CA1041985A - Lubricant composition containing amine salts of half-esters of alkyl or alkenyl succinic acid - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

Disclosed herein are lubricant compositions and in particular, water-base metal-working fluids, which include, as a biocidal and anti-rust agent, from about 0.5% to about 65%
by weight of an amino salt of a mono (C1-C5)alkyl ester of an alkyl or alkenyl succinic acid, the alkyl or alkenyl substituent of which contain from 6 to 22 carbon atoms The amino reacted with the partial ester of the alkyl or alkenyl succinic acid is preferably an alkanolamine, having 2 to 22 carbon atoms, and most preferably is triethanolamine.

Description

104~985 This invention relates to lubricant compositions,particularlg aqueous metalworking lubricants. The present compositions are distinguished by improved anti-rust, biocidal and non-ferrous metal deactivation properties.
Certain types of lubricants, especially metal-working fluids e.g. cutting oils, soluble oils (emulsifiable oils) and aqueous metalworking fluids are subject to deterioration during use. Microbial deterioration i6 particularly troublesome and may lead to rancidity and loss of valuable lubricating properties. The lubricants may also cause corrosion of metal articles with which they come into contact, e.g.
tools and workpieces. Additives have often-been used in order to over- -come these drawbacks but generally it has been found that each additive fulfills only one function and therefore it has been necessary to include a number of additives in the lubricant. Conventional water-based metalworking fluids have, in fact, been formNlated with as many as nine components in order to provide effective operation over a wide range of --conditions with the minimum of adverse ~ide-effects such as corrosion, hard water instability and foam formation. -~ e have now found that a certain class of material6, namely the am~ne salts of succinic acid partial esters, are effective as multi-functional lubricant additives. They exhibit biocidal, anti-corrosion and metal deactivation properties. Because of their anti-corrosion propertie~ they may be used in nltrlte-free aqueo~6 coolants.

5 . ~
The present invention re6ides in a water-ba6e metal working fluid consisting essentially of water and, as a biocidal and anti-rust agent, the trietha lamine salt of the nomethyl ester of an alkyl or alkenyl 6uccinic acid, the alkyl or alkenyl substituent of ~hich contain6 from 6 to Z2 carbon atoms. -These amine 6alts are especially useful in aqueous ~ ' .

10419~5 metalworklng lubricants but may also be used in other lubricating media e.g. oils, soluble oil6 and greases. As is well known, aqueous metalworking fluids ~also known as chemical or ~ynthetic fluids) are a class of lubricants characterised by their complete solubility in combination with water. When mixed with water they form clear ~transparent) fluids. Emul610n type lubricants (commonly called "soluble oils", "water soluble oils", "water miscible fluids" or "emulslflable cutting fluids") comprise an emulsion of minute oll droplets surrounded by a wates phase.
Emulslfying agents and coupllng agents are used to disperse the oll and maintaln emulslon stabllity.
Semi-aqueous coolants are a third class of water-based lubricant. These comprise an admixture of soluble 0118 and an aqueous fluld. Thelr general physlcal characteristics are similar to soluble oils. Cutting oils are generally oils of petroleum, animal, marine or vegetable orlgin, either singly or in combinatlon.
With all these .ypes of lubricant various additives may be present e.g. extreme pressure addltives (especially sulfur, phosphorus and chlorine compounds) and lubricity improvers. Further dlscussion of these flulds will be found ln a number of sources such as "Cuttlng and Grindlng Fluids: Selection and Appllcation", R. K. Springborn (Ed.), American Society of Tool and Manufacturing Engineers, Dearborn, Michigan, 1967.
A~ previously mentioned, the additives of the present invention are particularly effective in aqueous metalworking fluids. They confer improved non-ferrous metal deactivation, anti-rush and biocidal properties upon the fluid.
The ~m~ne salts are formed by reaction of an amine with a partial ester of an alkyl or alkenyl succinic acid. The reaction between .. . . . . . . .. . .

9~5 the amine and the ester usually takes place readily at room temperature.
The eRter is derived from an alkyl or alkenyl succinic acid in which the alkenyl or alkyl substituent group contains 6 to 22 carbon atoms. Exa_ples of such succinic acids are octenyl-, dodecenyl-, hexadece~yl-, iso-octadocenyl- and triacontenyl- succinic acids. The sub6tituent group may be a polyolefi~ic group e.g. as in the tetrapropenyl-or polybutenyl- succinic acids.
The alcohol used to form ehe partial ester preferably has 1 to 18 carbon atoms and is preferably an alkyl alcohol (alkanol) such as methanol, ethanol, propanol or butanol.
The amine whicn is reacted with the partial ester of the substltuted succinic acid is preferably an alkylamine, aromatic Rm~ne or an alkanolamine having 2 to 22 carbon atoms. The alkanolamines are most advantageously employed and may suitably range in chain length from 2 to 6 carbon atoms. These amines should preferably be liquid at room tempera-ture. The lower molecular weight amines are generally preferred and for this purpose, it has been found that such alkanolamines as mono-, or tri-ethanolamine are highly effective. The amines may be water-soluble or oil-soluble and may therefore include such alkanolamines as iso-propanolamines, e.g., mono-, di and tri-isopropanolamine, di-methylethanolamine, diethyl-ethanolamine, aminoethylethanolamine, N-acetyl ethanolamine, phenylethanol-amine, phenyldiethanolamine and mixtures of these.
For most applications these amine salts are employed in an arount from 0.5 to 65%, preferably from 5 to 50%, by weight, of the total lubricant composition.
~here the lubricant includes an oil, this may be a mineral or synthetic oil of lubricati~g viscosity. In instances where high tempera-ture stability is not a prime requirement, mineral oils having a viscosity of at least 40 SSU, (4cSt) particularly 60 SS~ to 6000 SSU at 100F. (10 to 1200 cSt. at 38C) are preferably employed. In instances where the lubricant comprises a synthetic oil by itself or in combination with a mineral oil various materials may be utilized. Typical synthetic oils include glycols e.g. polypropylene glycol; esters e.g. trimethylol propane esters, neopentyl and pentaerythritol esters, di-(2-ethyl hexyl)sebacate, di-(2-ethyl hexyl) adipate or dibutyl phthalate.
The oil may be employed in combination with a grease-forming quantity of a thickening agent as vehicles in the production of greases containing the ~m;ne salts. For this purpose, a wide variety of thickening or gelling agents may be used, e.g. nonsoap thickeners, such as surface-modified clays and silicas, aryl ureas, soap thickeners e.g. calcium complexes and similar materials.
The test results below show-that the amine salt materials of the present invention are effective as biocidal anti-rust and non-ferrous metal deactivating agents.
The Biocidal Activity Test referred to in the Table is conducted as follows:
In this procedure 0.5 x 0.5 x .027 inch (13x13x0.7mm) filter paper is saturated with the biocidal test solution (approximately 0.5 ml.).
This square is placed in the center of a nutrient agar plate previously inoculated uith bacteria (predominantly Pseudomonas). In this test an effective biocid~l agent should inhibit growth adjacent to the filter paper.
The distance from the edge of the paper to the point where bacterial growth begins, is indicative of activity. The data recorded in the Tables with -respect to reactant and water components is in percent, by weight. The test uas carried out on a filter paper saturated with a 45% triethanolamine ~olution as a comparison (Example 1l. The amine salt was prepared by reacting 1~ ' .'~r.~ . .

excess triethanolamine with the monomethyl ester of tetrapropenyl succinic acid in situ (Example 2).
In Example l, little or no bacterial inhibition resulted after 120 hours i.e., heavy bactçrial growth was observed lll6 inch (1.6 mm.) from the test paper. However, the same test performed on the triethanolami~e/tetrapropenylsuccinic ester salt of Example 2 resulted in 3/8 inch (9.5 mm.) growth inhibition, thus indicating biocidal activity.
The form~lation of Example 2 also provides an unexpected degree of rust protection for malleable iron and prevention of staining of non-ferrous metals, such as alllm;num. The Malleable Iron Rust Test is conducted as follows:
Malleable iron chips are placed in a 50 ml container together with the fluid composition which is to be evaluated. All excess liquid is then drained off, and the chips are stored in an atmosphere of approx;m~tely 90 percent relative humidity and at a temperature between 70 and 75F (2l-24DC). The sample is checked, after a period of 48 hour storage, for appearance of rust.
The Aluminum Stain Test is conducted as follows:
Approximately l¦2 oz. (14 g.) of the lubricant solution to be evaluated is placed in a 2 Z- (57 g.) jar, together with a 2.25 inch (57 mm.) rod of aluminum previously cleanet ~ith a medium grade of emery cloth. Approx~m~tely half of this rod was immersed below the surface of the test solution and the remaining portion exposed ~o air.
Staining tendency was observed over a period of ~8 hours.
The test results are given in the table below.

~.0419~5 TABLE
~- " ' Example 1 Example 2 Formulation, X Ueight Triethanolamine 45.00 30.00 Tetrapropenylsuccinic 15 00 acid/monomethyl ester - .
~'ater 55.00 ~ .55.00 . .
Biocide ActivitY Test Bacterial Growth Inhibition: .- 3/8 0 ~nches (mm.) from Test Square /16 Malleable Iron Rust Test : ~ 48 hours Rust ~o-rust --.: . , . ., -.` S Aluminum Stain Test ~;~. 230501 ~-ard48 hrs - Black Stain ~o'Stain ,,,, , , . . ! ' ~ From the foregoing tsble, it will be apparent that an amine ~;, . .
alt of a partial alkyl ester of an alkenyl succinic acid is markedly .: effective as biocidal and rust prevention agents and also as a non-ferrous deactivating agent.
.: :
, ,''. ': '~ ' --. . .
.,;, ; . c , . ~, . - - - . .. ..
~,. ;, . - - - -- -:,: - . .
-: ........ :., -. ~,. .
' ,':::
.~. ;~
:-.......... : , .

.'''~'. : , .
.. . . .
-: -6-.
~
..~;,.-: - .::
. .~:: - . - . -:

Claims (3)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A water-base metal working fluid consisting essen-tially of water and, as a biocidal and anti-rust agent, the triethanolamine salt of the monomethyl ester of an alkyl or alkenyl succinic acid, the alkyl or alkenyl substituent of which contains from 6 to 22 carbon atoms.

2. The fluid of claim 1 wherein said ester is the mono-methyl ester of tetrapropenylsuccinic acid.

3. The fluid of claim 1 wherein said water is present in an amount of 55%, by weight, and said salt is present in an amount of 45%, by weight, the triethanolamine component thereof being present in an amount of 30%, by weight, of the total composition and the monomethyl ester of tetrapropenylsuccinic acid component thereof being present in an amount of 15%, by weight, of the total composition.