US2434490A - Rust preventive lubricating oil compositions - Google Patents

Description

Patented Jan. 13, 1948 RUST PREVENTIVE LUBRICATING OIL COMPOSITIONS Gordon W. Duncan,

Westfield, N. J., assignor to Standard Oil Development Company, a corporation of Delaware No Drawing. Application December 30, 1944, Serial No. 570,787

4 Claims. (Cl. 252-56) This invention relates to slushing compositions, that is, to non-drying compositions of matter for arresting, preventing and inhibiting the corrosion of metals.

The corrosion of a sult'of chemical reactions between the environof the metal. By coating metallic surfaces with an inert, impervious film, by dipping, spraying, brushing, or swabbing, the development of these electrochemical relations can be impeded and arrested and thus active corrosion prevented. The use of a slushing formation of a relatively thick, viscous liquid or semi-solid layer which is easily removable from the surfaces over which it is spread by Wiping with a cloth or flushing with a readily available solvent. More durable application to facilitate treatment of the metal surface. In no case, however, is the protective layer of the nature of a diflicultly-removable varnish-like layer. The use of slushing compositions is particularly advantageous when metallic as engine parts during storage or tubing during shipment, yet must be freed of any coating before use.

ing on the film. In order to overcome this difficulty and to increase the effectiveness of the coating film, it has been suggested that materials in the nature of soaps be included in the hydrocarbon composition. Even though these soaps arises through the fact that they are ash-forming materials. It is often desirable to protect an internal combustion engine both internally and externally for storage purposes. When such engines are removed from storage the proper care is not taken to completely remove the protective coating; Thus, when the engine is put into service the protective coating is burned off, leaving an abrasive ash, which, by

increasing combustion chamber deposits, shortens the time interval before engine overhaul is required.- The presence of this ash promotes wear in the internal parts of the engine. Another objection to the soap type rust preventive agents is their relative ineffectiveness in certain base stocks, particularly high viscosity, highly-refined lubricating oils.

An object of the present invention is the formation of non-drying composition of matter for arresting, preventing, and inhibiting the corrosion of metals. This and other objects will be apparent to those skilled in the art upon reading the following description.

It has now been found that when small amounts of carboxylic acid esters of partially dehydrated polyhydric alcohols are incorporated in slushing compositions the composite is characterized by marked anti-corrosive properties and contains no ash-forming constituents. The compositions of the invention are therefore improved slushing oil compositions which contain, in addition to the above described esters, the usual constituents of a protective base material which is generally a mineral oil product such as a light mineral oil distillate, a mineral oil of about lubricating consistency, or a more resistant non-drying coating material such as petrolatum or any of the various petroleum waxes. Also waxes and oils of animal, including degras, lanolin, or vegetable origin may be used as the base material if desired. In many instances the rust preventive compositions may be diluted with a volatile solvent to facilitate application.

The anti-corrosion agents contemplated according to the present invention are carboxylic acid esters of partially dehydrated aliphatic polyhydric alcohols such as the hexitols. Partial dehydration converts the polyhydric alcohol to an epoxide or inner ether type of compound having hydroxyl substituents and either one or two mono-oxy, 4-7 membered carbon-oxygen rings in its probable chemical figuration. The hydroxyl groups attached to the inner ethers still retain the typical reaction of an alcohol,

a fatty acid to produce an ester. The esterification of one or more hydroxyl groups in the partially dehydrated polyhydric alcohol yields esters found to be useful for the purposes of the present invention. The acids useful for the esterification of the cyclic ether-alcohol compounds, are those fatty acids having 8 to 30 carbon atoms per molecule such as those which are present combined with glycerine in natural occurring animal and vegetable oils and fats and which are derived therefrom upon saponification thereof and are exemplified by the fatty acids derived from stearin, whale oil, menhaden oil, neats foot 011, castor oil, corn oil, cottonseed oil, coconut oil, linseed oil, palm kernel oil, rapeseed oil, China-wood oil, perilla oil, soya bean oil, sunflower oil, olive oil and the like and includes fatty acids such as caproic, capryllic, capric, lauric, myristic, palmitic, oleic, linoleic, linolenic, rlcinoleic, stearic. dihydroxy stearlc, oleostearic, erucic, and behenic. Also fatty acids such as synthetically prepared aliphatic monocarboxylic fatty acids as for instance margaric or fatty acids prepared by suitably oxidizing hydrocarbons or by hydrogenating naturally occurring fatty acids may be used. The naphthenic acids recovered from certain petroleums are also eminently satisfactory. It is also contemplated that mixtures of the foregoing acids may be used in the esterification of the partially dehydrated polyhydrlc alcohols. An example of a partially dehydrated polyhydrlc alcohol is a partially dehydrated sorbitol commonly known I as sorbitan.

The anti-corrosion agents of the present invention are made by reacting 1 mol of the polyhydric alcohol or 1 mol of the partially dehydrated alcohol with one to three mols of carboxyllc acid or carboxylic acid mixtures either in the presence of or absence of a catalyst. The catalyst may be acidic, for example, sulfuric or phosphoric acid or alkaline, like sodium hydroxide. The ingredients are commingled and heated in a kettle or other container preferably closed and equipped with suitable agitating means at a temperature of l50-300 C. until the reaction reaches the desired stage. It is frequently desirable to maintain an atmosphere of inert gas such as nitrogen or carbon oxide over the reacting mass as by passing an inert gas over or through the reacting mass in order to assist removal of the water of condensation and prevent discoloration of the esters formed or the reaction may be carried out in a refluxing hydrocarbon solvent, with means provided for trapping out the water formed. The esters useful as anticorrosion addition agents according to the present invention are known to the art, methods for their preparation having been described by K. R. Brown in U. S. Patent 2,322,820. Examples of such esters are the mono esters such as sorbitan mono-oleate, sorbitan mono-laurate, and the like which may also be referred to as mono-oleylepoxy sorbitolate or the corresponding lauryl compound, etc., as mentioned more specifically hereinafter.

The compositions of the present invention as before stated comprise an oleaginous base blended with a minor proportion of a carboxylic acid ester of partially dehydrated aliphatic straight chain polyhydric alcohols. Specific examples of the polyhydrlc alcohols which may be partially dehydrated and then esterified or converted to esters containing an reaction are mannitol, sorbitol and dulcitol. A specific example of an ester would be mono-oleylepoxymannitolate. The slushing compositions are produced by blending from .5% to 10% or lesser amounts, say from .1 to 5% of the ester in the oleaginous base using heat and stirring if necessary.

In many cases it is desirable iary agents These include carboxylate soaps, sulfonate' soaps, such as calcium soap of mahogany sulfonates, phenolates, phenol sulfides, wool grease, or-

to include auxil- 4 garlic bases. etc. For special purposes, such as to enable the composition to dislodge water from metal surfaces, alkylol amines, alcohols. esters, ethers, ether alcohols, and the like may be incorporated in the composition. In still other instances anti-oxidants, such as amine or phenols, thickeners, such as polybutene, acryloid, copolymers of styrene and olefins or diolefins, ester polymers, metal-deactivators, dyes, olliness agents, extreme pressure additives, and greaseforming soaps are desirable.

The efficiency of coating composition is evaluated by certain standard tests of which the humidifier is the more important.

Test procedure Sand blasted panels of hot rolled steel are dipped into slushing compound samples, then maintained vertically in a box for 16 hours under ordinary room conditions to allow the rust preventive film to reach an equilibrium condition. Compounds containing petrolatum or waxes are applied at temperatures above their melting point and fluid products are applied at room temperatures. The coated panels are then placed and spaced apart in an upright position in a humidifler chamber wherein at 100 F. they are subjected to continuous moisture condensation. The time, in hours, for a panel subjected to these conditions to develop initial evidence of rusting is observed and recorded as the resistance life of the coating composition.

The following data illustrate the rust preventive effectiveness of the present invention:

Blend Time Lubricating oil (100 Vis. at 100 F.) 1 hour. Lubricating oil+2.5% mono lauryl- 196 hours.

e xy sorbitolafe.

Lu rlcating 0' +5% mono lauryl-epoxy 200+ hours.

sorbitolafe.

Lubricating oil+2.5% mono eloyl- 196 hours.

epoxy sorhitola'e.

Lubricating oii+5% mono cleyl-epoxy 200+ hours.

sorbitolate.

Petrolatum Severe rust at 168 hour s.

Petrolatum-H% mono lauryl epoxy 500+ hours.

sorbitolate.

Aviation engine oil 1 hour.

Aviation engine oil+3% mono eloate 200+ hours.

of mono dehydrated sorbitol.

Aviation engine oil+2% mono oleate 200+ hours.

of mono dehydrated sorbitol+l% calcium sulronate.

100 F. Flash solvent naphtha+l0% 200+ hours.

wool grease, 8% naphthenic residual oil, 2% mono oleate of mono dehydrated sorbitol.

What is claimed is:

inner ether linkage by one in the rust preventive composition.

1. A slushing composition consisting essentially of a material selected from the class which consists of petroleum lubricating oils and petrolatum and 0.5 to 10% by weight of a fatty acid monoester of sorbitan, the fatty acid radical of said ester having between 8 and 30 carbon atoms. the quantity of said ester being sufficient to impart rust preventing properties to said petroleum composition.

2. A rust preventive, composition consisting essentially of a lubricating oil having a viscosity of about S. S. U. at 100 F. and from 2.5 to 5% of sorbitan mono-laureate.

3. A rust preventive composition consisting essentially of a lubricating oil having a viscosity of about 100 S. S. U. at 100 F. and from 2.5 to 5% of sorbitan mono-oleate.

4. A rust preventive composition consisting es- 5 sentially or petrolatum containing about 1% of Number sorbltan mono-laureate. 2,285,422 GORDON W. DUNCAN. 2,294,140 2,322,820 REFERENCES CITED 2,322,821 The following references are of record in the 2322-322 file of this patent: NITED STATES PATENTS 1 981193 Number Name Date 10 2,404,240 7 1,630,101 ,Wilkin May 24, 1927 6 Name Date .Epsteln June 9, 1942 Taylor Aug. 25, 1942 Brown June 29, 1943 Brown June 29, 1943 Brown June 29, 1943 Barnett Nov. 16, 1943 Brown Apr. 3, 1945 Sharp Apr. 9. 1946 MacLaurin July 16, 1946