GB2265149A

GB2265149A - Demulsifier system for lubricants and functional fluids

Info

Publication number: GB2265149A
Application number: GB9205395A
Authority: GB
Inventors: Helen Theresa Ryan
Original assignee: Afton Chemical Ltd
Current assignee: Afton Chemical Ltd
Priority date: 1992-03-11
Filing date: 1992-03-11
Publication date: 1993-09-22
Also published as: GB9205395D0

Abstract

Demulsifier systems are described which do not seriously impair or interfere with the effectiveness of rust inhibitors used in the oil, even in situations where an additive package consisting such components is exposed to mildly elevated temperatures during formulation, storage and/or use. Such systems comprise: a) at least one block copolymer or propylene oxide and ethylene oxide in which the central block is poly-(propylene oxide), in which the copolymer has a number average molecular weight of at least 4000 and in which the copolymer contains 5% to 30% (preferably 5% to 20%, and most preferably 10%) poly(ethylene oxide); and b) at least one oxyalkylated amino. The composition may also contain c) at least one oxyalkylated polyglycol having a number average molecular weight below 4000.

Description

DEMULSIFIER SYSTEM FOR LUBRICANTS AND FUNCTIONAL FLUIDS Various types of demulsifiers have been used or proposed for use in oils of lubricating viscosity, such as hydraulic fluids, gear oils, crankcase lubricants, and the like.

It has been found that, unfortunately, at least certain effective demulsifiers previously used for this purpose, such as block copolymers of propylene oxide and ethylene oxide, can seriously impair or interfere with the effectiveness of rust inhibitors used in the oil, especially where an additive package containing such components is exposed to mildly elevated temperatures during formulation, storage and/or use.

A need thus exists for an effective way of overcoming this problem. To fulfill this need, this invention provides in one of its embodiments a demulsifier composition which comprises: a) at least one block copolymer of propylene oxide and ethylene oxide in which the central block is poly(propylene oxide), in which the copolymer has a number average molecular weight of at least 4000 and in which the copolymer contains 5% to 30% (preferably 5% to 20%, and most preferably 10%) poly(ethylene oxide); b) at least one oxyalkylated amine; and optionally, c) at least one oxyalkylated polyglycol having an average molecular weight below 4000.Such compositions preferably contain on a weight basis a major amount of component a) and a minor amount of component b), and when component c) is used, the compositions preferably contain a major amount of component a) and a minor amount of components b) and c). In this connection, particularly preferred compositions are those in which 60 to 95 wt % (preferably 60 to 90 wt %) of the combination of a) and b) or of a), b) and c) is composed of component a). To facilitate handling and blending, the compositions will usually contain an inert diluent such as a light hydrocarbon solvent, most preferably an aromatic hydrocarbon solvent such as toluene, xylene, etc.

Another embodiment of this invention is oil of lubricating viscosity containing a small demulsifying quantity of a combination of components a), b) and optionally c), preferably proportioned as described above. Usually 0.1 wt % or less (e.g., 0.05 wt % or less) of combined components a) and b) (and c) if present) based on the total weight of the lubricant or functional fluid will suffice. However larger quantities can be employed whenever deemed necessary or desirable.

Another embodiment is an additive package (or concentrate) composed of one or more antirust additives together with one or more oil-soluble additives such as an ashless dispersant, an antioxidant, a phosphorus- and/or sulfur-containing antiwear and/or extreme pressure agent (preferably but not necessarily metal-free), a copper corrosion inhibitor, etc., and containing a small amount of a demulsifier composition of this invention in which, preferably, components a) and b), and optionally c), are proportioned as described above.

Usually the concentrate will contain no more than 7 wt % of a combination of components a) and b), (and c) if present) based on the total weight of the concentrate or additive pack.

Amounts of 5 wt % or less are typical and preferred. Lubricating oils and functional fluids containing a minor amount (usually 10 wt % or less, and preferably 0.5 to 5 wt %) of the foregoing mixtures of additives, preferably added as a concentrate of this invention, constitute still further embodiments of this invention. Here again it is possible to use higher (or lower) amounts of the additive mixtures whenever deemed necessary or desirable.

EXAMPLES 1-6 The advantages achievable from the practice of this invention are illustrated by the results obtained in a group of laboratory tests. In these tests a typical refined paraffinic mineral oil base stock blend containing 0.34 wt % sulfur and comprising a mixture of 130 and 500 Solvent Neutral oils blended to the ISO 46 specification viscosity grade was used.

This blend was treated at a treat level of 0.6 wt % with an additive package in which only the identity and proportions of the demulsifier (and in one case, the amount of process oil diluent) were varied. The additive package on a weight basis was composed of: 18.33% C1214 tertiary alkyl primary amine (Primenes 81-R) salt of diphenyl monothiophosphoric acid; 7.00% Boronated Mannich base ashless dispersant as a 48% oil concentrate; 1.25% Tolyltriazole; 25.00% Phenolic antioxidant composed of 85% 2,6-di-tert butyl phenol, 11% 2,4,6-tri-tert-butyl phenol, and 4% 2,4-di-tert-butyl phenol and others; 12.25% Bis(4-nonylphenylamine antioxidant; 20.00% Sulfurized fatty acid ester (9% sulfur) 10.83% Antirust additives (a combination of 2.5% Monacor 39 additive, Mona Industries, believed to be the diisobutyl ester of N-(3-carboxy-1-oxo-2-propenyl)- N-octadecenyl aminosuccinic acid, and HiTECs 536 additive, Ethyl Petroleum Additives, Ltd.; Ethyl Petroleum Additives Inc., a modified imidazoline rust inhibitor package having in which the princi pal active ingredient is primarily a condensation product of dodecenyl succinic acid and oleic acid with a polyethylene polyamine); 5.34% Demulsifier and process oil diluent.

Six additive packages were prepared as above. In each such package the demulsifier system was comprised of a block copolymer of propylene oxide and ethylene oxide in which the central block was poly(propylene oxide). Each such copolymer was reported to contain 10% poly(ethylene oxide). These copolymers were PLURADYNE (trademark) FL-11, BASF-Wyandotte Corporation, a product reported to have an average molecular weight of 3800, a density of 1.02 at 25"C and a Brookfield viscosity of 800 cP at 25 C; PLURONIC (trademark) PE 10100, BASF United Kingdom, Ltd., a product reported to have an average molecular weight of 3600, a density of 1.02 at 20 C and a viscosity of 300 mm2/sec at 40 C;; and SYNPERONIC (trade mark) PE L-121, Imperial Chemical Industries, P.L.C., a pro duct reported to have an average molecular weight of 4400, a density of 1.02 at 25"C and a viscosity of 1600 cP at 25 C.

The SYNPERONIC PE L-121 thus corresponds to component a) of the compositions of this invention. A combination of oxyalkylated polyglycols and oxyalkylated amines available from Petrolite Ltd. under the trade designation TOLAD 2899 constituted component b) of the compositions of this invention, and may have supplied optional component c) as well. The product, supplied as a solution in an aromatic hydrocarbon solvent, is reported to have a specific gravity at 16 C of 0.91-0.98, a viscosity at 38Cc of 7-28 cSt and a flash point of 50 C minimum. In the additive packages of Examples 1-5 the amount of process oil diluent was in each case 2.34 wt %. In Example 6 the amount was 0.84 wt %.

Table 1 summarizes the make-up of the demulsifier systems used in these examples.

Table 1

DEMwmThk COMPONEmS EL Ex 1 Ex. 2 Ex. 3 Ebb 4 EL Ex. 3 S EL 6 PLURADYNE Ft,ll 3.0% 2.0% none none none none PLURONIC PE 10100 none none 3.0% 2.0% none none SYNPERONIC PE 1,121 none none none none 20% 3.0% TOlAD 2899 none 1.0% none 1.0% 1.0% 15% It will be noted that Examples 5 and 6 are representative of this invention. Examples 1-4 represent compositions not of this invention.

An oil blend was made from each of the above six additive packages and tested for demulsification performance using the ASTM D 1401 procedure in which a "Pass" rating requires the water-emulsified test blend to reach the required phase separation in 30 minutes or less. In addition, each test oil blend was rated for antirust performance using the ASTM D 665B (IP 135B) test procedure. Then the six additive packages were aged at 50 C for three days and corresponding test oil blends made from the so-aged packages were tested for antirust per formance using the same test procedure. For a "Pass" rating in this test procedure, the oil must not produce any visible amount of rust on the steel rod which is exposed to the mixture of oil and synthetic sea water heated to 60 C throughout the 24 hour test period.Table 2 summarizes the results so obtained.

Table 2

PROPBRTYThS ELI 1 Edc 1 | Er. 2 | Ex. 3 Et 4 Edc 5 Edc Rust performance before aging at 50 C Pass Pass Pass Pass Pass Pass Rust performance after aging at 50 C Fail Fail Fail Fail Pass Pass Demulsibility Pass Pass Fail Fail Pass Pass It will be seen that only the compositions of this invention achieved a passing result in all of the tests.

Other suitable block copolymers for use as component a) include poly (oxyethylene) -poly (oxypropylene) -poly (oxyethylene) polyol block copolymer (average molecular weight 5000; poly (oxyethylene) content, 20%; HLB at 25 C, 4.0); poly(oxyethy lene) -poly(oxypropylene) -poly(oxyethylene) polyol block copolymer (average molecular weight 5750; poly(oxyethylene content, 30%; HLB at 25"C, 8.0); and similar block copolymers.

Oxyalkylated amines which may be used as component b) in the compositions of this invention include polyether monoamines, polyether diamines and polyether triamines in which the polyether backbone is based either on ethylene oxide, propylene oxide, or mixed ethylene oxide-propylene oxide, such as are available from Texaco Chemical Company under the JEFFAMINE trademark (including JEFFAMINE M-600, M-2070, D-230, D-400, D2000, D-4000, ED-600, ED-900, ED-2001, ED-4000, ED-6000, C346, DU-700, BuD-2000, EDR-148, T-403, T-3000 and T-5000 compounds); products formed by addition of ethylene oxide, propylene oxide, and/or butylene oxide to polyalkylene polyamines such as diethylene triamine, triethylene tetramine, tetraethylene pentamine, pentaethylene hexamine, 1,4-bis(2-amino ethyl)piperazine, or mixtures thereof; aliphatic substances such as are described in European Patent Application 452,004 published October 16, 1991; products formed by the addition of ethylene oxide, propylene oxide and/or butylene oxide to aliphatic diamines such as ethylene diamine, 1,2-propanediamine, 1,3-propanediamine, 1, 4-butanediamine, or hexamethylene diamine; products formed by the addition of ethylene oxide, propylene oxide and/or butylene oxide to alkanol amines, such as ethanol amine, diethanol amine, 1-amino-2-propanol, 3amino-1-propanol, and 6-amino-1-hexanol; and other similar substances.

Oxyalkylated polyglycols which may be used as component c) in the compositions of this invention include products derived by the addition of ethylene oxide, propylene oxide and/ or butylene oxide to polyglycols such as diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, and the like. These oxyalkylated polyglycols have number average molecular weights below 4000.Examples include: A. poly (oxyethylene) -poly (oxypropylene) -poly (oxyethylene) polyol block copolymer (number average molecular weight 1200; poly(oxyethylene) content, 30%); B. poly (oxyethylene) -poly (oxypropylene) -poly (oxyethylene) polyol block copolymer (number average molecular weight 1750; poly(oxyethylene) content, 30%); C. poly(oxyethylene) -poly(oxypropylene) -poly (oxyethylene) polyol block copolymer (number average molecular weight 1750; poly(oxyethylene) content, 20%); D. poly (oxyethylene) -poly (oxypropylene) -poly (oxyethylene) polyol block copolymer (number average molecular weight 950; poly(oxyethylene) content, 10%); E. poly(oxypropylene)-poly(oxyethylene)-poly(oxypropylene) polyol block copolymer (number average molecular weight 3250; poly(oxyethylene) content, 10%); F. poly(oxypropylene)-poly(oxyethylene)-poly(oxypropylene) polyol block copolymer (number average molecular weight 2700; poly(oxyethylene) content, 10%); G. poly(oxypropylene)-poly(oxyethylene)-poly(oxypropylene) polyol block copolymer (number average molecular weight 1900; poly(oxyethylene) content, 10%); H. poly(oxyethylene)-poly(oxypropylene)-poly(oxyethylene) polyol block copolymer (number average molecular weight 2750; poly(oxyethylene) content, 10%); and similar materials.

Various other additives can be employed in the compositions of this invention in order to partake of the properties made available through their use.

Amine salts of partially esterified monothiophosphoric acids comprise one preferred group of additives used in the compositions of this invention. Usually these amine salts are derived from C8 to C24 aliphatic amines. Examples include the oleylamine and the C1214 tert-alkyl primary amine salts of such acids as O-monobutylthiophosphoric acid, S-monobutylthiophosphoric acid, O-monobutylthionophosphoric acid, O,O-dibutylthiophosphoric acid, O,S-dibutylthiophosphoric acid, O,O-di- butylthionophosphoric acid, O-monoisobutylthiophosphoric acid, S-monoisobutylthiophosphoric acid, O-monoisobutylthionophosphoric acid, O,O-diisobutylthiophosphoric acid, O,S-diisobutylthiophosphoric acid, O,O-diisobutylthionophosphoric acid, O-monoamylthiophosphoric acid, S-monoamylthiophosphoric acid, O-monoamylthionophosphoric acid, 0, O-diamylthiophosphoric acid, 0, S-diamylthiophosphoric acid, 0, O-diamylthionophosphor- ic acid, O-monohexylthiophosphoric acid, S-monohexylthiophos- phoric acid, O-monohexylthionophosphoric acid, O,O-dihexylthi- ophosphoric acid, 0, S-dihexylthiophosphoric acid, O,O-dihexyl- thionophosphoric acid, O-monoheptylthiophosphoric acid, S-monoheptylthiophosphoric acid, O-monoheptylthionophosphoric acid, O,O-diheptylthiophosphoric acid, O,S-diheptylthiophosphoric acid, O,O-diheptylthionophosphoric acid, O-mono-2ethylhexylthiophosphoric acid, S-mono-2-ethylhexylthiophosphoric acid, O-mono-2-ethylhexylthionophosphoric acid, 0,0-di- 2-ethylhexylthiophosphoricacid, O,S-di-2-ethylhexylthiophos- phoric acid, O,O-di-2-ethylhexylthionophosphoric acid, O-monooctylthiophosphoric acid, S-monooctylthiophosphoric acid, 0 monooctylthionophosphoric acid, O,O-dioctylthiophosphoric acid, O,S-dioctylthiophosphoric acid, O,O-dioctylthionophosphoric acid, O-monononylthiophosphoric acid, S-monononylthiophosphoric acid, O-monononylthionophosphoric acid, O,O-dinonylthiophosphoric acid, O,S-dinonylthiophosphoric acid, 0,0dinonylthionophosphoric acid, O-monodecylthiophosphoric acid, S-monodecylthiophosphoric acid, O-monodecylthionophosphoric acid, O,O-didecylthiophosphoric acid, O,S-didecylthiophosphoric acid, O,O-didecylthionophosphoric acid, O-monododecyl thiophosphoric acid, S-monododecylthiophosphoric acid, O-mono- dodecylthionophosphoric acid, O,O-didodecylthiophosphoric acid, O,S-didodecylthiophosphoric acid, O,O-didodecylthiono phosphoric acid, O-monotridecylthiophosphoric acid, 5-monotri- decylthiophosphoric acid, O-monotridecylthionophosphoric acid, O,O-ditridecylthiophosphoric acid, O,S-ditridecylthiophosphoric acid, O,O-ditridecylthionophosphoric acid, O-monotetrade- cylthiophosphoric acid, S-monotetradecylthiophosphoric acid, O-monotetradecylthionophosphoric acid, O,O-ditetradecylthio- phosphoric acid, O,S-ditetradecylthiophosphoric acid, O,O-ditetradecylthionophosphoric acid, O-monohexadecylthiophosphoric acid, S-monohexadecylthiophosphoric acid, O-monohexadecylthionophosphoric acid, O,O-dihexadecylthiophosphoric acid, O,S- dihexadecylthiophosphoric acid, O,O-dihexadecylthionophosphoric acid, O-monooctadecylthiophosphoric acid, S-monooctade- cylthiophosphoric acid, O-monooctadecylthionophosphoric acid, O,O-dioctadecylthiophosphoric acid, O,S-dioctadecylthiophosphoric acid, O,O-dioctadecylthionophosphoric acid, O-monooleylthiophosphoric acid, S-monooleylthiophosphoric acid, O-monooleylthionophosphoric acid, 0, O-dioleylthiophosphoric acid, O,S-dioleylthiophosphoric acid, 0, O-dioleylthionophosphoric acid, O-monobenzylthiophosphoric acid, S-monobenzylthiophosphoric acid, O-monobenzylthionophosphoric acid, 0, O-dibenzylthiophosphoric acid, O,S-dibenzylthiophosphoric acid, 0, O-dibenzylthionophosphoric acid, O-monocyclohexylthiophosphoric acid, S-monocyclohexylthiophosphoric acid, O-monocyclohexylthionophosphoric acid, O,O-dicyclohexylthiophosphoric acid, O,S-dicyclohexylthiophosphoric acid, O,O-di cyclohexylthionophosphoric acid, O-mono-p-tolylthiophosphoric acid, s#mono#p-tolylthiophosphoric acid, O-mono-p-tolylthiono- phosphoric acid, 0,0- di-p-tolylthiophosphoric acid, O,S-di-p tolylthiophosphoric acid, 0, O-di-p-tolylthionophosphoric acid, o-monoxylylthiophosphoric acid, S-monoxylylthiophosphoric acid, O-monoxylylthionophosphoric acid, O,O-dixylylthiophosphoric acid, O,S-dixylylthiophosphoric acid, O,O-dixylylthionophosphoric acid, O-isopropyl-O-octadecylthiophosphoric acid, O-nonyl-S-butylthiophosphoric acid, O-undecyl-O-methylthionophosphoric acid, O-cyclohexyl-S -decylthiophosphoric acid, O-phenyl-S-tetradecylthiophosphoric acid, O-pentade cyl#O-cyc1ohexeny1thionophosphoric acid, O-ethyl-O- (p-tertamylphenyl)thionophosphoric acid, O-benzyl-S-isononylthiophosphoric acid, O-cyclopentyl-O-heptadecylthionophosphoric acid, O-oleyl-S-butylthiophosphoric acid, O-2-ethylhexyl-Oisooctylthionophosphoric acid, O-allyl-S-tridecylthiophosphoric acid, and the like.

Rust inhibitors which are preferably employed in the compositions of this invention include imidazolines and imidazoline derivatives; alkenyl succinic acids and anhydrides such as tetrapropenylsuccinic acid, tetrapropenylsuccinic anhydride, tetradecenylsuccinic acid, tetradecenylsuccinic anhydride, hexadecenylsuccinic acid, hexadecenylsuccinic anhydride, and the like; aminosuccinate esters; dimer and trimer acids, such as are produced from tall oil fatty acids, oleic acid, linoleic acid, or the like; and amine salts of one or more long chain (e.g, C a to Cso) carboxylic acids, which can be monocarboxylic acids or polycarboxylic acids. A variety of amines can be used in forming such salts, including primary, secondary and tertiary amines, and the amines can be monoamines, or polyamines.Further, the amines may be cyclic or acyclic aliphatic amines, aromatic amines, heterocyclic amines, or amines containing various mixtures of acyclic and cyclic groups. The amine salts can be preformed or formed in situ by interaction between separately added carboxylic acid and amine.

Also useful as rust inhibitors are the half esters of alkenyl succinic acids having 8 to 24 carbon atoms in the alkenyl group with alcohols such as the polyglycols. Other suitable rust inhibitors include ether amines; acid phosphates; amines; polyethoxylated compounds such as ethoxylated phenols and ethoxylated alcohols.

Preferred rust inhibitors are aminosuccinic acids or derivatives thereof represented by the formula:

wherein each of R1, R2, R5, R6 and R7 is, independently, a hydrogen atom or a hydrocarbyl group containing 1 to 30 carbon atoms, and wherein each of R3 and R4 is, independently, a hydrogen atom, a hydrocarbyl group containing 1 to 30 carbon atoms, or an acyl group containing from 1 to 30 carbon atoms.

The groups R1, R2, R3, R4, R5, R6 and R7, when in the form of hydrocarbyl groups, can be, for example, alkyl, cycloalkyl or aromatic containing groups. Preferably R1 and R5 are the same or different straight-chain or branched-chain hydrocarbon radicals containing 1-20 carbon atoms. Most preferably, R1 and R5 are saturated hydrocarbon radicals containing 3-6 carbon atoms. R2, either R3 or R4, R6 and R7, when in the form of hydrocarbyl groups, are preferably the same or different straight-chain or branched-chain saturated hydrocarbon radicals.Preferably a dialkyl ester of an aminosuccinic acid is used in which R1 and R5 are the same or different alkyl groups containing 3-6 carbon atoms, R2 is a hydrogen atom, and either R3 or R4 is an alkyl group containing 15-20 carbon atoms or an acyl group which is derived from a saturated or unsaturated carboxylic acid containing 2-10 carbon atoms.

Most preferred of the aminosuccinic acid derivatives is a dialkylester of an aminosuccinic acid of the above formula wherein R1 and R5 are isobutyl, R2 is a hydrogen atom, R3 is octadecyl and/or octadecenyl and R4 is 3-carboxy-1-oxo-2-propenyl. In such ester R6 and R7 are most preferably hydrogen atoms.

Mannich condensation ashless dispersant products can be used in the practice of this invention. Such products are preferably boronated, but can be employed in unboronated form.

Preferred Mannich condensation products are boronated products formed by reaction among a long chain alkylated phenol, formaldehyde or a formaldehyde precursor and one or a mixture of polyamines, preferably a polyalkylene polyamine or mixture thereof. The long-chain alkylated phenol is preferably derived from a polyolefin such as polyisobutene having a number average molecular weight in the range of 500 to 3000.

For a detailed description of Mannich condensation products suitable for use in the compositions in this invention, see for example the following U.S. Patents: 3,368,972; 3,413,347; 3,442,808; 3,448,047; 3,539,633; 3,591,598; 3,600,372; 3,634,515; 3,697,574; 3,703,536; 3,704,308; 3,725,480; 3,726,882; 3,736,357; 3,751,365; 3,756,953; 3,793,202; 3,798,165; 3,798,247; and 3,803,039.

The compositions of this invention can also contain inhibitors of copper corrosion. Such compounds include thiazoles, triazoles and thiadiazoles. Examples of such compounds include benzotriazole, tolyltriazole, octyltriazole, decyltri azole, dodecyltriazole, 2-mercaptobenzothiazole, 2, 5-dimercap- to-1,3,4-thiadiazole, 2-mercapto-5-hydrocarbylthio-1,3,4- thi adiazoles,2-mercapto-5-hydrocarbyldithio-1,3,4-thiadiazoles, 2,5-bis(hydrocarbylthio) -1, 3,4-thiadiazoles, and 2,5- (bis) hydrocarbyldithio) -1,3, 4-thiadiazoles. The preferred compounds are the 1,3,4-thiadiazoles, a number of which are available as articles of commerce. For further details, see for example U.S. Pat. Nos. 2,765,289; 2,749,311; 2,760,933; 2,850,453; 2,910,439; 3,663,561; 3,862,798; 3,840,549; and 4,097,387.

Antioxidants can be used, such as one or more phenolic antioxidants, aromatic amine antioxidants, sulphurized phenolic antioxidants, organic phosphites, and oil-soluble copper compounds, among others. Examples include 2,6-di-tert-butylphenol, liquid mixtures of tertiary butylated phenols, 2,6-ditert-butyl-4-methylphenol, 4,4'-methylenebis(2,6-di-tert-butylphenol), 2,2' -methylenebis (4-methyl6-tert-butylphenol), mixed methylene-bridged polyalkyl phenols, 4,4' -thiobis (2-me- thyl-6-tert-butylphenol), N,N'-di-sec-butyl-p-phenylenediamine, 4-isopropylaminodiphenyl amine, phenyl-anaphthyl amine, and phenyl-P-naphthyl amine.

Oil-soluble metal-free sulfur-containing antiwear and/or extreme pressure additives can be used in the practice of this invention. Examples are included within the categories of dihydrocarbyl polysulfides; sulfurized olefins; trithiones; sulfurized thienyl derivatives; sulfurized terpenes; sulfurized oligomers of Q-C8 monoolefins; xanthates; hydrocarbyl trithiocarbonates; sulfurized Diels-Alder adducts such as those disclosed in U.S. reissue patent Re 27,331; and sulfurized fatty acid esters.Specific examples include sulfurized polyisobutene of Mn 1,100, sulfurized isobutylene, sulfurized diisobutylene, sulfurized triisobutylene, dicyclohexyl polysulfide, diphenyl polysulfide, dibenzyl polysulfide, dinonyl polysulfide, and mixtures of di-tert-butyl polysulfide such as mixtures of two or more of di-tert-butyl disulfide, di-tert-butyl trisulfide, di-tert-butyl tetrasulfide and di-tert-butyl pentasulfide, among others. Combinations of such categories of sulfur-containing antiwear and/or extreme pressure agents can also be used, such as a combination of sulfurized isobutylene and di-tert-butyl trisulfide, a combination of sulfurized isobutylene and dinonyl trisulfide, a combination of sulfurized triisobutylene and dibenzyl polysulfide, and the like.

Other additives which can be employed include metal salts of dihydrocarbyl dithiophosphoric acids, alkali and alkaline earth metal-containing detergents, succinimide and succinamide ashless dispersants, succinic ester-amide ashless dispersants, succinic ester ashless dispersants, viscosity index improvers, pour point depressants, dispersant viscosity index improvers, seal swell agents, anti-squawk additives, friction modifiers, and the like.

The proportions of the foregoing ingredients can be varied to suit the needs of the occasion, and to some extent will be governed by the use to which the composition is to be put. Finished oils will normally contain no more than about 20% by weight of a combination of such additives. Additive concentrates of this invention will normally contain a minor amount of diluent oil and a major amount of the active additive ingredients. Additive concentrates containing up to 30% by weight of diluent oil are typical.

Claims

1. A demulsifier composition which comprises: a) a major amount of at least one block copolymer of propylene oxide and ethylene oxide in which the central block is poly(propylene oxide), in which the copolymer has an average molecular weight of at least 4000 and in which the copolymer contains 5% to 30% poly(ethylene oxide); and b) a minor amount of at least one oxyalkylated amine.

2. A composition according to Claim 1 wherein the block copolymer a) has an average molecular weight of 4400 and in which the copolymer contains 10% poly(ethylene oxide).

3. A composition according to Claims 1 or 2 further comprising c) at least one oxyalkylated polyalkylene glycol having a number average molecular weight below 4000, said composition containing a major amount of a) and a minor amount of b) and c).

4. An additive concentrate which contains at least one oilsoluble rust inhibitor and a demulsifier composition according to any of Claims 1-3.

5. A lubricant or functional fluid composition containing a minor demulsifying amount of a demulsifier composition according to any of Claims 1-3.

6. A lubricant or functional fluid composition containing a minor rust-inhibiting amount of at least one oil-soluble rust inhibitor and a demulsifying amount of a demulsifier composition according to any of Claims 1-3.

7. A composition according to Claims 5 or 6 wherein the base oil of the lubricant or functional fluid is principally or entirely a mineral oil of lubricating viscosity.

8. A composition according to Claim 4 or 6 wherein the oilsoluble rust inhibitor comprises at least one compound of the formula

9. A composition according to any of Claims 4-8 further comprising at least one amine salt of a partially esterified monothiophosphoric acid and at least one oil-soluble boronated Mannich condensation product of a long chain alkylated phenol, formaldehyde or a formaldehyde precursor and one or a mixture of polyalkylene polyamines.

10. A method of protecting an additive concentrate containing at least one antirust additive against loss of antirust performance, especially when the concentrate is exposed to mildly elevated temperatures during formulation, storage and/or use, which method comprises incorporating in said concentrate a demulsifier composition in accordance with any of Claims 1-3.