United States Patent: 3606990

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United States Patent	3,606,990
Gobert , et al.	September 21, 1971

PROCESS FOR WASHING LAUNDRY AND DETERGENT COMPOSITION FOR WORKING OF THIS PROCESS

Abstract

A process for bleaching and washing which comprises treating a stained cloth or the like with an aqueous solution containing a water-soluble peroxide bleaching agent said treatment being carried out in the presence of a compound capable of inhibiting enzyme-induced decomposition of said bleaching agent.

Inventors:	Gobert; Michel Rene Roger (Courbevoie, FR), Mouret; Gerard (Paris, FR)
Assignee:	Colgate-Palmolive Company (New York, NY)
Appl. No.:	05/011,028
Filed:	February 12, 1970

Current U.S. Class: 8/111 ; 252/186.21; 252/186.22; 252/186.3; 252/186.31; 510/302; 510/309; 510/346; 510/375; 510/380; 510/381; 510/499; 510/500; 510/505; 8/109

Current International Class: C11D 3/39 (20060101); D06l 003/02 ()

Field of Search: 8/111,109 252/95,DIG.12

References Cited [Referenced By]

U.S. Patent Documents


2667475	January 1954	Fick
2914374	November 1959	Harris et al.
3348903	October 1967	Baier
3454427	July 1969	Suzuki et al.

Primary Examiner: Weinblatt; Mayer

Parent Case Text

This application is a continuation-in-part of U.S. Ser. No. 579,491 filed Sept. 15, 1966 and now abandoned.

Claims

What is claimed is:

1. A process of bleaching and washing stained cloth having enzyme-containing stain, said enzyme being capable of decomposing water-soluble inorganic peroxide bleaching agent which comprises treating said cloth with an aqueous solution of from about 0.1 percent to about 15 percent by weight of an inhibitor compound capable of inhibiting enzyme-induced decomposition of said water soluble inorganic peroxide bleaching agent and a substance selected from the group consisting of (a) from about 2 percent to about 85 percent of said water soluble inorganic peroxide bleaching agent, (b) from about 5 percent to about 99 percent of a water soluble organic detergent and (c) mixtures of (a) and (b) with the proviso that in the case of mixtures of (a) and (b), at least about 10 percent by weight of each of said water soluble inorganic peroxide bleaching agent and said organic detergent are present; and with the further proviso that when only said organic detergent (b) is employed, said stained cloth is thereafter treated with a composition containing from about 2 to about 90 percent by weight of said water soluble inorganic peroxide bleaching agent: said inhibitor compound being selected from the group consisting of (A) hydroxylamine hydrochloride, hydroxylamine sulfate, hydrazine hydrochloride, 2,4-dinitrophenol-hydrazine, p-chlorophenol, 4-chloro-2-aminophenol, o-cresol, p-chloro-m-cresol, 2,4-dichlorophenol, resorcinol, pyrocatechol, pyrogallol, beta-naphthol, 2,7-dihydroxynaphthalene, hydroquinone, hydroquinone sulfate, 1,2-naphthoquinone, 1,2-cyclohexanediol, aminotriazole, sodium chlorate and sodium nitride when said substance is any of (a), (b) and (c) above, and (B) formaldehyde, sodium hypochlorite, potassium salt chlorocyanuric acid and potassium salt of monopersulfuric acid when said substance is (b) above.

2. A process according to claim 1 wherein said bleaching agent is sodium perborate tetrahydrate.

3. A process according to claim 1 wherein said bleaching agent is sodium perborate monohydrate.

4. A process according to claim 1 wherein said cloth is presoaked in aqueous media prior to contact with said aqueous solution containing peroxide bleaching agent.

5. A process according to claim 1 wherein said presoaking is effected in the presence of effective quantities of said inhibitor.

6. A process according to claim 1 wherein said inhibitor is selected from the group consisting of hydroxylamine hydrochloride, hydroxylamine sulfate, hydrazine hydrochloride, 2,4-dinitrophenolhydrazine, p-chlorophenol, 4-chloro-2-aminophenol, o-cresol, p-chloro-m-cresol, 2,4-dichlorophenol, resorcinol, pyrocatechol, pyrogallol, beta-naphthol, 2,7-dihydroxynaphthalene, hydroquinone, hydroquinone sulfate, 1,2-naphthoquinone, 1,2-cyclohexanediol, aminotriazole, sodium chlorate and sodium nitride.

7. A process according to claim 1 wherein said inhibitor is selected from the group consisting of formaldehyde, sodium hypochlorite, potassium salt chlorocyanuric acid and potassium salt of monopersulfuric acid.

8. A process according to claim 6 wherein said inhibitor is hydroxylamine hydrochloride.

9. A process according to claim 6 wherein said inhibitor is hydroxylamine sulfate.

10. A process according to claim 6 wherein said inhibitor is hydrazine hydrochloride.

11. A process according to claim 6 wherein said inhibitor is sodium nitride.

12. A process according to claim 6 wherein said inhibitor is p-chlorophenol.

13. A process according to claim 6 wherein said inhibitor is 4-chloro-2-aminophenol.

14. A process according to claim 6 wherein said inhibitor is resorcinol.

15. A process according to claim 6 wherein said inhibitor is hydroquinone.

16. A process according to claim 6 wherein said inhibitor is present in said substance (a) or (c).

17. A process according to claim 7 wherein said inhibitor is sodium hypochlorite.

18. A process according to claim 7 wherein said inhibitor is potassium dichlorocyanurate.

19. A process according to claim 7 wherein said inhibitor is potassium monopersulfate.

20. A process according to claim 7 wherein said inhibitor is formaldehyde.

21. A bleaching composition consisting essentially of on a weight basis (I) from about 0.1 percent to about 15 percent of hydroxylamine salt as inhibitor compound capable of inhibiting enzyme-induced decomposition of water soluble inorganic peroxide bleaching agent and (II) a substance selected from the group consisting of (a) from about 2 percent to about 85 percent of a water soluble inorganic peroxide bleaching agent, (b) from about 5 percent to about 99 percent of a water soluble organic detergent and (c) mixtures of (a) and (b) with the provision that in the case of mixtures of (a) and (b), at least about 10 percent being each of bleaching agent and detergent.

22. A composition according to claim 21 wherein said substance is selected from the group consisting of from about 2 percent to about 85 percent of a water soluble inorganic peroxide bleaching agent and mixtures of from about 10 percent to about 85 percent of a water soluble inorganic peroxide bleaching agent with from about 10 percent to about 99 percent of a water-soluble organic detergent.

23. A composition according to claim 21 wherein said bleaching agent is sodium perborate tetrahydrate.

24. A composition according to claim 21 wherein said bleaching agent is sodium perborate monohydrate.

Description

The present invention relates to an improved process for washing cloth and to bleaching of detergent compositions for carrying out this process.

The use of percompound containing compositions which liberate hydrogen peroxide in solution, i.e., compounds containing hydrogen peroxide or inorganic perhydrates, which, when dissolved, liberate the hydrogen peroxide enclosed in their crystal lattice (e.g., certain perborates, perphosphates) for domestic or industrial laundering is well known. There are, for example, detergent compositions in which sodium perborate frequently comprises between 1 and 35 percent of the total composition.

Hydrogen peroxide and the precursors which liberate it in solution are good oxidizing agents for removing certain stains from cloth, especially stains caused by wine, tea, coffee, cocoa, fruits, etc.

Hydrogen peroxide and its precursors have been found in general to bleach quickly and most effectively only at a relatively high temperature, e.g., about 80.degree. C. to 100.degree. C. However, such compounds tend to decompose and liberate gaseous oxygen at lower temperatures. The liberation of gaseous oxygen, which is not involved in oxidation of dyed goods, needlessly consumes a sizable amount hydrogen peroxide or precursors liberating it, both of which are expensive products. Moreover, it has been found that the various stains in cloth and the like greatly accelerates decomposition of hydrogen peroxide into gaseous oxygen during washing at ordinary temperature.

In general, washing cloth, either in a machine, by hand, or in broiler or tubs, is accomplished by dissolving a bleaching or detergent composition (containing perborate, for example) in cold or lukewarm water, adding to the solution thus formed the soiled cloth (from which some of the strains have often already been removed by soaking or previous washing) and heating, often just to boiling.

However, it was found that, by a phenomenon similar to that previously mentioned, all or part of the perborate was decomposed during heating and more specifically during the temperature rise, i.e., that all or part of the perborate was decomposed before the really effective temperature is reached.

It is believed, without wishing to be limited by any theory, that this rapid decomposition of hydrogen peroxide, perborate, or other precursors of hydrogen peroxide into gaseous oxygen at low temperature is due to the extremely powerful catalytic action of certain enzymes which are always present in stains, which are present on materials to be washed, and particularly on soiled cloth, such as linens, these enzymes coming from secretions or being of bacterial origin. Hydroperoxides are an especially active group of enzymes in this respect, particularly catalase, which is well known as a highly effective catalyst for decomposing hydrogen peroxide to gaseous oxygen. Such enzyme substances, whether termed "redox" or otherwise are nevertheless uniformly characterized in exhibiting a pronounced tendency to induce decomposition of peroxide bleaching agent, the decomposition products evolved thereby comprising ineffective bleaching species.

Thus, a primary object of the present invention resides in the provision of bleaching and detergent compositions and processing therewith wherein the foregoing and related disadvantages are eliminated or at least mitigated to a substantial extent.

Another object of the present invention resides in the provision of an improved washing process wherein problems associated with useless decomposition of peroxide bleaching agent e.g. perborate or hydrogen peroxide (in any form) into gaseous oxygen are substantially eliminated.

Yet another object of the present invention resides in the provision of bleaching and detergent compositions specifically adapted for use in carrying out said process.

A further object of the present invention resides in the provision of a process having exceptional bleach efficiency and wherein substantially all the oxidizing action of the bleaching agent is rendered available for useful purposes thereby permitting material reductions in the amount of bleaching agent needed (up to three times) or alternatively greatly increasing the effectiveness of an equal amount of material.

A still further object of the present invention resides in the provision of bleaching and detergent compositions for carrying out the foregoing process.

Other objects and advantages of the invention will be apparent from the following description.

The attainment of the foregoing and related objects is made possible in accordance with the present invention which in its broader aspects provides a process of bleaching stained cloth or the like which comprises treating said stained cloth with an aqueous solution of peroxide bleaching agent, said treatment being effected in the presence of a compound capable of inhibiting enzyme-induced decomposition of said bleaching agent.

Inhibitor compounds which may be effectively employed in the practice of the present invention encompass a relatively wide range of materials of diverse chemical nomenclature. Special representatives include, without necessary limitation, hydroxylamine salts like the neutral sulfate, hydrochloride, etc., hydrazine and phenylhydrazine and their salts, e.g. sulfates; substituted phenols and polyphenols, including mono- and polysubstituted, the substituents including at least one - NH.sub.2, SO.sub.2 NH.sub.2, -CI, -BR, -NO.sub.2, alkyl, etc., for example, aminophenols like o-amino-p-chloro-phenol, the compounds described in "The Japanese Journal of Tuberculosis" Vol. 4, Mar. 1956 No. 1-Part 59 (12-21 )--Article by Toshio Noda, and the polyphenols mentioned in an article by Hubert N. Alcoa and James Pace in the "The Journal of the American Chemical Society" Vol. LV, Sept. -Dec. 1933 (4801-6); aminotriazoles and derivatives thereof like 3-amino- 1,2,4,-triazole 3-ureido- 5-triazone, etc.; alkali metal chlorates; sodium nitride; alkali metal cyanurates, etc. as well as mixtures comprising two or more of the foregoing.

The use of mixtures of inhibitors permits the exploitation of the beneficial effects characterizing each of a plurality of such compounds and thus comprises a particularly effective mode of proceeding. Accordingly, the term "inhibitor" as used herein is to be accorded a significance consistent with the foregoing.

The aforedescribed inhibitors may be contacted with the stained cloth, during a soaking or prewashing stage prior to contact with the peroxide bleaching agent or, alternatively, during the washing step simultaneous to contact with such bleaching agent. They may also be added directly to the bath as an individual component or more preferably, incorporated in a detergent composition further containing a detergent of conventional type, the latter procedure being preferred when the composition is added during the soaking step. Alternatively, the inhibitor may be included a component of a composition further containing peroxide bleaching agent, and particularly in those instances wherein the composition is contemplated for use, i.e., is to be added, during the washing step. In the latter case, the composition may also contain one or more water soluble, organic detergent compounds if desired. Thus, the compositions provided in accordance with the present invention may comprise simply a mixture of inhibitor and detergent, compositions so constituted being particularly adapted for use in connection with soaking operations; a further embodiment pertains to compositions containing as essential ingredients, inhibitor and peroxide bleaching agent and, optionally, detergent, such compositions being particularly effective for use during the washing operation or cycle. Otherwise stated, the compositions of the present invention may be defined as containing as essential ingredients on a weight basis, (I) from about 0.1 to about 15 percent of an inhibitor compound capable of inhibiting or retarding enzyme-induced decomposition of peroxide bleaching agent and (II) a substance selected from the group consisting of (a) from about 2 to about 85 percent of a water soluble peroxide bleaching agent, (b) from about 5.0 percent to about 99 percent of a water soluble organic detergent and (c) mixtures of (a) and (b ) with the provision that, in the case of mixtures, at least about 10 percent and about 10 percent respectively of bleaching agent and detergent be present.

The peroxide bleaching agents prescribed for use in the instant invention are preferably those of the water soluble inorganic type including, for example, alkali metal perborates such as sodium perborate monohydrate and/or tetrahydrate; alkali metal perphosphates such as sodium and potassium perphosphate; alkali metal persilicates such as sodium and potassium persilicate; alkali metal percarbonate such as sodium and potassium percarbonate; peroxides such as sodium peroxide, hydrogen peroxide, etc. including mixtures of two or more of the foregoing. In any event, the peroxide bleaching agent is employed in amounts ranging from about 2 percent to about 90 percent by weight of total composition with a range of 5 percent to 20 percent being preferred.

The water soluble organic detergents or surface active agents, i.e., "surfactants" suitable for use in the practice of the present invention may be selected from a wide range of materials including the nonionics, anionics, cationics, amphoterics, zwitterionics, etc. Nothing critical resides in the selection of such detergent component provided of course the material selected exhibit the degree of "detergency" desired and water solubility.

Suitable anionic surface active agents include those detergent compounds which contain an organic hydrophobic group as well as an anionic solubilizing group. Typical of anionic solubilizing groups include sulfonate, sulfate, carboxylate, phosphonate, and phosphate. Examples of suitable anionic detergents falling within the scope of the invention include the soaps e.g., the water-soluble salts of higher fatty acids or resin acids the latter being derived from for example, fats, oils and waxes of animal, vegetable or marine origin e.g., the sodium soaps of tallow, grease, coconut oil, tall oil, as well as mixtures comprising two or more of the foregoing; the sulfated and sulfonated synthetic detergents, particularly those having from 8 to 26 carbon atoms and preferably from 12 to 22 carbon atoms per molecule.

As examples of suitable synthetic anionic detergents there may be mentioned the higher alkyl mononuclear aromatic sulfonates such as the higher alkyl benzene sulfonates containing from 10 to 16 carbon atoms in the alkyl group, the latter being either straight or branch chain e.g., the sodium salts of decyl, undecyl, dodecyl (lauryl) tridecyl, tetradecyl, pentadecyl, hexadecyl, benzine sulfonates; aromatic tallow (ethenoxy) ether sulfonates, alkyl naphthalene sulfonate, ammonium diamyl naphthalene sulfonate, and sodium dinonyl napthalene sulfonate. Other anionic detergents include the olefin sulfonates, include the olefin sulfonates, including long-chain alkene sulfonates, long-chain hydroxyalkane sulfonates or mixtures of alkene sulfonates and hydroxyalkane sulfonates. The olefin sulfonate detergents may be prepared in known manner as by the reaction of So.sub.3 with long-chain olefins the latter having from 8 to 25 and preferably 12 to 21 carbon atoms such olefins corresponding to the following formula.

RCH=CHR.sub.1

r is alkyl and R.sub.1 is alkyl or hydrogen, to produce a mixture of sultones and alkanesulfonic acids. The latter mixture is then suitably treated to convert the sultones to sulfonates. Examples of other sulfate or sulfonate detergents include paraffin sulfonates e.g., the reaction products of alpha olefins and bisulfites, e.g., sodium bisulfite, such as primary paraffin sulfonates of about 10 to 20 and preferably 15 to 20 carbon atoms; sulfates of higher alcohols; salts of alpha-sulfofatty esters e.g., of about 10 to 20 carbon atoms such as methyl, alpha-sulfomyrestate of alpha-sulfotallowate. Examples of sulfates of higher alcohols include without necessary limitation sodium lauryl sulfate, sodium tallow alcohol sulfate etc. Turkey Red Oil or other sulfated oils of sulfates of mono- or diglycerides of fatty acids e.g., stearic monoglyceride monosulfate, alkyl poly (ethnoxy) ether sulfates such as the sulfates of the condensation products of ethylene oxide and lauryl alcohol (usually having from one to five ethenoxy groups per molecule); lauryl or other higher alkyl glyceryl ether sulfonates of the condensation products of ethylene oxide and nonyl phenol (usually containing from one to 20 oxyethylene groups per molecule and preferably from 2 to 1.sup.2).

Suitable anionic detergents additionally include the acyl sarcosinates (e.g., sodium lauroylsarcosinate) the acyl esters (e.g., oleic acid esters) of isothionates and the acyl N-methyl taurides (e.g., potassium N-methyl lauryl or oleyl tauride.

The most highly preferred water-soluble anionic detergent compounds comprise the ammonium and substituted ammonium e.g., the mono- di- and triethanol amine), alkali metal (such as sodium and potassium) and alkaline earth metal (such as calcium and magnesium), salts of the higher alkyl benzene sulfonates, olefin sulfonates, the higher alkyl sulfates and the higher fatty acid monoglyceride sulfates. The detergent salt compound selected in a particular instance will depend, inter alia upon the nature of the formulation being prepared as well as the relative proportions of ingredients.

Nonionic surface-active agents suitable for use herein include those compounds containing both an organic hydrophobic moiety and a hydrophillic group which is a reaction product of a solubilizing group such as carboxylate, hydroxyl, amide or amino with ethylene oxide or with the polyhydration product thereof, polyethylene glycol etc. Examples of nonionic detergent compounds suitable for use include the condensation products of alkyl phenol with ethylene oxide e.g., the reaction product of isooctyl phenol with about six to 30 ethylene oxide units; condensation products of alkyl thiophenols with 10 to 15 ethylene oxide units; condensation products of higher fatty alcohols such as tridecyl alcohol with ethylene oxide; ethylene oxide addends of monoesters of hexahydric alcohols and inner ethers thereof such as sorbitan monolsurate sorbitol monooleated mannitan monopalmitate and the condensation products of polypropylene glycol with ethylene oxide.

Cationic surface active agents may also be employed; these compounds characteristically comprise surface active detergent compounds which contain an organic hydrophobic group and a cationic solubility group. Typical cationic solubilizing group include amine and quaternary groups.

As specific representative of cationic surface-active agents, there may be mentioned diamides such as those corresponding to the following structural formula:

RNHC.sub.2 H.sub.4 NH.sub.2

wherein R represents an alkyl group of about 12 to 22 carbon atoms e.g., N-2 aminoethyl stearyl amine N-2-aminoethylmyristly amine; amido-linked amines such as those corresponding to the following structural formula:

R'CONHC.sub. 2 H.sub.4 NH.sub.2

wherein R.sub.1 represents alkyl of about 9 -20 carbon atoms e.g., N-2-aminoethyl-stearyl amide and N-aminoethylmyristyl amide; quaternary ammonium compounds wherein typically one of the groups bonded to the nitrogen atoms is an alkyl group of about 12 to 18 carbon atoms and the other alkyl substituents contain from 1 to 3 carbon atoms which may contain further substituent group of an inert nature such as phenyl and there is present an anion such as halogen, acetate, methosulfate etc. Specific representatives of the aforedescribed class of compound include without necessary limitation ethyl-dimethyl-stearyl ammonium chloride, tetradecyl ammonium chloride trimethyl-stearyl-ammonium chloride, trimethyl-cetyl ammonium bromide, dimethyl-ethyl dilauryl ammonium chloride, dimethyl-propyl-myristyl ammonium chloride, benzyl-dimethyl-stearyl ammonium chloride as well as the corresponding methosulfates and acetates.

Amphoteric detergents may likewise be employed to advantage in the composition described herein i.e., detergent materials containing both an anionic and a cationic group as well as hydrophobic organic group which is advantageously a higher aliphatic radical e.g., containing from 10 to 20 carbon atoms. Specific representatives include the N-long-chain alkyl aminocarboxylic acids which, for convenience, may be represented according to the following structural formula:

the N-long-chain alkyl imino-dicarboxulic acids which may be represented according to the following structural formula:

RN (R' COOM ).sub. 2

and the N-long-chain alkyl betaines of the formula

wherein R represents a long-chain alkyl group of about 10 to 20 carbon atoms R.sup.1 represents a divalent radical joining the amino and carboxyl portions of an amino acid e.g., an alkylene radical of 1 to 4 carbon atoms; M represents hydrogen or a salt-forming metal R.sup.2 represents hydrogen or another monovalent substituent, e.g., methyl or other lower alkyl containing from 1 to 4 carbon atoms and R.sup.3 and R .sup.4 represent monovalent substituents joined to the nitrogen by carbon-to-nitrogen bonds e.g., methyl or other lower alkyl substituent. Specific examples of amphoteric detergents include the N-alkyl-beta-amine propionic acid, N-alkyl-beta imino dipropionic acid and N-alkyl N, N-dimethyl glycine; the alkyl group may be for example that derived from coco fatty alcohol, lauryl alcohol; myristyl alcohol or alternatively a lauryl-myristyl mixture, hydrogenated tallow alcohol, cetyl, stearyl, or blends of such alcohols. The substituted aminopropionic and iminodipropionic acids are often provided in the form of the sodium or other salt forms which may likewise be employed in the practice of the present invention. Examples of other amphoteric detergents are the fatty imidazolines such as those prepared by reacting a long-chain fatty acid containing from about 10 to 20 carbon atoms with diethylene triamine and mono-halo-carboxylic acid having 2 to 6 carbon atoms e.g., 1-coco- 5-hydroxyethyl-5 -carboxy-methylimidazoline, betaines containing a sulfonic group instead of the carboxylic groups; betaines in which the long-chain substituent is joined to the carboxyl group without an intervening nitrogen atom, e.g., inner salts of 2-trimethylamino fatty acids such as 2 -trimethylaminolauric acid as well as compounds of the aforementioned type in which the introged atom is replaced by phosphorous.

Detergents of the type enumerated hereinbefore may be employed in the compositions described herein in amounts varying over a relatively wide range; in any event, the particular quantity selected is not especially critical depending primarily upon the requirements of the formulator i.e., the nature of the detergent problem likely to be encountered in practice having reference to the use contemplated. Thus, where low-foaming characteristics are desired, the nonionics prove particularly effective; alternatively, the cationics prove beneficial in application requiring effective germ-killing capabilities since detergents of this type, in many instances, possess a high order of bacteriostatic activity. In any event, it has been ascertained that detergent or surfactant quantities in amounts ranging from about 2 percent to about 5 percent by weight are eminently suitable with a range of 2 percent to 20 percent being particularly preferred. It will be understood that unusual circumstances may well dictate departures from the aforedescribed ranges. The present invention, of course, contemplates such developments and accordingly should be so construed.

The compositions described herein may additionally contain one or more water-soluble builder salts; included in this group are the inorganic and organic; basic and neutral water soluble salts. The builder salt is employed in amounts ranging of from about 3 percent to about 70 percent by weight of the composition being preferred. Suitable builders include without necessary limitation,

Trisodium phosphate

Tetrasodium pyrophosphate

Sodium acid pyrophosphate

Sodium monobasic phosphate

Sodium dibasic phosphate

Sodium hexameta phosphate

Sodium silicates, SiO.sub.2 /NA.sub.2 O of 1/1 to 3.2/1

Sodium carbonate

Sodium sulfate

Borax etc.

Other organic builders salts of organic acids and, in particular, the water soluble salts of aminopolycarboxylic acids. The alkali metal salts such as sodium, potassium and lithium; ammonium and substituted ammonium salts such as methylammonium, diethanolammonium and triethanolammonium; and amine salts such as mono- , di- and triethanolamine methylamine, octylamine diethylenatriamine, triethylenetetramine and ethylediamine are efficacious. The acid portion of the salt can be derived from acids such as nitrilodiacetic; N-(2-hydroxyethyl) nitrilodiacetic acid, nitrilotriacetic acid (NTA), ethylene-diamine tetracetic acid, (EDTA); N-(2-hydroxyethyl) ethylene diamine triacetic acid; 2 -hydroxyethyl iminodiacetic acid; 1,2 -diaminocyclohexanediacetic acid; diethylenetriamine penta-acetic acid and the like. The builder salt is preferably employed in amounts sufficient to yield a pH in water of from 8 to 11 and preferably from 9 to 10.5.

Particularly preferred for use herein are the water-soluble, alkali metal pyrophosphate builder salts. These salts form water-soluble complexes with calcium and magnesium ions found in hard water and thereby prevent the formation of water-soluble salts which would otherwise tend to deposit upon textiles during the wash cycle. Moreover, such phosphates enhance the detersive efficiency of non-anionic detergents and aid in controlling sudsing, while keeping soil suspended in the washing both after its removal from the soiled textiles. It will likewise be understood that mixtures comprising two or more of the aforementioned builder salts may be employed depending, as stated, on the particular requirements of the formulator. Preferred compositions advantageously contain a hydrophobic colloidal cellulosic soil-suspending agent of a type which is soluble or dispersible in water. The conjoint use of the cellulosic compound and polyvinyl alcohol is found to be particularly effective as regards soil-suspension properties during the washing of a wide variety of fabrics including both cotton and synthetic fibers such as cotton, dacron, and resin-treated cottons. The soil-suspending agent can be employed in amounts ranging from 0 to 3 percent by weight of the composition solids with a range of 0.1 to 2 percent being particularly preferred. Cellulosic compounds found to be particularly suitable in this regard comprise the alkali metal salts of a carboxy lower alkyl cellulose having up to 3 carbon atoms in the alkyl group such as the sodium and potassium salts of carboxymethylcellulose. Suitable salts are sodium carboxyethylcellulose; the cellulose sulfates and lower alkyl and hydroxyalkylcellulose ethers such as methyl-ethyl, ethyl, and hydroxyethylcellulose. It should also be pointed out that little in the way of criticality attends the selection of builder salt concentration and thus, those ranges conventionally recommended for relationships of the aforedescribed type are eminently suitable.

The desired pH level may be readily achieved by the addition of suitable buffering agents to the composition, such agents being provided either as a solution, dry powder, granules, flakes, etc. The bleaching compositions of the present invention may be employed to optimum advantage at relatively high pH values thereby permitting the conjoint use of common household laundry soaps as well as detergents specifically designed for preventive bleaching of fibrous materials.

Other ingredients of an optional nature include, for example, optical bluing agents, anticorrosive products, perfumes, dyes and the like.

The amount of inhibitor required in implementing the processing described herein should correspond to "effective" quantities, the quoted term being used in its conventional sense to connote quantities sufficient to inhibit to a substantial extent, enzyme induced decomposition of peroxide bleaching agent. In any event, the addition of inhibitor in amounts sufficient to yield a concentration of at least about 0.005 up to about 0.05 g./liter and higher, e.g., 1.0 g./liter of soaking or washing medium is found to be eminently suitable for the vast majority of laundering problems likely to be encountered in practice. When included as an ingredient of a detergent and/or peroxide bleach composition, the inhibitor is present in amounts of about 0.1 to about 10 percent by weight of total composition with a range of 0.1 to 5 percent being preferred. Within the foregoing range, it will be understood that optimum concentrations will depend, for example, on the type of inhibitor employed. In addition, the concentration of peroxide bleaching agent in the aqueous washing medium should fall within the range of about 0.2 to about 3 g./liter; effective quantities of detergent in the soaking or washing medium range from about 0.5 to about 10 g./liter. Thus, in the case of hydroxylamine salts such as hydroxylamine sulfate, for example, such compound is preferably employed in amounts ranging from about 0.5 percent to about 2 percent by weight of total composition. Thus, the broad ranges recommended represent a locus of values found to assure the realization of efficacious practice.

Soaking and washing steps in the presence of the inhibitor composition are carried out in the usual way and preferably under the usual temperature conditions (about 80.degree. C. to 100.degree. C. for example) preferably for the usual time, typically one-half hour.

Certain enzyme inhibitors may in some instances be found to be somewhat toxic to or exhibit suboptimum compatibility with hydrogen peroxide. It is preferable to use such inhibitors in the process of the invention by adding them at the soaking or prewashing step of the process prior to contact with the peroxide bleaching agent. Such inhibitors are more effectively provided as a component of detergent compositions which omit peroxide bleaching agent.

Among the inhibitors found to be particularly effective "for soaking" are reducing agents like formaldehyde; strong oxidizers like alkali metal hypochlorites, alkali metal salts of chlorocyanuric acids, potassium salts of monopersulfuric acid, etc.; acid solutions which lower the pH of the bath below 4; basic solutions which raise the pH of the bath above 12; heavy metal salts e.g., mercuric salts, like mercuric chloride; certain solvents like acetone, etc., which precipitate proteins.

The amounts employed for this particular embodiment may also vary according to the inhibitor used; in any event, concentrations on the order of about 0.1 to about 1 g. of inhibitor per liter of soaking bath are admirably suitable.

When added to an aqueous soaking medium, processing employing the aforedescribed inhibitors is preferably carried out in two steps: a preliminary soaking step with said inhibitor, with or without detergent composition, and a washing step in the presence of peroxide bleach and/or detergent.

The following examples are given to illustrate the invention, but are not to be considered as necessarily constituting a limitation thereof. All parts and percentages given are by weight unless otherwise indicated.

EXAMPLE 1

This example illustrates the rate of sodium perborate decomposition when the goods are soaked by conventional methods.

Three grams of commercial sodium perborate are dissolved at ordinary temperature in 500 cm..sup.3 tap water and the increase in the volume of liberated gas measured over an interval at ordinary temperature by standard methods. There is no volume of gas ten minutes after perborate is added to the water.

The preceding test is repeated, except that tap water is replaced by the same volume of the aqueous suspension of soil (this suspension is obtained by soaking 1 kilo of normally soiled cloth in 4 liters water, treated with 20 grams of sodium dodecylbenzenesulfonate, for 30 minutes at room temperature, and the soaking bath drained off). An intense liberation of gas is observed a few seconds after perborate is added to the soaking bath; this gaseous liberation is 140 cc. after 5 minutes and 217 cc. after 10 minutes. The liberated gas is identified as oxygen. Calculation shows that the volume of gas liberated after ten minutes corresponds to the complete decomposition of three grams sodium perborate.

The above test results in complete decomposition of the perborate in a soaking bath from heavily soiled cloth in less than 2 minutes.

Examples 2 through 6, which follow illustrate the practice of the invention wherein the inhibitor compound is added during the soaking step.

EXAMPLE 2

Two loads of soiled cloth, as identical as possible, are prepared and soaked overnight at ordinary temperature in a 5-g./liter solution of sodium dodecylbenzene/sulfonate without bleaching agent but 2 cm..sup.3 per liter of a commercial 13 percent solution of sodium hypochlorite is added to one of the loads. A sodium dodecylbenzene sulfonate detergent composition containing 10 percent sodium perborate is then added and the washing of the soiled cloth continued at 80.degree. C.

The decomposition of perborate is measured after soaking as described in example

1. % perborate decomposed after 5 min. (average of 12 tests) Soaking without hypochlorite 90% Soaking with hypochlorite 0 %

Each load is then washed in a boiler tub (rug boiler for 30 minutes at boiling, with the same 5-g./liter detergent composition, and bleaching effectiveness measured during washing, as described in French Patent 1,338,856 of Mar. 24, 1961.

Increase in brilliancy of dyed cloths after one washing (average of 12 tests) Load soaked without hypochlorite 6.3 Load soaked with hypochlorite 21

The pieces washed during the 12 tests, on the other hand, were visually examined and numerically recorded. The statistical interpretation of the results illustrate that the washing method, which employs soaking in the presence of hypochlorite, yields significantly better results than the test washing without hypochlorite.

EXAMPLE 3

Tests similar to those in example 2 are performed, but the sodium hypochlorite solution is replaced by potassium dichlorocyanurate during soaking, so that the total concentration of this compound in the soaking bath is 0.25 g./liter.

The same results as those obtained in Example 2 indicate the advantage of soaking with potassium dichlorocyanurate.

EXAMPLE 4

Similar tests are performed, adding potassium monopersulfate to one of the soaking baths so that the concentration in the soaking bath is 1 g./liter.

The same results as those obtained in Example 2 show the advantage of soaking with potassium monopersulfate over the control experiment.

EXAMPLE 5

The process in Example 4 is repeated replacing potassium monopersulfate with a 30 percent solution of formaldehyde. The same advantageous results are obtained.

EXAMPLE 6

The same kind of experiment is performed, but the soaking bath including redox enzyme inhibitor is acidified by adding strong sulfuric acid to lower the pH of the soaking bath below 4 for several moments.

It is again observed that the acidified soaking water decomposes no more perborate, and better bleaching follows during washing when a powder containing hydrogen peroxide is used.

The following examples 7 through 12 illustrate the practice of the invention process during the enzyme inhibitor for either the soaking or washing step.

EXAMPLE 7

Two loads of soaked cloth, as identical as possible, are prepared and soaked overnight in a 5-g./liter sodium dodecyl benzene sulfonate solution without peroxide bleaching agent. One load of cloth is washed with the following type of detergent composition; --------------------------------------------------------------------------- --------------------------------------------------------------------------- COMPOSITION A

Sodium dodecylbenzenesulfonate 22% Sodium tripolyphosphate 30% Sodium silicate 7% Magnesium silicate 1% Hydrated sodium perborate 10% Various constituents, dye, perfume Sodium sulfate and moisture sufficient quantity __________________________________________________________________________

The other load of cloth is washed with composition A plus 10% by weight of sodium nitride Na.sub.3 N.

The following results are obtained:

Increase in brilliancy of dyed cloths after one washing (average of 12 tests) Composition A 7 Composition A + 10% sodium nitride 15

It is apparent that use of sodium nitride permits a marked increase of effectiveness of bleaching with the perborate compound.

EXAMPLE 8

Composition B is used, which differs from composition A of Example 7 in that it contains 15 percent perborate instead of 10 percent.

(a) (b) Composition B 1.7 1.7 Composition B + 1% hydroxylamine hydrochloride 7.8 4.7 (a) = % perborate remaining just before washing at boiling (average of 12 tests) (b) = increase in brilliancy of dyed cloths after one washing average of 12 tests)

After a series of 12 washings and visual inspection of the washed cloth, the composition containing hydroxylamine hydrochloride appeared greatly superior to the other.

2. Composition B is compared with composition A +1% hydroxylamine hydrochloride.

Increase in brilliancy of dyed cloths after one washing (average of 12 tests) Composition B 4.6 Composition A + 1% hydroxylamine Hydrochloride 9.6

Similarly, after 12 washings, composition A + 1% hydroxylamine hydrochloride appeared greatly superior to composition B.

3. Composition B is compared with composition C (identical to composition A but with only 5% perborate) + 1% hydroxylamine hydrochloride.

(a) (b) Composition B 1.6 3.7 Composition C + 1% hydroxylamine hydrochloride 2.4 5.3 (a) = % perborate remaining just before washing at boiling (average of 12 tests) (b) = increase of brilliancy of dyed cloths after one washing (average of 12 tests)

After a series of washing, composition C + 1 percent hydroxylamine hydrochloride was again found to be superior to composition B.

It is evident from the preceding that it is possible to reduce the amount of perborate in the composition from 15 percent to 5 percent by adding 1 percent hydroxylamine hydrochloride to the detergent composition and still maintain more than equally effective bleaching.

The results are the same, independent of the hydroxylamine salt used, and a completely different detergent composition may be used, as the following examples show.

EXAMPLE 9

Composition D, a low foam product for washing machines and having the following formula, is used. --------------------------------------------------------------------------- --------------------------------------------------------------------------- COMPOSITION D

Soap 6% Ethoxylate oleic acid 6% Sodium alkylarylsulfonate 3% Sodium tripolyphosphate 35% Magnesium silicate 1% Sodium silicate 7% Hydrated sodium perborate 15% Various ingredients, moisture sufficient quantity __________________________________________________________________________

1. A comparison is made with composition D + 1.2 percent hydroxylamine sulfate, according to example 2, but prewashing for one-fourth of an hour at 40.degree. C. is performed on two loads of essentially equivalent soiled cloth and the goods are washed in a drum-type washing machine for 5 minutes at boiling.

The concentration of the products used is always 5 g./liter.

The following results are obtained:

(a) (b) Composition D 2.2 1.6 Composition D + 1.2% hydroxylamine 7.3 6.1 sulfate

(a) and (b) have the same means as in Example 8.

After visual examination of the cloth, it is found that the composition with 1.2 percent hydroxylamine sulfate is significantly superior to composition D.

2. The amount of perborate in composition D is reduced, as in example 8, and it is observed that a composition containing 5 percent perborate and 1.2 percent hydroxylamine sulfate again gives better results than composition D; 3.1 increase in brilliancy compared with 1.8 for composition D, thereby indicating that when hydroxylamine sulfate is employed as the enzyme inhibitor it is possible to reduce the amount of perborate and still obtain more effective bleaching.

EXAMPLE 10

A test identical to the one from example 7 is made. Composition A (from example 7) is compared with composition A + 4 percent hydrazine hydrochloride and the decomposition of perborate is measured as before described.

% perborate decomposed after 5 minutes Composition A 98% Composition A + 4% hydrazine 23% hydrochloride

EXAMPLE 11

The procedure of the preceding example is repeated replacing the hydrochloride by hydrazine sulfate. The same result is obtained.

EXAMPLE 12

Soiled cloth is soaked, at ordinary temperature, in a detergent solution containing e.g. 5 g. of composition A from example 7 per liter of water, and decomposition of perborate after varying contact times determined by a colorimetric estimation of hydrogen peroxide.

This experiment is carried out with and without an inhibitor and the percentage inhibition furnished by each inhibitor tried, determined by the formula:

.mu.x = hydrogen peroxide concentration with inhibitor

m = hydrogen peroxide concentration under the same conditions without inhibitor

The following results are obtained: ---------------------------------------------------------------------------

After After a few more than minutes contact 12 hours contact __________________________________________________________________________ Concentration of inhibitor in solution 8.sup.. 10.sup..sup.-3 M 2.5.sup.. 10.sup..sup.-3 M Hydroquinone (sulfate) 100 -- Hydroquinone 100 15 p=chlorophenol 100 45 1,2-cyclohexanediol 12 -- Pyrocatechol 58 12 o-cresol 26 13 Resorcinol 100 22 2,4 dinitrophenolhydrazine -- 13 4-chloro-2-aminophenol -- 55 p-chloro-m-cresol 47 18 Pyrogallol -- 30 B-naphthol -- 27 1,2-naphthoquinone -- 28' 2,7-dihydroxynaphthalene 26 -- Hydrazine hydrochloride -- 74 Sodium chlorate -- 17 2,4-dichlorophenol -- 28 Aminotriazole -- 20 Composition A alone 0 0 __________________________________________________________________________

It was evident, moreover, that, in addition to hydroxylamine and hydrazine, p-chlorophenol, 4-chloro-2-aminophenol, resorcinol and hydroquinone are also very active. Furthermore, the other inhibitors also retarded perborate decomposition, even after more than 12 hours' contact, there being still some inhibition, when compared with the control test without inhibitor.

Results similar to those described in the preceding examples are obtained when the particular detergent component illustrated is replaced in equivalent quantities by those of the cationic, amphoteric, nonionic and zwitterionic types.

In the foregoing examples, the sodium perborate is employed in the form of the tetrahydrate. Particularly effective results are likewise found to obtain with the use of sodium perborate monohydrate. Moreover, any of the conventional water-soluble, inorganic peroxide bleaching agents may be employed to similar advantage including the persilicates, perphosphates, percarbonates, hydrogen peroxide and the like, the beneficial effects attributable to the inhibitor being manifestly evident with respect to any of such materials.

* * * * *

Current U.S. Class:	8/111 ; 252/186.21; 252/186.22; 252/186.3; 252/186.31; 510/302; 510/309; 510/346; 510/375; 510/380; 510/381; 510/499; 510/500; 510/505; 8/109
Current International Class:	C11D 3/39 (20060101); D06l 003/02 ()
Field of Search:	8/111,109 252/95,DIG.12