US3629122A - Low-foaming rinsing and washing agents for dish washers - Google Patents

Abstract

LOW-FORMING RINSING AND WASHING COMPOSITIONS ADAPTED FOR DISH WASHERS CONSISTING ESSENTIALLY OF (A) FROM 70% TO 98% BY WEIGHT OF WATER-SOLUBLE POLYVINYL ALCOHOLS HAVING A MOLECULAR WEIGHT OF BETWEEN 1000 AND 4000, AND (B) FROM 2% TO 30% BY WEIGHT OF FOAM-INHIBITING COMPOUNDS SELECTED FROM THE GROUP CONSISTING OF ALIPHATIC ALCOHOLS, ALIPHATIC CARBOXYLIC ACIDS ARE ALKALI METAL SALTS THEREOF, ALIPHATIC CARBOXYLIC ACID AMIDES AND ALIPHATIC AMINES, SAID COMPOUNDS HAVING AT LEAST ONE ALIPHATIC OR ALIPHATIC-CYCLOALIPHATIC RADICAL WITH FROM 8 TO 22 CARBON ATOMS, AS WELL AS AQUEOUS SOLUTIONS CONTAINING SAID LOWFOAMING RINSING AND WASHING COMPOSITONS.

Description

United States Patent 3,629,122 LOW-FOAMING RINSING AND WASHING AGENTS FOR DISH WASHERS Giinter Jakobi, Hilden, Rhineland, Germany, assignor to Henkel & Cie G.m.b.H., Dusseldorf, Germany No Drawing. Filed Feb. 17, 1969, Ser. No. 799,932 Claims priority, application Germany, May 4, 1968,

P 17 67 384.6 Int. Cl. C11d N00 US. Cl. 252-89 8 Claims ABSTRACT OF THE DISCLOSURE Low-foaming rinsing and washing compositions adapted for dish washers consisting essentially of (A) from 70% to 98% by weight of water-soluble polyvinyl alcohols having a molecular weight of between 1000 and 4000, and (B) from 2% to 30% by weight of foam-inhibiting compounds selected from the group consisting of aliphatic alcohols, aliphatic carboxylic acids and alkali metal salts thereof, aliphatic carboxylic acid amides and aliphatic amines, said compounds having at least one aliphatic or aliphatic-cycloaliphatic radical with from 8 to 2.2 carbon atoms, as well as aqueous solutions containing said lowfoaming rinsing and washing compositions.

THE PRIOR ART In an increasing measure, mechanical washing methods are being employed to wash china, glass, porcelain, ceramic, metal and synthetic articles. Detergents containing specific surface-active compounds are generally utilized. These detergents should be low foaming so that they do not affect the function of the Washing apparatus. A foam formation of too large a volume, caused and increased by the vigorous motion of the bath in the machine, leads to considerable trouble, as the foam mass decreases the mechanical efiect of the liquid sprayed onto the articles to be cleaned, and furthermore may cause the bath in the machine to run over.

Recently, developments in washing apparatus have been directed toward further increasing the intensity of the liquor motion as well as the water volume cycled per minute, and in this way to further improve the mechanical cleansing effect. As a result of such developments, it was found that conventional washing agents, such as higher molecular weight sulfates or sulfonates, caused too much foam. For this reason, in practice, nonionic surface-active agents such as ethylene oxide addition products to alkylphenols or polypropylene glycols, have been preferred. These products, as well, were found to have a relatively high foaming tendency in the ranges of concentration required for satisfactory wetting and cleansing effect when used in the modern dish washing machines.

It has also been suggested to utilize combinations of effective wetting agents of the known type of ethylene oxide addition products, with foam-inhibiting agents, such as ethylene oxide-propylene oxide mixed adducts with fatty alcohols or alkylphenols. However, such combinations require relatively large additions of the foam inhibitors in order to decrease, to a reasonable extent, the tendency of the combination to foam.

A further considerable disadvantage of the named alkylene oxide addition products is that they are not biologically decomposed to a sufficient extent. For this reason, they often play a part in the formation of foam on sluices, dams and overflows. Furthermore, such products often exhibit, even in small amounts of only a few mg./ 1., a distinct toxicity toward fish and other water organisms.

Patented Dec. 21, 1971 Thus, they can represent a considerable and undesired burden on waste waters and their treatment.

In my copending US. patent application S.N. 799,933, filed concurrently herewith, I have described and claimed highly effective and extremely low-foaming combinations of detergents adapted to dish washers which, thanks to their biological harmlessness, do not cause any waste water problems. These washing and cleansing compositions are characterized by a content of:

(A) 70% to 98% by weight of water-soluble polyvinylalcohols having molecular weights of from 1000' to 4000, and

(B) 2% to 30% by weight of interface active compounds containing polyoxypropylene radicals and/ or polyoxybutylene radicals with 2 to oxypropylene or oxybutylene units and preferably a further content of oxyethylene radicals or polyoxyethylene radicals, where the portion of oxypropylene or oxybutylene units in the total number of the oxyalkylene units amounts to at least 30% by mol.

OBJECTS OF THE INVENTION An object of the invention is the obtention of highly effective and extremely low-foaming dish and general purpose detergent combinations for dish washers which do not cause any waste water problems due to their biological harmlessness.

A further object is the obtention of low-foaming rinsing and washing compositions adapted for dish washers consisting essentially of (A) from 70% to 98% by weight of water-soluble polyvinyl alcohols having a molecular weight of between 1000 and 4000, and (B) from 2% to 30% by weight of foam inhibiting compounds selected from the group consisting of compounds of the formula wherein R is a member having from 8 to 22 carbon atoms selected from the group consisting of alkyl, alkenyl, alkadienyl, hydroxyalkenyl and alkylcycloalkyl; R is an alkyl having from l8 to 22 carbon atoms; R; and R are members selected from the group consisting of hydrogen and lower alkyl; and Me is an alkali metal.

Another object of the invention is the obtention of aqueous solutions of the above low-foaming rinsing and washing compositions.

A yet further object of the invention is the development of a method of washing and rinsing solid articles which comprises forcefully contacting said solid articles with water containing from 0.01 to 0.5 gram per liter of the above low-foaming rinsing and washing compositions.

These and other objects of the invention will become more apparent as the description thereof proceeds.

DESCRIPTION OF THE INVENTION Accordingly, the present invention relates to lowfoaming rinsing and washing compositions adapted for dish washers based on polyvinylalcohol and foam-suppressing agents, which is distinguished by a good compatibility with waste waters and harmlessness against fish and other water organisms.

In particular, these compositions are characterized by a content of (A) from 70% to 98% by weight of watersoluble polyvinylalcohols having a molecular weight of between 1000 and 4000, and (B) from 2% to 30% by weight of foam-inhibiting compounds selected from the group consisting of aliphatic alcohols, aliphatic carboxylic acids and alkali metal salts thereof, aliphatic carboxylic acid amides and aliphatic amines, said compounds having at least one aliphatic or aliphatic-cycloaliphatic radical with from 8 to 22 carbon atoms.

The claimed combination is extraordinarily low foaming even under extreme application conditions, both in household dish washers as well as in commercial dish washers. As a result of the high content of polyvinylalcohol, the compositions of the invention possess an excellent wetting effect with respect to hard surfaces such as porcelain. synthetics or metals. The combinations of the invention are particularly suitable as low-foaming, clear rinsing agents for dishes and silverware of all kinds, possibly with a preceding alkaline pre-washing phase, as well as for washing and clear rinsing of alkaline-sensitive glassware such as drinking glasses and other glassware. An exceptional run off of the rinsing water is obtained, resulting in shining, spot-free articles.

The special advantage of the combinations of the invention with respect to known low-foaming rinsing agents is that the requirement for non-toxicity with respect to fish and other water organisms is met to a satisfactory degree. Although polyvinylalcohol used as the component A is only slightly biologically decomposed, it can yet be considered as physiologically harmless since it does not exhibit any toxic properties, whatsoever, toward those organisms which live in water.

Generally, the biological decomposition of the foam inhibitors of type B is relatively good. Due to the fact that in practice the portion of component B of the mix- I ture is always relatively small, no disturbing burdens on the waste water are to be anticipated, even in cases where the biological decomposability is less due to the use of branched chain radicals or the like.

The water-soluble polyvinylalcohols having a molecular weight of between 1000 and 4000 used as component A are known products and are used in the trade. They can be obtained, for instance, by means of hydrolysis of polyvinyl acetates of the corresponding degree of polymerization. Within the framework of this invention such watersoluble polyvinylalcohols are preferred which have a hydrolysis degree of 85% to 90% and have molecular weights of approximately 1000 to 3000.

As compounds of group B, are, above all, saturated or unsaturated fatty alcohols with 10 to 18 carbon atoms. Particularly useful are compounds of the formula R-OH wherein R is a member having 8 to 22 carbon atoms selected from the group consisting of alkyl, alkenyl, alkadienyl, hydroxyalkenyl and alkylcycloalkyl. Employed in practice are above all mixtures of such fatty alcohols as are obtained from natural fats and oils. Examples for suitable fatty alcohols are dodecyl alcohol, hexadecyl alcohol, tallow alcohol mixtures of the chain length C to C coconut fatty alcohol mixtures of the chain length C to C and the like. In lieu of the natural fatty alcohols, alcohols of a corresponding chain length can be employed as well which are obtained through synthetic methods, as, or example, according to the Ziegler method. Furthermore, branched chain alcohols with up to 22 carbon atoms can be utilized as can be obtained through the oxo-synthesis or through the Guerbet reaction.

Other suitable compounds of group B are fatty acids with a chain length of C to C Particularly useful are compounds of the formula RCOOH and R'COOMe wherein R is a member having 8 to 2.. carbon atoms selected from the group consisting of alkyl, alkenyl, alkadienyl, hydroxalkenyl and alkylcycloalkyl; R is an alkyl having from 18 to 22 carbon atoms; and Me is an alkali metal. Here too, such fatty acids or fatty acid mixtures are preferred which have been obtained from natural fats and oils as, for instance, from fatty acid mixtures obtained from coconut fats of the chain length C to C or C to C oleic acid, behenic acid as well as preliminary faction fatty acids containing larger amounts of fatty acids of the chain length C to C Fatty acids containing more than 18 carbon atoms can be employed in form of their alkali metal salts as well.

Finally, fatty acid amides or fatty amines of the chain length C to C come also into consideration as foam inhibitors such as, for instance, tallow fatty acid-N,N- diethylamide, dodecylamine, the tallow amine mixture prepared from tallow fatty acids of the chain length C to C13, Ctc.

The individual components in the low-foaming rinsing agents of the invention amount to approximately to 98% by weight of component A and 2% to 30% by weight of component B. In practice it was, in particular, that mixtures from to by weight of component A and 5% to 15% by weight of component B are particularly suitable.

When the mixtures are used for the washing of dishes, particularly of drinking glasses, concentrations of approximately 0.05 to 0.5 gm./liter, preferably 0.1 to 0.4 gm./ liter in the cleaning fluid are required. If employed as rinsing agent subsequent to an alkaline washing phase, approximately 0.01 to 0.25 gm./liter, preferably 0.02 to 0.1 gm./liter are used. To a certain degree the concentrations are dependent upon the hardness of the water and the type of dishes. When washing or rinsing, utilizing hard and salty waters, or with plastic dishes, greater amounts of the rinsing agents are required.

Usefully, the compositions of the invention are prepared in the form of aqueous concentrates with a content of approximately 10% to 30% by weight of mixtures of components A and B. By variation of the amount of the components, the concentrates can be adjusted in such way that they possess a good temperature stability and do not tend to precipitate or separate into layers. Usefully, the concentrates are added into the washing and rinsing solution in the dish washing machines by means of an automatic dosing device as is common for such purposes.

The following specific embodiments of the invention are illustrative thereof. It is obvious, however, that other expedients may be employed and the specific embodiments are not to be deemed limitative in any manner.

EXAMPLES The foam behavior of different cleansing and rinsing admixtures was examined for comparison purposes in a special foam examination apparatus. The following table exhibits the extremely good foam behavior of the compositions of the invention.

The foam apparatus, as used, was constructed in similar manner as a modern dishwasher operating according to the jet spray system. By means of a pump about liters of water per minute were rotated and sprayed into the metering chamber by means of a rotating spray-arm provided with nozzles. Foam heads from 0 to 280 mm. may be measured in reproducible manner, whereas larger foam volumes can no longer be measured accurately, and, therefore, they are indicated in the table as 280. The liquor temperature during the tests was 50 C., the hardness of the water used was 16 dH and the duration of the foam test lasted 5 minutes. The reading of the foam height was done immediately after the machine came to a standstill and 30 seconds after the machine had come to a stop.

The foam apparatus is described in Fette, Seifen, Anstrichmittel." 66 I964], page 529.

The letters A and B in the following table represent the components in accordance with the preceding.

TABLE Foam height in mm.

30 sec.

Conc. On after Example Composition of mixture gm./liter standstill standstill 1o A. Polyvinylalcohol (viscosity of a 4% solution at 20 0., 3 cp., 0.12 280 280 hydrolysis degree: 88%).

1b {1L Polyvinyl alcohol (corresponding to la) 0. 12 15 B. Dodecyl alcohol 0.009

, {A Polyvinylalcohol (corresponding to la) 0.12 20 0 B. Hexadecylalcohol- 0.009

3 g A. Polyvinylalcohol (corresponding to la) 0.12 25 B. Dodecylamine... 0.02

4 A. Polyvinylalcohol (corresponding to la) 0.12 1o 0 '18. Sodium behenate 0.009

5 A. Polyvinylalcohol (corresponding to la) 0.12 0

"""""" "t B. Tallow fatty acidN,N-diethylamide.. 0.009

EXAMPLE 6 A liquid rinsing agent suitable for commercial dish washers had the following composition:

Percent Polyvinylalcohol (viscosity of a 4% solution at 20 C., 3 cp., hydrolysis degree: 88%) 20.0 Dodecyl alcohol 0.7 Water 79.3

At application temperatures of between 50 C. and 90 C., the product developed practically no foam. Subsequent to the alkaline main washing of the dishes, the above aqueous concentrate was dosed into the rinsing water in concentrations of 0.4 to 0.6 gm./liter. Spot-free, shining dishes were obtained.

EXAMPLE 7 An extremely low-foaming detergent for household dish washers had the following composition:

Percent Polyvinylalcohol (viscosity of a 4% solution at 20 C., cp., hydrolysis degree: 86%) 10.0 Sodium behenate 0.6

Water 89.4

At application concentrations of 0.5 to 1.5 gm./liter, an unobjectionable cleaning and clear drying eifect was obtained.

The preceding specific embodiments are illustrative of the practice of the invention. It is obvious, however, that other expedients known to those skilled in the art may be employed without departing from the spirit of the invention.

I claim:

1. Low-foaming rinsing and washing compositions adapted for dish washers consisting essentially of (A) from 70% to 98% by weight of water-soluble polyvinyl alcohols obtained by hydrolysis of polyvinyl acetates, having a hydrolysis degree of between 85% and 90% and having a molecular weight of between 1000 and 4000, and (B) from 2% to 30% by weight of foaminhibiting compounds selected from the group consisting of compounds of the formula wherein R is a member having from 8 to 22 carbon atoms selected from the group consisting of alkyl, alkenyl, alkadienyl, hydroxyalkenyl and alkylcycloalkyl; R is an alkyl having from 18 to 22 carbon atoms; R and R are members selected from the group consisting of hydrogen and lower alkyl; and Me is an alkali metal.

2. The low-foaming rinsing and washing compositions of claim 1 wherein said water-soluble polyvinyl-alcohols of component A are polyvinyl-alcohols having a molecular weight of between 1000 and 3000.

3. The low-foaming rinsing and washing composition of claim 1 wherein said component B is an alcohol having from 10 to 18 carbon atoms and having the formula wherein R is a member selected from the group consisting of alkyl, alkenyl, alkadienyl, hydroxyalkenyl, and mixtures thereof.

4. The low-foaming rinsing and washing composition of claim 1 wherein said component B is an acid compound selected from the group consisting of fatty acids having from 8 to 22 carbon atoms and alkali metal salts of fatty acids having from 18 to 22 carbon atoms.

5. The low-foaming rinsing and washing composition of claim 1 wherein said component B is a tallow fatty acid-N,N-diethylamide.

6. The low-foaming rinsing and washing compositions of claim 1 wherein said component A is present in an amount of from to 98% by weight and said component B is present in an amount of from 2% to 15% by weight.

7. Aqueous concentrates containing from 10% to 30% by weight of the low-foaming rinsing and washing compositions of claim 1.

8. The method of Washing and rinsing solid articles which comprises forcefully contacting said solid articles with water containing from 0.01 to 0.5 gram per liter of the low-foaming rinsing and washing compositions of claim 1.

References Cited UNITED STATES PATENTS 2,854,417 9/1958 Edwards et a1. 252-321 2,954,347 9/1960 St. John et a1 25232l 3,235,505 2/1966 Tuvell 252-89 POLY 3,254,028 5/1966 Wixon 25289 POLY DIG OTHER REFERENCES Biehn et al.: Polyvinyl Alcohol as an Emulsifying Agent, Industrial and Eng. Chem., August 1948, pp. 1449-1453.

Ross: Chem. Anti-Foaming Agents, May 1949, Chem. Industries, pp. 757-759.

Rose: Cond. Chem. Dict., 6th ed., 1960, p. 1098, Reinhold Publ. Co.

LEON D. ROSDOL, Primary Examiner W. E. SCHULTZ, Assistant Examiner US. Cl. X.R.

252l08, 152, 321, DIGEST2