Patent GB-767734-A (GB)
Title: Improvements in or relating to lubricating oils
Inventor: ELLIOTT JOHN SCOTCHFORD
Filed: 1954-05-17
Abstract: A composition, suitable for use as a turbine oil, a cutting oil or a metal-working oil, comprises a lubricating oil and minor proportions each of (i) an organic di- or poly-sulphide or selenium analogue thereof, (ii) a zinc, cadminum or iron salt of an organic dithiocarbamic acid and (iii) a cyclic ocmpound containing the group <FORM:0767734/III/1> as part of a ring structure or a derivative thereof capable of homolytic dissociation into free radicles containing the group <FORM:0767734/III/2> as part of a ring structure.  Suitable lubricating oils are mineral oil, fatty oils (e.g. castor oil or rapeseed oil) and synthetic oils such as dicarboxylic acid diesters and polyglycol ethers.  Ingredient (i) may contain the group <FORM:0767734/III/3> wherein m is 0, 1, 2, 3 or 4 and n is 0, 1, 2 or 3, the sum of m and n being not less than 2 and not greater than 4, and the carbon atoms being attached to other carbon atoms or to hydrogen or halogen atoms.  It may be an aliphatic, aromatic or alicyclic compound and may carry substituents such as halogen or nitro, hydroxyl or esterified carboxyl groups. Alternatively, ingredient (i) may be a cyclic compound in which the sulphur- and/or selenium-containing groups form part of a ring structure or it may be a sulphurized unsaturated organic compound such as sulphurized lard oil, sperm oil, oleic acid, tallow, woolfat or terpene.  Ingredient (ii) may have the formula. <FORM:0767734/III/4> wherein R1 and R2 are hydrogen of hydrocarbon radicles or together form part of a ring structure, M is zinc, cadmium or iron and x is the valency of M.  Ingredient (iii) may be 2-mercaptobenzothiazole, benzothiazole disulphide, hydroxymethyl thiobenzothiazole, triphenyl methyl thiobenzothiazole, 2-mercapto-4-methyl-6-isopropylthiazole, a 2-mercapto-oxazole, a 2-mercapto-imidazole, a 2-mercapto-thiazine or a 2-mercapto-thiazoline.  The composition may also contain other extreme pressure additives such as organic halogenated compounds (e.g. chlorinated paraffin wax) and organic phosphorus compounds.  In the examples, compositions are described consisting of (a) mineral lubricating oil, 2-mercaptobenzothiazole, zinc di-n-butyl dithiocarbamate, chlorinated paraffin wax and either sulphurized oleic acid or a blend of di (3-carbomethoxy-4-hydroxyphenyl) polysulphides and di (3-carbomethozy-4-hydroxyphenyl) thioether, (b) di (2-ethyl hexyl) sebacate, di (3-carbomethoxy-4-hydroxyphenyl) disulphide, benzothiazole disulphide, benzothiazole disulphide and zinc diethyl dithiocarbamate (c) mineral lubricating oil, di-n-butyl trithiodiacetate, benzothiazole disulphide, zinc di-n-butyl dithiocarbonate, ethylene glycol mononaphthenate acid phthalate and calcium petroleum sulphonrate, (d) mineral lubricating oil, di-n-butyl trithiodiacetate, zinc di-n-butyl dithiocarbamate and one of benzothiazole disulphide, hydroxymethyl-thiobenzothiozole and 2-mercapto-4, 6, 6-trimethyl-1, 3, 6 H thiazine, (e) di (2-ethyl hexyl) sebacate, di-n-butyl trithiodiacetate, zinc di-n-butyl dithiocarbamate and either 2-mercapto-benzoxazole or 2-mercapto-benzimidazole, (f) mineral lubricating oil, di-n-butyl trithiodiacetate, benzothiazole disulphide and one of zinc dimethyl or diethyl dithiocarbamate, cadmium or ferric dibutyl dithiocarbamate and cadmium cyclopentamethylene dithiocarbamate, (g) mineral lubricating oil, benzothiazole disulphide, zinc dibenzyl dithiocarbamate and one of dibenzyl trisulphide, di-n-butyl diseleno-diacetate and 4, 7-dimethyl-4, 7-di (21-dimethyl propyl)-1, 2, 5, 6-tetrathia-cyclo-octane and (h) mineral lubricating oil, 2-mercaptobenzothiazole, zinc dibutyl dithiocarbamate and either di-tert-butyl disulphide or sulphurized sperm oil.  For comparison purposes, lubricating compositions similar to (f) are described in which the dithiocarbamate is nickel dibutyl dithiocarbamate or piperidine cyclopentamethylene dithiocarbamate.  According to the Provisional Specification, ingredient (ii) is a salt of an organic dithiocarbamic acid and a metal of Group II (b) of the Periodic Table.  Specifications 557,756, 561,898, 561,941 and 714,497 are referred to.