US 3925234 A
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Hachmann et al.
[4 1 Dec. 9, 1975 1 COATED BLEACH ACTIVATOR  Inventors: Klaus Hachmann, Hilden; Herbert Saran, Dusseldorf-Holthausen; Gerhard Sperling, Hilden, all of Germany  Assignee: Henkel & Cie GmbH,
Dusseldorf-Holthausen, Germany  Filed: July 25, 1973  Appl. No.: 382,595
 Foreign Application Priority Data July 31, 1972 Austria 6594/72  US. Cl. 252/186; 252/97; 252/99;
 Int. (11. C01B 15/00; C1 1D 9/42  Field of Search 252/97, 99, 102, 186
 References Cited UNITED STATES PATENTS 3,042,621 7/1962 Kirschenbauer.... 252/99 3,163,606 12/1964 Viveen et a1 252/99 X 3,441,507 4/1969 Schiefer et a1 252/97 X 3,459,665 8/1969 Schiefer et a1... 252/97 X 3,519,570 7/1970 McCarty 252/135 3,789,002 1/1974 Weber et a1. 252/186 X 3,833,506 9/1974 Fries et a1. 252/186 X 3,847,830 11/1974 Williams et a1. 252/186 Primary Examiner-Benjamin R. Padgett Assistant ExaminerChristine M. Nucker Attorney, Agent, or FirmHammond & Littell 1571 ABSTRACT A stabilized bleaching assistant suitable for use in pulverulent washing and bleaching compositions comprising drop-shaped to globular-shaped particles at least 70 percent of which have a diameter within the range of 0.1 mm to 1 mm consisting of 10 percent to 70 percent by weight of at least one activator for active oxygen derived from compounds yielding H 0 in aqueous solution, substantially surrounded by from 30 percent to 90 percent by weightof a mixture of (a) from 2 to 10 parts of substantially saturated fatty acids having 12 to 24 carbon atoms and (b) 1 part of aliphatic alcohols having 10 to 20 carbon atoms or their lower alkoxylated products having 1 to 5 alkoxy units. The particles are obtained by spraying a fluid mixture of the components through a nozzle or by a spray disc, and cooling. The stabilized bleaching assistant can be incorporated with percompounds and other washing composition components.
8 Claims, N0 Drawings COATED BLEACH ACTIVATOR THE PRIOR ART Inorganic percompounds, especially perborates, are known as the active component of numerous bleaching agents, for example, those used for the bleaching and possibly for the simultaneous washing of textiles. Such bleaching agents have the disadvantage, however, that their bleaching action at temperatures below 80C is relatively low. The addition of organic activators to such bleaching agents containing percompounds is known. These activators act in such a manner that the active oxygen of the percompound also becomes effective at temperatures below 80C.
Washing compositions are known which contain, in addition to the usual detergent substances with a cleaning action, builder substances and the so-called bleaching activators causing percompounds to have a bleaching action. These activators are carboxylic acid derivatives which react with the percompounds with formation of peracids and, therefore, increase the bleaching action of the mixtures or make possible bleaching at relatively low washing temperatures. The storage of such washing compositions, however, causes considerable problems, since under the influence of relatively high air humidity, the percompounds and bleaching activators may react with one another even at room temperature, which leads to a loss of active oxygen. If substances susceptible to oxidation are added to the washing compositions, for example, optical brighteners, these may be oxidatively decomposed. In this case an unpleasant smell often occurs at the same time, which is due to volatile decomposition products. Trouble may also occur even in washing compositions in which the percompounds are enveloped with coating substances or are kept separate from the other washing components, in order to eliminate a mutual reaction with the other components. Since the bleaching activators are very reactive acylation agents, they may react with sensitive washing agent components, for example, perfumes or optical brighteners and adversely affect the properties of the latter.
It has already been proposed to purify the optical brighteners in a specified way in order to prevent the formation of unpleasant smelling products. However, the problem of a reduction of the active oxygen content is not thereby solved. Further, the suggestion has been made to provide the powder particles of the bleaching activator with a coating so as to suppress any mutual reaction between the activator and percompounds. Inorganic crystalline salts, for example, sodium sulfate, high molecular weight substances such as polyethyleneglycol, polyvinyl alcohol and cellulose ethers, or fatty substances such as fatty acids, fatty alcohols or fatty acid alkylolamides have been suggested as coating materials. In such case the coating material in dissolved form must be sprayed on or granulated on the activator. It has been found, however, that this pretreatment does not lead to an appreciable improvement of the stability on storage, especially when the coating material consists of water-soluble compounds. The use of watersoluble coating substances leads indeed to an improvement of the storage stability in the known process. However, the coated particles do not dissolve or only dissolve very slowly in cold water and in moderately heated washing liquors, consequently the particles are deposited on the textiles and may lead to the formation of spots or stains and the bleaching effort is insufficient at low temperatures.
OBJECTS OF THE INVENTION An object of the present invention is to develop a composition which is protected against decomposition during storage and has a sufficient solubility in cold water.
A further object of the present invention is to develop a stabilized bleaching assistant suitable for use in pulverulent washing and bleaching compositions comprising drop-shaped to globularshaped p rticles at least 70 percent of which have a diameter within the range of 0.1 mm to 1 mm consisting essentially of 10 percent to 70 percent by weight of at least one activator for active oxygen derived from compounds yielding H in aqueous solutions having an activating action of least 3 in the Per-Acid Formation Test selected from the group consisting of N-acyl compounds having 2 to 9 carbon atoms in the acyl, O-acyl compounds having 2 to 9 carbon atoms in the acyl, carbonic acid esters and pyrocarbonic acid esters, substantially surrounded by from 30 percent to 90 percent by weight of a mixture of (a) from 2 to 10 parts by weight of said mixture of acids having substantiallly from 12 to 24 carbon atoms selected from the group consisting of substantially saturated fatty acids, saturated hydroxy fatty acids, and mixtures thereof and (b) 1 part by weight of said mixture of alcohols selected from the group consisting of substantially saturated aliphatic monohydric alcohols having from 10 to 20 carbon atoms, their ethoxylated products, their propoxylated products and mixtures thereof, where the alkoxylated products are waterinsoluble and have from 1 to 5 alkoxy units.
A yet further object of the present invention is the development of a process for the production of the above stabilized bleaching assistant which consists of dispersing solid particles of said activator for active oxygen in a melt of said mixture of acids and alcohols, forming droplets of said dispersion at least percent of which have a diameter within the range of 0.1 mm to 1 mm by means selected from the group condisting of (1) pressure spraying through a nozzle having an opening having a diameter of from 0.3 mm to 2.5 mm at a pressure of from 10 to 30 kg/cm and (2) spraying from a spray disc rotating at a peripheral speed of from 5 to m/sec, and cooling said droplets without contact below their solidifying temperature.
Another object of the invention is the development of pulverulent washing and bleaching compositions containing said stabilized bleaching assistant.
These and other objects of the invention will become more apparent as the description thereof proceeds.
DESCRIPTION OF THE INVENTION According to the present invention, there is provided a bleaching assistant suitable for use in pulverulent washing and bleaching compositions which comprises drop-shaped to globe-shaped particles of which at least 70 percent have an average diameter of 0.1 to 1 mm, and not more than 30 percent have a diameter of not less than 0.01 and not more than 2.5 mm, and are constituted as follows: 10 percent to 70 percent by weight of at least one compound from the class of N-acyl and O-acyl compounds as well as carbonic acid esters and pyrocarbonic acid esters which act as an activator for percompounds, the activation value of which for the percompounds amounts to more than 3 in the Per-Acid Formation Test and 30 percent to 90 percent by weight of a mixture of substantially saturated fatty acids having 12 to 24 carbon atoms and aliphatic alcohols having 10 to 20 carbon atoms or their lower alkoxylated products in the proportion by weight of 10:1 to 2:1. The alcohols may possibly have up to glycolether groups.
More particularly, the invention comprises a stabilized bleaching assistant suitable for use in pulverulent washing and bleaching compositions comprising dropshaped to globular-shaped particles at least 70 percent of which have a diameter within the range of 0.1 mm to 1 mm consisting essentially of percent to 70 percent by weight of at least one activator for active oxygen derived from compounds yielding H 0 in aqueous solutions having an activating action at least 3 in the Per- Acid Formation Test selected from the group consisting of N-acyl compounds having 2 to 9 carbon atoms in the acyl, O-acyl compounds having 2 to 9 carbon atoms in the acyl, carbonic acid esters and pyrocarbonic acid esters, substantially surrounded by from 30 percent to 90 percent by weight of a mixture of (a) from 2 to 10 parts by weight of said mixture of acids having substantially from 12 to 24- carbon atoms selected from the group consisting of substantially saturated fatty acids, saturated hydroxy fatty acids, and mixtures thereof and (b) 1 part by weight of said mixture of alcohols selected from the group consisting of substantially saturated aliphatic monohydric alcohols having from 10 to carbon atoms, their ethoxylated products, their propoxylated products and mixtures thereof, where the alkoxyiated products are water-insoluble and have from 1 to 5 alkoxy units.
The bleaching assistants are preferably present in the mixture together with further pulverulent bleaching agent components, especially granular to pelverulent pea-compounds which liberate hydrogen peroxide in aqueous solution. in these mixtures the proportion by weight of the bleaching assistant to the percompound should amount to 1:5 to 5:1 and be chosen so that 0.05 to 2 mols of activator are present per gram atom of active oxygen. These solid, pulverulent-to-granular compositions useful in the preparation of aqueous coldbleaching baths, especially cold-bleaching washing liquors for textile consist essentially of (I) from 5 percent to 95 percent by weight of the above stabilized bleaching assistant, and (ll) from 5 percent to 95 percent by weight of at least one compound selected from the group consisting of (a) alkali metal builder salts, (b) percompounds giving H 0 in aqueous solutions and stabilizers for percompounds, (c) tensides selected from the group consisting of anionic surface-active compounds, non-ionic surface-active compounds and amphoteric surface-active compounds, (d) optical brighteners, (3) water-soluble organic builder salts, (f) antimicrobial agents, (g) soil suspension agents, (h) enzymes, (i) foam inhibitors, (k) textile softeners, and (l) corrosion inhibitors.
The activators for percompounds utilizable according to the invention are certain compounds of the N- acyl and O-acyl type as well as carbonic acid esters of pyrocarbonic acid esters, indicated below under (a) to (0), which have an activation value in the Per-Acid Formation Test of at least 3, preferably at least 4.5.
PER-ACID FORMATION TEST The activation value titre) for the activators is determined in the following way:
Solutions which contain 0.615 gin/liter of NaBO H O GH O (4 mlVlol/liter) and 2.5 grn/liter of Na P- 0 -10 R 0, are heated to C, and then are mixed with 4 mMol/liter of activator and maintained at the said temperature for 5 minutes with stirring. Then 100 ml of this liquid is added to a mixture of 250 mg of ice and 15 ml of glacial acetic acid and titrated immediately after addition of 0.35 gm of potassium iodide with 0.1 N sodium thiosulfate solution, using starch as indicator. Under the given experimental conditions, for a 100 percent activation of the peroxide used, 8.0 ml of thiosulfate solution are consumed, the titre is 8.0. This maximum value is, of course, seldom attained. Good activators have a titre of at least 4.5, preferably from 5 to 7. Useful results are often obtained with activators having a titre of at least 3.0.
Activators of the N-acyl or O-acyl compounds type contain an acyl residue R-CO-, in which R represents optionally substituted hydrocarbon residues with 1 to 8 carbon atoms. If the residues R are aliphatic, they preferably have 1 to 3 carbon atoms, and if they are aromatic, they may contain up to 8 carbon atoms. Consequently, the residue R is preferably one of the following: lower alkyl, such as methyl, ethyl, n-propyl or isopropyl; phenyl; alkylphenyl such as toluyl or xylyl residues. Suitable substituents for both aliphatic and aromatic residues are C alkoxy groups, halogen atoms, nitro or nitrile groups; when R is an aromatic residue, it may be chloro and/or nitro-substituted, especially mchloro or in or p-nitro-substituted. Such substituted R residues are, for example, chloroalkyi having 1 to 3 carbon atoms, m-chlorophenyl, p-nitrophenyl, and pmethoxyphenyi.
Or" the activators described below, compounds with a melting point of at least C, preferably at least C and especially at least 150C, are specially suitable. Furthermore, the equivalent weight of these compounds should be not more than 170, preferably not more than 130 and especially not more than (the equivalent weight is here the quotient of the molecular weight and the number of R-CO- residues present in the molecuie where the compound is N-acylated or O- acylated).
The types of compound mentioned under (a) to (o) are useful activators according to the invention. In the formuiae the numbered residues R have the meaning given for R above unless specifically otherwise indicated. lf several residues R are present in a molecule, they may be the same or different.
a. N-diacylated amines of the formula I, in which X represents a residue R or one of the residues la, lb or Ic.
From this class of compounds, N,N,N,N'-tetraacetylmethylenediamine (melting point 92 to 95C),
N ,N,N ,N -tetraacetylethylenediamine, N,N-
diacetylaniline and N,N-diacetyl-p-toluidine are named as examples.
b. N-acylhydantoins of formula II, in which at least one of the residues X and X represent an RCO- residue, while the other may also represent a residue R or a carboxymethyl or a lower alkoxycarbonylmethyl residue; Y and Y represent hydrogen or alkyl residues with l to 2 carbon atoms.
Suitable compounds are, for example, l,3-diacetyl-5,5-
dimethylhydantoin, 1,3-dipropionylhydantoin (melting point 104.5 to 106C) and 3-benzoylhydantoin-lacetic acid ethyl ester.
c. N-alkyl-N-sulfonyl-carbonamides of formula III, in
which R preferably signifies a C alkyl residue Activators of this type are, for example, N-methyl-N- mesylacetamide (melting point 73 to 79C), N-methyl- N-mesylbenzamide (m.p. 116 to 118.5C), N-methyl- N-mesyl-p-nitrobenzamide (m.p. 159 to 160C) and N-methyl-N-mesyl-p-methoxybenzamide (m.p. 117 to d. Cyclic N-acylhydrazides of formula IV, in which the two nitrogen atoms are part of a 5- or 6-membered hetero ring from the group of maleic acid hydrazide, phthalic acid hydrazide, triazole or urazole.
l N coR,,
A suitable compound, for example, is mono-acetylmaleic acid hydrazide.
e. O,N,N-trisubstituted hydroxylamines of formula V, in which R represents a residue R, preferably a methyl or ethyl residue, an optionally substituted aryl residue or the group Va, while X and X represent one of the residues RCO-, R-SO or one of the above-described aromatic residue, or each can be linked with the corresponding residue R or R to give a succinyl or phthalyl residue and n signifies a whole number from to 2.
Activators of this type are, for example, O-benzoyl- N,N-succinyl-hydroxylamine (m.p. 137 to 139C), 0- acetyl-N,N-succinyl-hydroxylamine (m.p. 132 to 134C), O-p-methoxybenzoyl-N,N-succinyl-hydroxylamine (m.p. 142 to 145C), O-p-nitrobenzoyl-N,N-suc- 6 cinyl-hydroxylamine (m.p. 212 to 215C) and O,N,N- triacetyl-hydroxylamine. f. N,N-diacyl-sulfurylamides of formula VI, in which R6 and R6 preferably represent C alkyl residues or aryl residues such as phenyl, while R and R preferably represent C alkyl residues, especially C alkyl residues.
to 60C) and N,N-diethyl-N,N-dipropiony1sulfurylamide (m.p. 95 to 97C) may be mentioned as examples g. Triacyl-cyanurates of formula VII oc R l H-O-CO-R x,, cH (V111) 0c R, To these belong 1,3-diformyl-4,5-diacetoxy-imida2olidine (m.p. 160 to 165.5C), 1,3-diacetyl-4,5- diacetoxy-imidazolidine (m.p. 139 to 140.5C), 1,3- diacety1-4,5-dipropionyloxy-imidazolidine (m.p. 85 to 87C). k. Acylated glycolurils of the general formula IX, in
which X represents the residue R or R-CO.
/N-CHN\ o=c c=o 1X) \N('IH--N/ R92CO OC-R9;,
tetraacylated glycolurils and especially tetraacetylglycoluril (m.p. 233 to 240C) are preferably used. In addition, the following acylated glycolurils are suitable:
di-(ch1oracety1)-diacety l-glycoluril 269C tetrapropiony 1- glycoluril (m.p. (m.p.
146C), 1-methyl-3,4,6-triacetylglycoluril (mp. 179 to 180C), diacetyl-dipropionylglycoluril (mp. 144 to 146C), and diacetyl-dibenzoyl-glycoluril (mp. 244 to 249C). The acylated glycolurils are not only of special practical importance on account of their excellent properties as activators, but to their high melting point, they are very suitable for the preparation of pulverulent products which are stable on storage.
1. Diacylated 2,5diketopiperazines of the general formula X CO-R in which R and R are R and R and R are hydrogen, alkyl having 1 to 3 carbon atoms, hydroxyalkyl having 1 to 3 carbon atoms, haloalkyl having 1 to 3 carbon atoms, nitroalkyl having 1 to 3 carbon atoms, nitriloalkyl having 2 to 4 carbon atoms and alkoxyalkyl having 2 to 5 carbon atoms, for example: 1,4-diacetyl- 2,5-diketopiperazine, l,4-dipropionyl-2,S-diketopiperazine (mp. 113 to 114.5C) and l,4-dipropionyl3,6- dimethyl-2,5-diketopiperazine (mp. 1 13 to 1 14C.).
m. N-acylated 2,4,6,8-tetraaza-bicyclo-( 3,3,1 )-nonan- 3,7-diones of the general formula XI in which R R R and R are R and R and R are hydrogen or methyl, for example: 2,4,6,8-tetraacetyl-2,4,6,8-tetraaza-bicyclo-( 3 ,3,1 )-nonan-3 ,7-dione (mp. 181 to 183C), 2,4,6,8-tetrapropionyl-2,4,6,8- tetraaza'bicyclo-(3,3,l )-nonan-3,7-dione (m.p. 145.5 to 146C), 2,4,6,8-tetraacetyl-9,9-dimethyl-2,4,6,8-tetraaza-bicyclo-(3,3,l )-nonan-3,7-dione (mp. 180 to 183C), and 2,4,6,8-tetrabenzoyl-2,4,6,8-tetraazabicycle-(3,3,1)-nonan-3,7-dione (m.p. 234 to 236.5C).
n. Carbonic acid esters of formula X11, in which X represents an electron-attracting residue, preferably selected from the group p-carboxyphenyl, p-sulfophenyl or alkoxycarbonyl with l to 4 carbon atoms in the alkoxyl group:
x -oco-o-k (X11) For example, p-ethoxycarbonyloxy-benzoic acid (mp.
157C) and p-propoxycarbonyloxy-benzene sulfonic acid.
0. Pyrocarbonic acid esters of C to C alkanols as, for
example, pyrocarbonic acid ethyl ester. Tetraacetylglycoluril mentioned under (j) is of particular interest.
In the activation of the percompounds in aqueous solutions by the said N-acyl and O-acyl compounds, carboxylic acids as, for example, acetic acid, propionic acid and benzoic acid, are liberated and it is advisable to add corresponding amounts of alkali to bind these carboxylic acids. In the case of effective activators, an activation is already to be noted when amounts of 0.05 mol of activator per gram atom of active oxygen are used. It is preferred to work with 0.1 to 1 mol of activator, but the amount may also be increased to 2 mols of activator per gram atom of active oxygen.
Suitable fatty acids, which are present in the activator-containing powder particles, as saturated fatty acids and saturated hydroxy-fatty acids having 12 to 24 carbon atoms, as well as their mixtures, such as lauric, myristic, palmitic, stearic, arachidic, behenic and lignoceric acid and also hydroxystearic and dihydroxystearic acids. When mixtures of naturally occurring or hydrogenated fatty acids are used, these may also contain some saturated fatty acids with 8 to 10 carbon atoms or some unsaturated fatty acids with 8 to 24 carbon atoms, for example, oleic acid, but the fraction of the low molecular weight acids or unsaturated acids or both should be less than 20 percent by weight and especially less than 10 percent by weight of the total fatty acids persent. The composition of the fatty acid mixtures should preferably be such that the softening point or melting point is above 40C.
The substantially saturated aliphatic monohydric alcohols having from 10 to 20 carbon atoms, possibly alkoxylated, present in admixture with the bleaching activator and the fatty acids may be of natural or synthetic origin, such as decyl, lauryl, myristyl, cetyl and arachly (anachidyl) alcohols, and their mixtures, for example, coconut or tallow alcohols, and also 0x0- alcohols or alcohols from paraffin oxidation. Small portions, up to 10 percent, of unsaturated alcohols may be present. The alcohols are preferably saturated. When alkoxylated, that is, ethoxylated and/or propoxylated, alcohols are used, the number of alkylene oxide groups, especially ethylene oxide groups, should be chosen so that no water-soluble compounds are present, i.e., they shoud not amount to more than 5, preferably not more than 3. Mixtures of non-alkoxylated and alkoxylated alcohols are also useful. Preferably saturated fatty alcohols having 12 to 18 carbon atoms and their mixtures are utilized.
The proportion by weight of fatty acid to alcohol or ethoxylated alcohol should amount to 10:1 to 2:1, preferably 5:1 to 3:1.
The activator-containing particles of the stabilized bleaching assistant of the invention should be present approximately in drop to globular shape and at least percent by weight shoudl have a diameter with the range of 0.1 mm to 1 mm, preferably more than percent by weight, should have an average diameter of 0.1 mm to 1.6 mm. Their composition should be largely homogeneous, and the surface should be smooth. Powder particles which fulfill these requirements are obtainable by homogenizing the bleaching activator, the fatty acid and the possible alkoxylated alcohol at a temperature which lies above the melting points of the fatty acid and the alcohol and preferably below the melting point of the bleaching activator and spraying, for example, by means of a nozzle under high pressure or by a spray disc into a fall space, in which the temperature lies below that of the solidifying point of the mixture of fatty acid and alcohol.
Preferably the stabilized bleaching assistant is produced by a process which consists of dispersing solid particles of said activator for active oxygen in a melt of said mixture of acids and alcohols, forming droplets of said dispersion at least 70 percent of which have a diameter within the range of 0.1 mm to 1 mm, by means selected from the group consisting of (l) by pressure spraying through a nozzle having an opening having a diameter of from 0.3 mm to 2.5 mm at a pressure of from 10 to 30 kg/cm and (2) spraying from a spray disc rotating at a peripheral speed of from 5 to 150 m/sec., and cooling said droplets without contact below their solidifying temperature.
When a spray nozzle is used, the aperature of the spray nozzle should have a diameter of 0.3 mm to 2.5 mm, preferably 0.6 mm to 1.8 mm. The pressure with which the dispersed melt is fed to the nozzle should amount to to 30, preferably to 25, kg/cm Instead of a nozzle, a rotating spray disc, which may be provided with round or slot-like orifices, may also be used. The peripheral speed of such a disc, which has usually a diameter of 150 to 300 mm, and rotates at 800 to 10,000 revolutions per minute, should be 5 to 150 m/sec., preferably 10 to 100 m/sec. The fall space, in which the sprayed particles solidify, suitably consists of a cylindrical chamber, which is fitted with supply lines for cooling air and a discharge divice for the powder, arranged at the conical base of the chamber. The cooling air, the temperature of which lies at least 10C below the solidifying temperature of the mixture of fatty acid and alcohol and, for example, ranges from -10 to +40C, may be led in the same direction or countercurrent.
When technically pure starting materials are used, the sprayed particles may be naturally cooled. By addition of dyestuffs or colored pigments before the spraying or dusting of the grains obtained with pigments, of example, titanium oxide, the natural color may be masked or altered.
The stabilized bleaching assistants may be present alone, admixture with percompounds or in admixture with pulverulent to granular washing compositions with or without bleaching agents. These washing compositions consist of at least one compound from the class of anionic, amphoteric and non-ionic surface-active compounds, at least one compound from the class of polymeric phosphates, sequestering agents and washing alkalis and at least one compound from the class of optical brighteners.
In addition to alkali metal peroxides, the most suitable percompounds which liberate hydrogen peroxide in aqueous solution are the perhydrates, for example, anhydrous or crystalline sodium perborate, also alkali metal percarbonates, perpyrophosphates and persilicates and urea perhydrate. Sodium perborate tetrahydrate is preferably used.
The average particle size of the percompounds and the possibly additionally used powder components should amount to 0.1 to 2 mm. The granular size of the percompounds as well as of possible further powder components is not in itself critical, but should be chosen so that at least 50 percent and preferably more than 80 percent of the particles have a diameter of at least 0.05 and not more than 2.5 mm, in order to prevent a dust formation, on the one hand, and on the other hand, to keep the powder mixture easy to trans port and pourable. Relatively large variations in the grain size of the individual powder components should be avoided in order to prevent an undesired setting of fines and specifically heavier particles to the bottom of the packing container during transport.
The union of the various powder components into a homogeneous powder mixture or the addition of further powder components is effected in known way by the usual mixing devices, while the structure of the individual components should be preserved as far as possible.
Preparations which comprise substantially the stabilized bleaching assistant, are suitabale for use in the textile industry or in industrial laundries, where they are used together with hydrogen peroxide or solid per compounds and possibly the usual additions for the preparation of the bleaching baths and bleaching washing baths.
If, in addition to the stabilized bleaching assistant, according to the invention, the compositions of the invention contain other constituents usually present in bleaching baths, the composition of such preparation lies approximately in the range of the following formulation:
5 percent to 95 percent, preferably 7 percent to 50 percent, by weight of a stabilized bleaching assistant defined above,
95 percent to 5 percent, preferably 93 percent to 50 percent, by weight of neutral and/or preferably alkaline-reacting builder salts and possibly other constituents usual in bleaching or bleaching washing compositions, such as, for example, surface-active compounds, soil suspension agents, foam stabilizers, dyestuffs and perfumes and so forth.
When in the above formulation the inorganic builder salts are wholly or partly replaced and present as percompounds yielding H O in aqueous solution, the preparations according to the invention represent specially interesting bleaching compositions for practical purposes, which on dissolving in water give coldbleaching washing liquors, in which the active oxygen is already effective at temperatures from 20 to C, especially 30 to 60C.
In such bleaching compositions the ratio of the activator in the stabilized bleaching assistant of the invention to the percompound is always such that from 0.05 to 2 mols, preferably 0. l to 1 mol, of activator is present per gram-atom of active oxygen of the percompound.
When such bleaching compositions contain more than 40 percent by weight of activator and percompound, this quantity relating to the pure activator and the pure percompound without the other constituents of the stabilized bleaching assistant, these preparations are preferably used as bleaching agent concentrates in the textile industry or in industrial laundries.
When the bleaching compositions of the invention contain up to 40 percent by weight of pure activator and percompound in the above-defined ratios, they are useful as bleaching washing compositions and washing assistants, which are of special practical interest and, therefor, represent a preferred field of application of the present invention. In such bleaching washing compositions and washing assistants, the proportions of activator and percompound constitute together mostly from 5 percent to 40 percent, especially from 10 percent to 35 percent, by weight of the composition. The composition of such bleaching agents generally lies within the range of the following formulation, the constituents of the granulate of the above-defined activator component being distributed according to the formulation in the various categories listed below:
5 percent to 40 percent, preferably 7 percent to 30 percent, by weight of a surface-active component, containing at least one surface-active compound of the type of the sulfonates, sulfates, soaps, non-ionics and, optionally, one or more of the following substances:
to 10 percent preferably 0.5 percent to 8 percent,
by weight of foam stabilizers,
0 to 10 percent, preferably 0.5 percent to 8 percent, by weight of non-surface-active foam inhibitors,
percent to 40 percent, preferably percent to 35 percent, by weight of pure activator and percompound,
10 percent to 80 percent, preferably 35 percent to 75 percent, by weight of builder salts, these substances being preferably alkaline-reacting and the amount of these substances preferably constituting 0.5 to 7 times, and especially 1 to 5 times, the total amount of surface-active compounds, and
O to 30 percent, preferably 3 percent to percent,
by weight of other bleaching and washing compositions constituents such as, for example, soil suspension agents, textile softeners, enzymes, optical brighteners, dyestuffs and perfumes, water,
where the activator in the above-defined stabilized bleaching assistant is present in an amount corresponding to 0.05 to 2 mols, preferably 0.1 to 1 mol per gram-atom of active oxygen of the percompound.
In this general formulation are also included bleaching fine washing compositions to be used at temperatures up to 70C, the surface-active compound content of which is generally in the range from 8 percent to 40 percent, preferably 12 percent to 40 percent, by weight. Provided these fine washing compositions are not intended for use in washing machines, especially in drum washing machines, they need not also contain foam inhibitors. Bleaching softening or after-rinsing compositions have usually a surface-active compound content of less than 5 percent by weight, and they also need not contain foam inhibitors.
The bleaching washing compositions intended for use in washing machines, preferably in drum Washing machines, are of particular practical importance in which the surface-active compound component constitutes usually 7 percent to percent by weight. These mostly contain at least one of the following two types of surface-active compound in the amounts there indicated:
15 percent to 100 percent, preferably percent to 90 percent, by weight of a sulfonate and/or a sulfate with preferably 8 to 18 carbon atoms in the hydrophobic residue,
10 percent to 60 percent, preferably 10 percent to percent, by weight of non-ionics and optionally one or more of the following substances:
5 percent to 70 percent, preferably 10 percent to percent, by weight of a soap,
0 to 10 percent, preferably 0.5 percent to 8 percent, by weight of a foam stabilizer,
O to 10 percent, preferably 0.5 percent to 8 percent, by weight of a non-surface-active foam inhibitor,
the foaming power, however, of the surface-active component being reduced either by simultaneous presence of different surface-active compounds reducing the foaming power and/or foam-inhibiting soap and/or non-surface-active foam inhibitors.
The said bleaching washing compositions are generally prepared by mixing the stabilized bleaching assistant according to the invention with granular percompounds and washing compositions which have been obtained by admixing a washing composition powder prepared by hot spray drying. Such cold-bleaching washing compositions are marked by a good stability on storage.
The further constituents of the compositions according to the invention are described below in more detail according to the class of substance.
Suitabale detergent substances which may be used in the washing agent-containing powder components are those anionic surface-active compounds of the sulfonate or sulfate type, for example, alkylbenzenesulfonates, especially n-dodecylbenzenesulfonate, and also olefinsulfonates, such as are obtained, for example, by sulfonation of primary or secondary aliphatic monoolefins with gaseous sulfur trioxide and subsequent alkaline or acid hydrolysis, as well as alkylsulfonates, such as are obtainable from nalkanes by sulfochlorination or sulfoxidation and subsequent hydrolysis or neutralization, or by addition of bisulfite to olefins. Further, a-sulfo-fatty acid esters, primary and secondary alkylsulfates, and the sulfates of ethoxylated or propoxylated higher molecular weight alcohols and alkylphenols are suitable.
Further suitable anionic surface-active compounds are alkali metal soaps from fatty acids of natural or synthetic origin, for example, the sodium soaps of coconut, palm kernel or tallow fatty acids. Suitable amphoteric surface-active compounds are alkylbetaines and especially alkylsulfobetaines, for example, 3-(N,N-dimethyl-N-alkylammonium)-propane-l-sulfonate and 3- (N,N-dimethyl-N-alkylammonium)-2-hydroxypropanel -sulfonate.
The anionic surface-active compounds may be present as the alkali metal salts such as the sodium and potassium salts and ammonium salts as well as salts of organic bases, for example, lower alkanolamines, such as mono, dior triethanolamines. If the said anionic and amphoteric compounds contain an aliphatic hydrocarbon residue, this should preferably have a straight chain and contain 8 to 22 carbon atoms. in the compounds with an araliphatic hydrocarbon residue, the preferably unbranched alkyl chains contain and average of 6 to 16 carbon atoms.
The most important non-ionic surface-active compounds are the polyglycolether derivatives of alcohols, fatty acids and alkylphenols, which contain 3 to 30 ethoxy units, and 8 to 20 carbon atoms in the hydrocarbon residue. Polyglycolether derivatives are particularly suitable in which the number of ethoxy units amounts to 5 to 15 and the hydrocarbon residues of which are derived from straight-chain primary alkanols having 12 to 18 carbon atoms or from alkylphenols having a straight alkyl chain having 6 to 14 carbon atoms.
Further suitable non-ionic surface-active compounds are the water-soluble polyethyleneoxide adducts to polypropyleneglycol, ethylenediaminepolypropyleneglycol and alkylenepolypropyleneglycol with l to 10 carbon atoms in the alkylene chain, which adducts contain 20 to 250 ethoxy units and 10 to propoxy units. The said compounds usually contain 1 to 5 ethoxy units per propoxy unit. Non-ionic compounds of the aminoxide and sulfoxide type, which may possibly also be ethoxylated, are also utilizable.
In addition, alkali metal polymeric phosphates may be contained in the powder component containing washing agents, especially pentasodium tripolyphosphate. The tripolyphosphates may also be present in admixture with higher condensed phosphates, such as tetrapolyphosphates, or their hydrolysis products, such as acid or neutral pyrophosphates.
The condensed phosphates may also be replaced wholly or partly by sequestering agents, for example, aminopolycarboxylic acids and their alkali metal salts. These include especially alkali metal salts of nitrilotriacetic acid and ethylenediaminetetraacetic acid. Further, the salts of diethylenetriamine-pentaacetic acid and the higher homologs of the said aminopolycarboxylic acids are suitable. These homologs may be prepared, for example, by polymerization of an ester, amide or nitrile of N-acetic acid-aziridine and subsequent saponification to give carboxylic acid or salts or by reaction of polyamines such as polyethyleneimine with a molecular weight of 500 to 10,000 with salts of chloroacetic acids or bromoacetic acids in alkaline me- 2 dium. Further suitable aminopolycarboxylic acids are poIy-(N-succinic acid)-ethyleneimine and poIy-(N-tricarballylic acid)-ethyleneimine of average molecular weight 500 to 500,000, which are obtainable similarly to the N-acetic acid derivatives.
Further, nitrogen-free compounds may be used as sequestering agents, for example, the water-soluble alkali metal salts, such as potassium and especially sodium salts of polyvalent hydrocarboxylic acids or ethercar-. boxylic acids, such as citric acid, gluconic acid, glucuronic acid and hydroxydiacetic acid, as well as of higher molecular weight polycarboxylic acids, for example, of polymerizates of ethylenic mono-, diand tricarboxylic acids, such as acrylic acid, maleic acid, fumaric acid, itaconic acid, citric acid, aconitic acid, mesaconic acid and methylenemalonic acid. Copolymerizates of these carboxylic acids with one another or with other copolymerizable substances as, for example, ethylenically unsaturated hydrocarbons, such as ethylene, propylene, isobutylene and styrene, with ethylenic monocarboxylic acids, such as acrylic acid, methacrylic acid, crotonic acid and 3-butenecarboxylic acid or with other ethylenically unsaturated alcohols, ethers, esters, amides and nitriles, such as vinyl alcohol, allyl alcohol, vinylmethylether, acrolein, vinyl acetate, acrylamide and acrylonitrile, can also be used. Copolymerizates from ethylenic mono-, diand tricarboxylic acids and several ethylenically unsaturated compounds of different structure are also suitable. The polymerizates and copolymerizates have an average degree of polymerization of 3 to 6,000 and should contain 1 to 9, preferably 2 to 9, carboxyl groups capable of forming salts, for every 3 monomer units.
So-called washing alkalis may be mentioned as further builder salts, such as the alkali metal silicates, especially sodium silicate, in which the ratio of Na O to SiO amounts to 1:35 to 1:1, and also carbonates, bicarbonates and borates of alkali metals such as sodium or potassium. The amount of alkaline-reacting substances including the washing alkalis and phosphates should be such that the pH value of a usable alkali Iiquor amounts to 9 to l l and during the washing process does not fall below values under 8 on account of consumption of alkali through the hydrolysis of the bleaching activator.
Increased effects may in many cases be obtained by suitable combination of different surface-active washing substances or builder salts with one another, for example, an improved washing power or a reduced foaming capacity. Such improvements are possible, for example, by combination of anionic with non-ionic and- /or amphoteric surface-active compounds with one anotheror by mixing washing substances of the same type, which differ with respect to their structure in the number of carbon atoms, the number and position of the double bonds or chain branchings in the hydrocarbon residue. Mixtures of inorganic and organic builder salts with a synergistic action may be used or may be combined with the abovementioned mixtures.
The washing compositions may also contain optical brighteners, especially derivatives of diaminostilben'edisulfonic acid or their alkali metal salts of the formula wherein R, and R may represent halogen atoms, lower alkoxy groups, the amino group or radicals of aliphatic, aromatic or heterocyclic primary or secondary amines as well as radicals of aminosulfonic acids where the aliphatic radicals, present in the above groups, contain preferably 1 to 4, and particularly 2 to 4 carbon atoms, while the heterocyclic ring systems are primarily rings with 5 or 6 members. As aromatic amine radicals preferably aniline, anthranilic acid or anilinesulfonic acid are of interest. Brighteners derived from the diaminestilbene sulfonic acids are mostly used as brighteners for cotton. The following products, derived from formula I, are commercially available, where R represents the N=(CH2-CH2OH)2 morpholino- -0cH For example, salts of 4,4'-bis-(2"-anilino-4"-morpholino-l ,3 ,S-triazinyl- 6 '-amino)-stilibene-2,2 -disulfonic acid, or similarly constructed compounds, which instead of the morpholino group contain' 'fa diethanolamine group, a methylamino group or a B-methoxylethylamine group are suitable. Furthermore, suitable brighteners for polyamide fibers are those of the diarylpyrazoline type, for example, l-(p-sulfonamidophenyl)-3-(p-chlorophenyl)-A pyrazoline, as well as similarly constructed compounds which, instead of the sulfonamindo group, contain a carboxymethyl or acetylamino group.
In addition, substituted aminocoumarins, for example, 4-methyl-7-dimethylamino-coumarin or 4-methyl- 7-diethylamino-courmarin, are useful. Further, the compounds l-(2-benzimidazolyl)-2-( l-hydroxyethyl-2- benzimidazolyl)-ethylene and l-ethyl-3-phenyl-7-diethylamino-carbostyril are useful as polyamide brighten- 15 ers. The compounds 2,5-di-(2-benzoxazolyl)-thiophene, 2-(2 benzoxazolyl)-naphtho-[2,3-b]-thiophene and l,2-di-(5-methyl-2-benzoxazolyl)-ethylene are suitable as brighteners for polyester and polyamide fibers. Brighteners of the substituted diphenylstyril type may also be present. Mixtures of the above-mentioned brighteners may also be used.
These optical brighteners are present in the products of the invention, particularly in the washing agents, according to the invention, generally in amounts of from 0.05 percent to 1.5 percent, preferably from 0.07 percent to 1 percent by weight.
The compositions may also contain enzymes from the class of proteases, lipases and amylases or their mixtures. Enzymic substances obtained from strains of bacteria or fungi, such as Bacillus subtilis, Bacillus licheniformis and Streptomyces griseus are specially suitable. Further constituents which may be contained in the powder components containing washing agents are neutral salts, especially sodium sulfate, antimicrobial substances, such as halogenated phenolethers and thioethers, halogenated carbanilides and salicylanilides, as well as halogenated diphenylmethanes, also stabilizing agents for percompounds, such as magnesium silicate.
For increasing the dirt-carrying capacity, known greying inhibitors or soil-suspending compounds, especially sodium cellulose glycollate (carboxymethylcellulose) are added.
If desired, the washing compositions may contain known foam-inhibiting means, such as saturated fatty acids or their alkali metal soaps with 20 to 24 carbon atoms, higher molecular weight fatty acid esters or triglycerides, trialkylmelamines or dialkyl and tetraalkyl ureas.
The constituents contained in the powder component containing washing agent may be contained in homogeneously composed powder particles. Such powder particles are obtainable, for example, by spray drying or granulation from aqueous concentrates or granulating the remaining constituents on previously formed powders in a known way. The powder component containing washing agent, however, may also consist of granular mixtures, in which the powder particles have a variable composition. Thus, for example, a specified fraction of the powder particles may contain the detergent substances and a part of the builder salts and have been obtained by hot spray drying, while a further part of the particles prepared, for example, by granulation, contains the residue of the builder salts and those active substances which decompose, volatilize or lose activity under the conditions of the hot spray drying as, for example, perfumes, biocides and certain foam inhibitors.
In the complex mixtures, the proportion by weight of the powder component containing washing agent to the sum of the stabilized bleaching assistant, according to the invention, and percompound should amount to 1:2 to l:l. preferably 111 to :1.
The bleaching assistants according to the invention as well as their mixtures with percompounds and/or washing agents are marked by a very high stability on storage, i.e., the decline of the bleaching activity occurs considerably more slowly than with known mixtures. The formation of undersired odorous substances by decomposition of components sensitive to oxidation is thereby avoided. On application the mixtures show excellent solubility properties, i.e., they are dissolved without residue within a short time on use. This was all the more surprising since neither the fatty acid nor the alcohol are sufficiently quickly soluble in cold alkali solutions. lf, therefore, fatty acid or higher melting fatty alcohols are used alone as coating substances for the bleaching activators, under the same conditions, no solution or only very slow solution takes place. On the other hand, water-soluble ethoxylated alcohols are suitable as coating substances, since they do not improve the stability on storage of the bleaching activators.
The preparation of the powder particles is particularly simple in comparison with the known process, in which the bleaching activators are grandulated or coated with coating substances, since the use of solvents for the powders and a recovery of the solvents, always combined with losses, is omitted.
The present invention will be further described with reference to the following specific Examples which are not to be deemed limitative of the invention.
EXAMPLE 1 20 parts by weight of stearic acid, 20 parts by weight of palmitic acid and 10 parts by weight of a tallow fatty alcohol, consisting of percent by weight of stearyl alcohol, 35 percent by weight of cetyl alcohol and 5 percent by weight of myristyl alcohol, were melted at 80C and, after addition of 50 parts by weight of tetraacetylglycoluril, the suspension was homogenized. The homogenized melt was sprayed by means of a nozzle with an aperture of 1 mm diameter at a pressure of 20 atmospheres into a spraying chamber. The temperature of the cooling air entering the chamber in countercurrent was 18C, and that of the issuing air 20C. The easily pourable non-adhering sprayed powder had mostly a globular structure and gave the following grain distribution on a screen analysis:
Screen No. (mm) (wt) The average particle size was 0.6 mm.
20 parts by weight of the sprayed product (a) were mixed with 10 parts by weight of sodium perborate tetrahydrate (b) having a weight per liter of 1,000 gm and an average particle size of 0.3 mm, as well as with 63 parts by weight of a washing agent mixture (c) obtain ed by hot spray drying, having a weight per liter of 420 gm and an average particle size of 0.65 mm. The finished powder mixture had the following composition (data in weight percent):
a 10.0 percent tetraacetylglycoluril 8.0 percent fatty acid 2.0 pecent tallow fatty alcohol b. 10.0 percent sodium perborate tetrahydrate 0.3 percent optical brightener 1.0 percent sodium carboxymethylcellulose 7.5 percent water The mixture was filled into a folding box of 600 gm capacity and stored at 20 and 70 percent relative air humidity. During the observation period of 20 weeks no decline in the available active oxygen took place.
For purposes of comparison the packets were stored at 30C and 80 percent relative air humidity in a conditioning cabinet. A washing composition (A) of the same composition in which the tetraacetylglycoluril, however, was not melted with the powder particules consisting of fatty acid and fatty alcohol, but was added to the washing composition component (e) before the spraying of the liquid concentrate (slurry), served for comparison.
In a second comparative experiment (B) a tetraacetylglycoluril coated with stearic acid and used, for the preparation of which, 75 gm of tetraaetylglycoluril on a granulation plate was sprayed with a solution of 25 gm of stearic acid in 75 gm of carbon tetrachloride and with the removal of the solvent, it was then aftergranulated. The screen analyses for this granulate are: 1.6 mm 1 percent; 0.8 mm 14 percent; 0.4 mm 8 percent; 0.2 mm 29 percent; 0.1 mm 42 percent; below 0.1 mm 6 percent.
The further comparative experiments C to E do not come within the state of the art. In Experiment C, corresponding to the method of operation given in the Example, 40 parts by weight of tetraacetylglycoluril were dispersed in 60 gm of molten polyethyleneglycol of molecular weight 10,000 and sprayed. The screen analysis of the powder consisting of globular particles gave: 0.8 mm 1 percent; 0.4 mm 4 percent; 0.2 mm 76 percent; 1 mm 18 percent; below 0.1 mm 1 percent.
In the same way (Experiment D) 50 parts by weight of tetraacetylglycoluril were dispersed in a melt of 50 parts by weight of an adduct of coconut fatty alcohol (chain lengths C C adducted with 30 mol of ethylene oxide, and sprayed. In the comparative experiment (E), instead of the ethoxylated coconut fatty alcohol, the same amount of stearic acid was used. The screen analysis led to the'following results:
The fractional amount of the still active perborate was determined by titration at weekly intervals and from this the half value time t /2 in which the perborate had half decomposed was determined.
The stability factor F gives the quotients from the half value time found and the half value time for washing composition according to Experiment A, in which, as described, the bleaching activator was incorporated by addition to the washing composition slurry of the powder component (c). A factor above 1 denotes a better, and one of less than 1 denotes a worse, perborate stabilization. The results are given in the following Table.
Ex- Perborate after Stability am- Protective substance weeks Factor ple for activator 1 2 3 4 5 t /2 F 1 (see Example) 96 95 94 86 70 6.4 3.1 A 82 54 23 1 2.1 1.0 B Stearic acid (coated) 86 59 22 3 2.5 1.2 C Polyglycol (sprayed) 88 56 17 2.2 1.1 D Ethoxylated fatty alcohol (sprayed) 77 27 5 1.6 0.8
E Stearic acid (sprayed) 95 93 89 82 65 6.0 2.8
The comparative experiments show that the stability on storage of the compositions according to the invention is greater than that of the comparative samples A and B belonging to the state of the art. The same applies to the comparative samples C and D, in which known coating means were used in a method not coming within the state of the art. The comparative sample E, which likewise is not within the state of the art, merely has similarly favorable storage properties. However, it was shown by means of the following experi- 5 ment that the dissolving properties of the comparative samples E and also B are insufficient.
In a commercial washing machine (AEG- LAVAMAT) dark blue colored textiles of synthetic fibers were washed by the above described washing composition in the so-callled Protective Washing Pro cess. 28 liters of washing liquor and 5 gm/liter of washing agent were used to 1 kg of dry laundry. The washing temperature was 30C, the whole washing program with three rinses with clear water tool 90 minutes.
Insepction of the pieces of washed textiles showed that the textiles washed with the washing agent according to the invention were perfectly clean and had no resides of undissoved particles of washing agent. On the textiles which had been washed using a washing agent according to comparative experiment B and E, a large number of light colored particles had been deposited from the activator coated with fatty acid, which gave a speckled appearance to the textiles. Samples of washing liquors which had been poured through a hair sieve after the washing process left in the first case no residues, but with the comparative samples B and E distinct residues of undissolved particles were left on the sieve.
Instead of the activators used in the washing composition of Example 1, those in which the tetraacetylglycoluril is replaced by other activators of (a) to (0) may also be used with a similar result.
Cotton brighteners, polyamide brighteners, polyester brighteners and their combinations may be used as optical brighteners, depending upon the purpose for which the washing composition according to the invention is to be used.
If preparations containing enzymes are to be made, 7 percent to 15 percent by weight of commercial products are used which, where solid enzyme concentrates are concerned, are adjusted by the manufacturer to the following activities by addition of inorganic salts, mostly sodium sulfate or sodium tripolyphosphate:
An amylase with 75,000 SKBE/gm, A lipase with 10,000 lE/gm.
The preceding specific embodiments are illustrative of the practice of the invention. It is to be understood, however, that other expedients known to those skilled in the art or disclosed herein may be employed without departing form the spirit of the invention or the scope of the appended claims.
1. A stabilized bleaching assistant suitable for use in pulverulent washing and bleaching compositions comprising drop-shaped to globular-shaped particules at least 70 percent of which have an average diameter within the range of 0.1 mm to 1 mm consisting essentially of percent to 70 percent by weight of at least one activator for active oxygen derived from compounds yielding H O in aqueous solutions having an activating action of at least 3 in the Per-Acid Formation Test selected from the group consisting of N-acyl compounds having 2 to 9 carbon atoms in the acyl, O- acyl compounds having 2 to 9 carbon atoms in the acyl, carbonic acid esters and pyrocarbonic acid esters, substantially surrounded by from 30 percent to 90 percent by weight of a mixture of (a) from 2 to 10 parts by weight of said mixture of acids having substantially from 12 to 24 carbon atoms selected from the group consisting of substantially saturated fatty acids, saturated hydroxy-fatty acids, and mixtures thereof, and (b) 1 part by weight of said mixture of alcohols selected from the group consisting of substantially saturated aliphatic monohydric alcohols having from 10 to carbon atoms, their ethoxylated products, their propyloxylated products, and mixtures thereof, where the alkoxylated products are water-insoluble and have from 1 to 5 alkoxy units.
2. The stabilized bleaching assistant of claim 1 wherein not more than 30 percent of said particles have a diameter of not less than 0.01 mm and not more than 2.5 mm.
3. The stabilized bleaching assistant of claim 1 wherein said mixture of acids and alcohols contains from 3 to 5 parts by weight of said acids to 1 part by weight of said alcohols.
4. The stabilized bleaching assistant of claim 1 wherein said alcohol is a saturated primary aliphatic alkanol having 12 to 18 carbon atoms.
5. The stabilized bleaching assistant of claim 1 wherein said alcohol is an ethylene oxide adduct of a saturated primary aliphatic alkanol having 12 to 18 carbon atoms adducted with l to 3 ethoxy units.
6. The stabilized bleaching assistant of claim 1 wherein at least percent by weight of said particles have a diameter within the range of 0.1 mm to 1.6 mm.
7. The stabilized bleaching assistant of claim 1 wherein said at least one activator has a melting point of at least C, and said mixture of acids and alcohols has a softening or melting point of above 40C.
8. The stabilized bleaching assistant of claim 1 wherein said activator is tetraacetylglycoluril.