GB2227757A

GB2227757A - Protection of metal surfaces

Info

Publication number: GB2227757A
Application number: GB8902387A
Authority: GB
Inventors: Robert Montgomery O'neil; Peter Collen Hamblin
Original assignee: Ciba Geigy AG
Current assignee: Novartis AG
Priority date: 1989-02-03
Filing date: 1989-02-03
Publication date: 1990-08-08
Anticipated expiration: 2009-02-03
Also published as: DE4002826A1; GB2227757B; GB8902387D0; JPH02243785A

Description

1 - 1 Protection method The present invention relates to the temporary

protection of metal surfaces.

The use of adducts of ether olefin oxides or glycidyl ethers and diethanolamines, as permanent oxidation- or corrosion inhibitors for ferrous metals, in various substrates, is known.

For example, in U.S. Patent Specification No. 2856363, the use is described, as oxidation inhibitors for lubricating oils, of compounds having the formula:

R 1_ CH(OH)-CH(R 2)-N(Y 1)R 3 OH in which R is C -c alkyl, R is hydrogen or c alkyl, 1 2 12 2 v-2- 12 R 3 is a C 2_ c 5 hydrocarbon chain and Y 1 is hydrogen or R 3-0H.

in GB Patent Specification NO. 1455476, a rust inhibited lubricating oil composition is described comprising a mineral oil base, 0.01-0.5 weight per cent of- an overbased alkaline earth metal compound and a minor rust inhibiting amount of a substituted trialkanolamine having the formula:

R - CH(OH)-CHM-)-N-ICH(Z)-(CH CH(OH)Y 4 3 1 2 xl 2 2 in which R is a C - c hydrocarbyl radical, TZ,., Y, and 47.1 4 1 24 & are hydrogen or a C 1_ c 10 hydrocarbyl radical and X 1 is 0 or 1.

In GB 2172284A, there are disclosed non-aqueous functional fluids containing, as corrosion inhibitors, at least one compound having the formula: R 6-X-CH 2 CH(OH)CH 2 NR 7 R 8 in which X is, inter alia, -0-, R 6 is, inter alia, C 2-C 20 alkyl, R 7 is monosubstituted C I- c 4 alkyl or C 2-C 5 alkyl substituted by one to three hydroxyl groups and R 8 is hvdrocen unsubstituted C -C alkvl or C -C alkvl p 1 4 2 5 substituted by one to three hydroxyl groups, with the provisos that at least one-of R 7 and R 8 is hydroxysubstituted, and, wh en X is -0-, R 6 is branched C 4-C 20 alkyl.

EP 252007 describes functional fluids containing, as corrosion inhibitor, at least one compound having theformula:

R 9 R 10 OCH 2 MOH)CH 2 NR 12 R 1-3 R 11 in which R.. P. and R independently, are, inter alia, ill hydrogen or C i_ C is alkyl, and R 12 and R13. Jndependen41.--1y, are hydrogen, 2-hydroxyethyl or 2-hydroxypropyl, with the provisos that: a) R 12 and R 13 are not simultaneously hydrogen; b) wben R 12 and R 13 are each -CH 2 CH 2 OH, R 9 and R 10 are not simultaneously hydrogen and R 11 is not a pentyl residue; and C) polyalkylene phenol or polycarboxylic acid ester co-additives are absent.

Each of these disclosures is concerned with the problem of providing permanent corrosion protection for metal surfaces in contac.IC with a functional fluid, during the time that the surface and the fluid are in contact.

Another problem which arises in the field of corrosion inhibition of metals, is the need to provide temporary protection to freshly-produced metal surfaces before a more permanent treatment is applied or before they are placed into their ultimate working environment e.g. into contact with a

1 j.

j functional fluid containing a corrosion inhibitor.

In US 4315957 it has been suggested to use wax compositions as such a temporary coating for metals, and to remove the wax coating by steaming, prior to further corrosion inhibitive treatment of the metals.

In US 4752336, a method of applying very thin, easilyremoved temporary protective coatings on to metal surfaces, is described which involves the use of a specified fatty acid ester in a volatile fluorocarbon solvent, which solvent can be evaporated to leave a film of ester on the metal surface. The ester is sufficiently volatile to be self-removed from the surface within a predetermined time.

We have found a simple and effective method of imparting temporary protection to a metal surface. The method involves simple immersion of the metal surface to be treated into a environmentally acceptable organic solution of a corrosion inhibitor, thereby avoiding evaporation of a potentially hazardous fluorocarbon solvent.

Accordingly, the present invention is a method of imparting tempiraj:-1, corros'-or. inhibition proteclCion to a metal surface, especially a ferrous metal surface, in contact with a corrosive atmosphere, which method comprises immersing the metal surface to be protected in an environmentally acceptable organic medium cu-iipristng at least one compound having the formula I:

R-O-CH1)-CH(OH)CH 2 N(CH 2 CH1)OH) 2 wherein R is a C 12- C 20 linear or branched alkyl group, or a group having the formula II:

1 - 4 R a-C II wherein R a is a C 8_ C is linear or branched alkyl group, and is situated in the 3- or 4-position of the phenyl residue; and then removing the metal surface from the medium.

Examples of C 12-C 20 alkyl groups R include, e.g.,, n-dodecyl, ntridecyl, n-tetradecyl, n-hexadecyl, n-octadecyl, n-eicosyl, tertiarydodecyl, tertiary-hexadecyl and tertiary-octadecyl, or mixtures of these.

C 8_ C is Alkyl groups a include e.g., n-octyl, n-nonyl, n-decyl, ndodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, iso-octyl, tert-octyl, isononyl tertiary-nonyl, isododecyl tertiary-dodecyl and tertiary pentadecyl or mixtures of these.

Preferred compounds of formula i are those wherein R is 4-nonylphenyl, 4dodecylphenyl, 3-pentadecylphenyl, dodecyl or tetradecyl or mixtures of these.

organic solvents which may be used to form the solution of the compound of formula i include for example, mineral oils, aromatic or aliphatic hydrocarbons, or other petroleum spirit-based solvents.

The mineral oil may be, e.g., a paraffin oil such as a paraffin oil having a viscosity of 46 mm 2 Is at 40IC; 11150 Solvent Neutral", a solvent-refined neutral mineral oil having a viscosity of 32 mm 2 Is at 40C, and "Solvent Brightstocks11 a high-boiling residue from the process of refining mineral oil and having a viscosity of 46 mm 2 Is at 400C.

1 j The aromatic hydocarbon medium may be e.g. toluene or o-, m- or p-xylene, trimethylbenzene, dodecylbenzene.

Aliphatic hydrodarbon'media are, e.g. n-decane or n-dodecane.

The compound of formula I is preferably dissolved in the organic medium in an amount ranging from 1.0 to 20% by weight, more preferably from 2 to 15 % by weight, based on the total weight of the organic medium.

The compounds of formula I are known compounds and may be prepared, e.g. by the method described in GB 2172284A. This method comprises the reaction of a compound of formula R-OH ill wherein R has its previous significance, or of a metal salt thereof, e.g. the sodium or potassium salt, in the absence or presence of a catalyst, with a compound of formula IM C1CH 2C-CH 2 0 IV to produce a compound having the formula V.

R-O-CH 2- CH CH 2 \\ / V wherein R has its previous significance; and then reacting the compound of formula V with diethanolamine -L-o produce a compound of formula 1.

The organic medium may contain, in addition to the compound of formula I, other additives known to be useful in providing temporary protection to metal surfaces, in particular further rust inhibitors and dispersing agents g 6 and/or surfactants. Examples of rust inhibitors are:. a) organic acids, their esters, metal salts and anhydrides, e.g. N-oleoyl sarcosine, sorbitan mono-oleate, lead naphthenate, dodecencylsuccinic anhydride, alkenylsuccinic acid half esters, 4-nonylphenoxyacetic acid; b) nitrogen- containing compounds, e.g. i) primary, secondary or tertiary aliphatic or cycloaliphatic amines and amine salts of organic and inorganic acids, e.g. oil-soluble alkylammonium carboxylates; and heterocyclic compounds, e.g.

substituted imidazolines and oxazolines.

c) phosphorus-containing compounds, e.g. amine salts of phosphoric acid partial esters d) sulfur-containing compounds, e.g. barium dinonyl naphthalene sulfonates and calcium petroleum sulfonates.

Examples of dispersing agents/surfactants are:

polybutenylsuccinic acid imides, polybuterrylphosphonic acid derivatives, and basic Mg, Ca and Ba sulfonates and Mg, Ca and Ba phenolates.

The following Examples further illustrate the present invention.

A 1 1 4 Examples 1 to 4 Cold-rolled steel panels (102 x 152 mm in size and 0.8 mm thick) are immersed in the respective test solutions for several minutes, then removed and the panels so treated are allowed to drain for approximately 15 hours.

Each test panel is then subjected to exposure to a continuous spray of a 5% sodium chloride solution at 350C for 24 hours in accordance with the procedure described in ASTM B117.

Each test solution was prepared using, as organic solvent medium, a naphthenic base oil having the following physical characteristics:

viscosity at 401C viscosity at 1000C % c A % S (mm'-/s) (mm'/s) 10.0 0.5 22.0 3.7 c A denotes percentage aromatic carbon content.

After exposure to the salt spray for 2, 4, 6, 8, and 24 hours' each panel was examined visually for rusting, and rated a---ord-,,-ng to t-he following z-2a.Le:

Test rating Visual assessment 0 no rust 1 20% of panel covered by rust 40% of panel covered by rust 3 60% of panel covered by rust 4 80% of panel covered by rust 100% of panel covered by rust The results obtained are set out in the following Table j Table

Additive: Additive conc. Test ratinqle osure time Example Structure of substit.R % by weight 2 4 6 8 24 1 c 9 H - 5 0-1 0-1 1 1-2 5 19 2 C H 2-55 0-1 0.;-1 1 1-2 5 12 3 Q- 5 0-1 0-1 1 2 5 15H 3 11 4 H.)q inixrure 5 U L - 3 5 14 control none 5 5 5 5 These results demonstrate the excellent temporary Protection afforded to L-he test panels by treatment according t-o the method of the present invention.

A A

Claims

9 We claim: 1. A method of imparting temporary corrosion inhibition

protection to a metal surface, especially a ferrous metal surface, in contact with a corrosive atmosphere, which method comprises immersing the metal surface to be protected in a non-toxic organic medium comprising at least one compound having the formula I:

R-O-CH2- CH(OH)CH2N(CH 2CH2OH)
2 wherein R is a C -Colo linear or branched alkyl group, or a 12 1group having the formula II:

a L7\ _Itz R II wherein R a is a C C linear or branched alkyl group, and is 8 is situated in the 3- or 4-position of the phenyl residue; and then removing the metal surface from t-he medium. 2. Method according to claim 1 wherein the metal surface is a ferrous metal surface.
3. Method according to claim 1 or 2 wherein R is dodecyl, tetradecyl, 4nonylphenyl, 4-rlodecvlplieny! or 3-1pentadecyl phenyl.
4. Method according to any nf the preceding clainis wherein the organic medium is a mineral oil, an aromatic or aliphatic hydrocarbon or other petroleum spirit-based solvent.
5. Method according to any of the preceding claims wherein the compound of formula I is present in the organic medium is an amount ranging from 1 to 20% by weight, based on the weight of the organic medium.
6. Method according to claim 5 wherein the compound of A formula I is present in the organic medium in an amount ranging from 2 to 15% by weight, based on the weight of the organic medium.
7. Method according to any of the preceding claims wherein the organic medium also comprises a further rust inhibitor and/or a dispersing agent and/or a surfactant.
8. Method of imparting temporary protection to a metal surface, according to claim 1, substantially as described with reference to any of the Examples.
9. A metal surface when temporarily protected according to a method claimed in any of the preceding claims.

Published 1990 at ThePatent Office. State House, 6671 High Holborn. London WC1R 4TP. Further copies maybe obtained from The Patent 0Ince. Wes Branch. St Mary Cray. Orpington, Kent B115 3RD. Printed by Multiplex techniques ltd, St Mary Cray, Kent, Con. 1187.

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