ACTIVATION OF PEROXIDE WASHING AND BLEACHING BATHS
United States Patent 3816319
The acylation products of dioximes are used as activators for washing and bleaching baths containing a peroxide compound.
US Patent References:
Textile bleaching composition
Viveen et al. - December 1964 - 3163606
STAIN REMOVAL
Gray - January 1972 - 3637339
Textile bleaching composition
Viveen et al. - December 1964 - 3163606
STAIN REMOVAL
Gray - January 1972 - 3637339
Inventors:
Sarot, Pierre (Vilvoorde, BE)
Delattre, Michel (Rixensart, BE)
Decamps, Alain (Brussels, BE)
Delattre, Michel (Rixensart, BE)
Decamps, Alain (Brussels, BE)
Application Number:
05/146932
Publication Date:
06/11/1974
Filing Date:
05/26/1971
View Patent Images:
Export Citation:
Assignee:
Solvay & Cie (Brussels, BE)
Primary Class:
Other Classes:
252/186.430, 252/186.410, 564/159, 8/111, 510/314, 564/254, 510/313
International Classes:
C11D3/386; C11D3/39; C11D3/38; C11D7/54
Field of Search:
252/95,99,186 260/566AE
Primary Examiner:
Weinblatt, Mayer
Attorney, Agent or Firm:
Lobato, And Zelnick
Claims:
What we claim as new and desire to secure by Letters Patent is
1. A process for the activation, in an aqueous medium, of an active oxygen releasing compound selected from the group consisting of hydrogen peroxide, sodium perborate and sodium percarbonate, which comprises activating said active oxygen releasing compound by an activator selected from the group consisting of diacylated glyoxime and diacylated dialkylglyoxime wherein the alkyl group contains from one to four carbon atoms and the acyl group contains from two to four carbon atoms, said activator being present in a quantity corresponding to about 0.05-1 mole per gram-atom of active oxygen contained in said active oxygen releasing compound.
2. A process according to claim 1 in which the activator is diacetylated methylethylglyoxime.
3. A process according to claim 1 in which the activator is diacetylated glyoxime.
4. A process according to claim 1 in which the activator is diacetylated dimethylglyoxime.
5. A process according to claim 1 in which the peroxide compound is hydrogen peroxide.
6. A process according to claim 1 in which the peroxide compound is sodium perborate.
7. A process according to claim 1 in which the peroxide compound is sodium percarbonate.
8. A solid composition for producing washing and bleaching baths by dissolution in water comprising an active oxygen releasing compound selected from the group consisting of sodium perborate and sodium percarbonate and an activator selected from the group consisting of diacylated glyoxime, diacylated dialkylglyoxime wherein the alkyl group contains from one to four carbon atoms and the acyl group contains from two to four carbon atoms, said activator being present in a quantity corresponding to about 0.05-1 mole per gram-atom of active oxygen contained in said active oxygen releasing compound.
1. A process for the activation, in an aqueous medium, of an active oxygen releasing compound selected from the group consisting of hydrogen peroxide, sodium perborate and sodium percarbonate, which comprises activating said active oxygen releasing compound by an activator selected from the group consisting of diacylated glyoxime and diacylated dialkylglyoxime wherein the alkyl group contains from one to four carbon atoms and the acyl group contains from two to four carbon atoms, said activator being present in a quantity corresponding to about 0.05-1 mole per gram-atom of active oxygen contained in said active oxygen releasing compound.
2. A process according to claim 1 in which the activator is diacetylated methylethylglyoxime.
3. A process according to claim 1 in which the activator is diacetylated glyoxime.
4. A process according to claim 1 in which the activator is diacetylated dimethylglyoxime.
5. A process according to claim 1 in which the peroxide compound is hydrogen peroxide.
6. A process according to claim 1 in which the peroxide compound is sodium perborate.
7. A process according to claim 1 in which the peroxide compound is sodium percarbonate.
8. A solid composition for producing washing and bleaching baths by dissolution in water comprising an active oxygen releasing compound selected from the group consisting of sodium perborate and sodium percarbonate and an activator selected from the group consisting of diacylated glyoxime, diacylated dialkylglyoxime wherein the alkyl group contains from one to four carbon atoms and the acyl group contains from two to four carbon atoms, said activator being present in a quantity corresponding to about 0.05-1 mole per gram-atom of active oxygen contained in said active oxygen releasing compound.
Description:
BACKGROUND OF THE INVENTION
The present invention relates to a process for the activation of peroxide compounds in aqueous solutions used for washing and bleaching, or for disinfection and decontamination, and also to solid compositions containing both a peroxide compound and the activator.
In washing and bleaching products it is known to use peroxide compounds such as hydrogen peroxide, sodium peroxide, sodium perborate, sodium percarbonate, urea peroxide, etc. These peroxide compounds provide a satisfactory bleaching action when the washing liquid is used at or close to boiling temperature, but their action is relatively slow at lower temperatures and for treatments of short duration. This disadvantage is important because of the increasing use of washing machines the operating temperature of which is for example from 30° to 60°C. and the washing time from 10 to 15 minutes.
It is for this reason that it has been proposed to add activators which even at low temperature permit washing and bleaching by means of liquids containing peroxide compounds while providing under these conditions good bleaching action and also satisfactory removal of stains. As examples of known activators, mention may be made of the anhydrides of lower carboxylic acids, for example, acetic anhydride, substances containing one or more nitrogen atoms and at least two acyl groups bonded to the same nitrogen atom, particularly tetraacetylethylenediamine, and also acylated derivatives of 2,4,6-trihydroxy-1,3,5-triazine, preferably trisacetyl cyanurate. Among these compounds the acetylated derivatives are the most effective, but their penetrating odor considerably limits their utility.
SUMMARY OF THE INVENTION
It has now been found that the acylation products of dioximes, particularly the reaction products of glyoximes and an acylation agent constitute remarkable activators for washing and bleaching baths containing peroxide compounds.
According to the invention, a peroxide compound in an aqueous medium is activated by the reaction product of a dioxime and an acetylation agent.
Also according to the invention, a solid composition useful for producing washing and bleaching baths is comprised of a solid peroxide compound and the reaction product of a dioxime with an acylation agent, which is effective as an activator for the peroxide compound.
BRIEF DESCRIPTION OF THE DRAWINGS
Each of the figures is a diagram wherein the time of soaking in hours (abscissa) has been plotted against the soil eliminated in percent (ordinate)
In FIG. 1, curves I and II concern soaking with a peroxide compound without an activator, curves III and IV concern soaking with a peroxide compound in the presence of 0.1 g. of an acylated dioxime, curves V and VI concern soaking in the presence of a peroxide compound and 0.5 g. of an acylated dioxime and curves VII and VIII concern soaking in the presence of a peroxide compound and 1.0 g. of an acylated dioxime. The soil to be eliminated is tea (curves I, III, V and VII) and wine (curves II, IV and VI).
In each of FIGS. 2, 3, 4 and 5, curve I concerns soaking with a peroxide compound without activation and curves II, III and IV concern soaking with a peroxide compound in the presence of diacetylated dimethylgloxime, diacetylated glyoxime and diacetylated methylethylglyoxime, respectively.
In FIGS. 2 and 4, the diagrams concern tests of fabrics soiled with tea and in FIGS. 3 and 5, the diagrams concern tests of fabrics soiled with red wine.
DESCRIPTION OF THE INVENTION
Up to the present time, it has not been possible to determine the structure of the acylation products of dioximes which, according to the invention have been found to be highly effective as activators for peroxides, so that it is not known whether these compounds are di-N-acylated dioximes or di-O-acylated dioximes.
Among the acylation products of dioximes according to the invention the preferred compounds are acylation products, the acyl group of which contains from two to four carbon atoms, particularly acetylation products. The compounds which can be used according to the invention are preferably the diacylated products of glyoxime and dialkylglyoximes in which the alkyl group contains from one to 12, preferably from one to four carbon atoms.
A particularly suitable compound is diacetylated dimethylglyoxime, the formula of which is probably one of the following: ##SPC1##
This compound is easily obtained by reacting acetic anhydride with dimethylglyoxime by the usual acetylation techniques. Its composition has been determined by elementary analysis and mass spectrometry. It is obtained in the form of a white powder of crystalline appearance an surprisingly is practically odorless, so that it has an undeniable advantage in the present application. The use of the activators according to the invention makes it possible to obtain a sufficient degree of whiteness even at relatively low temperatures, so that in the process according to the invention the objects to be treated may be brought into contact with an aqueous solution containing the peroxide compound and the activator at temperatures between ambient temperature and 80°C.
The process according to the invention is effective for bleaching paper pulp, textile materials, greases, oils, and all materials as well as all compounds usually bleached by means of peroxide solutions. These aqueous solutions of peroxide compounds and activators may also be used for decontamination and disinfection.
The amount of peroxide compound varies wih the nature of the objects to be treated and the degree of whiteness which is desired; thus, for the decoloration of oils and greases it may be necessary to use larger amounts of peroxide compounds than for the bleaching of textile materials.
The diacylated dioximes used as activators in the present invention are effective even when they are present in the washing and bleaching baths at the rate of 0.05 mole per gram-atom of active oxygen; it is obvious that larger amounts may be used, but it scarcely appears advantageous to use more than one mole of activator per gram-atom of active oxygen.
For the purpose of carrying out the process according to the invention, the activators proposed may be added to the washing and bleaching baths at the time of use.
When the activators proposed are in solid form, which is most frequently the case, they may also be mixed, preferably provided with a protective coating which is soluble in water or capable of dispersion therein, such as certain polyethylene glycols, polyvinyl alcohol, or other similar materials -- with the washing or bleaching powders containing peroxide compounds, so as to have available a pulverulent mixture ready for the preparation of the washing or bleaching bath by dissolving in water.
Such ready-to-use mixtures may contain, in addition to the peroxide compound and the activator, anionic or non-ionic detergents having a washing action, alkaline substances regulating pH, and assisting the washing action, for example, carbonates, phosphates, pyrophosphates, tripolyphosphates, and silicates, antiredeposition agents such as carboxymethyl cellulose, optical bleaching products, proteolytic and/or amylolytic enzymes, stabilizers, anti-corrosive agents, etc.
The following examples further illustrate the best mode currently contemplated for carrying out the invention, except of course those examples wherein no activator has been used or wherein an activator known in the art has been used for the purposes of comparison. The examples which illustrate the invention must not be construed as limiting the invention in any manner.
EXAMPLE 1
In this example, the activities imparted by diacetylated dimethylglyoxime (DMGA) and by a known activator, triacetylcyanurate (TACA), to a perborate washing powder containing no activator and used for washing clothes under mild temperature conditions are compared.
The washing tests were carried out in a "General Electric WA 550B" washing machine which treats the cloths in the following manner:
filling, maximum duration 5 minutes;
washing with 75 liters of preheated water, time: 14 minutes;
draining of water, time: about 1 minute;
rinsing for a period of 15 minutes with cold water;
spin drying for 5 minutes.
The total duration of a washing cycle is therefore about 40 minutes.
The water feeding the machine has a hardness of 16 to 17 French hydrotimetric degrees; its temperature in the machine is 40°C. ± 1°C.
The washing powder used at the rate of 2 g. per liter of 150 g. per cycle is a commercial product. Its composition, determined by analysis is as follows, in percent by weight:
surface active organic materials 20 sodium silicate 5 sodium tripolyphosphate 30 sodium pyrophosphate 5 sodium sulphate 10 tetrahydrated sodium perborate 20 water of crystallization, celluose derivatives, optical bleaching agent, etc. 10 100
The material to be washed is composed of two parts: a white load and various test pieces intended to evaluate washing effectiveness.
The load, with a total weight of 3.5 kg., is composed of various pieces of about 75 cm. in length and 50 cm. in width. These pieces are of mixed cloth based on cotton (65 percent) and polyester (35 percent). The whiteness of the cloth, measured by its reflectance in blue light, is 88.0 ± 0.1 percent referred to magnesium oxide.
Various test pieces of about 100 square cm. (12.5 cm. × 8 cm.) are sewn on the load. Fifteen types of test pieces were used at the rate of 10 test pieces per type. The fabrics to be tested were distributed in the following four groups;
First group: test pieces intended to measure the detergent effectiveness of the washing product.
Second group: fabrics covered with soil sensitive to the action of the enzymes used in washing powders.
Third group: test pieces soiled by products capable of decoloration by oxidation.
Fourth group: white fabrics serving to evaluate the amount of soil redeposition during washing.
The first group comprises three different cottons covered with pigmentary soil based on lampblack. These fabrics were prepared by the following specialized organizations: EMPA (Switzerland), TEST FABRICS (U.S.A.), and WFK KREFELD (West Germany).
The second group comprises EMPA 112 and 116 soiled cottons. One of the cottons is impregnated with soil containing blood, milk, India ink, etc.; the other is soiled with cocoa.
The third group is composed of mixed cloth soiled with seven different stains; the staining was obtained by impregnating the fabric with a concentrated solution of the staining element, padding the impregnated cloth and drying in the open air, this staining cycle being repeated three times in succession. Four stains were made with natural fruit jucies -- blackcurrant, bilberry, cherry, and grape and the other three are based on tea, coffee and red wine.
In the fourth group, three types of white fabrics were used to evaluate the antiredeposition power of the washing product; two test pieces are cotton and a third is a mixed cotton-polyester fabric.
The effect of the washing treatment on the various test pieces is measured by the variation of their whiteness. The latter is always determined on the hidden face of the test piece, that is to say the face in permanent contact with the load. Whiteness is measured with the aid of an ELREPHO reflectometer (Zeiss) giving diffused lighting of the test piece and having an effective wavelength of 457 nanometers; the values obtained for reflectances are given in percent, referred to magnesium oxide.
For each soiled test piece the rate of soil elimination in percent, that is to say the ratio,
(soil eliminated/soil to be eliminated) × 100,
is given by the formula: ##SPC2##
The mean rate of soil elimination is equal to the arithmetic mean of the above results for all the test pieces of the same group.
In the case of unsoiled fabrics, the soil to be eliminated obviously corresponds to initial reflectance, and soil eliminated or gain in whiteness corresponds to the difference between reflectance after washing and initial reflectance.
The relative efficiency of the various washing powders is expressed by the ratio, multiplied by 100, between the mean rates of elimination of soil with the aid of an activated powder and of an unactivated powder.
The tests carried out made it possible to compare the following products:
perborate powder without activation,
perborate powder activated by trisacetylcyanurate (TACA),
perborate powder activated by discetylated dimethylglyoxime (DMGA).
Detailed results of the tests relating to the fourth group of test pieces, that is to say, measurement of bleaching power, are given in Table 1 below.
Table 1 ____________________________________________________________ ______________ Number of successive washing cycles Test piece: Mixed 0 3 3 1 2 3 cotton/poly- ester fabric (65/35) Activator in g./l. Nature Nil TACA 0.4 DMGA 0.35 of stains soil soil elim- soil elim- soil elim- soil elim- soil elim- to be elim- ination elim- ination elim- ination elim- ination elim- ination elimin- inated rate inated rate inated rate inated rate inated rate ated ____________________________________________________________ ______________ Blackcurrant 60.8 1.3 2.1 11.0 18.1 5.8 9.5 9.5 15.6 12.1 19.9 Grape 50.5 20.9 41.4 34.6 68.5 27.4 54.3 31.3 62.0 33.6 66.5 Bilberry 59.2 14.4 24.3 24.7 41.7 22.2 37.5 26.3 44.4 29.5 49.8 Tea 66.2 0.0 0.0 10.8 16.3 8.6 13.0 13.2 19.9 17.5 26.4 Wine 39.5 0.7 1.8 11.2 28.4 10.0 25.3 13.6 34.4 16.6 42.0 Coffee 61.4 26.9 43.8 40.1 65.3 33.6 54.7 37.5 61.1 40.4 65.8 Cherry 52.5 11.8 22.5 20.9 39.8 16.9 32.2 19.6 37.3 21.8 41.5 mean: 19.4 mean: 39.7 mean: 32.4 mean: 39.3 mean: 44.4 ____________________________________________________________ ______________
In addition, the results obtained with the four groups of test pieces are summarized in Table 1a.
Table 1a ____________________________________________________________ ______________ Activator No. of Relative efficiency (unactivated powder = washing 100, result after 3 cycles) cycles Detergent Enzyme Bleaching Antiredep- action action action osition action ____________________________________________________________ ______________ TACA 0.4 3 88 109 205 100 g./l. DMGA 0.35 1 -- 107 167 89 g./l. 2 -- 120 203 117 3 93 126 229 118 ____________________________________________________________ ______________
It is therefore seen that, in relation to the results obtained after three washing cycles with the aid of an unactivated perborate powder, the powder activated with DMGA has a bleaching power twice as great after only two washing cycles. For an equal number of cycles the powder containing DMGA has a detergent power almost identical to that of the powder without activator (the differences measured are not visible to the eye); the enzymatic and antiredeposition powers are improved respectively by 26 and 18 percent.
EXAMPLE 2
In this example, the influence of the diacetylated dimethylglyoxime (DMGA) content on the activation of a perborate washing powder is determined. In addition, comparative tests are carried out with the TACA previously mentioned and with tetraacetylethylenediamine (TAED).
The washing tests were carried out in a Launder-O-meter with the aid of a perborate washing powder.
The Launder-O-meter is a laboratory washing machine manufactured and sold by Atlas Electric Devices Co. (U.S.A.). The washing conditions are as follows:
temperature °C. 40 time minutes 15 water used, hardness French degrees 16-17 volume cm. 3 250 perborate washing powder g./l. 2 Test pieces to be washed (100 cm. 2 , about 0.6 g.) mixed cotton-polyester fabric soiled with wine 1 mixed cotton-polyester fabric soiled with tea 1 ______________________________________
The washing powder used is the same as that described in Example 1. The test pieces subjected to washing were soiled as indicated in Example 1; they were, however, subjected to supplementary aging for 4 hours at 70°C.
The results obtained are given in Tables 2 and 2a as follow:
Table 2 ____________________________________________________________ ______________ Activator, g.l. Mixed cotton-polyester fabric (65-35) soiled with Tea Wine ____________________________________________________________ ______________ Soil to be eliminated 69.3 43.9 ____________________________________________________________ ______________ Soil Elimination Soil Elimination eliminated rate of soil eliminated rate of in % soil in % ____________________________________________________________ ______________ Nil 3.3 4.8 9.3 21.2 DMGA 0.1 7.1 10.2 16.9 38.5 0.2 12.7 18.3 20.2 46.0 0.3 13.3 19.2 22.1 50.3 0.4* 15.9 22.9 21.3 48.5 TACA 0.4 13.0 18.8 19.4 44.2 TAED 0.4 12.4 17.9 19.5 44.4 ____________________________________________________________ ______________ *mean of five tests Key: Soil to be eliminated: difference between initial reflectance and that after formation of stains Soil eliminated: difference between reflectance after washing and that before washing.
Table 2a summarizes the values of Table 2, expressed in terms of relative efficiency.
Table 2a ______________________________________ Activator, g./l. Relative efficiency of the activated powder refers to the same powder without activator Tea Wine ______________________________________ DMGA 0.1 215 182 0.2 385 217 0.3 403 238 0.4 482 229 TACA 0.4 394 209 TAED 0.4 376 210 ______________________________________
It is found that the use of small amounts of diacetylated dimethylglyoxime, of the order of 25 percent by weight referred to the sodium perborate, that is, 0.2 mole of activator per gram-atom of active oxygen, makes it possible for the efficiency of the washing solution containing perborate to be practically doubled. Moreover, the additional activity imparted to the powder increases with the amount of activator present.
EXAMPLE 3
The tests described in this example were carried out under the same conditions as those of Example 2. The perborate powder was nevertheless replaced by a percarbonate washing powder. This powder was used at the rate of 1.88 g./l. so as to give the washing solution the same oxidizing power as in Example 2. The percarbonate powder had the following composition:
surface active organic materials, % 21 sodium silicate 5 sodium tripolyphosphate 32 sodium pyrophosphate 5 sodium sulphate 11 sodium percarbonate (containing 14% of active oxygen) 15 water of crystallization, cellulose derivatives, optical whitener, etc. 11 100
The results obtained, as set forth in Tables 3 and 3a clearly show the considerable increase in efficiency imparted to the percarbonate washing powder by the use of DMGA.
Table 3 ____________________________________________________________ ______________ Activator, g./l. Mixed cotton-polyester fabric (65-35) soiled by Tea Wine ____________________________________________________________ ______________ Soil to be eliminated 69.3 43.9 ____________________________________________________________ ______________ Soil Elimination Soil Elimination eliminated rate of soil eliminated rate of in % soil in % ____________________________________________________________ ______________ Nil 3.3 4.8 10.0 22.8 DMGA (*) 0.1 8.2 11.8 13.1 29.8 0.2 11.7 16.9 16.7 38.0 0.3 13.8 19.9 18.4 41.9 0.4 14.9 21.5 20.1 45.8 ____________________________________________________________ ______________ (*)mean of two tests
Table 3a shows the preceding results expressed in terms of relative efficiency.
Table 3a ______________________________________ Activator, g./l. Relative efficiency (powder without activator = 100) Tea Wine ______________________________________ DMGA 0.1 248 131 0.2 355 167 0.3 418 184 0.4 452 201 ______________________________________
EXAMPLE 4
Tests carried out with the object of determining the action of DMGA on the efficiency of proteolytic enzymes which are sometimes introduced into washing powders.
The washing tests were carried out in a Launder-O-meter under the following conditions:
Temperature °C. 30 duration minutes 30 water used, hardness French degrees 17-18 amount cm. 3 250 Washing powder: perborate (see Example 1 for compo- sition g./l. 2 or percarbonate (see Example 3 for composition) g./l. 1.88 proteolytic enzymes at 300,000 units Delft/g. g./l. 0.02 Test pieces to be washed (about 100 cm. 2 ): EMPA 112 number 1 EMPA 116 number 1
The DMGA is used at the rate of 0.4 g./l. of washing liquid.
The results obtained are indicated in Table 4. They show that DMGA does not harm the action of enzymes in perborate or percarbonate biological powders.
Table 4 ____________________________________________________________ ______________ Cotton EMPA 112 EMPA 116 Mean (blood, India ink (cocoa) % etc.) Washing Powder Soil Elim- Soil Elim- Elim- ination Elim- ination inated rate in inated rate in % % ____________________________________________________________ ______________ Perborate powder 2.1 2.7 6.9 10.3 6.5 Ditto + enzymes 13.9 17.6 11.6 17.3 17.5 Ditto + enzymes and DMGA 13.9 17.6 12.4 18.5 18.1 Percarbonate powder 2.1 2.7 6.8 10.2 6.5 Ditto + enzymes 11.5 14.6 12.6 18.8 16.7 Ditto + enzymes and DMGA 11.3 14.3 13.7 20.5 17.4 ____________________________________________________________ ______________
EXAMPLE 5
The tests of Example 5 were carried out under the same conditions as those indicated in Example 2. The only change relates to the quality of the water. The water used in this example has a very high hardness of 36 French hydrotimetric degrees.
The results of the tests shown in Table 5 indicate that DMGA is also very efficient in very hard water.
Table 5 ____________________________________________________________ ______________ Mixed cotton-polyester fabric (65-35) soiled by tea ____________________________________________________________ ______________ Soil to be eliminated: 69.4 Soil eliminated, without activator 0.7 i.e. 1.0% with DMGA 0.4 g./l. (mean of 4 tests) 12.6 i.e. 18.2% Relative efficiency, without activator 100 with DMGA 1820 Mixed cotton-polyester fabric (65-35) soiled by wine Soil to be eliminated: 44.0 Soil eliminated, without activator 0.6 i.e. 1.4% with DMGA 0.4 g./l. (means of 4 tests) 15.6 i.e. 35.5% Relative efficiency, without activator 100 with DMGA 2600 ____________________________________________________________ ______________
EXAMPLE 6
Soaking tests were carried out in cold water under the following conditions:
Temperature °C. 25 Time hours 1/2 to 3 Water used, hardness French degrees 18 quantity cm. 3 1000 Perborate powder (see Example 1 for composition) g./l. 5 Test pieces (about 100 cm. 2 , 0.6 g.) Mixed cotton-polyester fabric soiled by wine Number 6 Mixed cotton-polyester fabric soiled by tea Number 6
The results are shown in FIG. 1. In this and the following diagram the abscissae represent the soaking time in hours, while the ordinates represent the soil eliminated in percent. Curves I, III, V and VII relate to fabric soiled by tea, while curves II, IV and VI relate to fabric soiled by wine. Curves I and II show soaking tests without activator; curves III and IV were obtained in the presence of 0.1 g. of DMGA per liter; curves V and VI relate to soaking in the presence of 0.5 g. of DMGA per liter, while curves VII and VIII relate to the presence of 1 g. of DMGA per liter.
The curves show the additional efficiency imparted to the soaking powder by DMGA. The amount of soil eliminated by the powder without activator after soaking for 3 hours is already attained after only one-fourth to one-half hour when DMGA is added to the soaking solution.
EXAMPLE 7
The tests described in this example were carried out under the same conditions as indicated in Example 6. The only change relates to the temperature of the test, which is 22°C.
Two other acetylated glyoximes were tested under the same conditions as DMGA, namely, diacetylated glyoxime (DAG) and diacetylated methylethylglyoxime (MEGA). ##SPC3##
The results obtained are shown in the accompanying diagrams (FIGS. 2 to 5). Diagrams 2 and 3 relate to a concentration of activator of 0.25 g./l. while diagrams 4 and 5 were obtained with an activator concentration of 0.5 g./l.
Diagrams 2 and 4 relate to soaking tests with fabrics soiled with tea, diagrams 3 and 5 to fabrics soiled with red wine.
Curves I relate to tests carried out without activator, curves II to tests carried out with DMGA, III with DAG and IV with MEGA.
These diagrams clearly show the considerable increase in efficiency of a soaking powder when one of these three activators is introduced into it.
Table 6 expresses these results in terms of relative efficiency.
Table 6 ____________________________________________________________ ______________ Nature of Concentration of Relative Efficiency After 3 hours Activator Activator of Soaking: g./l. TEA WINE ____________________________________________________________ ______________ nil (I) 0 100 100 DMGA (II) 0.25 176 264 0.50 239 386 DAG (III) 0.25 176 264 0.50 231 368 MEGA (IV) 0.25 176 243 0.50 200 305 ____________________________________________________________ ______________
Table 6a indicates the time required for a soaking powder containing one of the three diacetylated glyoximes to eliminate an amount of soil equivalent to that removed by the same unactivated powder after soaking for 3 hours.
Table 6a ____________________________________________________________ ______________ Nature of Concentration Soaking time equivalent to a soaking Activator of Activator of 3 hours without activator, minutes g./l. TEA WINE ____________________________________________________________ ______________ DMGA (II) 0.50 14 13 DAG (III) 0.50 36 14 MEGA (IV) 0.50 42 22 ____________________________________________________________ ______________
It can be seen in Table 6a, as we have already shown in Example 6, that after a soaking time of less than 1/4 hour with DMGA, the same quantity of soil is eliminated as is removed in 3 hours with the powder containing no activator.
In the case of DAG and META this time is slightly longer than one-half hour for fabrics soiled with tea and about one-fourth and one-half hour for fabrics soiled with wine.
The present invention relates to a process for the activation of peroxide compounds in aqueous solutions used for washing and bleaching, or for disinfection and decontamination, and also to solid compositions containing both a peroxide compound and the activator.
In washing and bleaching products it is known to use peroxide compounds such as hydrogen peroxide, sodium peroxide, sodium perborate, sodium percarbonate, urea peroxide, etc. These peroxide compounds provide a satisfactory bleaching action when the washing liquid is used at or close to boiling temperature, but their action is relatively slow at lower temperatures and for treatments of short duration. This disadvantage is important because of the increasing use of washing machines the operating temperature of which is for example from 30° to 60°C. and the washing time from 10 to 15 minutes.
It is for this reason that it has been proposed to add activators which even at low temperature permit washing and bleaching by means of liquids containing peroxide compounds while providing under these conditions good bleaching action and also satisfactory removal of stains. As examples of known activators, mention may be made of the anhydrides of lower carboxylic acids, for example, acetic anhydride, substances containing one or more nitrogen atoms and at least two acyl groups bonded to the same nitrogen atom, particularly tetraacetylethylenediamine, and also acylated derivatives of 2,4,6-trihydroxy-1,3,5-triazine, preferably trisacetyl cyanurate. Among these compounds the acetylated derivatives are the most effective, but their penetrating odor considerably limits their utility.
SUMMARY OF THE INVENTION
It has now been found that the acylation products of dioximes, particularly the reaction products of glyoximes and an acylation agent constitute remarkable activators for washing and bleaching baths containing peroxide compounds.
According to the invention, a peroxide compound in an aqueous medium is activated by the reaction product of a dioxime and an acetylation agent.
Also according to the invention, a solid composition useful for producing washing and bleaching baths is comprised of a solid peroxide compound and the reaction product of a dioxime with an acylation agent, which is effective as an activator for the peroxide compound.
BRIEF DESCRIPTION OF THE DRAWINGS
Each of the figures is a diagram wherein the time of soaking in hours (abscissa) has been plotted against the soil eliminated in percent (ordinate)
In FIG. 1, curves I and II concern soaking with a peroxide compound without an activator, curves III and IV concern soaking with a peroxide compound in the presence of 0.1 g. of an acylated dioxime, curves V and VI concern soaking in the presence of a peroxide compound and 0.5 g. of an acylated dioxime and curves VII and VIII concern soaking in the presence of a peroxide compound and 1.0 g. of an acylated dioxime. The soil to be eliminated is tea (curves I, III, V and VII) and wine (curves II, IV and VI).
In each of FIGS. 2, 3, 4 and 5, curve I concerns soaking with a peroxide compound without activation and curves II, III and IV concern soaking with a peroxide compound in the presence of diacetylated dimethylgloxime, diacetylated glyoxime and diacetylated methylethylglyoxime, respectively.
In FIGS. 2 and 4, the diagrams concern tests of fabrics soiled with tea and in FIGS. 3 and 5, the diagrams concern tests of fabrics soiled with red wine.
DESCRIPTION OF THE INVENTION
Up to the present time, it has not been possible to determine the structure of the acylation products of dioximes which, according to the invention have been found to be highly effective as activators for peroxides, so that it is not known whether these compounds are di-N-acylated dioximes or di-O-acylated dioximes.
Among the acylation products of dioximes according to the invention the preferred compounds are acylation products, the acyl group of which contains from two to four carbon atoms, particularly acetylation products. The compounds which can be used according to the invention are preferably the diacylated products of glyoxime and dialkylglyoximes in which the alkyl group contains from one to 12, preferably from one to four carbon atoms.
A particularly suitable compound is diacetylated dimethylglyoxime, the formula of which is probably one of the following: ##SPC1##
This compound is easily obtained by reacting acetic anhydride with dimethylglyoxime by the usual acetylation techniques. Its composition has been determined by elementary analysis and mass spectrometry. It is obtained in the form of a white powder of crystalline appearance an surprisingly is practically odorless, so that it has an undeniable advantage in the present application. The use of the activators according to the invention makes it possible to obtain a sufficient degree of whiteness even at relatively low temperatures, so that in the process according to the invention the objects to be treated may be brought into contact with an aqueous solution containing the peroxide compound and the activator at temperatures between ambient temperature and 80°C.
The process according to the invention is effective for bleaching paper pulp, textile materials, greases, oils, and all materials as well as all compounds usually bleached by means of peroxide solutions. These aqueous solutions of peroxide compounds and activators may also be used for decontamination and disinfection.
The amount of peroxide compound varies wih the nature of the objects to be treated and the degree of whiteness which is desired; thus, for the decoloration of oils and greases it may be necessary to use larger amounts of peroxide compounds than for the bleaching of textile materials.
The diacylated dioximes used as activators in the present invention are effective even when they are present in the washing and bleaching baths at the rate of 0.05 mole per gram-atom of active oxygen; it is obvious that larger amounts may be used, but it scarcely appears advantageous to use more than one mole of activator per gram-atom of active oxygen.
For the purpose of carrying out the process according to the invention, the activators proposed may be added to the washing and bleaching baths at the time of use.
When the activators proposed are in solid form, which is most frequently the case, they may also be mixed, preferably provided with a protective coating which is soluble in water or capable of dispersion therein, such as certain polyethylene glycols, polyvinyl alcohol, or other similar materials -- with the washing or bleaching powders containing peroxide compounds, so as to have available a pulverulent mixture ready for the preparation of the washing or bleaching bath by dissolving in water.
Such ready-to-use mixtures may contain, in addition to the peroxide compound and the activator, anionic or non-ionic detergents having a washing action, alkaline substances regulating pH, and assisting the washing action, for example, carbonates, phosphates, pyrophosphates, tripolyphosphates, and silicates, antiredeposition agents such as carboxymethyl cellulose, optical bleaching products, proteolytic and/or amylolytic enzymes, stabilizers, anti-corrosive agents, etc.
The following examples further illustrate the best mode currently contemplated for carrying out the invention, except of course those examples wherein no activator has been used or wherein an activator known in the art has been used for the purposes of comparison. The examples which illustrate the invention must not be construed as limiting the invention in any manner.
EXAMPLE 1
In this example, the activities imparted by diacetylated dimethylglyoxime (DMGA) and by a known activator, triacetylcyanurate (TACA), to a perborate washing powder containing no activator and used for washing clothes under mild temperature conditions are compared.
The washing tests were carried out in a "General Electric WA 550B" washing machine which treats the cloths in the following manner:
filling, maximum duration 5 minutes;
washing with 75 liters of preheated water, time: 14 minutes;
draining of water, time: about 1 minute;
rinsing for a period of 15 minutes with cold water;
spin drying for 5 minutes.
The total duration of a washing cycle is therefore about 40 minutes.
The water feeding the machine has a hardness of 16 to 17 French hydrotimetric degrees; its temperature in the machine is 40°C. ± 1°C.
The washing powder used at the rate of 2 g. per liter of 150 g. per cycle is a commercial product. Its composition, determined by analysis is as follows, in percent by weight:
surface active organic materials 20 sodium silicate 5 sodium tripolyphosphate 30 sodium pyrophosphate 5 sodium sulphate 10 tetrahydrated sodium perborate 20 water of crystallization, celluose derivatives, optical bleaching agent, etc. 10 100
The material to be washed is composed of two parts: a white load and various test pieces intended to evaluate washing effectiveness.
The load, with a total weight of 3.5 kg., is composed of various pieces of about 75 cm. in length and 50 cm. in width. These pieces are of mixed cloth based on cotton (65 percent) and polyester (35 percent). The whiteness of the cloth, measured by its reflectance in blue light, is 88.0 ± 0.1 percent referred to magnesium oxide.
Various test pieces of about 100 square cm. (12.5 cm. × 8 cm.) are sewn on the load. Fifteen types of test pieces were used at the rate of 10 test pieces per type. The fabrics to be tested were distributed in the following four groups;
First group: test pieces intended to measure the detergent effectiveness of the washing product.
Second group: fabrics covered with soil sensitive to the action of the enzymes used in washing powders.
Third group: test pieces soiled by products capable of decoloration by oxidation.
Fourth group: white fabrics serving to evaluate the amount of soil redeposition during washing.
The first group comprises three different cottons covered with pigmentary soil based on lampblack. These fabrics were prepared by the following specialized organizations: EMPA (Switzerland), TEST FABRICS (U.S.A.), and WFK KREFELD (West Germany).
The second group comprises EMPA 112 and 116 soiled cottons. One of the cottons is impregnated with soil containing blood, milk, India ink, etc.; the other is soiled with cocoa.
The third group is composed of mixed cloth soiled with seven different stains; the staining was obtained by impregnating the fabric with a concentrated solution of the staining element, padding the impregnated cloth and drying in the open air, this staining cycle being repeated three times in succession. Four stains were made with natural fruit jucies -- blackcurrant, bilberry, cherry, and grape and the other three are based on tea, coffee and red wine.
In the fourth group, three types of white fabrics were used to evaluate the antiredeposition power of the washing product; two test pieces are cotton and a third is a mixed cotton-polyester fabric.
The effect of the washing treatment on the various test pieces is measured by the variation of their whiteness. The latter is always determined on the hidden face of the test piece, that is to say the face in permanent contact with the load. Whiteness is measured with the aid of an ELREPHO reflectometer (Zeiss) giving diffused lighting of the test piece and having an effective wavelength of 457 nanometers; the values obtained for reflectances are given in percent, referred to magnesium oxide.
For each soiled test piece the rate of soil elimination in percent, that is to say the ratio,
(soil eliminated/soil to be eliminated) × 100,
is given by the formula: ##SPC2##
The mean rate of soil elimination is equal to the arithmetic mean of the above results for all the test pieces of the same group.
In the case of unsoiled fabrics, the soil to be eliminated obviously corresponds to initial reflectance, and soil eliminated or gain in whiteness corresponds to the difference between reflectance after washing and initial reflectance.
The relative efficiency of the various washing powders is expressed by the ratio, multiplied by 100, between the mean rates of elimination of soil with the aid of an activated powder and of an unactivated powder.
The tests carried out made it possible to compare the following products:
perborate powder without activation,
perborate powder activated by trisacetylcyanurate (TACA),
perborate powder activated by discetylated dimethylglyoxime (DMGA).
Detailed results of the tests relating to the fourth group of test pieces, that is to say, measurement of bleaching power, are given in Table 1 below.
Table 1 ____________________________________________________________ ______________ Number of successive washing cycles Test piece: Mixed 0 3 3 1 2 3 cotton/poly- ester fabric (65/35) Activator in g./l. Nature Nil TACA 0.4 DMGA 0.35 of stains soil soil elim- soil elim- soil elim- soil elim- soil elim- to be elim- ination elim- ination elim- ination elim- ination elim- ination elimin- inated rate inated rate inated rate inated rate inated rate ated ____________________________________________________________ ______________ Blackcurrant 60.8 1.3 2.1 11.0 18.1 5.8 9.5 9.5 15.6 12.1 19.9 Grape 50.5 20.9 41.4 34.6 68.5 27.4 54.3 31.3 62.0 33.6 66.5 Bilberry 59.2 14.4 24.3 24.7 41.7 22.2 37.5 26.3 44.4 29.5 49.8 Tea 66.2 0.0 0.0 10.8 16.3 8.6 13.0 13.2 19.9 17.5 26.4 Wine 39.5 0.7 1.8 11.2 28.4 10.0 25.3 13.6 34.4 16.6 42.0 Coffee 61.4 26.9 43.8 40.1 65.3 33.6 54.7 37.5 61.1 40.4 65.8 Cherry 52.5 11.8 22.5 20.9 39.8 16.9 32.2 19.6 37.3 21.8 41.5 mean: 19.4 mean: 39.7 mean: 32.4 mean: 39.3 mean: 44.4 ____________________________________________________________ ______________
In addition, the results obtained with the four groups of test pieces are summarized in Table 1a.
Table 1a ____________________________________________________________ ______________ Activator No. of Relative efficiency (unactivated powder = washing 100, result after 3 cycles) cycles Detergent Enzyme Bleaching Antiredep- action action action osition action ____________________________________________________________ ______________ TACA 0.4 3 88 109 205 100 g./l. DMGA 0.35 1 -- 107 167 89 g./l. 2 -- 120 203 117 3 93 126 229 118 ____________________________________________________________ ______________
It is therefore seen that, in relation to the results obtained after three washing cycles with the aid of an unactivated perborate powder, the powder activated with DMGA has a bleaching power twice as great after only two washing cycles. For an equal number of cycles the powder containing DMGA has a detergent power almost identical to that of the powder without activator (the differences measured are not visible to the eye); the enzymatic and antiredeposition powers are improved respectively by 26 and 18 percent.
EXAMPLE 2
In this example, the influence of the diacetylated dimethylglyoxime (DMGA) content on the activation of a perborate washing powder is determined. In addition, comparative tests are carried out with the TACA previously mentioned and with tetraacetylethylenediamine (TAED).
The washing tests were carried out in a Launder-O-meter with the aid of a perborate washing powder.
The Launder-O-meter is a laboratory washing machine manufactured and sold by Atlas Electric Devices Co. (U.S.A.). The washing conditions are as follows:
temperature °C. 40 time minutes 15 water used, hardness French degrees 16-17 volume cm. 3 250 perborate washing powder g./l. 2 Test pieces to be washed (100 cm. 2 , about 0.6 g.) mixed cotton-polyester fabric soiled with wine 1 mixed cotton-polyester fabric soiled with tea 1 ______________________________________
The washing powder used is the same as that described in Example 1. The test pieces subjected to washing were soiled as indicated in Example 1; they were, however, subjected to supplementary aging for 4 hours at 70°C.
The results obtained are given in Tables 2 and 2a as follow:
Table 2 ____________________________________________________________ ______________ Activator, g.l. Mixed cotton-polyester fabric (65-35) soiled with Tea Wine ____________________________________________________________ ______________ Soil to be eliminated 69.3 43.9 ____________________________________________________________ ______________ Soil Elimination Soil Elimination eliminated rate of soil eliminated rate of in % soil in % ____________________________________________________________ ______________ Nil 3.3 4.8 9.3 21.2 DMGA 0.1 7.1 10.2 16.9 38.5 0.2 12.7 18.3 20.2 46.0 0.3 13.3 19.2 22.1 50.3 0.4* 15.9 22.9 21.3 48.5 TACA 0.4 13.0 18.8 19.4 44.2 TAED 0.4 12.4 17.9 19.5 44.4 ____________________________________________________________ ______________ *mean of five tests Key: Soil to be eliminated: difference between initial reflectance and that after formation of stains Soil eliminated: difference between reflectance after washing and that before washing.
Table 2a summarizes the values of Table 2, expressed in terms of relative efficiency.
Table 2a ______________________________________ Activator, g./l. Relative efficiency of the activated powder refers to the same powder without activator Tea Wine ______________________________________ DMGA 0.1 215 182 0.2 385 217 0.3 403 238 0.4 482 229 TACA 0.4 394 209 TAED 0.4 376 210 ______________________________________
It is found that the use of small amounts of diacetylated dimethylglyoxime, of the order of 25 percent by weight referred to the sodium perborate, that is, 0.2 mole of activator per gram-atom of active oxygen, makes it possible for the efficiency of the washing solution containing perborate to be practically doubled. Moreover, the additional activity imparted to the powder increases with the amount of activator present.
EXAMPLE 3
The tests described in this example were carried out under the same conditions as those of Example 2. The perborate powder was nevertheless replaced by a percarbonate washing powder. This powder was used at the rate of 1.88 g./l. so as to give the washing solution the same oxidizing power as in Example 2. The percarbonate powder had the following composition:
surface active organic materials, % 21 sodium silicate 5 sodium tripolyphosphate 32 sodium pyrophosphate 5 sodium sulphate 11 sodium percarbonate (containing 14% of active oxygen) 15 water of crystallization, cellulose derivatives, optical whitener, etc. 11 100
The results obtained, as set forth in Tables 3 and 3a clearly show the considerable increase in efficiency imparted to the percarbonate washing powder by the use of DMGA.
Table 3 ____________________________________________________________ ______________ Activator, g./l. Mixed cotton-polyester fabric (65-35) soiled by Tea Wine ____________________________________________________________ ______________ Soil to be eliminated 69.3 43.9 ____________________________________________________________ ______________ Soil Elimination Soil Elimination eliminated rate of soil eliminated rate of in % soil in % ____________________________________________________________ ______________ Nil 3.3 4.8 10.0 22.8 DMGA (*) 0.1 8.2 11.8 13.1 29.8 0.2 11.7 16.9 16.7 38.0 0.3 13.8 19.9 18.4 41.9 0.4 14.9 21.5 20.1 45.8 ____________________________________________________________ ______________ (*)mean of two tests
Table 3a shows the preceding results expressed in terms of relative efficiency.
Table 3a ______________________________________ Activator, g./l. Relative efficiency (powder without activator = 100) Tea Wine ______________________________________ DMGA 0.1 248 131 0.2 355 167 0.3 418 184 0.4 452 201 ______________________________________
EXAMPLE 4
Tests carried out with the object of determining the action of DMGA on the efficiency of proteolytic enzymes which are sometimes introduced into washing powders.
The washing tests were carried out in a Launder-O-meter under the following conditions:
Temperature °C. 30 duration minutes 30 water used, hardness French degrees 17-18 amount cm. 3 250 Washing powder: perborate (see Example 1 for compo- sition g./l. 2 or percarbonate (see Example 3 for composition) g./l. 1.88 proteolytic enzymes at 300,000 units Delft/g. g./l. 0.02 Test pieces to be washed (about 100 cm. 2 ): EMPA 112 number 1 EMPA 116 number 1
The DMGA is used at the rate of 0.4 g./l. of washing liquid.
The results obtained are indicated in Table 4. They show that DMGA does not harm the action of enzymes in perborate or percarbonate biological powders.
Table 4 ____________________________________________________________ ______________ Cotton EMPA 112 EMPA 116 Mean (blood, India ink (cocoa) % etc.) Washing Powder Soil Elim- Soil Elim- Elim- ination Elim- ination inated rate in inated rate in % % ____________________________________________________________ ______________ Perborate powder 2.1 2.7 6.9 10.3 6.5 Ditto + enzymes 13.9 17.6 11.6 17.3 17.5 Ditto + enzymes and DMGA 13.9 17.6 12.4 18.5 18.1 Percarbonate powder 2.1 2.7 6.8 10.2 6.5 Ditto + enzymes 11.5 14.6 12.6 18.8 16.7 Ditto + enzymes and DMGA 11.3 14.3 13.7 20.5 17.4 ____________________________________________________________ ______________
EXAMPLE 5
The tests of Example 5 were carried out under the same conditions as those indicated in Example 2. The only change relates to the quality of the water. The water used in this example has a very high hardness of 36 French hydrotimetric degrees.
The results of the tests shown in Table 5 indicate that DMGA is also very efficient in very hard water.
Table 5 ____________________________________________________________ ______________ Mixed cotton-polyester fabric (65-35) soiled by tea ____________________________________________________________ ______________ Soil to be eliminated: 69.4 Soil eliminated, without activator 0.7 i.e. 1.0% with DMGA 0.4 g./l. (mean of 4 tests) 12.6 i.e. 18.2% Relative efficiency, without activator 100 with DMGA 1820 Mixed cotton-polyester fabric (65-35) soiled by wine Soil to be eliminated: 44.0 Soil eliminated, without activator 0.6 i.e. 1.4% with DMGA 0.4 g./l. (means of 4 tests) 15.6 i.e. 35.5% Relative efficiency, without activator 100 with DMGA 2600 ____________________________________________________________ ______________
EXAMPLE 6
Soaking tests were carried out in cold water under the following conditions:
Temperature °C. 25 Time hours 1/2 to 3 Water used, hardness French degrees 18 quantity cm. 3 1000 Perborate powder (see Example 1 for composition) g./l. 5 Test pieces (about 100 cm. 2 , 0.6 g.) Mixed cotton-polyester fabric soiled by wine Number 6 Mixed cotton-polyester fabric soiled by tea Number 6
The results are shown in FIG. 1. In this and the following diagram the abscissae represent the soaking time in hours, while the ordinates represent the soil eliminated in percent. Curves I, III, V and VII relate to fabric soiled by tea, while curves II, IV and VI relate to fabric soiled by wine. Curves I and II show soaking tests without activator; curves III and IV were obtained in the presence of 0.1 g. of DMGA per liter; curves V and VI relate to soaking in the presence of 0.5 g. of DMGA per liter, while curves VII and VIII relate to the presence of 1 g. of DMGA per liter.
The curves show the additional efficiency imparted to the soaking powder by DMGA. The amount of soil eliminated by the powder without activator after soaking for 3 hours is already attained after only one-fourth to one-half hour when DMGA is added to the soaking solution.
EXAMPLE 7
The tests described in this example were carried out under the same conditions as indicated in Example 6. The only change relates to the temperature of the test, which is 22°C.
Two other acetylated glyoximes were tested under the same conditions as DMGA, namely, diacetylated glyoxime (DAG) and diacetylated methylethylglyoxime (MEGA). ##SPC3##
The results obtained are shown in the accompanying diagrams (FIGS. 2 to 5). Diagrams 2 and 3 relate to a concentration of activator of 0.25 g./l. while diagrams 4 and 5 were obtained with an activator concentration of 0.5 g./l.
Diagrams 2 and 4 relate to soaking tests with fabrics soiled with tea, diagrams 3 and 5 to fabrics soiled with red wine.
Curves I relate to tests carried out without activator, curves II to tests carried out with DMGA, III with DAG and IV with MEGA.
These diagrams clearly show the considerable increase in efficiency of a soaking powder when one of these three activators is introduced into it.
Table 6 expresses these results in terms of relative efficiency.
Table 6 ____________________________________________________________ ______________ Nature of Concentration of Relative Efficiency After 3 hours Activator Activator of Soaking: g./l. TEA WINE ____________________________________________________________ ______________ nil (I) 0 100 100 DMGA (II) 0.25 176 264 0.50 239 386 DAG (III) 0.25 176 264 0.50 231 368 MEGA (IV) 0.25 176 243 0.50 200 305 ____________________________________________________________ ______________
Table 6a indicates the time required for a soaking powder containing one of the three diacetylated glyoximes to eliminate an amount of soil equivalent to that removed by the same unactivated powder after soaking for 3 hours.
Table 6a ____________________________________________________________ ______________ Nature of Concentration Soaking time equivalent to a soaking Activator of Activator of 3 hours without activator, minutes g./l. TEA WINE ____________________________________________________________ ______________ DMGA (II) 0.50 14 13 DAG (III) 0.50 36 14 MEGA (IV) 0.50 42 22 ____________________________________________________________ ______________
It can be seen in Table 6a, as we have already shown in Example 6, that after a soaking time of less than 1/4 hour with DMGA, the same quantity of soil is eliminated as is removed in 3 hours with the powder containing no activator.
In the case of DAG and META this time is slightly longer than one-half hour for fabrics soiled with tea and about one-fourth and one-half hour for fabrics soiled with wine.