US3556711A

US3556711A - Peroxymonosulfate compositions containing acylate oxidation promoters,and their use

Info

Publication number: US3556711A
Application number: US833697A
Authority: US
Inventors: Neil J Stalter
Original assignee: EI Du Pont de Nemours and Co
Current assignee: EIDP Inc
Priority date: 1967-12-20
Filing date: 1969-06-16
Publication date: 1971-01-19
Anticipated expiration: 1988-01-19
Also published as: BE725711A; FR1602569A; GB1257174A; NL6818435A; DE1815170A1; NL136747C

Abstract

PARTICULATE COMPOSITIONS COMPRISING ADMIXTURES OF A WATER-SOLUBLE PEROXYMONOSULFATE AND A WATER-SOLUBLE SALT OF A 1 TO 4 CARBON SATURAED ALIPHATIC MONOCARBOXYLICACID AS AN OXIDATION PROMOTER; ALSO, AQUEOUS COMPOSITIONS WHICH ARE SOLUTONS OF SUCH A PEROXYMONOSULFATE HAVING A PH OF 5 TO 10 AND CONTAINING THE ACYLATE ANION OF SUCH AN ACID. SUCH SOLUTIONS ARE USEFUL FOR OXIDATIVE PURPOSES SUCH AS THE BLEACHING OF TEXTILES WHICH ARE AMENABLE TO BLEACHING WITH PEROXYMONOSULFATE, AND THE REMOVAL OF STAINS THEREFROM. THE PREFERRED PEROXYMONOSULFATE IS THE TRIPLE SALT OF POTASSIUM PEROXYMONOSULFATE OF THE FORMULA KHSO4.52SO4.2KHSO5. THE PRFERRED PROMOTERS ARE THE ALKALI METAL ACETATES, E.G., SODIUM ACETATE. THE PREFERRED PARTICULATE COMPOSITIONS ARE SUBSTANTIALLY ANHYDROUS ADMIXTURES OF THE ABOVE POTASSIUM PEROXYMONOSULFATE, SODIUM ACETATE, A BUFFERING AGENT SUCH AS TRISODIUM PHOSPHATE OR TETRASODIUM PYROPHOSPHATE, AND A SOLID DESICATING AGENT, PREFERABLY ANHYDROUS MAGNESIUM SULFATE.

Description

Patented Jan. 19, 1971 3,556,711 PEROXYMONOSULFATE COMPOSITIONS CON- TAINING ACYLATE OXIDATION PROMOTERS,

AND THEIR USE Neil J. Stalter, Wilmington, Del., assignor to E. I. du Pont de Nemours and Company, Wilmington, Del., a corporation of Delaware No Drawing. Continuation-impart of application Ser. No. 691,952, Dec. 20, 1967. This application June 16, 1969, Ser. No. 833,697

Int. Cl. D061 3/02 US. Cl. 8-111 20 Claims ABSTRACT OF THE DISCLOSURE Particulate compositons comprising admixtures of a water-soluble peroxymonosulfate and a water-soluble salt of a l to 4 carbon saturated aliphatic monocarboxylic acid as an oxidation promoter; also, aqueous compositions which are solutions of such a peroxymonosulfate having a pH of 5 to and containing the acylate anion of such an acid. Such solutions are useful for oxidative purposes such as the bleaching of textiles which are amenable to bleaching with peroxymonosulfate, and the removal of stains therefrom. The preferred peroxymonosulfate is the triple salt of potassium peroxymonosulfate of the formula KHSO -K SO -2KHSO The preferred promoters are the alkali metal acetates, e.g., sodium acetate. The preferred particulate compositions are substantially anhydrous admixtures of the above potassium peroxymonosulfate, sodium acetate, a buffering agent such as trisodium phosphate or tetrasodium pyrophosphate, and a solid desicating agent, preferably anhydrous magnesium sulfate.

CROSS-REFERENCE TO RELATED CASE This application is a continuation-in-part of my copending application Ser. No. 691,952, filed Dec. 20, 1967 now abandoned.

BACKGROUND OF THE INVENTION Because of their well-known oxidative properties, many uses of peroxymonosulfuric acid and its salts (peroxymonosulfates) have been proposed in patents and chemical literature. Such uses include the shrink-proofing of wool, the bleaching of textiles, the removal of stains from textiles and solid surfaces, the cleaning of dentures, and the like. Peroxymonosulfuric acid and its salts are also known to exert bacteriocidal activity.

Peroxymonosulfuric acid (H 50 is also sometimes called monopersulfuric acid or Caros acid; and its salts, i.e., the peroxymonosulfates, are also sometimes called monopersulfates or caroates.

. While peroxymonosulfuric acid and its salts are useful for the above and other similar uses because of their oxidative properties, they are not as effective as desired for such uses. The present invention is based upon the discovery that certain readily available substances actively promote the oxidative action of peroxymonosulfates and thereby enhance their effectiveness and usefulness for the above purposes.

SUMMARY OF THE INVENTION Particulate compositions comprising admixtures of a water-soluble peroxymonosulfate and from about 0.2 to 12 moles of a water-soluble salt of a 1 to 4 carbon saturated aliphatic monocarboxylic acid for each mole of the peroxymonosulfate.

Also, compositions which are aqueous solutions having a pH of about 5 to 10 and containing the peroxymonosulfate ion (HSO and from about 0.2 to 12 moles of the acylate ion of a l to 4 carbon saturated aliphatic monocarboxylic acid per mole of the peroxymonosulfate ion.

Also, a method of bleaching textiles which are amenable to bleaching with peroxymonosulfates, or of removing stains therefrom, comprising subjecting the textile to the action of such a solution.

DETAILED DESCRIPTION AND PREFERRED EMBODIMENTS Any of the l to 4 carbon saturated aliphatic monocarboxylic acids or their water-soluble salts which are free of heavy metal or other cations which would adversely react with or catalyze decomposition of the peroxymonosulfate are suitable for use in accordance with the invention as the source of the acylate ion promoter of the oxidizing action of the peroxymonosulfate. Examples of suitable sources of acylate ions are formic, acetic, propionic and butyric acids; the alkali metal, ammonium, alkaline earth metal, magnesium, cadmium and zinc salts of such acids; and mixtures of two or more of such acids and/or salts. Examples of unsuitable sources of acylate ions are the heavy metal salts of the above carboxylic acids, e.g., the iron, cobalt, copper, chromium and manganese salts, which would introduce heavy metal ions which tend to catalyze decomposition of the peroxymonosulfates. The preferred sources of acylate ion promoters are the carboxylic acids themselves and their ammonium and alkali metal salts. The most preferred promoter is the acetate ion; and acetic acid and the ammonium and alkali metal acetates, particularly sodium and potassium acetate, are the preferred sources thereof.

Any of the water-soluble salts of peroxymonosulfuric acid together with a water-soluble carboxylic acid salt of the type indicated above as being suitable sources of acylate ion promoters, may be used in formulating the particulate compositions of the invention. Examples of such peroxymonosulfates are the alkali metal, the alkaline earth metal and ammonium salts of peroxymonosulfuric acid and mixtures of any two or more thereof. However, because of their superior stability, the potassium salts such as potassium peroxymonosulfate monohydrate,

and the triple salt of potassium peroxymonosulfate of the formula 2HSO -K SO' -2KHSO are preferred for this purpose. The commercially available form of this triple salt having an active oxygen content of about 4.7 weight percent is the most preferred peroxymonosulfate for use. For stability reasons, the particulate compositions should be essentially dry, i.e., they should be essentially devoid of free water and of water loosely held in the form of water of hydration. Preferably, all components will be in their essentially anhydrous forms and the presence of a desiccant material in particulate form to protect against the presence of free water due to moisture picked up from the atmosphere will be desirable.

When formulating the solution compositions of the invention, any of the above-mentioned peroxymonosulfates or peroxymonosulfuric acid itself may be employed as the source of the peroxymonosulfate in, H Similarly, any of the above-mentioned carboxylic acids, or the salts thereof previously indicated as being suitable, may be employed as the source of the acylate ion promoter. However, the aqueous solution containing both peroxymonosulfate and acylate ions should have a pH in the range of 5 to 10, since no significant promotional effect by the above acylate ions upon the oxidizing action of the peroxymonosulfate ion has been observed to be exerted at higher or lower pH values. Solutions having a pH in the range 5.5 to 8 are preferred. Adjustment of the pH of the solution so as to bring it within the pH range of 5 to 10, preferably 5.5 to 8, may be accomplished by the addition of any of the common soluble alkaline materials, when an adjustment of the pH upward is necessary or desired; or by the addition of any of the common soluble acidic materials, when an adjustment downward is necessary or desired. Suitable alkaline materials for this purpose are the alkali metal and ammonium hydroxides, and alkaline reacting salts such as the alkali metal carbonates, phosphates and the like. Suitable acidic materials are nitric, sulfuric, phosphoric, and peroxymonosulfuric acids, and acid salts such as sodium and potassium bisulfates.

In order to achieve significant promotion of the oxidizing action of the peroxymonosulfate ion, the mole ratio of acylate ion to peroxymonosulfate ion in the solution should generally be at least 0.211 and a mole ratio of about 0.7 to :1 is preferred. Mole ratios of acylate ion to peroxymonosulfate ion up to 12:1, or even higher, are also eifective and usable but generally are not attractive for cost reasons. Since the particulate compositions of the invention are especially useful in formulating solutions meeting the above requirements, the particulate compositions will generally be formulated by mixing the selected peroxymonosulfate and carboxylic acid salt in such proportions as to satisfy the above acylate ion to peroxymonosulfate mole ratio requirement.

The particulate compositions of the invention may be entirely free of components other than the peroxymonosulfate and carboxylic acid salt. However, they may also contain a source of alkali and/or a buffering agent such as tetrasodium pyrophosphate in such an amount that when the composition is dissolved in water to give a 3% solution thereof, the resulting solution will have a pH within the desired range of 5 to 10. Still other materials such as stabilizers, wetting agents, fluorescent brighteners and the like may also be incorporated, generally in minor amounts.

The particulate compositions of the invention containing both peroxymonosulfate and carboxylic acid salt may be used as the source of peroxymonosulfate in any of the various previously published uses of peroxymonosulfates. Thus, such compositions may be used in formulating dry bleaching compositions, e.g., for home laundry use, stain removal compositions, and as a component in home laundry detergent formulations and cleanser compositions. They may also be employed for sanitizing the waters of swimming pools and as components of denture cleaner compositions.

A dry home laundry bleach composition can be formulated, e.g., with a 1: 1 weight mixture of sodium acetate and the commercially available potassium peroxymonosulfate triple salt product. A bleaching composition containing 50% of such a mixture with the balance consisting of light granular soda ash can be used effectively for home laundry bleaching purposes when the composition is added to the laundry water to provide an active oxygen concentration of about 20 to 50 p.p.m. The incorporation of a alkyl aryl sulfonate, 35 to 50% of sodium tripolyphosphate, 10% of sodium sulfate, and 10% of sodium metasilicate. The incorporation of small amounts of a soilrelease agent such as sodium carboxymethylcellulose and an optical brightener is generally advantageous.

Powdered cleanser compositions for removing stains from the surfaces of porcelain, aluminum ware and stainless steel ware may also be formulated using a 1:1 mixture of sodium acetate and the potassium peroxymonosulfate triple salt product. Such a cleanser composition may be formulated using 5% of such a mixture, 5% of an alkyl aryl sulfonate, 5% of anhydrous tetrasodium pyrophosphate, 5% sodium carbonate and 80% powdered small amount, e.g., 0.1%, of a fluorescent brightener is generally advantageous. Such a composition can also be added directly to the washing water in washing machines to provide similar active oxygen concentrations. The same composition can also be used for removing heavy stains from clothing, particularly when added to hot tap water (l20-140 F.) to provide active oxygen concentrations in the water of from about 100 to 200 p.p.m. Such compositions are safe for use with Washable fabrics of all natural or synthetic fibers, with the possible exception of silk and wool which should be hand laundered at lower temperatures. They are also usable in the laundering of or the removal of stains from wash-fast cloth fabrics dyed with common vat or sulfur dyes.

Mixtures of sodium acetate and the above potassium peroxymonosulfate triple salt product, e.g., at a 1:1 weight ratio, are also usable in formulating home laundry detergent compositions. Thus, such a detergent composition may contain 5% to 20% of such a mixture, 20% of an silica. Such compositions are generally applied to the damp surfaces from which the stains are to be removed, or they may be applied to a damp cloth which is then rubbed over the stained surface to effect removal of the stain. Mixtures of a salt of a 1-4 carbon carboxylic acid such as sodium acetate with the above-mentioned potassium peroxymonosulfate triple salt product, e.g., a 1:1 weight mixture, can be used directly to form solutions for cleaning dentures. Alternatively, thesesolutions may also contain a synthetic detergent such as an alkyl aryl sulfonate, sodium pyrophosphate and a flavoring agent. A dry denture cleaner composition may be formulated to contain about 50% of such a mixture, 15% anhydrous sodium pyrophosphate, 1% of a synthetic detergent, 10% of trisodium phosphate, 19% sodium sulfate and 5% sodium metasilicate. Such a composition, when added to Water in an amount to provide from 50 to 250 p.p.m. of active oxygen, provides a solution which is effective for cleaning dentures.

When the particulate composition of the invention is intended for use in preparing solutions for bleaching textiles, it is preferred that it contain a peroxymonosulfate and a salt of a 1 to 4 carbon saturated aliphatic monocarboxylic acid together with a buifering agent in such an amount that when the composition is dissolved in water to give a bleach solution having the desired active oxygen content, e.g., 0.002 to 0.4% and preferably 0.01 to 0.2%, the solution will also have the desired pH, e.g., 5 to 10 and preferably 5.5 to 8, without requiring the separate addition of any pH adjusting agent. Buffering agents suitable for use in formulating such compositions include sodium tripolyphosphate (Na P O sodium metasilicate (Na SiO sodium tetraborate (Na B O disodium phosphate (Na HPO tetrasodium pyrophosphate (Na P O soda ash (Na CO and trisodium phosphate (Na PO Of such agents, soda ash, tetrasodium pyrophosphate (TSPP), trisodium phosphate (TSP) and disodium phosphate (DSP) are generally preferred. These preferred agents are highly effective and behave generally similarly, particularly in solutions for bleaching textiles, e.g., at temperatures from room temperature to 212 F., preferably to F.

In formulating the particulate compositions containing buffering agents, the peroxymonosulfate, the salt of the carboxylic acid and the buffering agent should be so proportioned that when the composition is dissolved in water at a concentration to give a solution having the desired active oxygen content, such solution will also have the desired pH and will contain the salt of the carboxylic acid at a. concentration to provide the desired mole ratio of acylate ion to peroxymonosulfate ion. As indicatedpreviously, the mole ratio of acylate ion:- peroxymonosulfate ion may generally range from 0.2 to 12:1, or higher, the preferred mole ratios being about 0.7 to 5 :1. When using sodium acetate as the carboxylic acid salt component and the commercially available form of the triple salt of potassium peroxymonosulfate of the formula KHSO -K SO -2KHSO (active oxygen content of about 4.7% as the peroxymonosulfate component, the weight ratios of sodium acetate: the triple salt will generally range from about 0.05 to 3.2:1, the

preferred range being 0.2 to 1.4:1. The amount of the buffering agent, e.g., soda ash, tetrasodium pyrophosphate (TSPP), trisodium phosphate (TSP), disodium phosphate (DSP), or mixtures thereof, in the particulate composition should be such that when a 3% aqueous solution of the composition is prepared, the solution will have a pH of to 10, preferably 5.5 to 8.

When the particulate composition of the invention is to be stored and/ or shipped in bulk, it is preferred that a desiccant material in particulate form be incorporated therein to guard against the adverse effects of moisture that may be picked up from the atmosphere. Suitable desiccant materials, i.e., desiccating agents, are anhydrous magnesium sulfate, magnesium sulfate monohydrate anhydrous calcium sulfate, anhydros sodium sulfate, phosphorous pentoxide and lime. Of these materials, the anhydrous salts, particularly magnesium and calcium sulfate, are preferred with anhydrous magnesium sulfate being the most preferred. Any amount of such desiccating agent will generally be beneficial in protecting against moisture pick-up, but amounts greater than about will seldom be used and usually will be undesirable because of their excessive diluting effect. The amounts most useful, particularly for the preferred desiccants are l to 4%, preferably 2.5 to 3.5%, based upon the total composition weight. The desiccant material is most effective when used in finely divided form. Preferably, the desiccant will be in powder form with at least 90% thereof passing through a 100 mesh screen (US. Standard Sieve Series). Anhydrous magnesium sulfate powder of that fineness has been used in preparing particulate compositions in accordance with the invention containing, on a weight basis, 53.4 2% of the potassium peroxymonosulfate triple salt product, 35.6:

2% anhydrous sodium acetate, 8.1:0.5% trisodium phosphate (TSP), and 2.91 0.5% magnesium sulfate. Such compositions exhibit good stability and protection against moisture pick-up. They will dissolve in water to give 3% solutions having a pH of 6.4102, and are generally useful for the purposes disclosed herein.

An important use of the compositions of the invention is in the bleaching of textile fabrics containing portions dyed with a sensitive dyestuff. For such use, the bleaching solution containing the peroxymonosulfate and acetate is preferably buffered to a pH of 5.5 to 8, e.g., using one of the buffering agents previously mentioned. The bleaching can be effected at usual room temperatures, but temperatures from 100 to 212 F. are preferred. At such temperatures, bleaching times of from 10 minutes to 5 hours may be employed, the lower temperatures generally requiring longer times than the higher temperatures. Bleaching may be effected by immersing the fabric in the bleaching solution maintained at the desiredtemperature. Preferably, the fabric will be impregnated or saturated with an amount of the bleaching solution equal to from about 50 to 150% of the fabric weight, and the saturated fabric will then be heated to the desired temperature, e.g., by contacting it with live steam or a mixture of steam and air, depending upon the temperature desired. Most preferably, the bleaching is carried out using equipment such as the well-known J-box which permits continuous operation.

The following examples illustrate specifically the effectivness of compositions of the invention for removing stains from textile fabrics and for bleaching textile fabrics. In the examples and elsewhere in the specification, all proportions expressed as parts or percentages are by weight.

EXAMPLE 1 A standard tea-coffee stained cotton fabric was prepared. The'whiteness value of the stained fabric was then determined using a Hunter Reflectometer. In such a determination, the whiteness values are reported as percent reflectance representing the percent light reflected from the sample as measured using the Hunter Reflectometer with a blue filter for which magnesium oxide gives a reflectance of percent. Samples of the stained fabric were then employed in home laundry bleaching trials using a standard Launder-O-Meter. In one series of trials the laundering liquid contained a commercial alkyl benzene sulfonate-based laundry detergent at a concentration of 0.1% with no other additive. In a parallel series of trials the laundering liquid contained in addition to the 0.1% detergent an amount of the abovementioned commercial potassium peroxymonosulfate triple salt product (active oxygen content 4.7%) to provide 25 p. p.m. of active oxygen. In a third series of trials the laundering liquid contained in addition to the detergent and the potassium peroxymonosulfate product at the above concentrations, sodium formate, or sodium acetate, or sodium butyrate at a concentration of 1.25 In each of the series or trials, the laundering operation was repeated 8 times for 10 minutes each at F. in the Launder-O-Meter, following which the fabric samples were washed and dried and the whiteness values determined. The results are tabulated below. In the tabulation, the Points Gained Over Base represents the gains in points reflectance for the laundered fabric over the reflectance of the original stained fabric (Base), whereas the Points Gained Over Base Detergent represents the points in reflectance gained over the reflectance of the stained fabric after it had been laundered with only the detergent.

It will be seen from the above data that the addtion of either sodium formate, sodium acetate, or sodium butyrate to the laundering liquid containing the peroxymonosulfate increased significantly the final whitness of the fabric. These salts clearly actively promoted the bleaching activity of the peroxymonosulfate. The promotional effect of sodium acetate Was particularl outstanding in that the gain in reflectance points over the base plus the detergent was 6.7 as compared with only 3.9 when only the peroxymonosulfate was used with the detergent. The increase of 2.8 points due, to the promotional effect of the sodium acetate represents an approximately 72% increase in whiteness over that obtained when the peroxymonosulfate was used alone with the detergent.

EXAMPLE 2 Two strips of stained fabrics were made by sewing together patches of heavily stained cotton fabric (obtained from Test Fabrics, Inc.) so that each test strip consisted of patches of variously' stained fabrics together with patches of the same fabric which had previously been bleached and patches which had not been bleached, i.e., the grey fabric. Each test strip was subjected to stain removal tests using solutions of the above-mentioned commercial potassium peroxymonosulfate triple salt product with and without sodium acetate as a promoter.

The stain removal solutions contained 0.2% of the peroxymonosulfate triple salt product and 0.4% sodium pyrophosphate decahydrate. One of the test solutions, Formula A, contained no sodium acetate, whereas the other solution, Formula B, contained 0.3% sodium acetate. The pH of each solution was 8.6 The test fabric strips were immersed in the solutions at a liquortfabric weight ratio of 20:1 and the time of immersion was 3 hours While the solutions were maintained at 140 F. The test strips were then removed, rinsed thoroughly with water and dried.

The dried strips were then examined by three individuals and in all examinations the individuals independently found that all of the stains in the strip treated with Formula B were lighter than were the corresponding stains in the strip treated with Formula A. Each patch in each test strip was then placed over the aperture of a Hunter Reflectometer and backed with a standard having a reflectance of 83%, and the percent reflectance of each patch was then determined. The results are reported in the following tabulation.

Percent Reflectance It will be seen from the above results that stain removal solution Formula B, containing sodium acetate, was substantially more effective than solution Formula A in removing the various stains from the test strips.

EXAMPLE 3 A solution A was made up to contain 1.5% of the abovementioned commercial potassium peroxymonosulfate triple salt product and 0.7% sodium pyrophosphate decahydrate. A similar Solution B was made up except that it also contained 1.6% sodium acetate trihydrate. The pH of each solution was 6.0. Samples of a caustic scoured 78 x 78, 4 yd./lb. cotton fabric were saturated with one or the other of the above solutions so as to contain 100% by weight of the solution, and the saturated samples were then bleached in a saturated steam atmosphere at 212 F. for minutes. After rinsing and drying, the whiteness of the cloth samples was determined. The percent reflectance of the sample treated with Solution A was 83.1%, whereas that of the sample treated with Solution B, containing sodium acetate, was 86.2%.

EXAMPLE 4 Samples of the same fabric used in Example 3 were treated as described in Example 3 except that the treating solutions contained 2% (instead of 1.5%) of the potassium peroxymonosulfate triple salt product and each solution contained 3% sodium pyrophosphate decahydrate with 1.5% sodium acid pyrophosphate being added to adjust the pH of all solutions to 6.0. The bleaching results obtained using 4 such solutions containing 0, 1, 2 and 5% sodium acetate trihydrate are shown below.

Percent sodium acetate trihydrate: Percent reflectance O 86.4

EXAMPLE 5 umn B are those obtained using solutions containing sodium acetate.

Two hundred grams of the commercial potassium peroxymonosulfate triple salt product was dry-blended with an equal weight of anhydrous sodium acetate for 20 minutes in a Twin Shell mixer. A bleaching solution was prepared by dissolving 20 g. of the resulting mixture in 880 ml. of water, then adjusting the pH of the solution with a mixture of 35 ml. of water and 89 ml. of a 6% solution of tetrasodium pyrophosphate decahydrate. A sample of caustic scoured 78 x 78 cotton fabric (4 yd./ lb.) was saturated with the bleaching solution so as to contain 10% by weight of the solution, and the saturated sample was heated with steam at 190 F. for 20 minutes. The whiteness (percent reflectance) of the fabric sample was raised from 68.8 to 85.1 by the bleaching treatment. When another sample of the fabric was similarly bleached with the solution at room temperature for 20 hours, the percent reflectance was raised from 68.0 to 84.7.

EXAMPLE 7 I A particulate composition was prepared by dry-blending two parts of anhydrous sodium acetate with three parts of the commercial potassium peroxymonosulfate triple salt product in a Twin Shell mixer. A 2.5% solution of the composition in water had a pH of 5.3. Portions of the resulting solution were then buttered by the addition thereto of various buffering agents in the amounts indicated in the following tabulation, whereby each of the resulting solutions had a pH of 6.4-6.5. The resulting solutions were used to bleach IO-gram samples of a caustic scoured cotton print cloth having an unbleached whiteness (percent reflectance) of 67.7. The bleaching was effected by saturating the cloth with an equal weight of the bleaching solution and then heating the saturated cloth at F. for 1 hour. After the bleaching treatment, the fabric was rinsed with 500 ml. of water, the pH of the rinse water and the percentage of residual active oxygen therein were determined and the whiteness of the bleached fabric was measured. The results, together with the amounts of buffering agents employed, are shown in the following tabulation.

In the following tabulations, TSP stands for trisodium phosphate, DSP stands for disodium phosphate and TSPP stands for tetrasodium pyrophosphate.

pH of Percent Percent cloth residual in rinse active Percent Test Identity Butler solution water oxygen reflectance A Anhydrous TSP 0. 26 5. 5 40 88. 1 B Anhydrous DSP 0.50 5. 45 35 87. 8 C. Anhydrous sodium metasilicate 0. 14 5. 35 52 87. 5 D Borax pentahydrate 0. 33 5. 3 47 8G. 8 E Anhydrous TSPP powder 0. 47 5. 6 48 88. 0

EXAMPLE 8 sodium pyrophosphate powder (TSPP) and 1.85 parts of anhydrous soda ash in place of the 2.25 parts of TSP. Compositions A, B and C were each dissolved in about 970 parts of water togive bleach solutions having a pH of 6.4 and containing 1.5% of the above triple salt product.

The resulting solutions were used to bleach samples of a caustic scoured cotton print cloth having starting whitenesses (percent reflectance) of 68.068.7%. Bleaching was effected ,by saturating the cloth sample with an equal weight of the bleach solution, then heating the saturated sample at 160 F. The bleaching times at 160 F., the percentages of residual or unused active oxygen at the end of the bleaching times and the bleach results are shown in the following tabulation.

Bleaching Residual When the above bleaching procedure is repeated using a composition composed of 54.7% of the triple salt product, 27.2% sodium acetate and 18.1% disodium phosphate in place of composition A, essentially the same results are obtained as those reported above for composition A.

EXAMPLE 9 Five samples of various colored fabrics, each about 6 ft. x 10 in., are butt-seamed together and the resulting assembly is butt-seamed into the center of a 100 yd. x 10 in. sample of unbleached cotton fabric to form a fabric train. The colored samples are: (a) an all-cotton fabric containing a /2-in. check pattern dyed with a blue copper phthalocyanine dye; (b) a 50:50 cotton/polyester fabric having a /2-in. check pattern containing disperse and naphthol red dyes; (c) an all-cotton light-weight fabric having a l-in. check. pattern dyed with a naphthol red dye; (d) a medium-weight all-cotton fabric having naphthol red stripes and yellow stripes against a white background; and (e) an all-cotton seersucker containing alternating Ms-in. white and green stripes dyed with a vat green dye. The fabric train is continuously saturated with an equal weight of a bleaching solution which is a 2.8% solution of a particulate composition containing 8.3% anhydrous trisodium phosphate, 36.7% anhydrous sodium acetate and 55% of the commercial potassium peroxymonosulfate triple salt product, the :pH of the solution being 6.4. The saturated fabric is passed continuously through a I-box maintained at about 185 F. with a mixture of steam and air, the rate of travel through the J-box being such as to give a residence time therein for the fabric of about 1 hour. The bleached fabric is withdrawn from the J-box and after being washed in hot water, all the colored fabric samples, in the train are found to be well bleached with no evidence of bleeding or mark-01f of the dyes onto undyed portions of the fabric.

When the above procedure is repeated using bleach solutions prepared from similar particulate compositions containing anhydrous soda ash, anhydrous tetrasodium pyrophosphate or anhydrous disodium phosphate in place of trisodium phosphate, generally similar results are obtained. Such bleach solutions are also effective in bleaching alkali sensitive fabrics such as those containing cellulose triacetate fibers.

The above examples demonstrate the effectiveness of sodium formate, sodium acetate and sodium butyrate in promoting the oxidative action of potassium peroxymonosulfate in removing stains from textiles and in bleaching textiles. Similar results are obtainable using other salts of the 1 to 4 carbon saturated aliphatic monocarboxylic acids, or the acids themselves, in place of the sodium formate, sodium acetate, or sodium butyrate shown. Similarly, corresponding results are obtainable using other water-soluble peroxymonosulfates, such as the sodium and ammonium peroxymonosulfates, in place of the potassium peroxymonosulfate triple salt product used in the examples. The effectiveness of such acylate compounds in promoting the oxidative action of peroxymonosulfates was entirely unexpected and obviously is highly advantageous and practical.

The promoting effect of ac'ylates of the above type on the oxidative action of peroxymonosulfates can be realized under any of the conditions that peroxymonosulfates are known to be active, e.g., in bleaching or stain removal operations. Thus, the compositions of the invention can be employed in bleaching or stain removal operations at ordinary or elevated temperatures, in immersion-type bleaching operations or in operations where the fabric to be bleached is simply saturated with 50 to 150%, preferably to of the bleach solution containing the peroxymonosulfate and the promoter and then permitted to bleach in the saturated state at either room or higher temperatures, e.g., steaming temperatures.

I claim:

1. A particulate composition consisting essentially of an admixture of a water-soluble peroxymonosulfate and a water-soluble salt of a carboxylic acid from the group consisting of formic, acetic, propionic and butyric acids, which salt is free of cations which would adversely react with or catalyze the decomposition of said peroxymonosulfate, said composition containing from 0.2 to 12 moles of said per mole of said peroxymonosulfate.

2. A composition according to claim 1 wherein the peroxymonosulfate is a potassium peroxymonosulfate and the salt of the carboxylic acid is an acetate.

3. A composition according to claim 1 wherein the peroxymonosulfate is a potassium peroxymonosulfate triple salt of the formula KHSO -K SO -2KHSO and the salt of the carboxylic acid is an acetate.

4. A composition according to claim 1 wherein the peroxymonosulfate is a potassium peroxymonosulfate and the salt of the carboxylic acid is sodium acetate, which composition also contains a buffering agent effective to buffer a 3% aqueous solution of the composition containing 0.002 to 0.4% active oxygen derived from said peroxymonosulfate at a pH in the range 5 to 10.

5. A composition according to claim 3 wherein the acetate is sodium acetate.

6. A composition according to claim 4 wherein the peroxymonosulfate is a potassium peroxymonosulfate triple salt of the formula KHSO -K SO -2KHSO and the buffering agent is from the group consisting of sodium tripolyphosphate, sodium metasilicate, sodium tetraborate, disodium phosphate, soda ash, tetrasodium pyrophosphate and trisodium phosphate.

7. A composition according to claim 6 wherein the weight ratio of sodium acetate:said triple salt is from 0.05 to 3.2: 1, which composition contains soda ash in an amount such that a 3% aqueous solution of the composition will have a pH of 5 to 10.

8. A composition according to claim 6 wherein the weight ratio of sodium acetate:said triple salt is from 0.05 to 3.211, which composition contains tetrasodium pyrophosphate in an amount such that a 3% aqueous solution of the composition will have a pH of 5 to 10.

9. A composition according to claim 6 wherein the weight ratio of sodium acetate:said triple salt is from 0.05 to 3.2: 1, which composition contains trisodium phosphate in an amount such that a 3% aqueous solution of the composition will have a pH of 5 to 10.

10. A composition according to claim 6 wherein the weight ratio of sodium acetate:said triple salt is from 0.05 to 3.2: 1, which composition contains disodium phosphate in an amount such that a 3% solution of the composition Will have a pH of 5 to 10.

11. A composition according to claim 6 which also contains a desiccating agent in an amount up to of the composition weight.

'12. A composition according to olaim 6 which also contains 1 to 4%, based on the composition weight, of a. finely divided desiccating agent which is anhydrous magnesium sulfate or anhydrous calcium sulfate.

13. A composition according to claim 9 consisting essentially of about 55 weight percent of said triple salt, about 36.7 weight percent of sodium acetate and about 8.3 weight percent of trisodium phosphate.

14. A composition according to claim 10 consisting essentially of about 54.7 Weight percent of said triple salt, about 27.2 weight percent of sodium acetate and about 18.1 weight percent disodium phosphate.

15. A composition according to claim 12 wherein the weight ratio of sodium acetatezsaid triple salt is from 0.05 to 3.2:1, the buffer is trisodium phosphate and the desiccating agent is anhydrous magnesium sulfate.

16. A composition according to claim 15 containing, on a weight basis, about 51.4 to 55.4% of said triple salt, 33.6 to 37.6% anhydrous sodium acetate, 7.6 to 8.6% trisodium phosphate and 2.4 to 3.4% anhydrous magnesium sulfate, which composition will dissolve in water to give a 3% solution having a pH of from 6.2 to 6.6.

17. A composition according to claim '16 which contains about 53.4% of said triple salt, about 35.6% an- 12 hydrous sodium acetate, about 8.1% trisodium phosphate and about 2.9% anhydrous magnesium sulfate.

18. A composition comprising an aqueous solution having a pH of 5 to 10 and consisting essentially of the peroxymonosulfate ion and from 0.2 to 12 moles of the acylate ion of an acid from the group consisting of formic, acetic, propionic and butyric acids, for each mole of peroxymonosulfate ion present in said solution.

19. A composition according to claim 18 in which the acylate ion is the acetate ion, which solution contains a buffer from the group consisting of sodium tripolyphosphate, sodium metasilicate, sodium tetraborate, disodium phosphate, soda ash, tetrasodium pyrophosphate and trisodium phosphate.

20. A composition according to claim 19 which has a pH of 5.5 to 8.

References Cited UNITED STATES PATENTS 2,996,350 8/1961 Taylor 252186X 3,048,546 8/1962 Lake et a1. 252 3,130,165 4/1964 Brocklehurst 252-99 MAYER WEINBLATT, Primary Examiner US. Cl. X.R. 252-95, 99, 186