Corrosion-protection system for treating metal surfaces

Abstract

The present invention relates to a corrosion-protection system suitable for producing aqueous metal treatment and metal processing fluids, particularly corrosion-protection, cleaning and cooling lubricant emulsions. The corrosion-protection system comprises carbonic and/or phosphonic acids, as well as at least one amine with at least one oxybis(alkylamine) unit. Such corrosion-protection systems effectively protect metal surfaces from corrosion and have a high level of water solubility, which is essential for formulating aqueous concentrates for metal treatment and metal processing fluids. The present invention further relates to an aqueous surface-active and corrosion-protecting preparation containing the corrosion protection system and an emulsifier system, as well as an oil-containing water-miscible emulsion concentrate, which supplies the ready-to-use corrosion-protection, cleaning and cooling lubricant emulsions by dilution with water.

Claims

1. A corrosion protection system for the manufacture of aqueous metal-treatment and metal-processing liquids, comprising a) one or more acids selected from the group consisting of carboxylic acids, having a carbon chain and oxygen heteroatoms inserted into the carbon chain, that comprise between 6 and 26 atoms in the carbon-heteroatom chain, one or more aliphatic straight chain monophosphonic acids having at least 6 but no more than 12 carbon atoms and combinations thereof; and b) at least one amine that comprises at least one oxybis(alkylamine) unit having tertiary amino groups, the alkyl chains of said unit being made up in each case of no more than 4 carbon atoms; wherein the corrosion protection system has a molar ratio of total quantity of acid groups of component a) to oxybis(alkylamine) units of the at least one amine of component b) that is no greater than 5:1, but no less than 1:3.

2. The corrosion protection system according to claim 1, wherein component b) comprises at least one amine of structural formula (1): ##STR00003## where m and n are natural integers in a range from 1 to 3; and where residues R.sub.1, R.sub.2, R.sub.3, and R.sub.4 are selected mutually independently from branched or unbranched alkyl residues having no more than 8 carbon atoms and ((CH.sub.2).sub.xO).sub.yR.sub.5, wherein x is a natural integer in the range from 1 to 3, y is a natural integer in the range from 1 to 6, and the residue R.sub.5 is selected from hydrogen, methyl, ethyl, or propyl.

3. The corrosion protection system according to claim 2, wherein component b) comprises at least one amine of the structural formula (1) wherein the residues R.sub.1, R.sub.2, R.sub.3, and R.sub.4 are selected mutually independently from branched or unbranched alkyl residues having no more than 8 carbon atoms, and in which the natural integers m and n are equal to 2.

4. The corrosion protection system according to claim 2, wherein at least 50 wt. % of component b) is comprised of the at least one amine of structural formula (1), based on total proportion of amines of component b).

5. The corrosion protection system according to claim 4, wherein at least 80 wt. % of component b) is comprised of the at least one amine of structural formula (1), based on total proportion of amines of component b).

6. The corrosion protection system according to claim 2, wherein at least 50 wt. % of component b), based on total proportion of amines of component b), is comprised of the at least one amine of the structural formula (1) wherein the residues R.sub.1, R.sub.2, R.sub.3, and R.sub.4 are selected mutually independently from branched or unbranched alkyl residues having no more than 8 carbon atoms, and in which the natural integers m and n are equal to 2.

7. The corrosion protection system according to claim 2, wherein at least 80 wt. % of component b), based on total proportion of amines of component b), is comprised of the at least one amine of the structural formula (1) wherein the residues R.sub.1, R.sub.2, R.sub.3, and R.sub.4 are selected mutually independently from branched or unbranched alkyl residues having no more than 8 carbon atoms, and in which the natural integers m and n are equal to 2.

8. The corrosion protection system according to claim 1, further comprising one or more aliphatic branched or unbranched monocarboxylic acids.

9. The corrosion protection system according to claim 8, wherein the aliphatic branched or unbranched monocarboxylic acids are selected from caprylic acid, ethylhexanoic acid, isononanoic acid, isodecanoic acid and mixtures thereof.

10. The corrosion protection system according to claim 1, wherein the corrosion protection system has a molar ratio of total quantity of acid groups of component a) to oxybis(alkylamine) units of the at least one amine of component b) that is no greater than 2:1, but no less than 2:3.

11. A method of using a corrosion protection system comprising steps of: a) providing a corrosion protection system according to claim 1 b) mixing the corrosion protection system with a liquid for metal treatment or metal processing selected from cleaning, corrosion-protection, and cooling-lubricant emulsions.

12. An aqueous surface-active and corrosion-protective preparation comprising, besides water: i) corrosion protection system (I) in accordance with claim 1; wherein the corrosion protection system has a molar ratio of total quantity of acid groups of component a) to oxybis(alkylamine) units of the at least one amine of component b) that is no greater than 3:1, but no less than 1:3; and ii) an emulsifier system (II) comprising: a) component a) selected from the group consisting of ethoxylates/propoxylates of fatty alcohols, said fatty alcohols having 8 to 18 carbon atoms, having 2 to 6 ethylene oxide units and 4 to 8 propylene oxide units; and b) component b) selected from the group consisting of fatty alcohols having 12 to 24 carbon atoms, fatty alcohol propoxylates having 12 to 24 carbon atoms in the alcohol and 1 to 3 propylene oxide units, distillation residuum of said fatty alcohols and mixtures thereof.

13. An oil-containing water-miscible emulsion concentrate comprising: i) 2 to 20 wt. % of the corrosion protection system (I) in accordance with claim 1, having a weight ratio of components a) to b) ranging from 1:0.2 to 0.3:1; ii) 2 to 50 wt. % of an emulsifier system (II) comprising: a. ethoxylates/propoxylates of fatty alcohols, said fatty alcohols having 8 to 18 carbon atoms, having 2 to 6 ethylene oxide units and 4 to 8 propylene oxide units; and b. fatty alcohols having 12 to 24 carbon atoms, and/or fatty alcohol propoxylates having 12 to 24 carbon atoms in the alcohol and 0 to 3 propylene oxide units, and/or distillation residuum of said fatty alcohols; wherein components c and d have a weight ratio from 1:0.3 to 0.3:1; and iii) 5 to 50 wt. % of an oil component (III), and optionally further adjuvants and active agents (IV), wherein amounts of I) to IV) add up to 60 to 95 wt. % of the concentrate, and any remaining weight proportion represents water.

14. The oil-containing water-miscible emulsion concentrate of claim 13, wherein oil component (III) is selected from paraffinic mineral oil, naphthenic mineral oil, dialkyl ethers having 12 to 20 carbon atoms, and ester oils and combinations thereof.

15. An aqueous surface-active and corrosion-protective preparation comprising, besides water: i) a corrosion protection system (I) comprising: a) one or more acids selected from the group consisting of carboxylic acids, having a carboxyl group and a carbon chain with oxygen heteroatoms inserted into the carbon chain, that comprise between 6 and 26 atoms in the carbon-heteroatom chain; aliphatic straight chain monophosphonic acids having at least 6 but no more than 12 carbon atoms and combinations thereof; and b) at least one amine that comprises at least one oxybis(alkylamine) unit having tertiary amino groups, the alkyl chains of said unit being made up in each case of no more than 4 carbon atoms; wherein the corrosion protection system has a molar ratio of total quantity of acid groups of component a) to oxybis(alkylamine) units of the at least one amine of component b) that is no greater than 5:1, but no less than 1:3; and ii) an emulsifier system (II) comprising: c) ethoxylates/propoxylates of fatty alcohols, said fatty alcohols having 8 to 18 carbon atoms, having 2 to 6 ethylene oxide units and 4 to 8 propylene oxide units; and d) one or more selected from the group consisting of fatty alcohols having 12 to 24 carbon atoms; fatty alcohol propoxylates having 12 to 24 carbon atoms in the alcohol and up to 3 propylene oxide units; distillation residuum of said fatty alcohols and mixtures thereof.

16. The aqueous surface-active and corrosion-protective preparation of claim 15, the corrosion protection system (I) further comprises one or more aliphatic branched or unbranched monocarboxylic acids selected from caprylic acid, ethylhexanoic acid, isononanoic acid, isodecanoic acid and mixtures thereof; and the emulsifier system (II) further comprises component e) alkoxylated fatty amines selected from the group consisting of saturated and unsaturated aliphatic amines having an aliphatic chain length of at least 8, but no more than 20 carbon atoms, optionally said alkoxylated fatty amines include ethoxylated fatty amines having at least 8, but no more than 16 ethylene oxide units.

17. The corrosion protection system according to claim 1, wherein component b) comprises at least one amine of structural formula (1): ##STR00004## where m and n are natural integers in a range from 1 to 3; and where residues R.sub.1, R.sub.2, R.sub.3, and R.sub.4 are selected from those residues which bridge the two nitrogen atoms of the oxybis(alkylamine) unit, such that the residue R.sub.1 or the residue R.sub.2 is respectively structurally identical to the residue R.sub.3 or R.sub.4, wherein bridging residues R.sub.1 or R.sub.2, or R.sub.3 or R.sub.4, are selected from polyoxyalkylenes or polyaminoalkylenes having no more than 6 carbon atoms.

18. The corrosion protection system according to claim 1, wherein component b) comprises at least one amine of structural formula (1a): ##STR00005## wherein m and n are natural integers in the range from 1 to 3; q, r, and s are natural integers in the range from 1 to 3 and Z is either a carbon, oxygen, or nitrogen atom; and the residues R.sub.1 and R.sub.2 are selected mutually independently from: alkyl residues, which may be branched or unbranched, having no more than 8 carbon atoms; and ((CH.sub.2).sub.oX).sub.pR.sub.5, wherein o is a natural integer in the range from 1 to 3, p is a natural integer in the range from 1 to 6, X is either an oxygen or nitrogen atom, and the residue R.sub.5 is selected from hydrogen, methyl, ethyl, or propyl.

19. The corrosion protection system according to claim 1, further comprising one or more aliphatic branched or unbranched monocarboxylic acids; wherein component b) comprises at least one bridging amine selected from the group consisting of N,N-dimethyl-1,7-dioxa-4,10-diazacyclododecane, N,N-diethyl-1,7-dioxa-4,10-diazacyclodecane, N,N-dimethyl-1,4,10-trioxa-7,13-diazacyclopentadecane, and N,N-diethyl-1,4,10-trioxa-7,13-diazacyclopentadecane.

20. The corrosion protection system according to claim 2, wherein at least one of the residues R.sub.1, R.sub.2, R.sub.3, and R.sub.4 is ((CH.sub.2).sub.xO).sub.yR.sub.5.

21. A corrosion protection system for the manufacture of aqueous metal-treatment and metal-processing liquids, comprising: a) one or more carboxylic acids, having a carbon chain and oxygen heteroatoms inserted into the carbon chain, that comprise between 6 and 26 atoms in the carbon-heteroatom chain, and one or more aliphatic straight chain monophosphonic acids having at least 6 and no more than 12 carbon atoms; and b) at least one amine that comprises at least one oxybis(alkylamine) unit having tertiary amino groups, the alkyl chains of said unit being made up in each case of no more than 4 carbon atoms.

22. The corrosion protection system according to claim 21, wherein component a) includes ether carboxylic acids having a general formula:
R(OC.sub.2H.sub.4).sub.nOCH.sub.2COOH wherein R denotes a linear or branched, saturated or unsaturated alkyl residue having 6 to 16 carbon atoms, and n represents a number in a range from 1 to 5.

23. The corrosion protection system according to claim 22, wherein the ether carboxylic acids include technical lauryl ether carboxylic acid, in which R denotes a mixture of linear, saturated alkyl groups having 12 and 14 carbon atoms, and n is approximately 2.5.

24. The corrosion protection system according to claim 1, wherein component b) comprises N,N,N,N-tetramethyl-2,2-oxybis(ethylamine).

Description

EXEMPLIFYING EMBODIMENTS

(1) The mode of operation of the corrosion protection systems according to the present invention is presented below by way of example, and compared with systems known in the existing art. For this a corrosion protection test per DIN 51360-2 is performed, in which cast-iron chips (type GG25) are wetted on a round filter with freshly manufactured dilute aqueous solutions containing various corrosion protection systems based on an amine and isononanoic acid.

(2) Table 1 lists the compositions of concentrated aqueous corrosion protection systems (stock solutions) based on an amine and isononanoic acid.

(3) TABLE-US-00001 TABLE 1 Stock solutions of corrosion protection systems each having an active-component proportion of 20 wt. % in water having a hardness of 20 dH (3.04 mmol CaCl.sub.2; 0.54 mmol MgSO.sub.4) Carboxylic Amine component wt. % acid wt. % B1 N,N,N,N-tetramethyl-2,2- 10.07 Isononanoic 9.93 oxybis(ethylamine) acid V1 Monoethanolamine 5.57 Isononanoic 14.43 acid V2 Triethanolamine 9.71 Isononanoic 10.29 acid V3 N,N,N,N-tetramethyl-1,6- 10.43 Isononanoic 9.57 hexamethylenediamine acid

(4) The stock solutions of Table 1 were further diluted with water having a hardness of 20 dH (3.04 mmol CaCl.sub.2; 0.54 mmol MgSO.sub.4), and the cast-iron chips on the filter paper were wetted with this dilute solution.

(5) Table 2 reproduces the degree of rust formation as a function of the active content of the solutions, based on an assessment of corrosion marks on the filter paper after the chips had been exposed for two hours at 20 C.

(6) Based on the corrosion results presented in Table 2, it is apparent that the corrosion protection system according to the present invention containing the amine having an oxybis(alkylamine) unit exhibits an appreciable corrosion protection effect starting at a weight proportion of only 6% based on the stock solution B1. At a weight proportion of at least 7% based on the stock solution B1, only slight corrosion phenomena are detectable on the filter paper, while for the remaining corrosion protection systems moderate (V3) to severe (V1, V2) corrosion can still be observed. The corrosion protection system (B1) according to the present invention containing the amine having the oxybis(alkylamine) unit is also superior to the corrosion protection system (V3) containing the hexamethylene-bridged tertiary diamine.

(7) TABLE-US-00002 TABLE 2 Corrosion results from filter test per DIN 51 360 of two samples in each case of cast-iron chips (type GG25) that had been brought into contact with variously diluted stock solutions in accordance with Table 1. Proportion of stock solution (wt. %) 5 6 7 8 B1 4/4 3/3 2/1 0/0 V1 4/4 4/4 4/4 2/2 V2 4/4 4/4 4/4 4/4 V3 4/4 4/4 3/3 1/1

(8) Corrosion assessment per DIN 51 360: 0 no corrosion/unchanged 1 traces of corrosion/maximum 3 corrosion marks 2 slight corrosion/no more than 1% of surface discolored 3 moderate corrosion/no more than 5% of surface discolored 4 severe corrosion/more than 5% of surface discolored.