EP0986631B1 - Low-foam detergent - Google Patents

Description

The invention relates to a cleaning agent for hard, in particular metallic, Surfaces. It is a so-called industrial cleaner, especially one so-called neutral cleaner. Because of its special combination of Glycol ether and cationic surfactants are low-foaming and can therefore be preferred as Spray cleaner in the entire application-relevant temperature range from about 15 to about 80 ° C can be used.

Such industrial cleaners are mainly used in the automotive industry as well their supplier industries for cleaning and passivation mainly in Spray cleaning systems used. They are suitable for intermediate and Final cleaning without cutting and machined parts in aggregate and Assembly plants. Practically all relevant materials, such as iron and steel, Aluminum, silumin, copper, brass, zinc and plastics can be treated and the majority of all contaminations are organic or inorganic Basis, such as cooling lubricants, rust protection oils, processing oils, drawing aids, Pigments and slight metal abrasion can be removed. Such Detergents can also be used in common immersion processes, however, their use in the spraying process is usually preferred.

The basic chemical components of such industrial cleaners are common Surfactants and organic corrosion inhibitors. The latter ensure you temporary corrosion protection during and after treatment. In addition Such cleaning agents usually contain substances that are able to to counteract undesirable foam development. The use of such In most cases, foam-inhibiting additives are caused by the fact that detached from the substrates and accumulated in the cleaning baths Impurities act as foaming agents.

In addition, the use of so-called anti-foaming agents can also be due to the fact that the detergents themselves are components included under the given working conditions - d. H. especially at Spraying process - give rise to undesirable foaming, for example anionic surfactants or foaming at the respective working temperature nonionic surfactants.

From "Ullman's Encyclopedia of Technical Chemistry", 4th edition, volume 22 (1982), Pages 489 to 493, is the use of fatty alcohol polyethylene glycol ethers - also called fatty alcohol ethoxylates - as a surfactant component in washing and Detergents known. However, such addition products are from Ethylene oxide on fatty alcohols not only suitable for use in spray processes, since they foam strongly at application temperatures in the range of 15 to 80 ° C. It is also known to use fatty alcohol ethoxylate propoxylates as low foaming Use raw materials for washing; see. for example the Ullmann volume cited above, Page 494.

DE-A-36 20 011 describes cationic surfactants based on quaternary Ammonium compounds and their use in detergents. The Cationic surfactants are used in the alkaline pH range, among others Detergent ingredients used.

EP-A-0 116 151 describes a method for regeneration or recycling of aqueous degreasing and cleaning solutions by adding cationic Surfactants or cationic modified polymers or mixtures thereof.

EP-A-0 054 895 describes a surfactant mixture composed of a nonionic surfactant and a quaternary ammonium compound as a cationic surfactant for cleaning of hard surfaces. The nonionic surfactant is in a proportion in the mixture from 20 to 95% by weight, the cationic surfactant in a proportion of 5 to 80% by weight contain.

DE-A-40 14 859 describes a low-foam surfactant combination for Cleaning hard surfaces consisting of at least one quaternary Ammonium compound and at least one alkyl polyethylene glycol mixed ether consists. These mixed ethers either have an acyclic alkyl or Alkenyl radical with 6 to 18 carbon atoms or a cyclic alkyl radical with 5 to 6 C atoms. In addition, this surfactant combination can be alkyl ethoxylates or Contain alkyl ethoxylate propoxylates, each with an alkyl or alkenyl radical Have 6 to 18 carbon atoms.

EP-A-275 987 discloses a cleaning agent for compressors of gas turbines which contains 4 to 95% by weight glycol ether, 0.1 to 14% by weight nonionic surfactant, 0.01 to 6% by weight cationic surfactant and 0 contains up to 95 wt .-% water. EP-A-691 397 discloses an antimicrobial cleaner for hard surfaces, the solvent being C _1-6 alkanol-C _3-24 alkylene glycol ether, amphoteric and / or nonionic surfactants. Contains cationic surfactants, builders and water. DE-C-41 02 709 proposes a means for degreasing metal surfaces which contains 15 to 30% by weight of adducts of lower alkylene oxides with fatty alcohols with cloud points below 50 ° C, 0.5 to 3% by weight of cationic surfactants and 10 to Contains 20 wt .-% auxiliary solvent from the group of the C _2-5 alkanols and lower glycol ether in water.

Accordingly, agents are known which are fatty alcohol ethoxylates, cationic surfactants and Solvents or solubilizers contain lower glycols. The invention lies based on the surprising finding that with a suitable combination of Glycols and cationic surfactants have an excellent cleaning effect, without these agents additionally having amphoteric surfactants or surfactants Contain fatty alcohol alkoxylates such as ethoxylates or propoxylates. Here are fatty alcohol alkoxylates according to the disclosure of EP-A-691 397 alkoxylates of alcohols with at least 6 carbon atoms in the alkyl radical Roger that.

1. Um Schaumarmut zu gewährleisten, erfolgt die Anwendung oberhalb des sogenannten Trübungspunkts. Die Anwendungslösungen sind demnach durch eine dispergierte, tensidreiche Phase eingetrübt. Diese tensidreiche Phase wird leicht durch übliche standzeitverlängernde Maßnahmen wie zum Beispiel Skimmer, Separatoren. Zentrifugen oder Membranfiltration abgetrennt und steht für den Reinigungsprozeß nicht mehr zur Verfügung.

2. Die üblichen nichtionischen Tensidsysteme wie zum Beispiel Fettalkohol- oder Fettaminethoxylate oder -propoxylate sowie deren Mischether sind in der Wassergefährdungsklasse 2 eingestuft.

3. Die gut entfettenden nichtionischen Tenside, zum Beispiel Fettalkoholethoxylate mit mehr als 4 Mol Ethylenoxid oder Fettaminethoxylate mit mehr als 5 Mol Ethylenoxid, die bei den üblichen Anwendungstemperaturen selbst keinen Trübungspunkt aufweisen, schäumen extrem stark und kommen für Spritzanwendungen allein nicht in Betracht. Vielmehr müssen Antischaummittel zugesetzt werden, die zur Reinigungsleistung selbst keinen oder nur einen geringen Beitrag leisten. Um diese Antischaummittel in die flüssigen Reinigerkonzentrate einzuarbeiten, sind häufig Lösevermittler, sogenannte hydrotrope Substanzen, erforderlich, um klare Konzentrate zu erhalten. Diese Lösevermittler stellen einen weiteren Ballast dar, der selbst nicht zur Reinigungsleistung beiträgt.

All sprayable surfactant systems have a number of disadvantages in the application concentration of about 0.5 to about 5% by weight:

1. To ensure low foam, the application is above the so-called cloud point. The application solutions are therefore clouded by a dispersed, surfactant-rich phase. This phase, which is rich in surfactants, is easily made by conventional measures to extend the service life such as skimmers and separators. Centrifuges or membrane filtration separated and is no longer available for the cleaning process.

2. The usual nonionic surfactant systems such as fatty alcohol or fatty amine ethoxylates or propoxylates and their mixed ethers are classified in water hazard class 2.

3. The highly degreasing nonionic surfactants, for example fatty alcohol ethoxylates with more than 4 moles of ethylene oxide or fatty amine ethoxylates with more than 5 moles of ethylene oxide, which themselves have no cloud point at the usual application temperatures, foam extremely strongly and are not suitable for spray applications alone. Rather, anti-foaming agents must be added that make little or no contribution to the cleaning performance itself. In order to incorporate these anti-foaming agents into the liquid cleaner concentrates, solubilizers, so-called hydrotropic substances, are often required in order to obtain clear concentrates. These solubilizers represent another ballast that does not itself contribute to the cleaning performance.

In contrast, the invention has the task of a new cleaning effective To provide a combination of substances that do not have the disadvantages mentioned above having. In particular, a new cleaning-active substance combination is to be provided that are clear in the practical temperature range of about 15 to about 80 ° C, delivers low-foaming and sprayable cleaning solutions without additional ones Defoamers and solubilizers needed.

a) Glykolether der allgemeinen Formel R-O-(CH₂-CH(CH₃)-O)_n-H, wobei R einen Alkylrest mit 1 bis 4 C-Atomen oder einen Phenylrest und n eine Zahl im Bereich von 1 bis 5 bedeuten, und

b) Kationtenside im Gewichtsverhältnis a) zu b) zwischen 8 : 1 und 100 : 1 enthält.

This object is achieved by a cleaning agent concentrate containing glycol ether and cationic surfactants, characterized in that it contains less than 0.1% by weight of fatty alcohol alkoxylates and / or amphoteric surfactants and that it

a) Glycol ether of the general formula RO- (CH ₂ -CH (CH ₃ ) -O) _n -H, where R is an alkyl radical having 1 to 4 carbon atoms or a phenyl radical and n is a number in the range from 1 to 5, and

b) contains cationic surfactants in the weight ratio a) to b) between 8: 1 and 100: 1.

Such glycol ethers of the above formula are preferably used in which R is an alkyl radical with 1 to 4 carbon atoms or a phenyl radical and n is a number in Range from 1 to 3 mean. It is further preferred that the Detergent concentrate glycol ether and cationic surfactants in the weight ratio a): b) contains between 8: 1 and 25: 1.

This cleaning agent concentrate preferably contains the glycol ethers a) im Concentration range from about 5 to about 200 g / l and the cationic surfactants b) in Concentration range from about 0.2 to about 25 g / l. The rest is water or an aqueous solution of other active ingredients or auxiliaries, in particular Corrosion inhibitors.

Glycol ethers which can be used according to the invention are, for example Tripropylene glycol monoethyl ether, dipropylene glycol n-butyl ether, Tripropylene glycol n-butyl ether and propylene glycol phenyl ether. To be favoured Tripropylene glycol monomethyl ether and tripropylene glycol n-butyl ether are used.

R¹ ein linearer oder verzweigter Alkylrest mit 1 bis 22 C-Atomen,

R² Wasserstoff oder ein linearer oder verweigter Alkylrest mit 1 bis 22 C-Atomen sein kann, wobei die Gesamtzahl der C-Atome der Reste R¹ und R² im Bereich von 10 bis 22 liegt,

n = 0 oder 1 ist,

R³ und R⁴ unabhängig voneinander für Methyl, Ethyl, 2-Hydroxyethyl oder Hydroxypropyl,

R⁵ für Alkylreste mit 1 bis 12-Atomen, einen Benzylrest oder für Alkylphenylreste mit 1 bis 3 C-Atomen im Alkylrest stehen und

wobei die Gesamtzahl der Kohlenstoffatome des quartären Ammoniumkations mindestens 9 beträgt und mindestens einer der Reste R¹ und R⁵ mehr als 4 Kohlenstoffatome aufweist, und

X^- für Halogenid, Methylsulfat oder ein Anion einer aliphatischen oder aromatischen organischen Säure mit bis zu 15 C-Atomen stehen.

The cationic surfactants b) are preferably selected from quaternary ammonium compounds of the general formula R ¹ - (CHOH-CHR ² ) _n -N ⁺ R ³ R ⁴ R ⁵ X ^- in the

R ^{1 is} a linear or branched alkyl radical having 1 to 22 carbon atoms,

R ^{2 can be} hydrogen or a linear or branched alkyl radical having 1 to 22 C atoms, the total number of C atoms of the radicals R ¹ and R ^{2 being} in the range from 10 to 22,

n = 0 or 1,

R ³ and R ⁴ independently of one another are methyl, ethyl, 2-hydroxyethyl or hydroxypropyl,

R ^{5 stands} for alkyl radicals with 1 to 12 atoms, a benzyl radical or for alkylphenyl radicals with 1 to 3 C atoms in the alkyl radical and

wherein the total number of carbon atoms of the quaternary ammonium cation is at least 9 and at least one of the radicals R ¹ and R ^{5 has} more than 4 carbon atoms, and

X ^- stand for halide, methyl sulfate or an anion of an aliphatic or aromatic organic acid with up to 15 carbon atoms.

Cationic surfactants are preferably used in which, in the general formula given, R ³ and R ^{4 are} methyl and R ^{5 is} benzyl.

Examples of such cationic surfactants are lauryl-dimethyl-benzylammonium salts or 2-hydroxydodecyl-dimethyl-benzylammonium salts. Anions X ^- in these salts are, for example, halides, in particular chloride, or anions of organic acids which form water-soluble salts with the quaternary ammonium ions. Examples of such organic anions are acetate, propionate, lactate or benzoate.

The use of such cationic surfactants together with nonionic surfactants for low-foam industrial cleaners is, for example, from DE-A-40 14 859 known. There, however, these cationic surfactants are mixed with nonionic surfactants Alkyl or alkenyl radicals with at least 5, preferably with 6 to 18, carbon atoms combined. In contrast, it is new and surprising that instead of these usual nonionic surfactants which can use glycol ether a). Since this one Have alkyl radicals with only 1 to 4 carbon atoms, it is surprising that they show a degreasing effect at all. Compared to the non-ionic surfactants state of the art they have the ecological advantage in Water hazard class 1 to be classified. Together with the cationic surfactants form them in the application concentration of the detergent concentrate in Water from about 0.5 to about 5 wt .-% clear application solutions, which in Spray processes are low-foaming and their cleaning performance with the conventional spray cleaners is at least comparable.

The cleaning agent concentrates according to the invention are in dilute aqueous Application solution in principle without further additives for cleaning purposes applicable. Because they focus on cleaning unpainted metal surfaces to be used, however, it is preferable that the Detergent concentrates also contain corrosion inhibitors. Their concentration in the concentrates is preferably in the range of approximately 100 to about 700 g / l. These corrosion inhibitors prevent the corrosion of the cleaned bare metal parts, if they are not directly processed, but for example, packed or stored wet.

Alkanolamines, for example, can be used as corrosion inhibitors. Monoethanolamine, monoisopropanolamine, Triethanolamine, triisopropanolamine or mixtures thereof. Dialkanolamines would also be due to their excellent corrosion protection applicable. Avoided for toxicological reasons (risk of nitrosamine formation) but nowadays the use of dialkanolamines.

Furthermore, the corrosion inhibitors can be selected from branched or unbranched, saturated or unsaturated aliphatic carboxylic acids with 6 to 10 carbon atoms and / or from aromatic carboxylic acids with 7 to 10 carbon atoms. At the desired usual pH values of the so-called neutral cleaners, which in the Range from about 6.5 to about 9, the carboxylic acids are largely as Anions. As counterions with which the acids can be neutralized can, for example, alkali metal ions such as in particular sodium or Potassium ions, but preferably the cations of those listed above Alkanolamines are used.

Examples of suitable carboxylic acids are caproic acid, caprylic acid, Ethylhexanoic acid, heptanoic acid, isononanoic acid and benzoic acid or their Derivatives, especially 3-nitrobenzoic acid or 4-hydroxybenzoic acid.

The detergent concentrates can be used as further auxiliaries or active ingredients contain: builder substances such as alkali metal orthophosphates, polyphosphates, silicates, borates, carbonates, polyacrylates and gluconates. This Builders sometimes have complexing properties and work thereby water softening. Instead of or in addition to this, stronger ones Complexing agents such as 1-hydroxyethane-1,1-diphosphonic acid or 2-phosphonobutane-1,2,4-tricarboxylic acid be used. Ethylenediaminetetraacetate and nitrilotriacetates can also be used, but if necessary, too Lead to problems with wastewater treatment. To the Detergent concentrates and the application solutions made from them To protect against contamination, biocides can be added if desired.

The cleaning agent characterized above represents a concentrate from which the ready-to-use cleaning solution can be prepared by dilution. In principle, it would be possible to find the cleaning solution by dissolving the individual Produce active components in water in the required concentration range. In the industrial sector concerned, however, it is common for the manufacturer to concentrate delivers, which contain all active ingredients in the required ratio and from which the user is ready to use by simply diluting with water Can produce cleaning solution. The concentrates are usually like this set that they are used as about 0.5 to about 5 wt .-% aqueous solution come, d. H. that they are for use with water in a ratio of about 1: 200 be diluted to about 1:20. Accordingly, the invention also includes ready-to-use aqueous cleaning agent, which can be obtained by the cleaning concentrate according to one or more of claims 1 to 7, such as it is described in more detail above, in a ratio of 1: 200 to 1:20 with water diluted. In particular, this aqueous cleaning agent is used for Degreasing of metal parts in spraying systems, whereby a temperature in Range of about 15 to about 80 ° C and especially in the range of about 15 to about 30 ° C is set.

Embodiments example 1

Aqueous application solutions and comparison solutions according to the invention state of the art in terms of cleaning results, surfactant separation and foaming behavior compared. For this, were initially through Mixing the individual components made of detergent concentrates. For the application tests, these were washed with water as indicated below diluted.

Test results:

A basic cleaner formulation consisting of 30% triethanolamine and 4% Isononanoic acid, as well as the rest 100% water, is mixed with various "Tensiden" added and then a cleaning, tenside and Foam test (all percentages are percentages by weight).

a) 5,0 % Tripropylenglykolmonomethylether 0,5 % 2-Hydroxydodecyl-dimethyl-benzyl-ammonium-benzoat

b) 5,0 % Kokosamin + 12 EO

c) 5,0 % Fettalkohol C_12/14 + 3 EO + 6 PO

d) 5,0 % Octanol + 4,5 EO-butylether mit eingeengter Homologenverteilung jeweils zu 100 % aufgefüllt mit Kondenswasser.

Tensidmischung a (erfindungsgemäß) b (Vergleich) c (Vergleich) d (Vergleich) Reinigungsergebnis ++ ++ -- -- Tensidabscheidung ++ ++ -- -- Schaumverhalten + -- + ++ ++ = sehr gute Reinigung, keine Tensidabscheidung, kein Schaum + = gute Reinigung, Schaumhöhe im Spritzverfahren <= 1,5 cm -- = praktisch keine Reinigung, starke Tensidabscheidung, starke Schaumentwicklung Surfactants:

a) 5.0% tripropylene glycol monomethyl ether 0.5% 2-hydroxydodecyldimethylbenzylammonium benzoate

b) 5.0% coconut amine + 12 EO

c) 5.0% fatty alcohol C _12/14 + 3 EO + 6 PO

d) 5.0% octanol + 4.5 EO-butyl ether with a narrow homolog distribution, each filled 100% with condensed water.

Surfactant mixture a (according to the invention) b (comparison) c (comparison) d (comparison) Cleaning result ++ ++ - - Surfactant separation ++ ++ - - Foaming behavior + - + ++ ++ = very good cleaning, no surfactant separation, no foam + = good cleaning, foam height in the spray process <= 1.5 cm - = practically no cleaning, strong surfactant separation, strong foaming

Example 2

There were further aqueous application solutions according to the invention different glycol ethers e), f) and g) tested:

Detergent formulation:

1.2% by weight of citric acid

1.5% by weight isononanoic acid

10.4% by weight boric acid

3.8% by weight of triethanolamine

11.2% by weight of monoethanolamine

2.0% by weight glycol ether e), f) or g)

0.15% by weight of 2-hydroxydodecyldimethylbenzylammonium benzoate (50% Solution)

Rest of water

Glycol ether

e) Dipropylene glycol n-butyl ether

f) tripropylene glycol n-butyl ether

g) propylene glycol phenyl ether

Test results:

Glycol ether e f G Cleaning result ++ ++ + Surfactant separation ++ ++ ++ Foaming behavior + + +

Description of the test methods: 1. Cleaning test

Steel sheets of quality St 1405 are manually pre-cleaned with surfactant solution and soiled with lapping paste (original dirt from practice). After 2 days. They are stored in a warming cabinet at 60 ° C with a 2% cleaning solution sprayed in a laboratory spraying system at 60 ° C for 10 min. The surfaces are visually assessed and the residual contamination determined gravimetrically.

Very good cleaning means that> 99% of the dirt has been removed, practically no cleaning means a result <70%.

2. Surfactant separation

A 2% cleaning solution is placed in a 1000 ml beaker (tall form) Set water at 20 ° dH, 5 min on a magnetic stirrer at approx. 600 Revolutions per minute and then stirred for 24 hours at 60 ° C without Bath movement stored in the warming cabinet. The appearance of the solution is assessed as well as the deposition on the liquid surface.

++ = keine erkennbaren Abscheidungen

o = Abscheidungen sichtbar, Lösung deutlich trüb

-- = starke Abscheidungen, klare Lösung

Evaluation criteria:

++ = no recognizable deposits

o = deposits visible, solution clearly cloudy

- = strong deposits, clear solution

3. Foam behavior

2% by weight were obtained from the concentrates according to recipes a to d Detergent solutions made in water with a hardness corresponding to 20 ° dH. In each case 10 l of this solution were at temperatures in the range between about 30 and about 45 ° C in a one-nozzle spraying system with a spray pressure of 5 bar sprayed for a period of 60 minutes. During the operation of the spraying system the foam height was measured, which is defined as the height of the foam above the liquid level in the initial state.

++ = kein Schaum

+ = Schaumhöhe <1,5 cm

o = Schaumhöhe <4,0 cm

- = Schaumhöhe <5,5 cm

-- = Anlage schaltet sich ab, da Schaumhöhe >5,5 cm

The evaluation is as follows:

++ = no foam

+ = Foam height <1.5 cm

o = foam height <4.0 cm

- = foam height <5.5 cm

- = system switches off because foam height> 5.5 cm

As can be seen from the test results, the invention offers Significant advantages over existing systems.

Claims (11)

1. A cleaning agent concentrate, containing glycol ethers and cationic surfactants, characterized in that it contains less than 0.1 wt. % of fatty alcohol alkoxylates and/or amphoteric surfactants and that it contains:

   (a) glycol ethers corresponding to the general formula: R-O-(CH₂-CH(CH₃)O)_n-H, wherein R represents an alkyl group having 1 to 4 carbon atoms or a phenyl group; and n represents a number of from 1 to 5; and

   (b) cationic surfactants;

   in the weight ratio (a) to (b) between 8 : 1 and 100 : 1.
2. A cleaning agent concentrate as claimed in claim 1 wherein it contains glycol ethers corresponding to the general formula: R-O-(CH₂-CH(CH₃)O)_n-H, wherein R represents an alkyl group having 1 to 4 carbon atoms or a phenyl group; and n represents a number of from 1 to 3.
3. A cleaning agent concentrate as claimed in claim 1 or claim 2 wherein it contains glycol ethers (a) and cationic surfactants (b) in the weight ratio (a) to (b) between 8 : 1 and 25 : 1.
4. A cleaning agent concentrate as claimed in any of claims 1 to 3 wherein it contains 5 to 200 g/l of glycol ethers (a) and 0.2 to 25 g/l of cationic surfactants (b) and water or an aqueous solution of further active or auxiliary substances as the remainder.
5. A cleaning agent concentrate as claimed in any of claims I to 4 wherein the cationic surfactants (b) are selected from quaternary ammonium compounds of the general formula: R¹-(CHOH-CHR²)_n-N⁺R³R⁴R⁵X^- wherein

   R¹ represents a straight or branched alkyl group having 1 to 22 carbon atoms;

   R² may represent hydrogen or a straight or branched alkyl group with 1 to 22 carbon atoms; wherein the total number of carbon atoms of the groups R¹ and R² is from 10 to 22;

   n represents 0 or 1,

   R³ and R⁴ independently represent methyl, ethyl, 2-hydroxyethyl or hydroxypropyl;

   R⁵ represents alkyl groups having 1 to 12 carbon atoms, a benzyl group or for alkylphenyl groups having 1 to 3 carbon atoms in the alkyl group; and

   wherein the total number of carbon atoms of the quaternary ammonium cation is at least 9 and at least one of the groups R' and R⁵ has more than 4 carbon atoms; and

   X^- represents halide, methyl sulfate or an anion of an aliphatic or aromatic organic acid having up to 15 carbon atoms.
6. A cleaning agent concentrate as claimed in claim 5 wherein, in the general formula of the cationic surfactants, R³ and R⁴ represent methyl and R⁵ represents benzyl.
7. A cleaning agent concentrate as claimed in any of claims 1 to 6 wherein it contains 100 to 700 g/l of corrosion inhibitors as further active substances.
8. A cleaning agent concentrate as claimed in claim 7 wherein the corrosion inhibitors are selected from alkanolamines and/or from branched or unbranched, saturated or unsaturated aliphatic carboxylic acids having 6 to 10 carbon atoms and/or from aromatic carboxylic acids having 7 to 10 carbon atoms.
9. A cleaning agent concentrate as claimed in any of claims 1 to 8 wherein it additionally contains builder substances, biocides and/or complexing agents.
10. An aqueous cleaning agent, which may be obtained by diluting a cleaning agent concentrate as claimed in any of claims 1 to 9 with water in the ratio 1 : 200 to 1 : 20.
11. A use of the aqueous cleaning agent according to claim 10 for degreasing metal components in spray installations.