DE2505252A1 - PROCEDURE FOR CLEANING AND DEGREASING OBJECTS - Google Patents

Description

PATENT LAWYERS

DR. ING. A. VAN DERWERTH DR. FRANZ LEDERER

(1934-1974) 8 MONKS SO

IUCtLE-GRAHN-STR 22 TEL. 108914729

Munich, 11, 2, 1975 C 518

UNILEVER N.V.

Burgemeester s'Jacobplein 1, Rotterdam, Netherlands

Process for cleaning and degreasing objects

The invention relates to a method for cleaning and degreasing of objects, especially of metals, whereby it can also be applied to hard surfaces other than those of metals is. Such a process is particularly necessary in metalworking and repair work, and it uses aqueous systems.

The invention is particularly applicable to the treatment of surfaces which are greasy, with dirt particles, metal dust and / or rust particles carry contaminated dirt. So far, the removal of such contamination has been possible Metal parts and equipment, e.g. B. electric motors, combustion engines, Metal plates, crane magnets, vehicles and

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TELEGRAMMEi LEATHER PATENT MOKCHEN

Tractors only with difficulty using solvent cleaners, which contained solvents in the form of hydrocarbons or halogenated hydrocarbons, combined with aqueous cleaning to remove the insoluble dirt particles. Under the Sewage pollution, environmental protection point of view and the use of such mineral oil-based solvents is undesirable for safety.

Several aqueous systems have been used to clean metals. Usually these are either highly alkaline or relatively strongly acidic systems, which in many Terms cannot be beneficial.

The object of the invention is to create a method for cleaning and degreasing objects, in particular Metals that do not have the disadvantages of the previously known processes.

The method according to the invention for the effective cleaning and degreasing of objects, especially metals, under mild, alkaline conditions in aqueous systems without the use of such solvents are characterized by that aqueous solutions are used, which a synergistic mixture of 0.1 to 20 wt .-% and in particular from 1 to 15% by weight of an organic, hydrotropic electrolyte substance in the form of benzenesulfonate, lower-C.-C ^ -alkyl or -dialkylbenzenesulfonates or mixtures thereof and from 0.1 to 25% by weight, in particular from 2 to 20% by weight, of an organic Sequestering agents in the form of aminopolycarboxylic acids and / or their salts, aminopolyphosphonic acids and / or their salts

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or mixtures thereof in a ratio of 2: 1 "to 1: 3 and in particular from 1: 1 to 1: 3, the pH of the solution in the range from approximately 9 to 13 and in particular is from 9.5 to 12.5.

In the Austrian patent specification 299 4-21 an aqueous, liquid composition for mechanical dishwashing is described, which 2 to 6% of a non-ionic, surface-active agent, 15 to 25 % of an organic sequestering agent, 7 to 15% of a hydrotropic substance, 3 contains up to 15% of a ethanolamine and 0.1 to 0.6 % of a corrosion inhibitor. It is known that mechanical dishwashing generally uses higher working temperatures and high mechanical energy

Surprisingly, it has now been found that industrial objects provided with typical dirt, in particular metal objects, at lower temperatures effectively by treatment with an aqueous system under mild, alkaline ones Conditions can be cleaned and degreased.

It has been found that a high cleaning and degreasing effect is observed if the solution is two essential Components, namely the specific hydrotropic substance and the specific sequestering agent, in those given above Contains quantities and proportions, and that this cleaning and degreasing effect especially on greasy, with dust particles mixed dirt occurs, as it normally occurs in the metalworking industry, in workshops, etc. This avoids the need to use highly alkaline cleaning systems and / or high temperatures. While highly alkaline systems, especially at higher temperatures, attack metal surfaces and non-metal parts of the objects treated therewith tend, the cleaning method according to the invention does not have this disadvantage.

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Typical dirt that occurs in the metalworking industry and in workshops are e.g. B. Preservation oils,
Greases, lubricants, processing oils and polishing pastes,
which generally embedded therein dirt particles,
Have metal dust and / or rust particles. The method according to the invention enables such dirt to be removed from hard surfaces, in particular from metals. The inventive method is applicable to the cleaning of metals as a pretreatment for further processing as well as to the cleaning of metals during maintenance work and also for cleaning workshops, e.g. B. of workshop benches, concrete hallways, etc., which carry the same typical pollution, suitable.

Hydrotropes are known per se in the art and are used in liquid detergent formulations as a solubilizing agent for certain components in the
Fluid system has been applied.

The hydrotropic ones selected for the process according to the invention Substances are active substances that have a highly active, dirt-removing effect, especially in combination with the previously defined, specific, organic sequestering agents.

Typical examples of hydrotropic electrolyte substances which are used according to the method of the invention are the sodium, potassium and ethanolamine salts of benzenesulfonic acid, toluenesulfonic acid, xylene sulfonic acid and cumene sulfonic acid. Preferred hydrotropes are potassium toluene sulfonate and potassium xylene sulfonate. Other electrolyte hydrotropes known in the art, such as alcohols and glycols, can additionally be added to the washing solutions used according to the invention, but they are inactive and do not replace the hydrotropes
Electrolyte substance.

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! Typical examples of organic sequestering agents that are used according to the invention are nitrilotriacetic acid, ethylenediaminetetraacetic acid, ethylenediaminetetramethylphosphonic acid, Nitrilotrimethylene phosphonic acid and / or its sodium or potassium salts. Preferred compounds are Potassium and sodium nitrilotriacetate.

The pH of the aqueous cleaning solution used according to the invention is generally within the range from 9 to 13 voa.d. preferably within the range of 9 * 5 to 12.5 · To keep the pH at this value, it may be necessary to add a buffering agent to the mixture.

Buffering agents used with preference are low molecular weight C 1 -C ₂ -alkanolamines such as mono-, di- or triethanolamines and isopropanolamines. Other low molecular weight, water soluble amines such as ethylenediamine, diethylenetriamine, oxazine and morpholine can also be used either alone or in combination.

Preferably the aqueous washing composition according to the invention contains a minor proportion of a detergent active material. A proportion as low as 0.01 to 1.00% by weight in the aqueous solution is generally sufficient for detergency the solution to increase.

The detergent active material can be incorporated in the form of non-soap, anionic and nonionic detergents or surfactants known in the art, for example as Cg-C 1-4 alkylbenzene sulphonates, Cg-C20 alkane or alkene sulphonates , Cg-C ^ g-alkyl sulfonates, Cr ₇ -C _x .2 ~ alkylphenol ethylene oxide condensates with 5 to 12 ethylene oxide groups, primary and secondary

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ß ^ condensed with 5 "to 12 ethylene oxide groups, Propylene oxide-ethylene oxide block polymers with molecular weights of approximately 1ΟΟΟ-3ΟΟΟ.

Without being limited to any particular theory, it is believed that the powerful effect of removing dirt of the hydrotropic electrolyte substances selected according to the invention, z. B. of potassium toluene sulfonate, the consequence of their affinity for adsorption to greasy dirt on the one hand and their affinity for the polar water molecules on the other hand is. The specific molecular structure of such electrolytes causes the adsorption of its hydrophobic part on the hydrophobic dirt surface as well as the attraction of the polar water molecules on their hydrophilic groups, creating a molecular bridge between the hydrophobic soil and the aqueous system is trained. This molecular bridge causes the hydrotropic electrolytes to have a dispersing effect on the greasy dirt, especially if it is contaminated with dirt particles, which prevents the hydrotropic electrolyte from penetrating through the Fat layer is caused. Obviously encourages attendance of sequestering agents in the system the grease-soil removal effect, which is based on the theory given above can be based to a considerable extent.

The aqueous cleaning solution can be used as a general cleaning bath or in electrolytic cleaning and ultrasonic cleaning can be used, or it can be sprayed onto the objects in a so-called spray cleaning. A Heating can be performed if necessary, although in many cases a working temperature of up to 70 ° C is appropriate is.

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A conventional way of preparing the aqueous cleaning solution consists in preparing a liquid base composition with the following ingredients:

a) 5 to 20% by weight of the organic, hydrotropic electrolyte substance, as previously defined,

b) 5 "to 25% by weight of the organic sequestering agent as defined above, the ratio of a) to b) being from 2: 1 to 1: 3 and preferably from Λ : 1 to 1: 3,

c) 0 to 10 wt .-% of a buffering agent for adjusting the pH as previously defined, and

d) 0 to 2% by weight of active detergent material (surfactant).

This composition can depend on the nature of the objects to be cleaned, the working method and the extent and the nature of the pollution as such or diluted with water in the desired ratio. Other Ingredients can optionally also be added, provided that they do not interact with the basic components step and disturb the previously defined, balanced basic conditions. Such additional ingredients are e.g. other organic builders or structural substances or sequestering agents, other alkaline substances, corrosion inhibitors, dyes or other hydrotropes. Inorganic salts tend to be however, to cause interference and are generally excluded.

The chemical explanation for better degreasing could be be that in the system according to the invention there is practically no electrolytic barrier (no coagulation), as with the previously known, inorganic, highly alkaline cleaners.

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The main advantages of the method according to the invention are:

1) In the method according to the invention, both a system for spray cleaning and for immersion cleaning, either in the cold or in the heat, possible, thereby creating previously unsolvable problems in a satisfactory manner can be solved, especially when removing oily and greasy types of dirt that are difficult to remove are, for example, from Molykote, graphite, etc .;

2) the dosages used in the process according to the invention are low compared to those of conventional ones Ee inigertyp s;

3) the system used according to the invention has a descaling effect;

4 ·) the process only requires relatively short process times;

5) the method according to the invention enables a high working capacity for repeated use of the bath;

6) the method of the invention is labor saving;

7) the system used in the present invention is environmentally beneficial.

The invention is illustrated in more detail by means of the following examples.

example 1

It became the following aqueous, basic, liquid composition

manufactured:

Components wt »-%

liatrium nitrilotriacetate Ealiumxyloisulfonat Potassium toluenesulfonate! Triethanolainin Honyl phenol / 9 x ethylene oxide

20, 0 5, 0 5, 0 5, G O, 2

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Components% by weight

Propylene oxide-ethylene oxide condensation

product (10 % polyoxyethylene;

MG - Ϊ 2000). 0.2

Benztriazole (corrosion inhibitor) 0.01

Topped up with water

This composition is a clear, homogeneous, mildly alkaline liquid with a pH of 12.6.

A portion of this composition was mixed with a portion of water to form a solution having a pH of 12.1. The solution was applied "at ambient temperature" to a heavily polluted automobile engine using a spray gun sprayed on. Five minutes after the end of spraying the engine was rinsed with a jet of water. The result was an extremely clean machine. It wasn't another Treatment required.

Similar good cleaning effects were observed on other soiled machines, with dilutions of 1: 3 or 1: 4 being used became.

Example 2

A cleaning solution was prepared by mixing 3 parts by weight of the composition of Example 1 with water.

Tram electric motors / machines of 2500 HP, which were normally cleaned in a double cleaning process, were cleaned in one step using this solution at a temperature of 70 ⁰ C in the manner described in Example 1,

Example 3

This test was carried out in a spray cleaner for metal parts. The use consisted of electric motors, Crane magnets and various other metal parts.

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The filling capacity was 5 tons.

The cleaning solution had the following composition:

0.2% sodium nitrilotriacetate

0.1 % potassium toluene sulfonate / potassium xylene sulfonate 0.05% triethanolamine

0.02% non-ionic detergent (surfactant) 0.2% sodium tripolyphosphate

1.0% sodium metasilicate

Remainder water + corrosion inhibitor working temperature = 70 ⁰ C

Working pressure = 4 atm.

Very good results have been observed even with Viscote and Molycote oil spills. The dirt could easily can be removed by spraying with water.

When using a solution at the same dilution obtained from a commercial product and non-ionic Detergent, sodium tripolyphosphate and sodium toluenesulfonate but did not contain the sequestering agent used in the invention

y became
medium / unsatisfactory cleaning achieved, whereby

manual cleaning later became necessary. Example 4

It became an aqueous detergent solution in a satisfactory manner For cleaning dirty workshop corridors by spraying on, allowing it to act for 5 minutes and then rinsing off with water used. ·

The detergent solution had the following composition in% by weight: Potassium nitrilotriacetate 4% by weight

Potassium xylene sulfonate 1 "

Potassium Toluenesulfonate 1 '-'

Triethanolamine 1 "

non-ionic detergent (surfactant) 0.1 "

Water - 92.9 "

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Claims (9)

Claims 1. Process for the industrial cleaning and degreasing of objects, in particular metals, by treatment the objects with a solvent-free, aqueous solution which contains an organic sequestering agent and a contains hydrotropic substance, characterized in that an aqueous solution is used, which from 0.1 to 20 wt .-% of the organic, hydrotropic electrolyte in the form of benzenesulfonates, lower-alkylbenzenesulfonates, Di (lower alkyl) benzene sulfonates or mixtures thereof and from 0.1 to 25% by weight of the organic Sequestering agents in the form of aminopolycarboxylic acids, aminopolycarboxylic acid salts, Aminopolyphosphonic acids, aminopolyphosphonic acid salts or mixtures thereof, the weight ratio of the electrolyte to the sequestering agent from 2: 1 to 1: 3 and the pH of the solution from 9 to 13. 2. The method according to claim 1, characterized in that the cleaning solution contains 1 to 15 wt .-% of the electrolyte. 3. The method according to claim 1 or 2, characterized in that the cleaning solution 2 to 20 wt .-% of the sequestering agent contains. 4. The method according to any one of claims 1 to 3, characterized in that that the weight ratio of the electrolyte to the sequestering agent is from 1: 1 to 1: 3. 509833/1050 5. Method according to one of claims 1 to 4-, characterized characterized in that the pH of the solution is from 9.5 to Is 12.5. 6. The method according to any one of claims 1 to 5 * characterized in that the solution is free of inorganic salts. 7 · The method according to any one of claims 1 to 6, characterized characterized in that the organic sequestering agent is an alkali metal nitrilotriacetate. 8. The method according to any one of claims 1 to 7, characterized characterized in that a buffering agent is added to the solution in the form of low molecular weight C.-C ^ alkanolamines will. 9. The method according to any one of claims 1 to 8, characterized in that the solution continues to have a smaller one Amount of a compound that is active as a detergent (surfactant) contains. 509833/1050