EP0489768B1 - Anti-foaming agents for machine-washing of crockery and bottles - Google Patents

Abstract

The invention concerns multi-component foam-inhibiting mixtures with surfactant properties, comprising up to 40 % by wt. of polyethyleneglycol ethers with terminal groups of formula (I): R1?O-(CH2?CH2?O)n?R2?, in which R1?O- = a 2-branched even alkanol residue with 16-20 C-atoms, n = 5 to 9 and R2? = a C4?-C8? alkyl group and/or up to 40 % by wt. of polyethyleneglycol ether compounds not capped by terminal groups, of formula (II): R5?O-(CH2?CH2?O)z?-H, in which R5?O- = a 2 branched even alkanol residue with 12-20 C-atoms and z = 2 to 5; plus 20-98 % by wt. of mixed ethers of formula (III): R6?O-(EO)u?-(PO)v?-H in which R6?O- = a straight-chain or branched-chain C8?-C18? alkanol residue, EO = ethyleneglycol, PO = propyleneglycol, p = 2 to 6 and q = 3 to 7 plus, optionally, 0-80 % by wt. of polyethyleneglycol ethers capped with terminal groups, of formula (IV): R3?O-(CH2?CH2?O)m?-R4?, in which R3? = a straight-chain C8?-C18? alkyl residue or a branched-chain C8?-C14? alkyl residue, R4? = a C4?-C10? alkyl residue and m = 5 to 15 for the machine-washing of crockery and bottles. In preferred compounds, the R5?O- residdue derives from 2-butyloctanol-1, 2-butyldecanol-1, 2-hexyloctanol-1, 2-hexyldecanol-1, 2-hexyldodecanol-1, 2-octyldecanol-1 or 1-octyldodecanol-1, and the R1?O- residue from mixtures of 2-hexyldodecanol-1 and 2-octyldecanol-1. Advantage: highly effective and can be incorporated in liquid systems stable to alkali to give cleanly soluble aqueous concentrates.

Description

The invention relates to novel, selected active substance mixtures of alkali-resistant polyalkylene glycol ether compounds which, in the case of their own surfactant action, are distinguished in particular by pronounced foam-suppressing properties when formulated with other known components of foam-like cleaning agents, and their use for machine dishwashing and bottle cleaning in the home and business.

The use of nonionic surfactants based on polyoxyalkylated alkylphenols and / or fatty alcohols for cleaning hard surfaces is known. In many areas of application, for example when used as a component in dishwashers, however, the high foaming power of these compounds has an unfavorable effect.

There are a number of proposals to dampen the undesirable high foaming tendency of such cleaning agents by using suitable mixture components. For example, the use or concomitant use of block polymers of polypropylene glycol and ethylene oxide and other foam damping systems is known. A particular difficulty in the field of mechanical surface cleaning with such systems is the frequently present alkali instability of the auxiliaries used. It is known that, for example, machine dishwashing detergents are highly alkaline systems with considerable contents of alkali hydroxides, alkali silicates and / or alkali phosphates.

DE-OS 25 56 544 describes cleaning agents, in particular machine dishwashing detergents, which also use end-capped non-ionogenic polyalkylene glycol ether compounds, the class of compounds highlighted there being derived from polyoxyalkylated alcohols having 6 to 22 carbon atoms in the straight-chain or branched alkyl or alkylene radical and are characterized in that they are end-capped with a tert-butyl ether group. Compounds of this type are said to be able to be used as foam dampers for nonionic and cationic compounds.

EP 254 208 A2 describes a special low-foam or foam-suppressing surfactant mixture composed of 20-80% by weight of polyethylene glycol ethers of the general formula R₁-O- (CH₂CH₂O) _n -R₂, in which R₁ is a straight-chain or branched alkyl radical or alkenyl radical with 8 - 18 carbon atoms, R₂ is an alkyl radical with 4 to 8 carbon atoms and n is a number from 3 to 7, 10 to 40 wt .-% alkyl polyalkylene glycol mixed ether of the general formula
R₃-O- (CH₂CH₂O) _x - (CH₂-CH (CH₃) O) _y -H, in which R₃ is a straight-chain or branched alkyl radical having 8 to 18 carbon atoms, x is a number from 1 to 3 and y is a number of 3 to 6, and 0 to 40% by weight of alkyl (poly) propylene glycol ether of the general formula R₄-O- (CH₂CH (CH₃) O) _z -H, in which R₄ is a straight-chain or branched alkyl or alkenyl radical 16 to 22 carbon atoms and z represent a number from 1 to 3.

In EP 124 815 A3 the use of polyglycol ethers of the formula R¹-O- (CH₂CH₂O) _n -R², in which R¹ is a straight-chain or branched alkyl or alkenyl radical with 8 to 18 carbon atoms, R² is an alkyl radical with 4 to 8 carbon atoms and n is a number from 7 to 12, recommended as foam-suppressing additives for low-foam cleaning agents. Such compounds can optionally also be part of the active ingredient combination according to the invention.

In EP 326 795 A2 the use of polyethylene glycol ether of the general formula (I) R₁O- (CH₂CH₂O) _n -R₂, in which R₁ is a straight-chain or branched alkyl or alkenyl radical having 20 to 28 C atoms, R₂ is an alkyl radical having 4 up to 8 carbon atoms and n are a number from 6 to 20, described as foam-suppressing additives for low-foam cleaning agents. These compounds are very effective, but sometimes insoluble.

The use of ethoxylated Guerbet alcohols is not mentioned in the prior art.

The teaching of the present invention is based on the object of enabling further improvements of such cleaning and / or rinsing agents for hard surfaces, in particular for the mechanical cleaning of glass, dishes, bottles and the like. In particular, the invention intends to provide mixtures of substances which, on the one hand, are themselves surfactant-like, but in particular are suitable for use as strongly foam-suppressing additives in low-foam alkali-resistant detergent mixtures of the type concerned here. This addresses both the area of solid and / or liquid cleaning agents of the type mentioned here and the area of so-called rinse aids, which are known to be used in a final process step before the cleaned items are dried. The active substance combinations according to the invention should be able to be used in particular in combination with other customary nonionic, cationic or anionic surface-active substances, builders and other additives or auxiliaries in the dishwashing and cleaning agent formulations of the subject area concerned.

The teaching of the invention is based on the finding that those specified below are definitely selected Mixtures of active ingredients meet the complex requirement profile. Mixtures of active substances of the type according to the invention are also notable for improved formulability in liquid systems, so that additional relief is provided here for commercial use.

• 1. bis zu 40 Gew.-% Endgruppen-verschlossener Polyethylenglykolether der allgemeinen Formel (I)
  
  
  
          R₁O-(CH₂CH₂O)_n-R₂   (I)
  
  
  
  in der sich der Rest R₁O- von Guerbetalkoholen mit 16 bis 20 C-Atomen ableitet, der Rest R₂ einen Alkylrest mit 4 bis 8 C-Atomen und n eine Zahl von 5 bis 9 bedeuten

und

• 2. bis zu 40 Gew.-% nicht Endgruppen-verschlossener Polyethylenglykolether-Verbindungen der allgemeinen Formel (II)
  
  
  
          R₅O-(CH₂CH₂O)_z-H   (II)
  
  
  
  in der sich der Rest R₅O- von Guerbetalkoholen mit 12 bis 20 C-Atomen ableitet und z eine Zahl von 2 bis 5 ist

zusammen mit

• 3. 20 bis 98 Gew.-% an Mischethern der allgemeinen Formel (III)
  
  
  
          R₆O-(EO)_u-(PO)_v-H   (III)
  
  
  
  in der R₆O- den Rest eines linearen oder verzweigten Alkanols mit 8 bis 18 C-Atomen, EO den Rest des Ethylenglykols, PO den Rest des Propylenglykols, u eine Zahl von 2 bis 6 und v eine Zahl von 3 bis 7 bedeuten

sowie gewünschtenfalls

• 4. Endgruppen-verschlossener Polyethylenglykolether der allgemeinen Formel (IV)
  
  
  
          R₃O-(CH₂CH₂O)_m-R₄   (IV)
  
  
  
  in der R₃ einen linearen Alkylrest mit 8 bis 18 C-Atomen oder einen verzweigten Alkylrest mit 8 bis 14 C-Atomen, R₄ einen Alkylrest mit 4 bis 10 C-Atomen und m eine Zahl von 5 bis 15 bedeuten.

The invention accordingly relates to the use of selected mixtures of alkali-resistant polyalkylene glycol ether compounds with surfactant character and foam-suppressing action for machine dishwashing and bottle cleaning in household and commercial use, the characterizing feature of the invention being that active substance combinations of the following components are used - wt .-% each based on active ingredient combination:

• 1. up to 40% by weight end-capped polyethylene glycol ether of the general formula (I)
  
  
  
  R₁O- (CH₂CH₂O) _n -R₂ (I)
  
  
  
  in which the radical R₁O is derived from Guerbet alcohols with 16 to 20 C atoms, the radical R₂ is an alkyl radical with 4 to 8 C atoms and n is a number from 5 to 9

and

• 2. up to 40% by weight of non-end-capped polyethylene glycol ether compounds of the general formula (II)
  
  
  
  R₅O- (CH₂CH₂O) _z -H (II)
  
  
  
  in which the rest R₅O- is derived from Guerbet alcohols with 12 to 20 carbon atoms and z is a number from 2 to 5

along with

• 3. 20 to 98% by weight of mixed ethers of the general formula (III)
  
  
  
  R₆O- (EO) _u - (PO) _v -H (III)
  
  
  
  in the R₆O- the residue of a linear or branched alkanol with 8 to 18 carbon atoms, EO the rest of the ethylene glycol, PO the rest of the propylene glycol, u is a number from 2 to 6 and v is a number from 3 to 7

as well as if desired

• 4. End group-capped polyethylene glycol ether of the general formula (IV)
  
  
  
  R₃O- (CH₂CH₂O) _m -R₄ (IV)
  
  
  
  in which R₃ is a linear alkyl radical having 8 to 18 carbon atoms or a branched alkyl radical having 8 to 14 carbon atoms, R₄ is an alkyl radical having 4 to 10 carbon atoms and m is a number from 5 to 15.

• 1) bis zu 30 Gew.-% an Verbindungen der allgemeinen Formel (I)
• 2) bis zu 40 Gew.-% an Verbindungen der allgemeinen Formel (II)
• 3) 40 bis 95 Gew.-% an Verbindungen der allgemeinen Formel (III)
• 4) 0 bis 50 Gew.-% an Verbindungen der allgemeinen Formel (IV).

It may be preferred according to the invention to use the active ingredient components of (1) to (4) in the following mixing ratios:

• 1) up to 30% by weight of compounds of the general formula (I)
• 2) up to 40% by weight of compounds of the general formula (II)
• 3) 40 to 95% by weight of compounds of the general formula (III)
• 4) 0 to 50% by weight of compounds of the general formula (IV).

An essential component for the active ingredient mixtures of the invention are the mixed ethers of the general formula (III) which, as a rule, can even make up the main part of the active ingredient mixture described according to the invention and used for the stated purpose. These components known per se are substantially improved by the addition of the active ingredient components to (1) and (2) provided according to the invention. This improvement affects both the ability to inhibit or limit foam and that Formulation of the active ingredient mixture into clearly soluble aqueous concentrates.

The invention provides for the mixture components of the general formula (I) to (1) on the one hand and the mixture components of the general formula (II) to (2) on the other hand in combination with one another together with the compounds of the general formula (III) - mixture component to ( 3) - and the mixture components (4) additionally used if desired. In addition, even comparatively small amounts of these mixture components to (1) and (2) can produce effective effects in the sense of the desired improvements. Thus, with the addition of up to about 20% by weight, based on the total mixture of the active compounds according to the invention, of the components to (1) and (2) or even with amounts of up to about 10% by weight of these additives according to the invention, a significant reduction foam formation on the one hand and improvement of the aqueous formulability of the active ingredients on the other hand can be achieved.

The following applies in detail to the mixture components for (1) and (2) provided according to the invention:

Mixture components of the general formula (I) to (1)

and

Mixture components of the general formula (II) to (2)

Representatives of these two classes, which are derived from branched alkanols of the type of Guerbet alcohols, have proven to be particularly effective. As is known, alcohols of this type are formed by the condensation of fatty alcohols with a lower carbon number in the presence of alkali, e.g. As potassium hydroxide or potassium alcoholate. The reaction takes place, for example, at temperatures from 200 to 300 ° C. and leads to branched Guerbet alcohols which have branching in the 2-position to the hydroxyl group. In a particular embodiment, the invention predominantly or preferably exclusively uses straight-chain fatty alcohols for the preparation of the 2-branched Guerbet alcohols and ultimately for the synthesis of the compounds of the general formula (I). Fatty alcohols of natural origin are known to have at least largely predominantly even chain lengths, so that their 2-branched Guerbet alcohol with 18 C atoms cannot be obtained as a uniform condensation product of only one selected fatty alcohol via their dimerization. The necessary dimerization of a mixture of the two fatty alcohols with 8 and 10 C atoms leads to the isomer mixture of the 18 C Guerbet alcohol from 2-hexyldodecanol-1 and 2-octyldecanol-1. In addition, the condensation products of the two alcohols used arise with themselves, i. that is, the 2-hexyldecanol-1 from the octanol used and the 2-octyldodecanol-1 from the decanol used. Analogous considerations apply to Guerbet alcohol with 14 carbon atoms.

Mixtures of this type which are suitable for achieving the object according to the invention are described in claim 4. The alternative (1b) provided according to the invention, which is free of Guerbet alcohols with 18 C atoms, but suitable mixing ratios of the Guerbet alcohols with 16 and 20 C atoms on the one hand, leads to the goal.

The end group-capped fatty alcohol polyglycol ethers of the formula (I) are prepared in accordance with the specifications of DE-OS 33 15 951. The fatty alcohols of higher carbon number described above are advantageously reacted with ethylene oxide in a molar ratio of 1: 5 to 1: 9 and then etherified the hydroxyl groups present in the reaction product obtained. The reaction with ethylene oxide takes place under the known acoxylation conditions, preferably in the presence of suitable alkaline catalysts. The etherification of the free hydroxyl groups is preferably carried out under the known conditions of Williamson's ether synthesis using straight-chain or branched C₄- to C₈-alkyl halides. The n-butyl radical for the radical R₂ from the general formula (I) is of particular importance in the course of the inventive action. Examples of such a final etherification are accordingly n-butyl halides such as n-butyl chloride. However, the invention is not limited to this. Further examples are amyl halides, hexyl halides and the higher alkyl halides in the range mentioned. It may be expedient to use alkyl halide and alkali in a stoichiometric excess, for example from 10 to 50%, over the hydroxyl groups to be etherified.

The compounds of the general formula (II) which are not end-capped are prepared in a manner known per se by reacting the selected Guerbet alcohols with ethylene oxide in a molar ratio of 1: 2 to 1: 5.

Correspondingly, the compounds of the general formula (III) - mixture components to (3) - are obtained in a manner known per se - by reacting the selected linear or branched alkanols ROH with ethylene oxide and propylene oxide - in particular 1,2-propylene oxide - in the stated molar ratios. The preparation of the if necessary the mixture components of the general formula (IV) used are analogous to the information on the preparation of the end group-sealed mixture components of the general formula (I).

As already stated, the active compound mixtures according to the invention are suitable both as a foam-suppressing additive to typical cleaning agent mixtures, in particular low-foam mixtures of the type mentioned, in order to further reduce their tendency to foam, and also for the formulation of rinse aids. In the last-mentioned case too, low-foam surfactants can be used in a manner known per se, the foam formation of which is further suppressed by the active ingredient systems according to the invention. In the last-mentioned field of use in particular, however, it is also sensible to make use of the surfactant properties of the active compound mixtures used according to the invention.

The content of the active ingredient mixtures of (1) to (4) in the detergents and cleaning agents can vary within wide limits. It is essential that the polyglycol ether mixtures give effective effects even in low concentrations. In a preferred embodiment, they are added to the cleaning agents in such amounts that their concentration in the ready-to-use solutions is approximately in the range from 50 to 500 ppm. However, the invention is not restricted to this; in particular, far higher amounts of the active compound mixtures according to the invention can be used.

Examples

In the following examples, the foam damping of the additives selected according to the invention - and, in comparison, a structurally similar additive mixture which does not fall within the scope of the invention - is determined using a test method which is described as follows:

50 g of a whisked whole (egg yolk and egg white) are homogeneously distributed in 450 ml of water with a water hardness of 16 ^o dH and this liquid is heated to 60 ^o C in a double-walled 2000 ml measuring cylinder. With the help of a laboratory hose pump, this solution is sucked from the bottom of the measuring cylinder with a glass tube. The liquid is returned to the measuring cylinder via a second tube, the lower end of which ends at the height of the upper edge of the measuring cylinder. The liquid is at a circulation rate of 4 l / min. pumped over and falls back into the measuring cylinder. By pumping around this liquid can be foamed up to 2000 ml. When this is achieved, 0.1 ml of the low-foam or foam-suppressing active substance mixture to be tested - here products A, B, C and D - are metered into the liquid, the foam formed depending on the effectiveness of the product more or less quickly collapses. If the pump is pumped further, a rise in the foam is always observed. After 0.5, 1, 2, 3, 5, 10, 15, 20 and 30 minutes of pumping over after metering in the low-foam active ingredient mixture, the volumes given in the table are then read, which have formed from foam and liquid after these times.

The examined products are the following:

Product A (for comparison)

95% coconut alcohol (EO) ₅- (PO) ₄
5% 2-hexyldecanol-1, reacted with 2 moles of ethylene oxide

Product B (according to the invention)

R₁OH =

28 % 2-Octyldodecanol-1
25 % 2-Hexyldodecanol-1
25 % 2-Octyldecanol-1
22 % 2-Hexyldecanol-1

90% coconut alcohol (EO) ₅- (PO) ₄
5% 2-hexyldecanol-1, reacted with 2 moles of ethylene oxide
5% R₁O- (CH₂CH₂O) ₇-n-butyl ether, where applies

R₁OH =

28% 2-octyldodecanol-1
25% 2-hexyldodecanol-1
25% 2-octyldecanol-1
22% 2-hexyldecanol-1

Product C (for comparison)

47.5% coconut alcohol (EO) ₁₀-n-butyl ether
47.5% coconut alcohol (EO) ₅- (PO) ₄
5% R₁O- (CH₂CH₂O) ₇-n-butyl ether according to product B.

Product D (for comparison)

50% coconut alcohol (EO) ₅- (PO) ₄
50% coconut alcohol (EO) ₄- (PO) ₅
The values determined in each case are summarized in the table below: min. Product A Product B Product C Product D 0 2000 2000 2000 2000 0.5 600 560 560 620 1 600 580 600 620 2nd 660 640 640 680 3rd 700 660 680 760 5 820 740 800 960 10th 1060 880 1000 1500 15 1110 940 1060 2000 20th 1240 1060 1140 30th 1460 1220 1180

The following tests are carried out to determine the formulability of the respective product mixtures:

Recipe 1

20% product A
5% cumene sulfonate (40%)
75% water
This formulation is clear-liquid up to 46 ^o C.

Recipe 2

20% product B
5% cumene sulfonate (40%)
75% water
This formulation is clear-liquid up to 46 ^o C.

Recipe 3

20% product C
5% cumene sulfonate (40%)
75% water
This formulation is clear-liquid up to 46 ^o C.

Recipe 4

20% product D
5% cumene sulfonate (40%)
75% water
This formulation is only clear and liquid up to 40 ^o C.

Result:

Product B has a better anti-foaming effect than products A, C and D.

Claims (6)

1. The use of selected mixtures of alkali-resistant, surface-active and foam-suppressing polyalkylene glycol ether compounds in domestic and institutional dishwashing and bottle-washing machines, characterized in that combinations of the following active components (% by weight, based on 100% by weight of the combination) are used:

   1. up to 40% by weight of end-capped polyethylene glycol ethers corresponding to general formula (I):
   
   
   
           R₁O-(CH₂CH₂O)_n-R₂   (I)
   
   
   
   in which R₁O is derived from C₁₆₋₂₀ Guerbet alcohols, R₂ is a C₄₋₈ alkyl radical and n is a number of 5 to 9,

   and

   2. up to 40% by weight of non-end-capped polyethylene glycol ether compounds corresponding to general formula (II):
   
   
   
           R₅O-(CH₂CH₂O)_z-H   (II)
   
   
   
   in which R₅O is derived from C₁₂₋₂₀ Guerbet alcohols and z is a number of 2 to 5,

   together with

   3. 20 to 98% by weight of mixed ethers corresponding to general formula (III):
   
   
   
           R₆O-(EO)_u-(PO)_v-H   (III)
   
   
   
   in which R₆O- is the residue of a linear or branched C₈₋₁₈ alkanol, EO is an ethylene glycol residue, PO is a propylene glycol residue, u is a number of 2 to 6 and v is a number of 3 to 7,

   and, if desired,

   4. end-capped polyethylene glycol ethers corresponding to general formula (IV):
   
   
   
           R₃O-(CH₂CH₂O)_m-R₄   (IV)
   
   
   
   in which R₃ is a linear C₈₋₁₈ alkyl radical or a branched C₈₋₁₄ radical, R₄ is a C₄₋₁₀ alkyl radical and m is a number of 5 to 15.
2. The use claimed in claim 1, characterized in that active components (1) to (4) are used in the following quantities in 100% by weight of the combination:

   1) up to 30% by weight of compounds corresponding to general formula (I),

   2) up to 40% by weight of compounds corresponding to general formula (II),

   3) 40 to 95% by weight of compounds corresponding to general formula (III),

   4) 0 to 50% by weight of compounds corresponding to general formula (IV).
3. The use claimed in claims 1 and 2, characterized in that polyethylene glycol ether compounds corresponding to general formula (II), in which R₅O- is derived from at least one of the following alkanols: 2-butyl-1-octanol, 2-butyl-1-decanol, 2-hexyl-1-octanol, 2-hexyl-1-decanol, 2-hexyl-1-dodecanol, 2-octyl-1-decanol and/or 2-octyl-1-dodecanol, are used.
4. The use claimed in claims 1 to 3, characterized in that polyethylene glycol ether compounds corresponding to general formula (I), in which R₁O- is derived from the following alcohol mixtures (a) or (b):

   a) 10 to 100 mole-% of an equimolar isomer mixture of 2-hexyl-1-dodecanol and 2-octyl-1-decanol,
   0 to 90 mole-% of 2-hexyl-1-decanol,
   0 to 50 mole-% of 2-octyl-1-dodecanol,

   or

   b) 40 to 70 mole-% of 2-hexyl-1-decanol, 60 to 30 mole-% of 2-octyl-1-dodecanol,

   are used.
5. The use claimed in claims 1 to 4, characterized in that polyethylene glycol ether mixtures corresponding to general formula (I), in which R₁O- is derived from alcohol mixtures of the following composition:
   at least 45 mole-% of the isomer mixture of 2-hexyl-1-dodecanol and 2-octyl-1-decanol,
   0 to 55 mole-% of 2-hexyl-1-decanol,
   no more than 30 mole-% of 2-octyl-1-dodecanol,
   are used.
6. The use claimed in claims 1 to 5, characterized in that the substituents R₂ (general formula (I)) and/or R₄ (general formula (IV)) are also linear alkyl radicals containing the number of carbon atoms mentioned.