US3408300A - Stable,alkaline,non-forming cleansing agents - Google Patents

Description

United States Patent 3,408,300 STABLE, ALKALINE, NON-FORMING CLEANSING AGENTS Hans-Joachim Schliissler, Dusseldorf-Hoithausen, He lmut V. Freyhold, Dusseldorf-Oberkassel, and Heinz Groschopp and Karl-Heinz Worms, Dusseldorf-Holthausen, Germany, assignors to Henkel & Cie GmbH, Dusseldorf-Holthausen, Germany N Drawing. Filed Dec. 13, 1965, Ser. No. 513,550 16 Claims. (Cl. 252-156) ABSTRACT OF THE DISCLOSURE Solid, alkaline, water-soluble cleansing agents which are stable on prolonged storage and substantially nonfoaming. They consist of essentially 40-95 percent caustic alkali and a foam-suppressant which is an ethylene or propylene or ethylene-propylene oxide adduct having a cloud point of '60 C. in 1% aqueous solution. These adducts are deposited on finely divided silica. The latter prevents the deterioration of the adducts on storage. An acid reacting salt and/or customary cleansing aids may also be present, such as phosphates, glucomates, soda or potash.

The invention relates to cleansing and rinsing agents, usable for cleaning of bottles, which are alkaline, stable upon prolonged storage, and substantially non-foaming. More particularly, i; relates to agents of this nature which are characterized by a given content of silica, or silicic acid.

The use of alkaline products containing rather large quantities of caustic alkali plus such ingredients as orthoand/or polyphosphates, gluconates, silicates and, if desired, wetting agents or detergents, as cleansing agents is known. Such materials are employed especially for the cleaning of bottles. For their application in automatic bottle washing machines and in spray cleansers, foam suppressants frequently are added. The latter are to prevent an overflow of the foaming cleansing agent and simultaneously to facilitate the removal of labels which have come oif the bottles, in order to obviate breakdowns of the machines. It therefore is preferred to incorporate in the agents detergents which have a pronounced foamsuppressing action.

It also is known that foam suppressants are not uniformly effective, depending upon the source of the foam. The same can form in manyfold ways, especially in bottle cleaning. For instance, the label adhesives generally con sist of dextrin or casein glues which promote foam formation. Chain lubricants and printing inks frequently contain detergents or wetting agents, especially alkylbenzenesulfonates or soaps, which thus enter into the cleansing solutions. Finally, the residual bottle contents, such as milk, beer or soft drinks, give rise to foam formation.

It thus is diflicult to find foam supressants which are effective for all knids of foam. In practice, nonionic compounds frequently are employed, such as ethylene oxide condensates with a hydrophobic component. Suitable hydrophobic component are fatty alcohols, fatty amines, alkylphenols and condensates of propylene oxide with propyleneglycol or with ethylenediamine. These nonionic substances labor under the disadvantage that they cannot be incorporated in cleansing agents containing solid caustic alkali. In the presence of solid, and preferably finely grained, caustic alkalis, they lose their effectiveness completely upon storage. Even after a short period of time, the substantially non-foaming cleansing and rinsing agents convert into strong foam promoters.

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An attempt at using coarse alkali flakes in lieu of the fine grains, in order to delay the loss of effectiveness of the foam supressants, has met with no success at higher alkali content.. Moreover, upon filling and upon storage, separation of the ingredients occurs.

A way now has been found, and is the object of the instant invention, to obviate these drawbacks. This is accomplished by applying cleansing and rinsing agents which have an alkali content of 40-95 weight percent and which further contain foam-suppressing addition products of ethylene oxide and/or propylene oxide having a cloud point of 10-60% C. in a 1% aqueous solution, and which are deposited on finely divided silica (also known as silicic acid).

Especially suitable for the cleaning and rinsing agents according to the invention are finely grained or powdered caustic alkalis because they readily yield cleansers which do not separate upon storage, refilling, or in transit. The grain size of the caustic alkali preferably is less than 3 mm. Coarsely grained caustic alkali also can be used, albeit separation can occur. Preferred caustic alkalis are sodiumand potassium hydroxide.

Addition products of ethylene oxide and proylene oxide are understood to be condensates of ethylene oxide with a hydrophobic component or condensate or propylene oxide with a hydrophilic component, respectively. Compounds of this kind, known as Pluronics and Tetronics (registered trade marks) are shown in McCutcheon, Detergents and Emulsifiers, 1967 Annual, and are condensates of ethylene oxide, propylene oxide and propylene glycol having a molecular weight of 2,000; and adducts of propylene oxide on ethylene diamine and ethylene oxide, respectively.

Appilcable hydrophobic components, added to ethylene oxide, are lipophilic compounds having at least one available hydrogen atom, such as fatty acids, fatty alcohols, fatty acid alkanolamides, alkylphenols, polypropyleneglycols and propylene oxide adducts or aliphatic amines or polyamines. Particularly suitable addition products of ethylene oxide are those condensates which simultaneously contain ethyleneand propylene oxide in their molecules.

In order to attain the cloud points named above, a given amount of ethylene oxide groups must be added onto the hydrophobic component. This amount depends upon the kind of hydrophobic component present. In general, the cloud point rises with the increasing numbers of ethylene groups.

The cloud point is determined by slow heating of a 1% aqueous solution and noting the first clearly discernible cloudiness. The cloud points named relate to pure solutions of the substances investigated. Addition of extraneous materials changes the cloud point.

As hydrophilic components added onto propylene oxide, polyalcohols may be employed, preferably glycerol,

polyglycerols (particularly those having 210 glycerol radicals in their molecules), polyethyleneglycols, sugars, short-chain alkanolamines and aliphatic polyamines whose number of carbon atoms between the nitrogen atoms is l to 5, and the number of nitrogen atoms is 2 to 8, preferably polyamines prepared by addition of ethyleneimine on ammonia or amines.

To attain the cloud points named above, a definite number of propylene oxide groups must be added onto the hydrophilic component. This number depends upon the kind of hydrophilic component used. Generally, the cloud point is lowered with increasing propylene oxide groups.

The addition products of ethylene oxide and/or propylene oxide, which are produced in a manner known per se, are employed in a preferred concentration of 0.5-3.5 weight percent, calculated on the total solid cleansing and rinsing agents.

The ethylene oxide and/ or propylene oxide adducts are deposited on finely divided silicic acids and thus are protected from decomposition by solid alkali. A surface as large as possible of the silica used exerts a favorable protecting action on the adducts. Especially effective have proven the silicic acids produced by precipitation and hydrolysis of silicon halides in the vapor phase, known as silica gels. Of the gels thus produced those are most suited for the instant purpose which had been refined by intensive milling. Other applicable silicic acids are those manufactured by sublimation or in a carbon arc.

The finely divided silica is added to the ethylene oxide and/or propylene adducts in a ratio of 0.2 to :1, and preferably of 0.5 to 3:1. These nonionic wetting agents or detergents are completely absorbed by the finely divided silica upon mixing. Mixing can be carried out in the customary mixing and blending devices. Depending upon the ratio employed, finely to coarsely grained products form. The silica readily and completely dissolves upon dissolution of the cleansing agent so that clear cleansing and rinsing solutions are obtained.

In certain instances, a further addition of acid, Watersoluble salts to the ethylene and/or propylene adducts, precipitated on the finely divided silica, has proven advantageous. The effectiveness of the silica is further increased thereby. As acid salts, in the case at hand, those salts are defined which react acidic in aqueous solution. Preferably primary alkaliphosphate and alkalibisulfate are employed because no alien ions are introduced into the cleasing solution by their use. The acids salts are incorporated in the ethylene oxide and/or propylene oxide adducts in a ratio of 0.2 to 10:1, and preferarbly 0.5 to 3:1. The acid salts'can be added to the adducts prior to, or after, deposition on the silica, or simultaneously therewith.

The cleansing and rinsing agents according to the invention may contain, beside finely or coarsely grained caustic alkali and the adducts deposited on silica, as described above, the customary ingredients, such as orthoand/or polyphosphates, soda, potash, gluconates, and, if desired, detergents. The cleaning agents are applied in the customary bath concentrations of 0.1-2 weight percent, preferably 0.5-1%. The most favorable application temperature is 60-80 C.

The cleasing agents are completely stable upon storage over a prolonged 'period of time. Their foam-suppressing properties do not change thereby, and the agents are effective against all kinds of foams usually encountered during cleaning.

The invention now will be further described by the following examples. However, it should be understood that these are given merely by way of illustration, and not of limitation, and that numerous changes may be made in the details without departing from the spirit and the scope of the invention as hereinafter claimed.

All percentages are percent by weight, all temperatures degrees centigrade, unless otherwise specified.

EXAMPLE 1 A commercial addition product of ethylene oxide and propylene oxide on ethylenediamine, known under the trade name Tetronic 701, (cf. McCutcheon, Detergents and Emulsifiers, 1967 Annual), and hereinafter identified as foam suppressant A, was stirred with 1.5 and 2 times the weight, respectively, of precipitated silica in a mixer. A dry and readily pulverizable mixture formed whose resistance in the presence of solid, finely grained caustic alkali, as compared to the pure foam suppressant A alone, was determined as follows:

Finely powdered NaOH was intimately mixed with the substance to be tested in a high-speed mixer and stored 4 f at room temperature. The following mixtures were produced:

Premixed with Aerosil (a pyrolitically produced, highly dispersed SiO The cloud point of these mixtures was determined in 1% aqueous solution, once every month within a period of 4 months. The determination of the cloud point was carried out by slow heating of the solutions and observation and notation of the first discernible occurrence of cloudiness. Those mixtures whose cloud points remained practically unchanged during'these times were considered storage-stable. Upon decomposition of a mixture, the cloud point rose sharply. The results obtained are listed in Table 1.

Like results were obtained by employing finely powdered KOH in lieu of NaOH.

TABLE 1 Cloud Point 0.) After Months- Mixture U 2e 45 95 95 26 27 2s 2s 2s 25 26 27 21 27 26 26 26 2e 21 26 28 28 2s 2s EXAMPLE 2 A commercial propylene oxide and ethylene oxide adduct on propyleneglycol, known under the trade name Pluronic L61, having a molecular weight of 2,000, as identified by McCutcheon, Detergents and Emulsifiers, 1967 Annual, and hereinafter identified as foam suppressant B; and an adduct of polyglycerol (OH value 1,080) on 6.6 mols propylene oxide (per free OH group), hereinafter identified as foam suppressant C; were mixed with 1.5 times their weight of precipitation silica.

Finely grained, dry mixtures formed whose resistance to decomposition by finely powdered solid caustic alkali was observed as compared to the pure foam suppressants alone, and the cloud points noted in a 1% solution, as described in Example 1. The results are listed in Table 2.

Like results were obtained when, in lieu of NaOH, finely powdered KOH was used.

The cloud points of the pure foam suppressants B and C were 15 and 26.5 respectively.

Foam suppressants A, B and C, as describedin the preceding examples, and also an adduct of 27.5 mols propylene oxide on triethanolamine, hereinafter designated foam suppressant D, were each stirred with an equal amount and 1.5 times the amount, respectively, of NaH PO and then well mixed with an equal amount and 1.5 times the quantity respectively of precipitated SiO The resistance of the mixtures against decomposition by solid finely grained caustic alkali upon storage was practically unchanged, even though different mixing procedures had been used. The resistance again was tested, as in the preceding examples, by observation of the cloud points during four months of storage at room temperature. The results are listed in Table 3.

The employment of KOH in lieu of NaOH led to like results. The cloud point of the pure foam suppressant D alone was 30.5".

aOH Foam Suppressant C-.. NaH zPO4 TABLE 3 Per- Cloud Point C.) After Months Mixture cent 0am uppressan NaHzPO4 2 26 26 26 27 27 Precipitated S10 2 NaOH 94 Foam Suppressant B 2 NaH2PO4 2 Precipitated S102 2 N 92 2 3 Foam Suppressant N8HzPO4 3 Precipitated SiOz 3 113121011 K- 93 0am uppressant KHSO 2 26 26 27 27 27 Precipitated S102 2 EXAMPLE 4 To a 0.00125 tetrapropylenebenzenesulfonate solution, 1% NaOH were added, and 100 ml. of this solution heated to 65 in a measuring cylinder suitable for shaking. The mixture was vigorously shaken times, and the foam volume thus formed read immediately from the cylinder graduations.

The test was repeated after adding to the tetrapropylenebenzenesulfonate solution 1% of one of the mixtures named below:

Foam suppressant A 1 Carbon arc S10 1 12. NaOH Foam suppressant A 1 Neuburg chalk 1 5 13. NaOH 93 Foam suppressant A 1 2 Kaolin 1 5 14. NaOH 92 Foam suppressant A 1 2 Na2HPO4 1 3 Na CO 1 3 15. NaOH 92 Foam suppressant A 2 Na SO 6 zistirred together to a finely grained product before adon.

TABLE 4 Foam Volume (ml.) after Months- Mixture No. (1%) EXAMPLE 5 The tests in this example were identical with the ones in Example 4, except that mixtures were produced and employed utilizing foam suppressants B, C and D. The composition of these mixtures follows, and the results obtained with 1% thereof is listed in Table 5.

The foam suppressants and SiO used were combined prior to the addition to NaOH to a finely grained product by stirring them together. Other additives as listed were stirred in with the foam suppressant and S10 Percent 16. NaOH 98 Foam suppressant B 2 17. NaOH 94 Foam suppressant B 2 Precipitated S10 4 18. NaOH 94 Foam suppressant B 2 NaH PO 2 Precipitated S10 2 19. NaOH 95 Foam suppressant C 2 Precipitated S10 3 20. NaOH 92 Foam suppressant C 2 NaH2PO4 3 Precipitated SiO 3 21. NaOH 95 Foam suppressant D 2 Precipitated SiO 3 22. NaOH 94 Foam suppressant D 2 NaH PO 2 Precipitated S10 2 TABLE 5 Foam Volume (ml.) After Months- Mixture N0. (1%) Blank NaOH) 300 16 30 305 325 325 325 30 140 80 80 so so 40 60 55 55 00 50 50 so 50 50 40 65 75 95 100 50 70 70 75 EXAMPLE 6 A bottle cleansing agent was produced having the composition as named below and stored for 6 months:

Percent NaOH (grain size less than 3 mm.) 85 Polymeric phosphate 10 Foam suppressant B 1.5 Precipitated SiO 3.5

The foam suppressant and Si0 had been stirred together to a finely grained mixture prior to incorporation in the cleanser.

The agent was used in a mechanical bottle cleansing machine at a treating temperature of 65 in a concentration of 1 and 2 percent, respectively, for clearing beer-, milkand soft drink bottles, part of which carried paper labels. The bottles were faultlessly clean after the treat ment, and the labels could be removed without difiiculty.

EXAMPLE 7 A bottle cleansing agent was produced having the composition as named below and stored for 6 months.

Percent KOH (grain size less than 1.5 mm.) 60 Polyphosphate 20 Sodium silicate NazO:SiO =325) 6 Filler (Na SO 7 Foam suppressant A 3 Aerosil (see mixture 5, Example 1) 4 The foam suppressant and Aerosil had been stirred together to a finely grained product prior to incorporation in the cleanser.

The agent was used in an automatic bottle washing machine at 80 in a concentration of 1.5 percent for cleaning of 'bear-, milkand soft drink bottles, some of which bore paper labels. The cleansing effect was excellent, foam formation negligible, and the labels which had come off the bottles could readily be removed.

EXAMPLE 9 Dirty motor parts were cleaned in an automatic washer having two chambers with a 1.5% solution of a solid cleanser having the following composition:

Percent NaOH (grain size less than 2 mm.) 70 Polymeric phosphate Sodium silicate ((Na O:SiO =3.25) 6 Foam suppressant D 3 NaH PO 3 Precipitated SiO 3 The last named 3 compounds had been stirred together to form a finely grained product prior to incorporation in the cleanser. The motor parts were sprayed with the cleanser at 80 and were well cleaned thereby.

We claim as our invention:

1. Solid, alkaline water-soluble cleansing agents, stable upon prolonged storage and substantially non-foaming upon application in solution, consisting essentially of:

substantially 40-95 weight percent caustic alkali;

an effective amount of a foam-suppressant selected from the group consisting of ethylene oxide and propylene oxide adducts and mixtures thereof, having a cloud point of substantially 10 to 60 C. in a 1% aqueous solution;

finely divided silica as a carrier for said foam-suppressant.

2. The cleansing agents as defined in claim 1, wherein said caustic alkali has a grain size of less than 3 mm. diameter.

3. The cleansing agents as defined in claim 1, wherein said silica is selected from the group consisting of silica gels; carbon arc silica; or sublimation silica.

4. The cleansing agents as defined in claim 1, having incorporated therein acid salts in aqueous solution wherein said salts are present in a ratio of 0.2 to 10:1 calculated on said foam suppressants.

5. The cleansing agents as defined in claim 4, wherein said salts are selected from the group consisting of primary alkali metal phosphate and alkali metal bisulfate.

6. The cleansing agents as defined in claim 1, wherein said silica is present in a ratio of 0.2 to 10:1, calculated on said foam suppressant.

8 7. The cleansing agents as defined in claim 1, wherein said foam suppressants are present in a concentration of 0.5-3.5 weight percent, calculated on the total cleansing agent.

8. The cleansing agents as defined in claim 1, containing, in addition, water-soluble substances selected from the group consisting of orthoand polyphosphates, soda, potash, gluconates,wetting agents, and mixtures thereof.

9. Solid, alkaline, water-soluble cleansing agents, stable upon prolonged storage and substantially non-foaming upon application in solution, comprising:

substantially 40-95 weight percent caustic alkali having a grain size of less than 3 mm. diameter;

0.5-3.5 weight percent, calculated on the total cleansing agent, of a foam suppressant selected'from the group consisting of ethylene oxide and propylene oxide adducts and mixtures thereof, having a cloud point of substantially 10-60 C. in a 1% aqueous solution;

finely divided silica in a ratio of 0.2-10:1, calculated on said foam suppressant.

10. The cleansing agents as defined in claim 9, wherein said substances are present in amounts up to 20 weight percent, calculated on the total mixture.

11. A process for the manufacture of solid, alkaline, water-soluble cleansing agents, stable on prolonged storage and substantially non-foaming upon application, which comprises absorbing substantially 0.5-3.5 weight percent, calculated on the total mixture, of a foam suppressant selected from the group consisting of ethylene and propylene oxide adducts and mixtures thereof, having a cloud point of substantially 10-60 C. in a 1% aqueous solution, on finely divided silica in a ratio of 0.2-10:1, calculated on said foam suppressant, and blending the mixture thus obtained with 40-95 weight percent caustic alkali, thus rendering the cleansing agent produced resistant to deterioration and separation on storage.

12. The process as defined in claim 11, wherein materials are added to said agent selected from the group consisting of primary alkali metal phosphate, and alkali metal bisulfate.

13. The process as defined in claim 12, wherein said materials are present in a ratio of 0.2 to 10:1, calculated on said foam suppressant.

14. The process as defined in claim 11, wherein water-soluble substances are incorporated in said agent selected from the group consisting of orthoand polyphosphates, soda, potash, gluconates, wetting agents, and mixtures thereof.

15. The process as defined in claim 13, wherein said substances are present in quantities up to 20 weight percent, calculated on the total mixture.

16. The process as defined in claim 11, wherein said caustic alkali has a grain size of less than 3 mm. diameter.

References Cited UNITED STATES PATENTS 2,329,694- 9/ 1943 Bodman 252-368 2,746,930 5/ 1956 Wells et al. 252- 3,010,907 11/ 1961 Carroll 252-156 3,169,905 1/1965 Lambert 252156 3,247,123 4/ 1966 Schralger et al. 252.l35 3,257,325 6/1966 Koster et al. 252135 LEON D. ROSDOL, Primary Examiner.

WILLIAM D. MARTIN, Examiner.

W. E. SCHULZ, Assistant Examiner.