US3422020A - Low-sudsing detergent compositions - Google Patents

Description

United States Patent H 57,959 US. Cl. 252-99 Int. Cl. Clld 3/28 14 Claims ABSTRACT OF THE DISCLGSURE Low-sudsing detergents comprising at least one washactive agent and a water-insoluble melamine derivative having the formula:

wherein R R and R each represent hydrogen or an organic radical containing 1 to 24 carbon atoms, and R R and R are each an organic radical containing 1 to 24 carbon atoms.

This invention relates to low-sudsing detergents. It more particularly relates to laundry detergents which contain suds inhibitors capable of effectively and lastingly inhibiting suds formation.

Detergents which produce large volumes of suds are known to be unsuitable for use in the modern drum-type washing machines and automatic dishwashers. Strong sudsing action often results, especially at elevated temperatures, in a foaming-over of the wash-water, with a considerable loss of wash-active substances, as well as inconvenience to the user. It has furthermore developed that large amounts of suds interfere with the mechanical agitation of the goods, i.e., laundry and dishes, being cleaned, so that the detergents are not capable of achieving their full cleaning capacities in the machines.

As a result, substances have been added to the highsudsing detergents and cleaning agents containing anionic wash-active substances of the sulfate or sulfonate type, which are designed to suppress the su-dsing or at least to keep it within tolerable limits. Non-ionic wash-active substances, such as the high-molecular ethers and esters of ethylene oxide and propylene oxide condensation prodacts, which have a relatively low sudsing capacity, have already been proposed as such additives. However, mixtures of such non-ionic tensides, anionic substances and washing alkalis still produce suds to a degree that they cannot be used in drum washing machines at temperatures above 60 C. It has also been proposed to add to the detergents and cleansing agents, alkali soaps of fatty acids, particularly those having a chain length of C to C as suds inhibiting agents. Although in some cases a very effective foam inhibition can be achieved with such substances, they are not universally applicable. When soft tap water having a hardness of 5 dH and less is used, the suds-suppressing action of the long-chain fatty acid soaps is inadequate. Furthermore, the suds reduction is limited to certain detergent combinations. For example, it has not been possible hitherto to reduce appreciably the sudsing action of the alkyl sulfates, and for this reason it has not been possible to use these substances (only to a slight extent if at all) in laundry and dishwater de- 3,422,020 Patented Jan. 14, 1969 tergents. Nevertheless, the use of alkyl sulfates merits special interest because of their good wash-active and physiological properties, as well as their easy biological degradability.

Foam inhibitors of various chemical constitution have also been proposed for use together with the active detergent substances. As yet, no substance has become known which in low concentration brings about an effective and lasting foam suppression, independently of the chemical constitution of the surface-active substance and the content of hardness forming agents in the water, without impairing the cleaning power of the detergent.

It is therefore an object of this invention to provide a detergent composition which is usable for machine washing of laundry and dishes over a broad temperature range and independent of the degree of hardness of the water.

It is another object of the invention to provide a suds inhibitor for use in detergent compositions.

It is still another object of the invention to provide a suds inhibitor for use in detergent compositions effective in low concentrations and independent of the nature of the surface-active component of the detergent and of the degree of hardness of the water.

It is a still further object of the invention to provide solid and liquid detergent compositions containing waterinsoluble melamine derivatives as suds inhibitors.

Other and additional objects of this invention will be apparent from a full consideration of this entire specification including the claims appended hereto.

In accordance with the invention, it has now been found that water-insoluble melamine derivatives of the general formula wherein R R and R each represents hydrogen or an organic radical containing 1 to 24 carbon atoms, and R R and R each represents an organic radical containing 1 to 24 carbon atoms, can be used as foam inhibitors for detergents and cleaning agents. The organic radicals suitably consist of straight or branched chain aliphatic, cycloaliphatic or aromatic hydrocarbons, and can contain hetero atoms such as nitrogen, oxygen or sulfur atoms, or additional substituents such as halogen atoms. They cannot, however, have any water-solubilizing groups.

The aliphatic radicals can be alkyl or alkylene groups, for example, methyl, ethyl, propyl, bu'tyl, hexyl, octyl, decyl, dodecyl, tetradecyl, hexadecyl, octadecyl, propylene, butylene, .decylene, octadecylene, etc. As cycloaliphatic radicals, the following may be mentioned: cyclohexyl, cyclohexenyl, alkyl-substituted cyclohexenyl, etc. Illustrative of aromatic and araliphatic hydrocarbon radicals within the scope of the invention are phenyl, naphthyl, diphenyl, alkylphenyl, in which the alkyl group contains from 1 to 20 carbon atoms. Exemplary instances of alkylphenyl include tolyl, Xylenyl, hexylphenyl, dodecylphenyl, etc.

Thereby in the melamine molecule the substituents can be the same or different, that is, the substituents can be entirely or partially aliphatic, cycloa'liphatic, aromatic or araliphatic. If the groups R -R contain hetero atoms, these can be in the form of amino, nitro, ether, ester, carbonyl, and thioether groups. The preparation of symmetrical and asymmetrical substituted melamine derivatives is described. in Journal of American Chemical Society, vol. 73 (1951), pp. 2981 to 2986; Journal of Organic Chemistry, vol. 26 (1961), pp. 2786 to 2789.

The aforesaid compounds which will be referred to hereinafter as melamine derivatives for the sake of brevity, can be produced in the known manner, as for example by the reaction of cyanuric acid chloride with a primary or secondary amine having the above-designated number of carbon atoms or with a mixture of such amines. As melamine derivatives having only shortchained substituents are not very effective, the two radicals on at least one of the amine nitrogen atoms should contain together at least 6 and preferably 8 to 20 carbon atoms.

Of particular practical importance in accordance with the invention are melamine derivatives in which R R and R each represents hydrogen; and R RyandR each represents straight-chain saturated or unsaturated hydrocarbons having a chain length of C to C and preferably C to C Such melamine derivatives are formed in the reaction of cyanuric acid chloride with a three molar quantity of alkylamines of the stated chain length. Alkylamines having-8 to 24 carbon atoms can be obtained, for example, in the prior art manner from naturally occurring fatty acid mixtures, such as coconut, palm nut and tallow fatty acids, rape-oil fatty acids and other fatty acids of vegetable or animal origin.

The foam retardant action of the melamine derivatives is greatly dependent on temperature. Depending on the structure of the radicals R to R it does not begin to be fully effective until above a certain temperature range corresponding approximately to the fusion point of the melamine derivative. Melamine derivatives in which the radicals R to R are unalike, that is, in which R to R consist of saturated or unsaturated alkyl radicals of different chain length, exhibit a wax-like behavior; they do not have a sharp fusion point and they soften or melt within a temperature range from about 5 to 40 C. The foam reduction produced by the melamine derivatives which are present in the solid state is less than that produced when they are used in the liquid or semisolid state. As the temperature increases, foam inhibition is increased to the extent that the initially solid melamine derivative softens or melts, reaching its full value as soon as the fusion point is exceeded.

The temperature range in which the melamine derivatives become effective increases with the number and chain length of the substituents. For the purposes of the invention, preference is given to melamine derivatives which at 100 C. are in the completely fused state. For this purpose, the total number of carbon atoms contained in the substituents R to R should not amount to more than 72, and preferably not more than 60.

By the selection of appropriate substituents or by mixing different melamine derivatives each of uniform structure, it is possible to a great extent to adapt the melting range to practical requirements, and with it the onset of a heavy breakdown of suds. For example, fine detergents which produce large quantities of suds are often desired because the suds interfere with the mechanical working of the goods, which in the case of delicate wool and silk fabrics may promote matting and similar deterioration. Mixtures that can be used equally as fine detergents and as boiling detergents are advantageously so adjusted that they foam moderately to well in the fine laundry range, i.e., at temperatures between 20 and 50 C., while at a high temperature, especially around 100 C., the suds formation is substantially suppressed. In such formulations, it is desirable to use for the suds regulation, melamine derivatives in which the radicals R R and R consist of hydrogen, and the radicals R R andR have an average alkyl chain length of C to C The softening or melting range of these melamine derivatives generally lies between 25 and 60 C.

A foam reduction that is substantially independent of temperature can be achieved on the one hand by the use of melamine derivatives having a 'very broad fusion range, but on the other hand also by combining two melamine derivatives one of which is of low molecular weight and melts at low temperature, while the other has long-chained substituents and melts at relatively high temperature. Melamine derivatives of low molecular Weight, e.tg., melting at 10 to 30 0., exhibit a decrease in their activity as soon as temperatures above 70 to C. are reached, while the high melting product, which is less active at lower temperatures, develops its full effect at the increased temperature.

The anti-foaming agents of the invention are suitable for use with many different kinds of anionic, ampholytic, cation-active and non-ionic wash-active substances. The anionic substances are exemplified by alkali soaps of fatty acids, and fatty -acid condensation products such as derivatives of aminocarboxylic acids; tensides of the sulfate or sulfonate type such as primary or secondary alkyl sulfates, fatty acid alkanolamide sulfates, fatty acid isothionates, fatty acid taurides, alkanesulfonates and olefin sulfonates, alkylbenzenesulfonates, alpha-sulfofatty acid esters, etc. The melamine derivatives are also effective in relation to ampholytes are exemplified by alkyl-betaines and alkylsulfobetaines, and in relation to cation-active tensides such as quaternary ammonium salts. Furthermore, they can be combined with non-ionic wash-active substances such as alkyl and acyl polyglycol ethers, al'kylphenol polyglycol ethers, fatty acid sugar esters, aminoxides, fatty acid alkanolamides and other fatty acid condensation products, as well as with saponines.

The detergents and cleaning agents containing the melamine derivatives can also contain the customary fillers and additives in addition to the above-named surface-active compounds. These include the wash alkalis and, in particular, the orthophosphates, pyrophosphates and more highly condensed phosphates as, for example, tetrasodium and tetrapotassium pyrophosphate, pentasodiumtriphosphate, pentapotassiumtriphosphate, sodiumtetrarnetaphosphate, sodium hexametaphosphate, etc., as well as mixtures thereof; silicates, carbonates, borates and hydroxides of alkalis; oxygen-yielding or active chlorine bleaches such as sodium perborate, hydrogen peroxide, carbamic peroxide, dichlorocyanuric acid, etc.; complex formers such as polyaminopolycarboxylic acids, as for instance ethylene diaminotetraacetic acid, nitriloacetic acid, etc.; stabilizers as for instance magnesium silicate and neutral salts. Other additives include dirt-dispersing agents, particularly cellulose derivatives such as cellulose glycolate, methyl cellulose and the like, and optical brighteners as well as perfumes and colorants. These additives have no substantial influence on the foam-suppressing action of the melamine derivatives.

The quantities of melamine derivatives to be used in the detergent or cleansing composition depends on the quantity of the surface-active or wash-active substance present, and on the magnitude of the effect desired. The concentrations that are important in practice range from 0.1 to no more than 20 percent of the weight of the wash-active substance. It is, of course, possible to use still greater amounts of the melamine derivative, as for example amounts of as much as 50% of the weight of wash-active substance for suppressing the sudsing action almost completely, but this is usually unnecessary with detergents.

The special advantage of the melamine derivatives is to be seen in the fact that, even in low concentration, they produce a considerable foam suppression with all of the known wash-active substances, both in hard and in soft water, without diminishing the washing action. It is of special importance in practice that in this manner controlled suds detergents for use in machine-washing and dish'washing detergents can be manufactured on the basis of fatty alcohol sulfates. Furthermore, the additives of the invention do not impair the pulverulent qualities of deter-gents, and can easily be incorporated into the detergent concentrates prepared by spray-drying or into prepared liquid detergents.

It is particularly advantageous to mix the melamine derivatives with the solid detergents or with a component thereof. This can be done, for example, by mixing the finely divided solid, or liquid, or fused melamine derivatives, or melamine derivatives dissolved in organic solwents, as the case may be, with the powdered or granulated detergent or a part thereof, such as the sodium perborate, or by spraying them onto same.

In accordance with the foregoing, the melamine derivatives contained in the detergent are present in a coarsely dispersed state and are found for the most part on the surface of the detergent components. Because of their Wax-like, plastic characteristics, the melamine derivatives are substantially agglomerated and fuse with the detergent components and thus no tendency toward decomposition.

It is also possible to provide that the melamine derivatives at least envelop the detergent components. Particularly those preferred detergents comprise oxygen-or active chlorine-containing bleaches, in which the powdered or granulated bleach particles, preferably sodium perborate, are covered by a coating of the claimed melamine derivatives. The coating of the detergent particles may be accomplished by the methods well known in the art, for example, by maintaining the detergent components in a state of constant movement in the conventional mixing, granulating or coating devices and simultaneously adding thereto and/or spraying thereon the melamine derivate in finely divided or fused form. If sodium perborates are employed, a melamine derivative coating will prevent the specifically heavier perborate body from separating and/or disintegrating from the specifically lighter particles of the detergent powder during packaging, storage or transport.

The melamine derivatives may also be used as a Waxlike coating on the detergent tablets, thus, simultaneously, protecting the tablets from untimely decomposition, as for example due to atmospheric variations.

In the following Examples 1 to 8 and 21, the sudsing action of solutions of detergent compositions in accordance with the invention was measured by the DIN method (DIN 53,902). This method makes it possible to establish the foam inhibiting action of the melamine derivatives herein taught. The foam volume was read 30 seconds after the beating machine had been shut off and was again read after 5 and minutes to determine the extent of the collapse of the foam. Instances in which the maximum readable foam volume of 590 ml. were observed are indicated in the tables by the abbreviation Gmax7 However, since with the above DIN method it is not possible to determine directly the performance of the washing solutions in closed drum washing machines at temperatures between 60 and 100 C., an apparatus was used in Examples 9 to which had been developed on the basis of the applicants experience with dishwashing and clothes-washing machines and which is capable of results closely approaching that in actual use of the conventional machines. The construction of the apparatus which will be referred to hereinafter as the foam tester, is now described.

It consists of a cylindrical vessel of high-grade steel having an inside diameter of 44 cm. and an inside depth of 85 cm., which is surrounded by a double jacket provided with an insulating material. The vessel is sealed with a lid containing a vent tube. About 5 cm. below the upper rim is an annular tube which is equipped with numerous downwardly directed outlet orifices, and which is connected by a supply line and a pump having a pumping capacity of about 160 to 180 liters per minute, with the bottom of the vessel. The depth of the foam can be observed by means of two oppositely located windows, the front one of which is graduated. The testing apparatus is furthermore equipped with an electrical heating element, stop-cocks for filling and emptying the vessel, a thermometer, and a thermostat for keeping the temperature constant.

The sudsin g test is carried out as follows:

34 liters of solution are introduced into the vessel and heated to the testing temperature. The suds are produced by 2 minutes of constant recirculation of the solution. Immediately thereafter the depth of the foam is read off. The maximum measurable suds depth is 590 mm., at which point the foam line reaches the tube. Any rise above this limit is also indicated in the following tables by the abbreviation max.

The following examples are set forth as illustrative of the instant invention and should be in no way construed as limitative of the scope thereof. In the examples, unless otherwise stated, the percentage figures are percentages by weight. The percentage amounts of melamine derivative refer to the total amount of powdered or liquid product used.

Example 1 (a) A solution having the following composition was made to foam at 60 C. by the DIN method:

1.5 g. n-dodecylbenzenesulfonate (sodium salt) 3.5 g. sodium sulfate 1 1. water TABLE I Ml. of foam volume aiter Water Hardness 30 see. 5 min. 10 min.

(a) 0 dH- max. max. 310 20 dH max. 590 540 (b) 0 dH 40 20 20 60 30 20 Example 2 Example 1 was repeated, but in place of the n-dodecylbenzenesulfonate, the same quantity of fatty alcohol sulfate (chain lengthC to C average chain length C was used. The results of these tests are set out in the following table:

TABLE II Ml. of foam volume after- Water Hardness 30 sec. 5 min. 10 min.

max. 590 500 max 590 500 50 20 100 60 20 Example 3 (a) 5 g. of the following detergent mixture were dissolved in one liter of water and foamed at 60 C. by the DIN method.

15% n-dodecylbenzenesulfonate (sodium salt) 3% fatty alcohol polyglycol ethers (alkyl chain length C to C l0 ethylene glycol groups) 1' 45% penta sodium triphosphate 1% carboxymethylcellulose (sodium salt) Remainder: sodium sulfate and water.

(b) The same experiment was repeated following the addition of 5% of the melamine derivative as set out in Example 1, [i.e., 5% of the detergent mixture consisted of the melamine derivative] The results are set out in the table which follows:

TABLE III Ml. of foam volume after- Water Hardness 30 see. 5 min. 10 mm.

Example 4 (a) A low-sudsing machine detergent having the following composition was foamed by the DIN method at 60 C. (concentration 5 g./l.):

7.5% n-dodecylbenzenesulfonate (sodium salt) 7.5% soap (sodium salt) 5.0% fatty alcohol polyglycol ethers (l0 ethylene glycol groups) 1.5% carboxymethylcellulose (sodium salt) 40% penta sodium triphosphate Remainder: silicates, perborate and water.

(b) 5% of the melamine derivative used in Example 1 was added to the above mixture and foaming produced as in (a). The results are set out in the following table:

TABLE IV M1. of foam volume after- Water Hardness 30 sec. 5 mm. mm.

(a) 0 dH 530 520 430 20 ML 80 50 40 (b) 0 (191.. 10 0 0 The data show that the anti-foaming agent based on soap and polyglycolether was effective only in hard water, While the melamine derivative completely suppressed the foam in both hard water and soft water.

Example 5 (a) A solution of 5 g. of saponin per liter of water dH) was treated at 60 C. by the DIN method.

(b) The same experiment was repeated but with the addition of 0.5 gram per liter of the melamine derivative of Example 1. The results are set out in the following table:

TABLE v M1. of foam volume after- 30 sec. 5 min. 10 min.

(b) The experiment was repeated following the addition of 0.5 g./l. of the melamine derivative used in Example 1.

The results are set out in the following table:

TABLE VI Ml. of foam volume after- Water Hardness 30 sec 5 min. 10 min.

20 dH max. max. 320 (b) 0 (1H. 140 110 00 Example 7 (a) Solutions containing 5 g./l. of cation active tensides were foamed at 60 C. by the DIN method and the foam depth was read after 30 seconds.

(b) The same experiment was repeated following addition of 0.5 g./l. of the antifoaming agent described in Example 1 to the solutions.

The results are set out in Table VII which follows:

TABLE VII M1. of foam volume after 30 seconds 0 (Hi 20 dH Alkyldimethylbenzylammonium chloride (Alkyl==0s to C18):

Example 8 A boiling detergent having the following composition:

12l4% n-dodecylbenzenesulfonate (sodium salt) 34% oleyl alcohol polyglycol ether (10 ethylene glycol groups) 40-45% pentasodium triphosphate 56%sodium silicate (Na O-3.3 SiO 3% magnesium silicate 0.51.5% carboxymethyl cellulose (sodium salt) 14-16% sodium perborate Remainder: Neutral salts, optical brighteners, perfumes,

water,

was found to form excessive suds at temperatures above 40 C., in experiments carried out in the above-described suds testing apparatus. It therefore was unsuitable for drum-type washing machines. When 0.5 to 7.5 Wt. percent of the melamine derivative described in Example 1 was added to the above mixture, a controlled-suds machine detergent was obtained which did not form excessive suds in hard or in soft water.

When used in a concentration of 5 g./ 1., in hard and soft water (0 and 15 dH), it had the following foam characteristics at the various temperatures shown:

TABLE VIII Depth of suds in mm. Percentage added 19 C. 38 C. 58 C. 76 C. 93 C 97 C.

275 475 max. max. max max. 280 360 560 480 280 270 235 365 420 315 175 140 220 380 160 60 30 10 210 340 60 30 10 220 245 40 35 15 5 Example 9 Example 8 was repeated, but in place of the alkylbenzenesulfonate used in that example the same amount of a sodium fatty alcohol sulfate (alkyl chain length C to C was used. In water of 15 dH, the following sudsing characteristic was found:

TABLE IX Depth of suds in mm. Percentage added 19 C. 38 C. 58 C. 76 C. 93 C. 975 C.

No e 310 470 max max max. max.

. Example 10 A detergent as described in Example 8 but in which the alkylbenzenesulfonate had been replaced by salts of a-sulfo fatty acid esters-that is, the detergent contained 8% of a sodium salt of an a-sulfo-fatty acid methyl ester prepared from hydrogenated palm kernel fatty acid, and

5.5% of a sodium salt of an ot-sulfo-stearic acid methyl ester-was tested.

The following sudsing characteristics were determined using the suds testing apparatus above described and using the melamine derivative described in Example 1 (15 dH):

TABLE X Percentage Depth of suds in mm.

added 19 C. 38 0. 58 C. 76 C. 93 C. 97.5 C.

A suds depth of to mm. is within the margin of reading error.

Example 11 TABLE XI Percentage Depth of suds in mm.

added 19 C. 38 C. 58 C. 76 C. 93 C. 97.5 0.

None 280 390 420 380 330 315 1.0% 250 330 85 65 60 50 Example 12 If the alkylbenzenesulfonate of Example 8 was replaced with the same amount of oleylmethyltauride sodium salt, the following sudsing characteristics were found in water having a dH:

A liquid detergent having the following composition:

% N-alkyl-N-fl-oxethyl-aminoethanesulfonic acid sodium (alkyl chain length C to C 23% pentapotassium triphosphate Remainder: water produced the following suds depths in the suds tester in water of 15 dH at a concentration of 5 g./-l. when tested with and without the addition of the melamine derivative used in Example 1:

TABLE XIII Suds depth in mm.

Percentage added 19 C. 39 C. 58 C. 76 C. 90 C. 97 C.

None 305 500 max. max. max. max. 5.0% 235 330 50 35 30 Example 14 A fine detergent on a non-ionogenic tenside basis, having the following composition:

15% fatty alcohol polyglycol ethers (alkyl chain length C to C 8.7 ethylene glycol groups) pentasodium triphosphate 20% sodium perborate 30% sodium sulfate was prepared with and without the addition of the melamine derivative used in Example 1 and exhibited the following sudsing characteristics in the suds testing apparatus in water of 15 dH and in a concentration of 5 g./l.

TABLE XIV Percentage Suds depth in mm.

added 17 C. 40 C. 59 C. 76.5 0. 925 C. 975 C.

None 170 280 *340 20 15 10 1.0% .2 5 10 50 10 5 5 5.0% 10 0 0 0 0 0 *Suds breakdown due to exceeding the dehydration temperature of the polyglycol ether.

Example 15 Ethoxylated nonylphenol (20 ethylene glycol groups; dehydration temperature 100 C.) in a concentration of 2 g./l. with and without the melamine derivative of Example 1 exhibited the following sudsing characteristics in the suds testing apparatus in water of 15 dH;

TABLE XV Suds depth in mm. Percentage added 17 C. 385 C. 59C. 78 C. 92 C. 98 C.

Example 16 One-half of the dodecylbenzenesulfonate in the detergent composition of Example 8 was replaced with the sodium salt of a tallow fatty alcohol sulfate having a chain length of C to C In addition to the melamine derivative used in Example 1 (average carbon number in the side chains=C a melamine derivative with an average carbon number of C which had been prepared in a similar manner by the reaction of cyanuric chloride with alkylamines from tallow fatty acids and had a melting range of 30 to 70 C., was also used as an antifoaming agent. The following sudsing characteristics were observed in the suds testing apparatus in Water of 15 TABLE XVI Percentage Foam depth in min.

added None 250 360 max. max. max. max. C17 135 100 260 300 300 300 1% 013....-- 145 125 230 235 235 340 Example 17 A melamine derivative was employed, which had been made by the reaction of 1 mol of cyanuric acid chloride with 3 mols of a mixture of alkylamines having a chain length of C to C (average chain length C The sudsing characteristics were determined using the above described suds tester and water of 0 and 15 dH.

I. designates a detergent according to Example 8.

II. designates a detergent according to Example 9.

These detergents were used in a concentration of 5 g./1.

TABLE XVII Percentage added Suds depth in mm.

40 C. 59 C. 76 C. 92 C. 98 C.

475 max. max. max. max. 260 360 70 20 15 475 max. max. max. max. 50 40 40 Example 18 A melamine derivative in which the radicals R to R consisted of n-butyl groups, when combined with a deter- 1 1 gent according to Example 8, had the following sudsing characteristics in water of and 15 dH (concentration used g./l.):

ing sudsing action when combined with a detergent according to Example 9 (concentration used 5 g./l.; dH):

TABLE XIX Suds depth in nun. Per eentage added 16 C. 39 C. 59 C. 77 C. 93 C. 98 C.

None 310 470 max. max. max. max. 5% 200 370 400 200 180 80 Example 20 A melamine derivative produced from 1 mol of cyanuric acid chloride, 1 mol of benzylamine and 2 mols of alkylamine having a chain length of C to C (average C exhibited the following sudsing charatceristics when used in combination with a detergent according to EX- ample 9 (concentration used 5 g./ 1.; 15 dH):

TABLE XX Percentage Suds Depth in mm.

added 10 C. 39 C. 59 0. 77 C. 03 C. 98 0.

None 310 470 max. max. max. max. 5% 150 370 520 540 380 270 Example 21 A melamine derivative was used, in which R R and R each was represented by hydrogen, and R and R were each represented by alkyl chains having 12 to 18 15 carbon atoms, and R was a radical of the formula:

The sudsing characteristics were determined by the DIN method at C. in water of 0 dH. Detergent I was a detergent according to Example 8, and detergent II a 55 detergent according to Example 9. A concentration of 5 grams per liter was used in each instance.

TABLE XXI laundry (table linens and underclothing) and 20 liters of washing solution. The detergent contained:

Percent Sodium-n-dodecylbenzenesulfonate 7.5 Sodium fatty alcohol sulfate (Cm-C18) 7.5 Oleyl alcohol polyglycol ether (10 ethylene glycol groups) 3 5 Sodium silicate (Na O-3.3SiO 5 Magnesium silicate 3 Carboxymethylcellulose (sodium salt) 1 Foam inhibitor 2.6 Water 7.5 Neutral salts, optical brighteners, perfumes 2.4

The detergent had been prepared by spray drying a concentrate containing about 45% water. Thereafter, 15% sodium perborate tetrahydrate was added with mixing. The following were used as foam inhibitors:

(a) 2.6% of a melamine derivative according to Example 16 (R R R =hydrogen, R R and R =alkyl C C melting range 25 to 36 C.)

(b) 2.6% of a melamine derivative according to Example 17 (R R R hydrogen, R R and R alkyl C C melting range 30 to C.)

(c) 2.6% of a mixture of equal parts of a and b.

The items to be laundered were first given a preliminary washing at a temperature of 20 to 30 C. using a detergent concentration of 5 g./l., then the water was pumped out and the goods were washed with a new formulation at a temperature of 98 C. and a detergent concentration of 7 .5 g./l.

While the detergent without inhibitor over-sudsed in all temperature ranges, the detergent containing inhibitor showed the following suds depths:

TABLE XXII Suds Depth in mm.

25 0 30 0. 40 0. 50 0. 00 0. 0. as" o.

(a) 45 05 s0 s0 so 100 (b) 100 so 70 so 70 (c) 70 80 00 85 50 00 75 In test a, the detergent produced less suds in the fine laundering range and more in the boiling laundry range,

while its behavior is the opposite in test b. The detergent used in b would consequently be a universal detergent capable of producing much suds at low temperatures and little, if any, suds at high temperatures. Test 0 indicates a sudsing action that is largely independent of the temperature.

Example 23 A detergent according to Example 22 and a foam inhibitor according to Example 220 were used in this experiment. In this case, however, the foam inhibitor was not mixed into the liquid detergent mixture and then spray-dried to form a concentrate, but was sprayed in the fused state onto the dry sodium perborate and toga g ML of mm after 60 gether with the latter was mixed into the washing powder. 30sec. 5min. 10 min The sudsing action was tested as described in Example max 560 400 22 in a drum washing machine containing dirty laundry. 130 80 40 The results are summarized in the following table. The 3 2% 28 results of Example 220 have been included for com 110 100 80 65 parrson:

TABLE XXIII Example 22 P Suds Depth in mm.

- o o s a o o The following experiments were carried out in a fully Inlulntor 25 o. 30 o. 40 o. 50 o. 00 0. s0 0. 9s 0. automatic household washing machine having a 1'1011- 0 0 0 0 0 0 0 m o 11 mounted drum and viewin window Model: 23(b)17 00 70 00 so 60 70 80 Z nta y g axe-2.0%... 70 80 00 85 50 60 75 MIELE Automatic 410). A scale was mounted on the viewing window with divisions in millimeters to indicate the depth of suds; the depth to the overflow amounted to mm. The machine was filled with 4 kg. of dirty 75 The melamine derivative added after spray-drying demonstrates a considerably augmented effect.

The composition of the detergents in which the foam inhibitors of the invention preferentially find use can vary within wide limits. For example, solid or powdered, lowsudsing detergents suitably contain the following as principal components:

5-60% anion-active, ampholytic or non-ionic wash-active substances and mixtures thereof;

0.1-10% melamine derivative 90% inorganic wash-active salts, such as for example anhydrous phosphates, alkali silicates and alkali carbonates;

0-25% per compounds;

0.1% dispersing agents of high molecular weight such as carboxymethylcellulose;

01% colorants and perfumes as well as optical brighteners;

also stabilizing agents for percompounds, inorganic neutral salts and moisture.

Liquid detergents suitably contain:

5-50% anionic, ampholytic or non-ionic wash-active substances and mixtures thereof;

0.1-% melamine derivative;

045% anhydrous phosphates, preferably as potassium salts;

0-l0% solubilizers, preferably alkylbenzenesulfonates having lower alkyl groups;

O 1% colorants and perfumes, and optical brighteners;

also water, and if desired, organic solvents.

The action of the melamine derivatives, however, is not limited to the detergent compositions and quantity ratios stated above and in the examples.

We claim:

1. A low sudsing detergent consisting essentially of at least one wash-active agent selected from the group consisting of anionic, ampholytic, cation-active and non-ionic wash-active substances and 0.1 to referred to the weight of the wash active agent of a water-insoluble melamine derivative of the formula:

Bk N\ /Rs N-C C-N Rz I H \R4 0 Rs-F-Rg wherein R R and R each represents a member selected from the group consisting of hydrogen and organic radicals containing 1 to 24 carbon atoms, and R R and R each represents an organic radical containing 1 to 24 carbon atoms wherein at least one of the groups of R plus R R plus R and R plus R contains a total of at least 6 carbon atoms and wherein the total number of carbon atoms contained in said groups R R does not exceed 72, said organic radicals R R being free of any water-solubilizing groups.

2. A low sudsing detergent according to claim 1 wherein at least one of the group of R plus R R plus R and R plus R contains from 8 to 20 carbon atoms.

3. A low sudsing detergent according to claim 1 wherein R R and R each represents hydrogen and R R and R each represents a hydrocarbon group containing 4 to 24 carbon atoms.

4. A low sudsing detergent according to claim 1 wherein R R and R each represents hydrogen am R R and R each represents a hydrocarbon group containing 8 to 20 carbon atoms.

5. A low sudsing detergent according to claim 1 wherein R R and R each represents hydrogen and R R and R each represents a hydrocarbon group containing 10 to 16 carbon atoms.

6. A low sudsing detergent according to claim 1 wherein the total number of carbon atoms contained in said substituents R -R does not exceed 60.

7. A low sudsing detergent according to claim 1 wherein said water-insoluble melamine derivative is present in an amount of from 0.1 to 10% referred to the weight of the wash-active agent.

8. A low sudsing detergent according to claim 1 wherein said water-insoluble melamine derivative is present in a coarsely dispersed state at least in part afiixed on the surface of said wash-active agent.

9. A low sudsing detergent according to claim 1 containing sodium perborate wherein said sodium perborate is covered with a coating comprising said water-insoluble melamine derivative.

10. A low sudsing detergent according to claim 1 wherein said wash-active agent is present in tablet form, said tablet being covered with a coating comprising said waterinsoluble melamine derivative.

11. A low sudsing detergent according to claim 1 consisting essentially of 5-60% wash-active agent selected from the group consisting of anionic, ampholytic, cation-active and nonionic wash-active substances,

0.140% water-insoluble melamine derivative of the wherein R R and R each represents a member selected from the group consisting of hydrogen and organic radicals containing 1 to 24 carbon atoms, and R R and R each represents an organic radical containing 1 to 24 carbon atoms,

O% inorganic alkaline salt 0-25% per compound 0.1-5% dispersing agent 01% of at least one member selected from the group consisting of colorants, perfumes, and optical brighteners in solid form.

12. A low sudsing detergent according to claim 1 wherein said wash-active agent is present in pulverulent form at least a part thereof being coated with said waterinsoluble melamine derivative.

13. A low sudsing detergent according to claim 1 consisting essentially of water and 550% wash-active agent selected from the group consisting of anionic, ampholytic, cation-active and nonionic wash-active substances,

0.1-10% water-insoluble melamine derivative of the wherein R R and R each represents a member selected from the group consisting of hydrogen and organic radicals containing 1 to 24 carbon atoms, and R R and R each represents an organic radical containing 1 to 24 carbon atoms,

035% anhydrous phosphates 0l0% solubilizer 0-1% of at least one member selected from the group consisting of colourants, perfumes, and optical brighteners. 14. A low sudsing detergent according to claim 1 consisting essentially of 15 16 12-14% n-dodecylbenzem: sulfonate (sodium salt) 5 References Cited 3;Z;up:;Cyl alcohol polyglycolether (10 ethylene UNITED STATES PATENTS 40 45% pentasodium triphosphate 3,318,817 5/ 1967 Cunningham 252-437 5 Sodium Silicate (Na2)'3 3 sioz) 5 3,336,231 8/1967 Marsh et al 202 102 3% magnesium silicate O N PATENTS 0.5-1.5 carboxymethyl cellulose (sodium salt) 1,124,956 8/1959 Germany.

1416% sodium perborate 0.5-7.5 wt. percent of said water-insoluble melamine MAYER WEINBLATT, P i E ine derivative wherein R R and R are each hydrogen 10 and R R and R each has a chain length of from Us CL 12 to 18 carbon atoms- 252-95, 102, 110, 117, 137, 152; 260249.6

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,422,020 January 14, 1969 Edmund Schmadel et a1.

It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below: In the heading to the printed specification, line 8, after "Germany," insert Feb. 11, 1965, H 55,120; Column 10, TABLE XVI, first column, line 2 thereof, "C should read l% C Column 14, line 43, cancel "in solid form." and insert the same between lines 43 and 44, at the left-hand margin, same column 14.

Signed and sealed this 17th day of March 1970.

(SEAL) Attest:

Edward M. Fletcher, Jr. WILLIAM E. SCHUYLER, JR.

Attesting Officer Commissioner of Patents