JPH02213486A - Aqueous purifying agent for metal surface and its use - Google Patents

Abstract

PURPOSE: To provide the detergent having a remarkably high allowableness for an oily contaminant by incorporating the nonsoap surfactant contg. acyclic di- and/or oligoazalkane having the specified number of Ns in the molecule, with each of the C atoms of the alkane joined to ≤1N atom and having the specified number of C atoms.

CONSTITUTION: An aq. detergent for a metal surface contg. the nonsoap surfactant contg. 2-12N acyclic di- and/or oligoazalkane (e.g. 1,6-aminohexane(1,8- diazaoctane)) and having ≥12 C atoms in the molecule is provided. In this case, the detergent is kept at ≥pH 7, and the C atom of the azalkane should be joined to ≤1 N atom. The aq. detergent having such characteristics can be used for a remarkably long time.

COPYRIGHT: (C)1990,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an aqueous cleaning agent for metal surfaces having a pH value greater than about 7 and its use by spraying.

[Conventional technology]

In the metalworking industry, many stages of the manufacturing process, such as machining before precision machining or intermediate storage, are
or must be degreased and cleaned to remove corrosion-inhibiting oils or lubricants prior to phosphating. It is common and advantageous to use aqueous solutions for this purpose, as well, since widely used organic solvent purification agents, such as chlorinated hydrocarbons, are hazardous to health and can contaminate groundwater. This is a problem in some respects.

Such aqueous systems are, for example, so-called neutral or alkaline cleaning agents. The former is preferably used in the spray method, and the latter is used in the spray and dipping methods.

Neutral decontaminants have a p
It has an H value. Neutral detergents usually contain surfactants, which are nonionic, and corrosion inhibitors, such as alkanolamine salts of short-chain fatty acids having less than 10 carbon atoms.

Corrosion inhibitors serve to protect treated parts from corrosion during cleaning, drying and subsequent storage (DE-C-
2614234, EP-A-99598).

Alkaline cleaning agents, which usually have a pH value greater than 8, are in particular anionic and/or nonionic surfactants and so-called alkali carbonates, silicates, phosphates, borates, gluconates, sodium hydroxide and potassium hydroxide. Contains bilgoo.

Dirt adhering to the parts to be cleaned enters the cleaning agent as a result of cleaning. Since, for economic and environmental reasons, cleaning agents are usually used for long periods of time, loose dirt, usually oily contaminants, accumulates during cleaning. As the soil content of the cleaning agent increases, the cleaning power of the cleaning agent decreases. A remedy for this can be to increase the concentration of cleaning chemicals, but this measure has only limited success.

Most of the time, the used cleaning agent must be flooded or replaced in whole or in part with new cleaning agent. In addition to increasing chemical costs, such measures significantly increase the strain on the plant's drainage systems and canals.

[Problem to be solved by the invention]

The object of the present invention is to avoid the disadvantages of known cleaning agents and, in particular, to
It is an object of the present invention to provide an aqueous cleaning agent for metal surfaces which has an extremely high tolerance to oily contaminants and can therefore be used for an extremely long time.

[Means to solve the problem]

The above-mentioned problem was solved by converting the plurality of aqueous purifying agents mentioned at the beginning into acyclic di- and/or
or an oligoazaalkane, each carbon atom of said azaalkane being bonded to up to one nitrogen atom, achieved by formulating a non-soap surfactant having more than 12 carbon atoms. .

Azaalkanes are compounds in which one or more carbon atoms of the alkane are replaced by one nitrogen atom.

The name of the birthmark is determined according to the alkane it is based on. A number in front indicates that the carbon atom with that number is substituted.

According to a preferred embodiment of the invention, cleaning agents having up to 5 nitrogen atoms in the molecule are used.

Particularly advantageous cleaning agents are those containing the following compounds.

1,6-diazahexane (1,8-diazaoctane),
1,4-diaminobutane (1,6-diazahexane),
3-(2-aminoethyl)-aminopropylamine (1
,4,8-)diazaoctane), N,N'-bis-(3-aminopropyl)-ethylenediamine (1,5,8,12-tetraazadodecane), diethylenetriamine (1,4,7-driazahebutane)
, or triethylenetetramine (1,4,7,10-tetraazadecane).

According to another preferred embodiment of the invention, the purifying agent is 0.05 to Lo
g/j! of azaalkanes. Concentrations in the lower range are particularly desirable for spraying, and concentrations in the upper range are desirable for dipping.

It is expedient for the cleaning agent of the invention, like other cleaning agents, to contain the usual virgoos substances. As the surfactant, anionic or non-soap surfactants are preferred.

A particular advantage of the cleaning agents of the invention appears when used in sprays. The addition of di- and/or oligoazaalkanes does not result in significant undesirable foaming, as compared to conventional cases where the surfactant concentration is adjusted to a high level.

The invention will be explained in more detail and exemplified by the following examples.

〔Example〕

For the experiment, quality RSt 1405 with dimensions 105X85X
A steel plate with an O87 fin was used. This steel plate has been subjected to the following treatments in advance. .

1.1.1 - Vapor degreasing with trichloroethane, wiping with cotton cloth, 1.1.1 - Vapor degreasing with trichloroethane, pickling by soaking in 1.0% citric acid at room temperature for 1 minute, washing with water for 1 minute, 0° for 5 minutes. After rinsing with isopropanol and spraying with compressed air, apply drying and anti-corrosion oil (Ru5ti Ito from Castro 1).
845).

In order to determine the quality of the cleaning agent, the so-called minimum cleaning time (MRZ) was determined with increasing oil content.

The minimum cleaning time is the shortest cleaning time required to completely wet the steel plate (more than 95% of the surface) in a subsequent water wash.

[The cleaning agents used were 3.6 g/l NaJPO4 and 0.4 g/l nonionic surfactant (GAF's Ant
arox B L 330) and was used in a spray method at 55°C. Corrosion-inhibiting oils were emulsified in various amounts to reproduce the contamination build-up that occurs in normal practice.

The minimum purification times obtained are:

Corrosion prevention oil (g/jr 0 1 2 330 seconds 5
0 seconds 90 seconds 120 seconds Adding 0.4 g # of 1,4.8-triazaoctane to the above purification agent resulted in the following minimum purification times.

Corrosion prevention oil (g/jr 0 1 2 320 seconds 2
5 seconds 45 seconds 60 seconds 11 seconds 1 The purifying agent used was 5 g/l NaJPO.

1 g/j2 NazPzO+o and 0.4 g/β alkyl polyethylene glycol polypropylene glycol ether (zSChiI111Ie
Propetal 99 from r&schwarz
).

The minimum cleaning times used in the spray method at 60°C were as follows:

Corrosion prevention oil (g/l) 0 1 2 330 seconds 3
0 seconds 50 seconds > 120 seconds When the surfactant content was reduced by 0.2 g/l in the cleaning agent and 0.2 g/l of 1,8-diazaoctane was added, the following minimum cleaning times were obtained.

Corrosion prevention oil (g/jr 0 1 2 320 seconds 2
5 seconds 40 seconds 45 seconds Tsuyonuki J- A so-called neutral purifying agent having the following composition was used.

5 g/l jetanolamine 0.8 g/l 2-ethylhexanoic acid 0.8 g/l alkyl polyethylene glycol polypropylene glycol ether The minimum purification time determined by the spray method at 45 DEG C. was as follows.

Corrosion prevention oil (g#) 0 1 2 365 seconds 90 seconds 〉240 seconds 〉240 seconds 1 in the neutral purifying agent
Addition of 1.5.8.12-tetraazadodecane at g/z resulted in the following minimum cleanup times:

Corrosion prevention oil (g#) 0 1 2 340 seconds 70
120 seconds 140 seconds A purifying agent having the following composition was used.

20g/l Na, Si0° 18g/l Na, CO3 10g/l NaOH 1,5g/f dodecylbenzenesulfonate (BAS
Company F's Luteusit ALBN).

The minimum purification time determined by the immersion method at 90°C was as follows.

Corrosion inhibiting oil (g/jl O25 2.5 minutes 5 minutes 20 minutes Addition of 3 g/l of 1.3,7.10-tetraazadecane to the cleaning agent resulted in the following minimum cleaning times.

Corrosion-inhibiting oil (g/j) O25 2.0 minutes 4 minutes 6 minutes For all examples using the spray purification method, the purification agents without the addition of azaalkanes exhibit a marked tendency to foam;
Cleaning agents containing azaalkanes did not exhibit any significant foaming even when sprayed for periods well in excess of the minimum cleaning time.

Claims (1)

[Scope of Claims] 1. An aqueous cleaning agent for metal surfaces having a pH value greater than about 7, which comprises an acyclic di-containing agent having 2 to 12 nitrogen atoms in the molecule.
and/or an oligoazaalkane, each carbon atom of said azaalkane being bonded to up to one nitrogen atom;
An aqueous cleaning agent for metal surfaces, characterized in that it contains a non-soap surfactant having more than 3 carbon atoms. 2. The aqueous purifying agent according to claim 1, which contains a di- and/or oligoaza-alkane having up to 5 nitrogen atoms in the molecule. 3,1,6-aminohexane (1,8-diazaoctane), 1,4-diaminobutane (1,6-diazahexane), 3-(2-aminoethyl)-aminopropylamine (1,4,8-tria zaoctane), N,N'-bis-
(3-aminopropyl)-ethylenediamine (1,5,
8,12-tetraazadodecane), diethylenetriamine (1,4,7-triazaheptane) or triethylenetetramine (1,4,7,10-tetraazadecane). The aqueous purifying agent described in 2. 4. The aqueous purifying agent according to claim 1, 2 or 3, characterized in that it contains 0.05 to 10 g/l of di- and/or oligoaza alkanes. 5. The aqueous purifying agent according to any one of claims 1 to 4, further comprising a builder substance. 6. The aqueous purifying agent according to any one of claims 1 to 5, which contains an anionic and/or nonionic surfactant. 7. A method of using the aqueous purifying agent according to any one of claims 1 to 6 by a spray method.