EP0275478A2 - Use of diethanol amine derivatives as solubilizers for low-foaming tensides - Google Patents

Abstract

Aqueous low-foam cleaning compositions containing at least one surfactant which is a water-soluble or water-emulsifiable polyalkylene glycol ether of a long-chain alcohol, and at least one diethanolamine derivative of the formula <IMAGE> (I) <IMAGE> (IIa) <IMAGE> (IIb) in which R1 and R2 are linear or branched alkyl or alkenyl radicals containing 8 to 14 carbon atoms for R1 and 9 to 17 carbon atoms for R2, and r, s, t, u, v and w are integers of from 1 to 3.

Description

DE-OS 33 15 951 (D 6859) relates to the use of selected polyethylene glycol ethers of the formula 1,
R¹ - O - (CH₂CH₂O) n - R² (I)
in which R¹ is a straight-chain or branched alkyl or alkenyl radical having 8 to 18 carbon atoms, R² is an alkyl radical having 4 to 8 carbon atoms and n is a number from 7 to 12, as foam-suppressing additives for low-foam cleaning agents. In particular, n in this formula means a number from 8 to 10, the preferred radical R 2 being the n-butyl radical and the preferred value for n being the number 9. The end group-capped polyglycol ethers of this type are preferably used in amounts such that their concentration in the ready-to-use cleaning solutions is 10 to 2500 ppm, preferably about 50 to 500 ppm. These end group-capped addition products of ethylene oxide with longer-chain aliphatic alcohols meet the requirements with regard to their usability in terms of application technology and above all with regard to their biodegradability.

• I) 20 bis 80 Gewichtsprozent an Polyethylenglykolethern der allgemeinen Formel I
  R₁ - O - (CH₂CH₂O)_n - R₂      (I)
  in der R₁ einen geradkettigen oder verzweigten Alkylrest oder Alkenylrest mit 8 bis 18 C-Atomen, R₂ einen Alkylrest mit 4 bis 8 C-Atomen und n eine Zahl von 3 bis 7 bedeuten,
• II) 10 bis 40 Gewichtsprozent Alkylpolyalkylenglykol-­Mischether der allgemeinen Formel II
  
  
  in der
  R₃ einen geradkettigen oder verzweigten Alkylrest mit 8 bis 18 C-Atomen,
  x eine Zahl von 1 bis 3 und
  y eine Zahl von 3 bis 6 bedeuten
  sowie
• III 0 bis 40 Gewichtsprozent
  Alkyl-(poly)-propylenklykolether der allgemeinen Formel III
  
  
  in der R₄ einen geradkettigen oder verzweigten Alkyl- oder Alkenylrest mit 16 bis 22 C-Atomen und z eine Zahl von 1 bis 3 bedeuten.

In practical use, surfactant components of this type have been shown to have the best effectiveness Develop temperatures from about 50 ° C upwards, while in the temperature range below, improvements in foam behavior appear to be desirable, especially when cleaning methods are used which particularly favor foam formation from the mechanics of the procedure used. The older application P 36 25 078.3 (D 7664) is concerned with improvements in this class of biodegradable low-foam surfactants. The subject of this earlier application is low-foam or foam-suppressing surfactant mixtures based on water-soluble and / or water-emulsifiable polyalkylene glycol ethers of longer-chain alcohols, the further development described therein being that these surfactant mixtures of the components I, II and, if desired, III given below contain the quantitative ratios also shown below - the quantitative ratios in percent by weight each relate to the total weight of the mixture of components from I to III:

• I) 20 to 80 percent by weight of polyethylene glycol ethers of the general formula I
  R₁ - O - (CH₂CH₂O) _n - R₂ (I)
  in which R₁ is a straight-chain or branched alkyl radical or alkenyl radical with 8 to 18 C atoms, R₂ is an alkyl radical with 4 to 8 C atoms and n is a number from 3 to 7,
• II) 10 to 40 percent by weight of alkyl polyalkylene glycol mixed ether of the general formula II
  
  
  in the
  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 from 3 to 6
  such as
• III 0 to 40 percent by weight
  Alkyl (poly) propylene glycol ethers of the general formula III
  
  
  in which R₄ is a straight-chain or branched alkyl or alkenyl radical having 16 to 22 carbon atoms and z is a number from 1 to 3.

The weight fractions of these components I to III are preferably within the following quantitative ranges:
Compounds of the general formula I 50 to 80% by weight
Compounds of the general formula II 10 to 25% by weight
Compounds of the general formula III 0 to 20% by weight.

For further details, reference is made to the disclosure of the older applications for property rights mentioned according to DE-OS 33 15 951 and 36 25 078.3 (D 7664), the disclosure of which is hereby expressly made the subject of the present disclosure of the invention.

In the meantime, it has been found that surfactants or surfactant mixtures of those mentioned in the two older property right applications of the type described may still need improvement in the following directions:

At low temperatures, such as those found in practical use in the cold season, the surfactants can become cloudy from their aqueous solutions. Aqueous solutions, in particular of the low-foam surfactant components described in DE-OS 33 15 951, show corresponding cloudiness, for example below 5 ° C. Improved solubilities may also be desirable in another special area of application. These are preferably strongly acidic cleaning formulations. Low-foaming surfactants of the type described are only insufficiently soluble, for example, in formulations containing phosphoric acid, especially when the phosphoric acid content is high.

The present invention is based on the task of closing the remaining gaps in the solution behavior of these low-foaming surfactant components, which are desired per se, by using selected solubilizers. However, the existing advantages of these surfactant components and, in particular, their foam-suppressing or low-foam properties should not be adversely affected. The technical solution to the problem according to the invention is based on the finding that the use of selected diethanolamine derivatives now also opens up the areas of application conditions for the use of the surfactant classes described which previously caused the difficulties described.

in der R₁ und R₂ geradkettige und/oder verzweigte Alkyl- und/oder Alkenylreste mit 8 bis 14 C-Atomen für R₁ und 9 bis 17 C-Atomen für R₂ und r, s, t, u, v, w, ganze Zahlen von 1 bis 3 bedeuten als Lösungsvermittler für Tenside beziehungsweise Tensidgemische auf Basis wasserlöslicher und/oder wasser­emulgierbarer Polyalkylenglykolether längerkettiger Alkohole bei deren Einsatz in schaumaren Reinigungsmitteln bei niederen Temperaturen und/oder im sauren Bereich.The invention accordingly relates to the use of diethanolamine derivatives of the general formulas I, II a and / or II b

in the R₁ and R₂ straight-chain and / or branched alkyl and / or alkenyl radicals with 8 to 14 carbon atoms for R₁ and 9 to 17 carbon atoms for R₂ and r, s, t, u, v, w, integers from 1 to 3 as solubilizers for surfactants or surfactant mixtures based on water-soluble and / or water-emulsifiable polyalkylene glycol ethers of longer-chain alcohols when used in foaming cleaning agents at low temperatures and / or in the acidic range.

The solubilizers of the general formula I, II a and / or II b are preferably used in amounts of up to about 150 percent by weight and preferably in amounts of about 5 to 100 percent by weight, in each case based on the weight of the low-foaming surfactants.

Solubilizers of the general formula I can be prepared in a manner known per se as defined compounds, for example from diethanolamine and alkyl halides of the specified C number in the alkyl radical. In practice, the solubilizers of the general formulas II a and II b will generally be present as mixtures. They are obtained in a simple manner by reacting terminal epoxy compounds of the prescribed carbon number with diethanolamine and are obtained in a manner known per se - depending on the reaction conditions used in a mixture of the two components according to II a and II b. These compounds I, II a and II b are then further reacted with ethylene oxide as required.

In a first important embodiment, the solubilizers according to the invention are used together with the end group-capped polyethylene glycol ethers of DE-OS 33 15 951, this component being part of the systematic description of the invention of the general formula
R₃ - O - (CH₂CH₂O) _n - R₄ (III)
corresponds. In this formula, R₃ is a straight-chain or branched alkyl or alkenyl radical having 8 to 18 carbon atoms, R₄ is an alkyl radical having 4 to 8 carbon atoms and n is a number from 7 to 12. The preferred numerical value for n is 8 to 10, in particular 9, during the preferred meaning of R₄ is the n-butyl radical. As already stated, reference is made to the disclosure of DE-OS 33 15 951 for further details.

• a) 20 bis 80 Gewichtsprozent an Polyethylenglykolethern der allgemeinen Formel IV
  R₅ - O - (CH₂CH₂O)_p - R₆      (IV)
  in der R₅ einen geradkettigen oder verzweigten Alkylrest oder Alkenylrest mit 8 bis 18 C-Atomen,
  R₆ einen Alkylrest mit 4 bis 8 C-Atomen und p eine Zahl von 3 bis 7 bedeuten,
  b) 10 bis 40 Gewichtsprozent Alkylpolyalkylenglykol-Mischether der allgemeinen Formel V
  
  
  in der
  R₇ einen geradkettigen oder verzweigten Alkylrest mit 8 bis 18 C-Atomen,
  x eine Zahl von 1 bis 3 und
  y eine Zahl von 3 bis 6 bedeuten
• c) O bis 40 Gewichtsprozent Alkyl-(poly)-propylenglykolether der allgemeinen Formel VI
  
  
  in der
  R₈ einen geradkettigen oder verzweigten Alkyl- oder Alkenylrest mit 16 bis 22 C-Atomen und
  z einen Zahl von 1 bis 3 bedeuten.

In a further preferred embodiment of the invention, the solubilizers of the general formula I, II a and / or II b according to the invention are used together with low-foam or foam-suppressing surfactant mixtures as described in the earlier application 36 25 078.3 (D 7664). In the systematics of the description of the invention given here, these surfactant mixtures can be represented as mixtures of components of the following compounds IV to VI.

• a) 20 to 80 percent by weight of polyethylene glycol ethers of the general formula IV
  R₅ - O - (CH₂CH₂O) _p - R₆ (IV)
  in which R₅ is a straight-chain or branched alkyl radical or alkenyl radical with 8 to 18 C atoms,
  R₆ is an alkyl radical with 4 to 8 carbon atoms and p is a number from 3 to 7,
  b) 10 to 40 percent by weight of alkyl polyalkylene glycol mixed ether of the general formula V
  
  
  in the
  R₇ 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 from 3 to 6
• c) O to 40 percent by weight of alkyl (poly) propylene glycol ether of the general formula VI
  
  
  in the
  R₈ is a straight-chain or branched alkyl or alkenyl radical having 16 to 22 carbon atoms and
  z is a number from 1 to 3.

For the present invention, the details of the older property right mentioned apply, according to which components IV to VI are preferably present in the following mixing ratios:
IV 50 to 80 weight percent
V 10 to 25 percent by weight
VI 0 to 20 percent by weight

In the preferred embodiment, the R der radical in the compounds of the general formula IV denotes a straight-chain or branched alkyl radical or alkenyl radical having 12 to 18 C atoms, while the preferred R₆ radical in these compounds of the general formula IV denotes the butyl radical. In the compounds of the general formula V, the preferred meaning for the radical R₇ is a straight-chain or branched alkyl radical having 12 to 14 carbon atoms, while the preferred chain length for the radical R₈ in the compounds of the general formula VI is 16 to 18 carbon atoms.

The residues R₅, R₇ and R₈ are residues of corresponding longer-chain alcohols, wherein in a further preferred embodiment of the invention applies that alcohol cuts as they incurred in the synthesis of such alcohols in practice, are particularly suitable, in which case at least the predominant proportion of the individual components specifically present in these alcohol cuts correspond to the specified C number ranges. Corresponding synthetic alcohols are suitable, but in particular corresponding fatty alcohols or fatty alcohol mixtures, such as are obtained in a known manner from the conversion of natural fats and / or oils.

A particularly suitable alcohol cut for the radical R₅ in the compounds of the general formula IV can be what is known as “LT coconut alcohol”, which shows the following carbon chain length distribution - with consistently saturated hydrocarbons
C₁₀ 0 to 3%
C₁₂ 48 to 58%
C₁₄ 19 to 24%
C₁₆ 9 to 12%
C₁₈ 11 to 14%.

An oleyl alcohol cut with the following carbon chain length distribution and an iodine number in the range from 40 to 110 is particularly suitable as radical Rzahl in the compounds of general formula VI:
C₁₂ 0 to 2%
C₁₄ 0 to 9%
C₁₆ 2 to 33%
C₁₈ 60 to 95%
C₂₀ 0 to 3%

The improved behavior of corresponding surfactant mixtures with the addition of the solution mediators according to the invention compared to comparable, but no solubilizers in the sense of Surfactant mixtures containing the invention can be seen from the following examples according to the invention and the associated comparative examples.

In addition to the solubilizing properties, the use of the diethanolamine derivatives of the formulas I, IIa and / or IIb also improves the foam-suppressing properties of the surfactant mixtures, especially at an application temperature of 20 ° C., as can be seen from the table. The foam-suppressing properties of the surfactant mixtures are determined by adding the amounts of a foam-rich surfactant (triethanolamine salt of tetrapropylene benzene sulfonate) listed in the table to the surfactant mixture to be tested and foaming these mixtures by pumping around them. The surfactant mixture to be tested has the better foam-suppressing properties, the lower the figures for liquid and foam volume listed in the table are and the more the surfactant mixture can be loaded with the foam-rich surfactant until the maximum number of 2000 ml of liquid and foam volume is reached.

Examples example 1

40% phosphoric acid 85%
6% oleyl alcohol-2 PO
2% coconut alcohol-5 EO-butyl ether
2% coconut alcohol-2 EO-4 PO
10% product of formula II a / b with R₂ = C 11
40% water

This mixture is bright liquid in the temperature range from -5 ° C to 50 ° C.

Comparative Example 1

40% phosphoric acid 85%
12% oleyl alcohol-2 PL
4% coconut alcohol-5 EO-butyl ether
4% coconut alcohol-2 EO-4 PO
40% water

The mixture is cloudy at 20 ° C and separates into an oil and a water phase after a few hours.

Comparative Example 2

40% phosphoric acid 85%
20% coconut alcohol-10 EO-butyl ether
40% water

This mixture is bright liquid in the temperature range above +5 ° C. At temperatures below 5 ° C, clouding occurs after long periods of storage.

Example 2

20% phosphoric acid 85%
10% coconut alcohol-10 EO-butyl ether
2% product of formula II a / b with R₂ = C 11
68% water

This mixture is bright liquid in the temperature range from -5 ° C to +50 ° C.

Example 3

In the active ingredient mixture of Example 1, the solubilizer II a / b used according to the invention is exchanged for a solubilizer of the general formula I in which the radical R 1 is a C 12 radical.

The mixture is bright liquid in the temperature range from -5 ° C to +50 ° C.

Example 4

The active ingredient mixture of Example 2 according to the invention is varied in that a diethanolamine derivative of the general formula I is used instead of the solubilizer of the formula II a / b, in which the radical R 1 is a C 12 radical.

This mixture is also bright liquid from -5 ° C to +50 ° C.

Example 5

The foaming behavior of some of the surfactant mixtures described above is determined.

Test method

300 ml of a 1% aqueous sodium hydroxide solution are heated to 20 or 65 ° C. in a double-walled 2 l measuring cylinder. Now add 0.5 ml of a concentrate, as described in Examples 1 and 2 or in Comparative Examples 1 and 2, and pump the liquor at 4 l / min. a.

After 30 seconds, 1 ml of a 1% strength aqueous solution of the triethanolamine salt of tetrapropylene benzene sulfonate is metered into the liquor and after a further 30 seconds the volume formed, which is formed by liquid and foam, is determined.

The 30 second determinations (metering / reading) are maintained until the surfactant solution in the measuring cylinder is foamed to 2000 ml.

Claims (4)

1. Use of diethanolamine derivatives of the general formulas, I, II a and / or II b

in the R₁ and R₂ straight-chain and / or branched alkyl and / or alkenyl radical having 8 to 14 carbon atoms for R₁ and 9 to 17 carbon atoms for R₂ and r, s, t, u, v, w, integers from 1 to 3 mean as solubilizers for surfactants or surfactant mixtures based on water-soluble and / or water-mulsifiable polyalkylene glycol ethers of longer-chain alcohols when used in low-foam cleaning agents in the range of low temperatures and / or acidic pH values. 2. Embodiment according to claim 1, characterized in that the solubilizers of the general formula I, II a and / or II b in amounts of up to 150 percent by weight, preferably in amounts of about 5 to 100 percent by weight - each based on low-foaming surfactants - are used . 3. Embodiment according to claims 1 and 2, characterized in that the diethanolamine derivatives for solubilizing polyethylene glycol ether of the formula III
R₃ - O - (CH₂CH₂O) _n - R₄ (III)
are used in which R₃ is a straight-chain or branched alkyl or alkenyl radical having 8 to 18 carbon atoms, R₄ is an alkyl radical having 4 to 8 carbon atoms and n is a number from 7 to 12. 4. Embodiment according to claims 1 and 2, characterized in that the diethanolamine compounds are used in surfactant mixtures which contain surfactant components of the formulas IV, V and VI according to the following information: a) 20 to 80 percent by weight of polyethylene glycol ethers of the general formula IV
R₅ - O - (CH₂CH₂O) _p - R₆ (IV)
in the
R₅ is a straight-chain or branched alkyl radical or alkenyl radical with 8 to 18 carbon atoms,
R₆ is an alkyl radical with 4 to 8 carbon atoms and p is a number from 3 to 7, b) 10 to 40 percent by weight of alkyl polyalkylene glycol mixed ether of the general formula V

in the
R₇ 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 from 3 to 6, and c) 0 to 40 percent by weight of alkyl (poly) propylene glycol ether of the general formula VI

in the
R₈ is a straight-chain or branched alkyl or alkenyl radical having 16 to 22 carbon atoms and
z is a number from 1 to 3.