodium Chlorite 1.6 1.6 1.6 1.6 Acid Blue No. 9 0.33 0.33 0.33 0.33 ~C.I. No. 42090) Sodium Borate 0 0 0.75 0.75 Water (By difference) Anionic Surfactant o 4 o 4 Perfume 0 0.1 0 0.1 . , .

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1~C)6~;~3 The Compositions A-D were prepared and analyzed as described above. To accelerate the tests, the ~amples were placed in an oven at 180F for approximately 1.5 hrs.

Composition A and B not containing ~odium borate produced C102(g). No C102 was detected in Compositions C and D.

Example 2 Constituent __Concentration, Wt._%
E F G H

Sodium Chlorite 1.6 1.6 1.6 1.6 Direct Blue 86 (C.I. No. 74180) Sodium C~rbonate 0 0 Water (By differe~ce) Anionic Surfactant o 4 o 4 The Composition E-~ were prepared and analyzed as described above, with storage conducted at room temperature. Compositions E
and F produced C102(g) within 5 days. No C102(g) or drop in pH
was detected for Compositions G and H after 1 month.

' 9~3 ` .., Example 3 Constitutent _ Concentration, Wt. % _ _ I J X L M N N' Sodium Chlorite 1 1.6 1.6 1.5 1.6 1.6 1.6 1.6 Dye (see below)( ~ 1 1 1 1 1 1 2 Alpha Olefin Sulfonate 0 4 0 0 4 4 6 Sodium Borate 0 0 1 0 1 0 Sodium Carbonate 0 0 0 1 0 Perfume 0 0 0 0 0 0 0.25 Water ~By difference) (l)Dye concPntration reported "as i6~ received from manufacturer.
Activity is reported in the table next appearing below.

The dyes included in the Compositions H - N' are:

Dye Trade Name Class C.I. No. _ Activity~ %
Hidacid Azure Blue Triarylmethane 42090 33 Hidacid Aqua Blue Triazine 52035 91 Pyazole FT GLL-120% Phthalocyanine 74180 100 Hidacid Green (1) Triarylmethane 42090/45350 21 (1) Hidacid Green is a mixture of the C.I. No. 42090 and yellow dye C.I. No. 45350.

The results of stability testing at room temperatures were as ~ollows:

Composition I J K L M N N' Run No. Dye 1 Hidacid Azure Blue C102 C102 S S S S S

2 Hidacid Aqua Blue C102 C12 S S S S S

3 Pyrazole FT GLL-120% C102 C102 S S S S S
: 4 Hidacid Green C102 C102 S S S S S
S = Stable; C102 = Chlorine dioxide formed; unstable.

~J ~3~6 !323 Example 4 Dye Common Name Color Index No. Run No. ~_tivity, %

Acid Blue No. 1 42045 1 100 Acid Blue No. 7 42080 2 100 Acid Blue No. 9 42090 3 67 Basic Blue No. 1 4 100 These dyes were incorporated into the compositions reported below.
Concentration, wt.
Constituent P

Sod~ ~ Chlorite 1.6 Dye Sodium Borate Surfactant 6 Perfume 0.25 ; Water 90.15 (l)"As is" concentration.

No C102(g) was produced in any of the Compositions Pl through P4. The dye Basic Blue No. 1 in Compositi~ns P4 did fade, however.

Example 5 Composition P'-R were prepared:

~3~ 3 Constituent Concentration, wt. ~
P' Q R
Sodium chlorite 1.6 1.6 1.6 Acid Blue No. 1 0.5 0.5 0.67 Sodium Borate 0 Surfactant 0 0 6 Perfume 0 0 0.25 Water 97.9 96.9 91.48 Composition p' produced chlorine dioxide, ~hile Compositions Q and R did not.

Example 6 Constituent Concentration, wt. ~
Sl S2 S3 S4 S5 Sodium Borate Perfume 0.25 0.25 0.25 0.25 0.25 Sodium Chlorite 1.6 1.6 1.6 1.6 1.6 Acid Blue No. 9 0.67 0.495 0.33 0.165 0.0066 Water (By difference) So~ium Borate Perfume 0.25 0.25 0.25 0.25 0.25 AOS 4 3 2 1 0.02 Sodium Chlorite 1.6 1.6 1.6 1.6 1.6 Acid Blue No. 9 0.67 0.495 0.33 0.165 0.0033 Water (By difference) C102(g) was not produced in any of the above compositions Sl throu~h S10.

~IL3~ 23 Example 7 Constituents Concentratlon. wt. ~
AA ~ CC D~ ~ GG
Acid Blue No. 9 0.67 0.S7 0.67 0.67 0.67 0.67 0.67 Perfu~e 0.25 0.25 0.25 0.25 0.25 0.25 0.25 Borax Sodium Chlorite 1.6 1.2 0.8 0.4 0.20 0.08 0 Anionic Surfacta~t 4 4 4 4 4 4 4 __~ater tBy difference) No C102(g) was produc~d.

Fxam~le 8 ; Constitutent Concentration, wt. %
HH II JJ KX LL MM NN 00 P~
~cid Blue No. 9 0.33 0.67 0.67 0.33 0.33 0.33 0.33 0,33 0.33 Sodium Chlorite 1.6 1.6 1.6 1.6 1.6 1.6 1.6 0.8 0.8Sodium Borate 0 2 1 0.75 0.S 0.25 0.15 0O05 0.02 AOS o 6 6 4 4 4 ~ 4 4 Perfume 0 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 Water (By difference) C102(g) was produced in Compositions XH, OO, and PP, but not in II-NN. With 1.6~ chlorite and 0.1% perfume, mor~ than about 0.05% so~iu borate level is required for stability.

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Exa~ple 9 Constltutent (l~oncentration. wt. %
~;! R~ SS
Aqua Blue 0.91 0.91 0.91 Sodium Chlorite 0.8 1.6 1.6 Water 97.79 96.49 96.49 Sodium Carbonate 0 1 o Sodium Bicarbonate 0 0 NaOH ~0.5 0 0 (1) pH of Dye, water adjusted to 10 with NaOH; then NaC102 was added.
Intial pH = 10.7.
Compositions QQ and SS produced C102(g); Composition RR did not.

The above detailed description is not intended to bP limiting of the scope of the present invention as provided in the claims appended below, wherein all recited concentrations are on an activ2 constituent basis.

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Claims (26)

1. An aqueous, alkaline cleaning composition having a pH of about 9 or above comprising on a weight basis from about 0.01 to about 5% of an alkali metal halogenite; from about 0.01 to about 3% of a colorant normally chemically incompatible with said halogenite in aqueous media, and a stabilizer selected from the group consisting of alkali metal carbonate and borate salts and mixtures thereof, said stabilizer being present in the composition in an amount effective to stabilize the composition as evidenced by a substantial absence of chlorine dioxide in the composition.

2. The composition of claim 1 wherein the colorant is a dye.

3. The composition of claim 2 wherein the composition has a pH of from about 9 to about 10.5.

4. The composition of claim 3 wherein the dye is selected from the group consisting of phthalocyanine, diazo, thiazine and triarylmethane dyes.

5. The composition of claim 3 wherein the dye is a triarylmethane dye.

6. The composition of claim 3 wherein the dye is selected from the group consisting of Acid Blue Dye 185 and Colour Index Dye Nos. 22,610; 42,090; 52,035, and 74,180.

7. The composition of claim 3 wherein the dye is Colour Index Dye No. 42,090.

8. The composition of claim 3 wherein the dye is Colour Index Dye No. 52,035.

9. The composition of claim 1 wherein the halogenite is sodium chlorite.

10. The composition of claim 4 wherein the halogenite is sodium chlorite.

11. The composition of claim 6 wherein the halogenite is sodium chlorite.

12. An aqueous, alkaline cleaning composition having a pH of about 9 or above comprising on a weight basis from about 0.01 to about 5% sodium chlorite; from about 0.01 to about 3% of a stabilizable dye, said dye being normally chemically incompatible with said sodium chlorite in said aqueous composition, and a stabilizer selected from the group consisting of alkali metal carbonates, borates, and mixtures thereof, said stabilizer being present in the composition in an amount effective to stabilize the composition as evidenced by the substantial absence of chlorine dioxide therein and a dye half-life of at least about two weeks.

13. The composition of claim 12 wherein the pH of the composition is from about 9.0 to about 10.5, the dye being selected from the group consisting of Acid Blue Dye 185 and Colour Index Dye Nos. 22,610; 42,090; 52,035;
and 74,180.

14. The composition of claim 13 wherein the dye is Colour Index Dye No. 42,090.

15. The composition of claim 13 wherein the dye is Colour Index Dye No. 52,035.

16. The composition of claim 13 further comprising an anionic surfactant in an amount of from about 0.1 to about 20%.

17. The composition of claim 13 further comprising an anionic fluorosurfactant in an amount of from about 0.005 to about 1%.

18. An aqueous, alkaline cleaning composition comprising on a weight basis from about 0.01 to about 5%
sodium chlorite, from about 0.01 to about 3% of a stabilizable dye, said dye being normally chemically incompatible with said sodium chlorite in said aqueous composition, the dye being selected from the group consisting of Acid Blue Dye 185 and Colour Index Dye Nos.
22,610; 42,090; 52,035; and 74,180, the composition having a pH of from about 9.0 to about 10.5; a stabilizer selected from the group consisting of alkali metal carbonates, borates and mixtures thereof, the stabilizer being present in the composition in an amount of from about 0.15 to about 3%, said amount of the stabilizer being effective to stabilize the composition as evidenced by the substantial absence of chlorine dioxide in the composition and by a dye half-life of at least about 2 weeks, and a surfactant selected from the group consisting of anionic surfactants and anionic fluorosurfactants, the anionic surfactants being includable in the composition in an amount of up to about 20% and the anionic fluorosurfactant being includable in an amount of up to about 1%.

19. The composition of claim 18 wherein the dye is Colour Index Dye No. 42,090.

20. The composition of claim 18 wherein the dye is Colour Index Dye No. 52,035.

21. The composition of claim 18 wherein the sodium chlorite is present in an amount of from about 1 to about 3%.

22. The composition of claim 21 wherein the dye is present in an amount of from about 0.1 to about 2%.

23. The composition of claim 22 containing from about 1 to about 10% of the anionic surfactant.

24. The composition of claim 23 containing from about 0.01 to about 0.1% of the fluorosurfactant.

25. The composition of claim 23 wherein the dye is Colour Index Dye No. 42,090.

26. The composition of claim 23 wherein the dye is Colour Index Dye No. 52,035.