EP0054895B1 - Mixture of surfactants for the cleaning of hard surfaces - Google Patents

Abstract

A detergent composition is described which is particularly suitable for the mechanical cleaning of hard surfaces, in particular glass, porcelain and the like, in a cleaning liquor which is within the alkaline range. This detergent composition is composed of (A) a nonionic surfactant selected from the group comprising polyalkylene glycol monoalkyl ethers containing ethylene oxide and propylene oxide units, polyglycol ether formals containing ethylene oxide units and, if appropriate, propylene oxide units, or polyalkylene glycol dialkyl ethers containing ethylene oxide units and, if appropriate, propylene oxide units, and (B) a selected quaternary ammonium compound as a cationic surfactant. These compositions are particularly suitable for industrial crockery and bottle washing plants which are operated within the highly alkaline pH range and with vigorous mechanical agitation of the liquor.

Description

The invention relates to a surfactant mixture for the mechanical cleaning of hard surfaces, in particular bottles and dishes in the alkaline to highly alkaline range of the cleaning liquor.

For cleaning bottles and other objects with hard surfaces, such as dishes made of porcelain, ceramics, glass or plastic, as well as other glass or metal objects, mechanical cleaning processes are largely used today. While only relatively small movements of the liquor are required in accordance with the low throughput of items to be cleaned in household dishwashers, commercial and in particular industrial cleaning systems work with high throughput with very high liquor movements and spray intensities. Because of the higher contamination levels, high demands are placed on the quality of the surfactant-containing cleaning agents used with regard to their cleaning, dirt absorption and wetting properties. In order to ensure the necessary rapid detachment and emulsification of the adhering impurities, work is usually carried out in highly alkaline liquors in such commercial and in particular in industrial cleaning plants. Because of the high mechanical movements of the liquor, the system must also be as low-foam or foam-free as possible, since excessive foam formation can lead to malfunctions in the operating behavior of the system, for example if the dirt accumulating in the foam layer cannot be removed sufficiently. Additional tendencies towards foam formation are caused by the impurities carried in by the items to be cleaned, especially by protein-containing residues on the items to be cleaned. In the case of bottle cleaning, this also applies in particular to the labels to be removed, through which the glue residues and residues of printing inks, including the surfactant auxiliaries contained in the latter, are introduced into the cleaning liquor.

It is known to use non-ionic surfactants with low-foaming characteristics as cleaning agents for hard surfaces in alkaline baths. These are, in particular, addition products of ethylene oxide and / or propylene oxide onto amines, longer-chain fatty alcohols or alkylphenols, polyglycol ether formals or acetals or block copolymers of ethylene and propylene oxide. Such surfactant systems can be adjusted, in particular by suitable variation of the ethylene oxide and propylene oxide proportions, to the lowest possible foam tendency and increased cleaning action, an excess weight of the propylene oxide favoring the former property and an excess weight of the ethylene oxide promoting the latter property. However, such an adjustment of these properties is always a compromise, and it would be desirable to get more of one property without sacrificing portions of the other. In machine cleaning processes for bottles, crockery and the like in the industrial sector, which take place with high mechanical movement, the low foam of the surfactant systems mentioned is very desirable, but the detachment of dirt in the available time during the throughput of the items to be cleaned and also the dirt absorption capacity are often not sufficient and in need of improvement.

Attempts have already been made to compensate for this disadvantage by means of certain mixtures of the classes of nonionic surfactants mentioned, as described in DE-B-27 23 139. Such mixtures have an advantageously low foam tendency at the elevated working temperature of the system, but an excessive foam tendency at lower temperatures, which is disadvantageous when filling and heating the system. It is hardly possible to use anionic surfactants, which would increase the cleaning and wetting properties, as this increases the tendency to foam too much. Attempts have also been made to include cationic surfactants with long alkyl chains in bottle detergents for disinfection. This is described in DE-A-2449354, using quaternary ammonium salts which contain one or two long-chain alkyl radicals or alkylaryl radicals in the molecule in addition to short-chain radicals as cationic surfactants. Since this type of cationic surfactant tends to form relatively strong foams, a defoamer must also be added, for which orthophosphoric acid monoalkyl esters are provided there. If necessary, nonionic surfactants can also be present in the mixture. Such formulations including cationic quaternary ammonium compounds containing at least one long alkyl chain, however, have the decisive disadvantage that the compounds mentioned absorb substantially onto the items to be cleaned. This prevents the liquid from running off smoothly, drops form, which then leave disruptive edges when drying. This effect, which is very desirable when used as a laundry aftertreatment agent for textiles, makes the use of the named quaternary ammonium compounds in dishes and bottle cleaning agents very problematic for alkaline liquors. Also, if the quaternary ammonium compounds mentioned are used in a mixture with non-ionic surfactants, as is also described in DE-A-24 49 354 and also in DE-A-25 23 588, there is no appreciable increase in the dirt absorption capacity of the achieved non-ionic component.

The task was therefore to improve the dirt-holding capacity of such mixtures without having to accept the disadvantage of substantivity.

• A) 20 bis 95 Gew.-% eines nicht-ionischen Tensids der Formel
  
  
  
  oder eines Gemisches der Formeln
  • A'), A²) und/oder A³), worin
  • R' ein Alkylrest mit 6 bis 18 C-Atomen,
  • R² ein Alkylrest mit 1 bis 4 C-Atomen,
  • R³ ein Alkylrest mit 1 bis 4 C-Atomen,
  • a ein statistischer Mittelwert im Bereich von 3 bis 6,
  • b ein statistischer Mittelwert im Bereich von 3 bis 5,
  • c ein statistischer Mittelwert im Bereich von 6 bis 12 und
  • d ein statistischer Mittelwert im Bereich von 0 bis 3 ist,
  
  und worin die Ethylenoxid- und Propylenoxid-Einheiten von A' in Form von Blöcken vorliegen und zumindest ein Teil des Propylenoxids nach Anlagerung des Ethylenoxids aufkondensierf ist, und die Einheiten von A² und A³ statistisch oder in Blöcken angeordnet sind, und
• B) 5 bis 80 Gew.-% eines kationischen Tensids der Formel
  
  worin
  • R⁴, R⁵ und R⁶, gleich oder verschieden, Alkylreste mit 1 bis 8 C-Atomen sind und R⁷ ein Alkylrest mit 1 bis 4 C-Atomen oder ein Benzylrest ist sowie.

According to the invention, this is achieved by a surfactant mixture which is characterized in that that it consists of

• A) 20 to 95 wt .-% of a non-ionic surfactant of the formula
  
  
  
  or a mixture of the formulas
  • A '), A ² ) and / or A ³ ), wherein
  • R 'is an alkyl radical with 6 to 18 carbon atoms,
  • R ^{2 is} an alkyl radical with 1 to 4 carbon atoms,
  • R ^{3 is} an alkyl radical with 1 to 4 carbon atoms,
  • a a statistical mean in the range from 3 to 6,
  • b a statistical mean in the range from 3 to 5,
  • c is a statistical mean in the range of 6 to 12 and
  • d is a statistical mean in the range from 0 to 3,
  
  and wherein the ethylene oxide and propylene oxide units of A 'are in the form of blocks and at least part of the propylene oxide is condensed after the ethylene oxide has been added on, and the units of A ² and A ³ are arranged randomly or in blocks, and
• B) 5 to 80% by weight of a cationic surfactant of the formula
  
  wherein
  • R ⁴ , R ⁵ and R ⁶ , identical or different, are alkyl radicals with 1 to 8 carbon atoms and R ^{7 is} an alkyl radical with 1 to 4 carbon atoms or a benzyl radical and.

A means an anion.

The effectiveness of these agents for the mechanical cleaning of dishes, bottles and other glass objects or metals in alkaline liquors, especially in the highly alkaline liquors used in the industrial sector, is based on the surprising finding that the inclusion of quaternary ammonium compounds with only short ones to medium chains in the molecule as a cationic component, the dirt-holding capacity of such mixtures can be considerably improved, these cationic surfactants practically not substantively absorbing the items to be cleaned in the alkaline range, and furthermore such agents also have an advantageous low foam tendency both at elevated and at low temperatures exhibit.

• A) sind bekannt. Es handelt sich dabei um
  • A¹) Anlagerungsprodukte von Alkoholen mit 6 bis 18 Kohlenstoffatomen an Ethylenoxid und Propylenoxid, wobei diese Ethylenoxid- und Propylenoxid-Einheiten in Form von Blöcken vorliegen und zumindest ein Teil, vorzugsweise das gesamte Propylenoxid, nach Anlagerung des Ethylenoxids aufkondensiert wird. Derartige Kondensationsprodukte sind insbesondere aus ihrer Anwendung bei Waschmitteln für Textilien bekannt, beispielsweise aus der DE-B-1135122. Sie entsprechen der allgemeinen Formel
    
    darin bedeutet
  • R¹ einen Alkylrest mit 6 bis 18 C-Atomen, vorzugsweise mit 7 bis 14 C-Atomen,
  • a einen statistischen Mittelwert im Bereich von 3 bis 6, vorzugsweise 3,5 bis 5,5,
  • b einen statistischen Mittelwert im Bereich von 3 bis 5, vorzugsweise 3,5 bis 4,5.

The non-ionic surfactants used as a component

• A) are known. It's about
  • A ¹ ) adducts of alcohols having 6 to 18 carbon atoms with ethylene oxide and propylene oxide, these ethylene oxide and propylene oxide units being in the form of blocks and at least part, preferably all, of the propylene oxide being condensed after the ethylene oxide has been added on. Such condensation products are known in particular from their use in detergents for textiles, for example from DE-B-1135122. They correspond to the general formula
    
    means in it
  • R ^{1 is} an alkyl radical with 6 to 18 carbon atoms, preferably with 7 to 14 carbon atoms,
  • a a statistical mean in the range from 3 to 6, preferably 3.5 to 5.5,
  • b a statistical mean in the range from 3 to 5, preferably 3.5 to 4.5.

Such an average can be an integer or a fraction. The ratio of the ethylene oxide to propylene oxide units should preferably be in the range from 0.8 to 1.5.

• A²) Polyglykoletherformale der allgemeinen Formel
  
  diese Formale enthalten Ethylenoxid-Einheiten und gegebenenfalls Propylenoxid-Einheiten, wobei beim Vorliegen beider diese statistisch verteilt oder in Blöcken eingebaut sein können. Solche Polyglykoletherformale können hergestellt werden, beispielsweise aus den entsprechenden Polyglykolethern, Alkoholen und Formaldehyd, wie in der DE-A-25 23 588 beschrieben ist. In der genannten Formel bedeuten R¹ einen Alkylrest mit 6 bis 18 C-Atomen, vorzugsweise mit 8 bis 14 C-Atomen, R² einen Alkylrest mit 1 bis 4 C_-Atomen, bevorzugt den n-Butylrest, c einen statistischen Mittelwert im Bereich von 6 bis 12, vorzugsweise von 6 bis 10, und d einen statistischen Mittelwert im Bereich von 0 bis 3, vorzugsweise 0.

It is also about

• A ² ) Polyglycol ether formals of the general formula
  
  these formals contain ethylene oxide units and, if appropriate, propylene oxide units, it being possible for these to be statistically distributed or incorporated in blocks if both are present. Such polyglycol ether formals can be prepared, for example from the corresponding polyglycol ethers, alcohols and formaldehyde, as described in DE-A-25 23 588. In the above formula R ¹ represents an alkyl group having 6 to 18 carbon atoms, preferably having 8 to 14 carbon atoms, R ² an alkyl group having 1 to 4 C _- atoms, preferably the n-butyl radical, c is a statistical average in the range from 6 to 12, preferably from 6 to 10, and d has a statistical mean in the range from 0 to 3, preferably 0.

• A³) ein Polyalkylenglykoldialkylether der Formel
  
  sein, der Ethylenoxid- und gegebenenfalls Propylenoxid-Einheiten enthält, die statistisch oder in Blöckken angeordnet sein können. In dieser Formel bedeuten R¹ einen Alkylrest mit 6 bis 18 C-Atomen, vorzugsweise mit 8 bis 14 C-Atomen, R³ einen Alkylrest mit 1 bis 4 C-Atomen, vorzugsweise den tert.-Butylrest, c einen statistischen Mittelwert im Bereich von 6 bis 12, vorzugsweise von 7 bis 10, und d einen statistischen Mittelwert im Bereich von 0 bis 3, vorzugsweise 0.

Finally, the non-ionic component can also

• A ³ ) a polyalkylene glycol dialkyl ether of the formula
  
  be, which contains ethylene oxide and optionally propylene oxide units, which can be arranged statistically or in blocks. In this formula, R ^{1 is} an alkyl radical with 6 to 18 C atoms, preferably with 8 to 14 C atoms, R ^{3 is} an alkyl radical with 1 to 4 C atoms, preferably the tert-butyl radical, c is a statistical mean in the range from 6 to 12, preferably from 7 to 10, and d has a statistical mean in the range from 0 to 3, preferably 0.

The aforementioned non-ionic surfactants can also be present as mixtures within groups A ¹ ), A ² ) or A ³ ) or else between groups A ¹ ), A ² ) and / or A ³ ). The non-ionic surfactants of group A ¹ ) are preferred.

in der R⁴ und R⁵, gleich oder verschieden, einen Alkylrest mit 1 bis 8 C-Atomen, vorzugsweise mit 4 bis 6 C-Atomen, R⁶ einen Alkylrest mit 1 bis 8 C-Atomen, vorzugsweise 1 bis 6 C-Atomen, sowie R⁷ einen Alkylrest mit 1 bis 4 C-Atomen oder einen Benzylrest, bedeuten. A ist ein Anion, vorzugsweise ein Chlorid-oder Bromidanion oder ein solches der Formel CH₃OSO₃- .The surfactant mixture contains a quaternary ammonium compound B) of the formula as a cationic component

in which R ⁴ and R ⁵ , the same or different, are an alkyl radical with 1 to 8 C atoms, preferably with 4 to 6 C atoms, R ^{6 is} an alkyl radical with 1 to 8 C atoms, preferably 1 to 6 C atoms , and R ^{7 is} an alkyl radical having 1 to 4 carbon atoms or a benzyl radical. A is an anion, preferably a chloride or bromide anion or one of the formula CH ₃ OSO ₃ -.

The composition of the surfactant mixture is essential for the advantageous properties. In order to achieve the required optimal combination of dirt absorption capacity, the lowest possible foam tendency and practically non-substantive behavior, the ratio of components A: B should be in the range from 20:80 to 95: 5% by weight, preferably 40:60 to 85:15% by weight: -%, lie.

The surfactant mixtures can be used as a mixture of components A + B in undiluted, liquid form. However, they can also be used in the form of aqueous concentrates, for example for better meterability, if appropriate also with the addition of an organic solvent. Components A and B can of course also be added separately to the aqueous cleaning liquor.

The application concentration is expediently 0.05 to 10 g of the mixture A + B per liter of cleaning liquor, preferably 0.1 to 2 g per liter. The application concentrations mentioned are non-critical statements, since the amount varies to a certain extent according to the type to be cleaned Surface and depending on the type and extent of contamination.

If appropriate, further additives and auxiliaries can be added to the surfactant mixtures according to the invention in the production of commercially available formulations. These include dyes, fragrances, corrosion inhibitors and disinfectants. In particular, the known builders, which are optionally also complexing agents, should also be mentioned here. Here, for example, the condensed phosphates, such as tripolyphosphates and in particular pentasodium triphosphate, come into consideration. Furthermore, these are complex-forming aminopolycarboxylic acids and their salts, such as, in particular, alkali metal salts of nitrilotriacetic acid and ethylenediaminetetraacetic acid, and also also complex-forming hydroxycarboxylic acids and polymeric carboxylic acids, such as citric acid, tartaric acid and the like. Another class of complexing builders are polyphosphonic acid salts, such as the alkali salts of aminophosphonic acid. Finally, builders such as silicates, for example sodium metasilicate, carbonates, bicarbonates, borates and citrates, can also be added. With the aid of such additives, the surfactant mixtures according to the invention can optionally be converted into powder form and can also be used in this form.

The surfactant mixtures according to the invention are suitable for the mechanical cleaning of hard surfaces in alkaline liquors. This applies to cleaning in household dishwashers and so-called commercial cleaning systems.

However, the mixtures are particularly suitable for industrial cleaning systems for hard surfaces, for example dishwashing and bottle washing systems, which operate under high mechanical liquor movements in continuous operation and in highly alkaline liquors at pH values of # 10, preferably> 12.

The necessary alkaline additives, preferably sodium or potassium hydroxide for the highly alkaline pH range of the liquor, can be dissolved in the aqueous cleaning liquor before the surfactant mixture according to the invention is introduced. However, they can also be added directly to the surfactant mixture and metered together with it. The alkaline agent is expediently added in the form of powder, flakes or cookies.

In addition to the high alkali stability required for this, the mixtures according to the invention have the low foaming tendency which is indispensable for industrial cleaning systems and which, as a rule, makes the addition of additional defoamers superfluous. Only in the case of extremely high movements of the liquor or in the presence of soiling with an extremely high tendency towards foaming can the addition of foam-suppressing agents be expedient, which must have the required stability to alkali. These are, for example, orthophosphoric acid esters, ethylenediamine condensation products with ethylene oxide and propylene oxide and also fatty alcohols.

In addition to the advantages already mentioned, the surfactant mixtures according to the invention as cleaning agents for the mechanical cleaning of hard surfaces, in particular with regard to the high demands placed on industrial cleaning systems, also have the following significant advantages: the mixtures are not only resistant to alkali, but also together with Alkali stable in storage for long periods. They have an extremely low tendency to foam formation not only at the working temperatures of such cleaning systems, i.e. h., above about 40 ° C, but also at low temperatures, so that when refilled with cold water and heating there is no formation of disruptive foam, which can then lead to over-foaming or to disturbances in the circulation of the system. The excellent dirt absorption capacity allows long service life in the system until it is refilled without impairing the cleaning effect. Good wetting capacity and drainage behavior enable dirt to be removed quickly and thus a high throughput of items to be cleaned. The freedom from stains and streaks as well as high gloss of the cleaned goods is also guaranteed. This makes the mixtures according to the invention, for example, extremely suitable for cleaning bottles in breweries, and it is also found that when the cleaned bottles are filled with foaming beverages, there is no impairment due to foam breakdown.

"Objects with a hard surface in the sense of the application of the surfactant mixtures according to the invention are to be understood here primarily as all types of dishes and bottles made of glass, porcelain, ceramic and plastic, as well as other objects made of the materials mentioned or of metals.

The invention is illustrated by the following examples:

• In those used in the following examples, surfactant mixtures containing the following components (C _7-11 means etc. chain sectional R ^l range mentioned above):
• Non-ionic surfactants of the formula A ^I ):
  
  
  
  
  Non-ionic surfactants of the formula A ² ):
  
  
  Non-ionic surfactants of formula A ³ ):
  
  

• i) Dibutyldimethylammoniumchlorid
• j) Tetrabutylammoniumchlorid
• k) Dioctyldimethylammoniumchlorid
• I) Dihexyldimethylammoniumchlorid
• In den Beispielen werden folgende Mischungen aus den Tensiden a bis I eingesetzt :
  

Quaternary ammonium compounds of formula B.

• i) Dibutyldimethylammonium chloride
• j) tetrabutylammonium chloride
• k) dioctyldimethylammonium chloride
• I) Dihexyldimethylammonium chloride
• The following mixtures of surfactants a to I are used in the examples:
  

• a) Schaumverhalten der Tensidmischung in wäßriger alkalischer Lösung nach DIN 53 902 bei 25 und 65 °C (Spalte 2 und 3 der Tabelle).
• β) Ermittlung des Schmutzaufnahmevermögens
  • Das Schmutzaufnahmevermögen durch Prüfung der Schaumneigung bei Schmutzbelastung wird ermittelt, indem die Reinigungsflotte mit einem Testschäumer versetzt wird. Als Testschäumer wird ein Weizenbier (Export-Weizenbier der Klosterbrauerei Raitenhaslach-Burghausen) in einer Konzentration von 6 Gew.-% in der Flotte verwendet. Unter Schlagschaumbedingungen nach DIN-Norm 53 902 wird daran bei 65 °C die Schaumbildung gemessen (Spalte 4 der Tabelle).
• y) Prüfung des Ablaufverhaltens in gereinigten Flaschen

The following properties are measured on the mixtures mentioned (all measurements are carried out on cleaning liquors which contain 1.5 g of surfactant mixture A + B per liter and are adjusted to a pH of 13 using NaOH):

• a) Foaming behavior of the surfactant mixture in aqueous alkaline solution according to DIN 53 902 at 25 and 65 ° C (columns 2 and 3 of the table).
• β) Determination of the dirt absorption capacity
  • The dirt absorption capacity by checking the foam tendency when contaminated with dirt is determined by adding a test foam to the cleaning liquor. A wheat beer (export wheat beer from the monastery brewery Raitenhaslach-Burghausen) is used as a test frother in a concentration of 6% by weight in the fleet. Under blow foam conditions according to DIN standard 53 902, the foam formation is measured at 65 ° C (column 4 of the table).
• y) Checking the drainage behavior in cleaned bottles

Clean 0.5 liter beer bottles are filled with 100 ml of the cleaning liquor and shaken vigorously 5 times with a cork stopper. After a short period of action (approx. 1 minute), the shaking process is repeated 5 times and the detergent-containing cleaning liquor is then poured out. This is followed by rinsing 4-5 times in succession with 100 ml of distilled water until pH 7 is reached.

Visual observation of the drainage behavior on the inside of the bottle: Drop formation indicates substantivity on the bottle walls (column 5 of the table).

Results

Claims (3)

1. A detergent composition for the mechanical cleaning of hard surfaces in alkaline liquors, characterised by

A) 20 to 95 % by weight of a non-ionic surfactant of the formula

or of a mixture of the formulae

A') , A²), and /or A3), in which

R' is an alkyl radical having 6 to 18 C atoms,

R² is an alkyl radical having 1 to 4 C atoms,

R³ is an alkyl radical having 1 to 4 C atoms,

a is a statistical average value within the range from 3 to 6,

b is a statistical average value within the range from 3 to 5,

c is a statistical average value within the range from 6 to 12 and

d is a statistical average value within the range from 0 to 3,

and in which the ethylene oxide and propylene oxide units are present in the form of blocks and at least part of the propylene oxide has been condensed after adding the ethylene oxide, and in which the units of A²) and A3) are distributed statistically or in the form of blocks, and

B) 5 to 80 % by weight of a cationic surfactant of the formula

in which

R⁴, R⁵, and R^S are identical or different and are alkyl radicals having 1 to 8 C atoms and R⁷ is an alkyl radical having 1 to 4 C atoms or a benzyl radical, and A adenotes an anion.

2. A detergent composition as claimed in claim 1, characterised in that 40 to 85 % by weight of the non-ionic surfactant A) and 15 to 60 % by weight of the cationic surfactant B) are present.

3. Use of the detergent composition as claimed in claims 1 and 2 in aqueous alkaline cleaning liquors having a pH value of≧10 for the mechanical cleaning of hard surfaces, in particular of bottles.