US2421672A - Rust preventive composition - Google Patents

Description

Patented June 3, 1947 UNITED STATES l PATENT orrlca RUST PREVENTIVE COMPOSITION Chester E. Wilson, San Pedro,

Dodge, Long Beach,

and Mary Iiouise 0.1m, assignors to Union Oil Company of California, Los Angeles, Calif., a corporation of California No Drawing. Application January 21, 1944, Serial No. 519,202

21 Claims.

' exposure, when applied in thin films.

Another object of the invention is to prepare a rust preventive composition which may be readily applied to metal surfaces and which may be easily removed from such metal surfaces by ordinary solvents even after long periods of exposure to the atmosphere,

A further object of the invention is to prepare a rust preventive composition which will dry in a relatively short time yielding a non-tacky film which is tough and will resist shock and which will also adhere tenaciously to the metal surfaces even under wide extremes of temperature variations.

In its broadest aspects the invention comprises oil-soluble soaps of fats, fatty oils and organic acids capable of adhering tenaciouslyto metal surfaces in the presence of moisture and under varying temperature conditions after such soaps have been applied as a solution in a thinner, as

V for example, a light mineral solvent. Such oilsoluble soaps may be typified by a lead soap of tall oil which may be considered to be a semidrying oil and the lead soap of acids which may be produced by oxidizing hydrocarbons, as for example, by oxidizing, paraflin wax or a highly parafimic lubricating oil fraction or petrolatum.

While these soaps may be used separately for best results both of these types of soap are employed. Roughly about one-half of the finished rust preventive composition will be the mixture of soaps, the other half being thinner. Depending upon the purity of the synthetic acids, 1. e., their freedom from unoxidized or partially oxidized oil and/or wax we may employ for the purpose of promoting greater water resistance, a few per cent of a lowmelting point paraflin wax or petrolatum, i. e., from about 1% to perhaps 6%. Similarly, depending upon the purity of the synthetic acids employed, a small percentage of a parafllnic type lubricating oil may be added, e. g., from about 1% to about 6% for the purpose of plastlcizing the product and avoiding objectionable brittleness in the applied and dried film. Relatively small proportions of an oil-soluble metal sulfonate may also be included in our rust preventive composition. The sulfonate has the efiect of furnishing increased protection against corrosion and it re- 55 duces materially the pour composition.

The term oil-soluble as "used herein is meant to include good dispersibillty or colloidal distribution in oil and not necessarily true solution.

In addition-to the above indicated ingredients and in order to secure an important object of the invention, that is drying to a non-tacky film in point of the finished l0 portion of an active drier is employed. Driers which are found to be particularly effective for this purpose are oil-soluble cobalt salts, i. e., cobalt naphthenate, linoleate, tall oil soap, or the like, or in some cases the corresponding mangaposes the flnished rust preventive composition should contain in the order of about 0.01% of cobalt calculated as the metal where about onehalf of the composition is thinner.

One very desirable composition contained the following:

Approximate Per Cent by Weight With Without Thinner Thinner Lead Soap of Tall Oil 38.0 v 69 Lead Soap of Wax Oxidate l 12.0 22

Sodium Sulfonate 5. 0 9

Cobalt Drier (as metal) 0. 01 0.02 Petroleum Thinner 45. 0 None This wax oxidatc was prepared by oxidizing a paraflin wax (122 F. to 125 F. M. P.) for a period of hours at 250 F. and at normalatmospheric pressure. in the presence of 0.5% manganese m. hthenate catalyst, the oxidate had an acid number of mg. K H/g. and a saponiflcation number of 210 mg. KOH/g.

I The sodium salt of oil-soluble (mahogany) sulfonic acids.

Another very desirable composition contained the following:

1 The wax acids were obtained from the was oxidate used in the first composition noted above by saponil'yin'g said oxidate with aqueous NaOH, separating the aqueous sodium soap phase from the unseponiflable phase and freeing the acids from the soap phase by acidifying with dilute mineral acid.

a comparatively short period of time, a small pronese salts may be employed. For practical pur- The proportions of the various components ofthe above rust preventive-compositions may be required in a given product for a given use. The effect of composition. upon the characteristics of the resultant rust preventive film is briefly discussed herebelow.

If the composition consists wholly of thinner and oil-soluble lead tall Oil soap or oilsoluble soap or another semi-drying oil, the product would be hard and brittle when dried and, moreover would not be readily removable by ordinary solvents after a few months of exposure and therefore the product would not be satisfacto y for most uses. Similarly. if the proportion of tail oil soap with respect to other constituents is too great. the dried product becomes too brittle. Again, if the oil-soluble metal soap of synthetic acids is the only constituent employedwith the thinner the resulting dried film is too soft and the viscosity and pour pointof the solvent or thinnersolution' of this soap are too high, making its application to metal surfaces needlessly difilcult. If, however, from about to about 30% of the oil-soluble metal soap of synthetic acids, based on the non-volatile constituents, is

used the product remains readily removable after long periods of exposure. Around 5% of the synthetic acid soap (based on the non-volatile con stituents) appears to be the minimum neces sary to insure, ready removal of the resultant rust preventive film'after several weeksor months of I x s e The most desirable "proportion of oil-soluble metal soap of synthetic acids in a finished rust preventive'composition is between about and about 40% by weight of the non-volatile constituents or between about 5%"a'nd about 20% by weight of the thinned composition. However, we may use between about 3% and about 85% by weight of. this soap based on the non-volatile constituents and, correspondingly, between about 1.5% and about 42.5% by weight based on the thinned product. Similarly, we prefer to use between about 50% and about 90% by weight of an oil-soluble metal soap of a semi-drying oil, based on the non-volatile constituents, or between about 25% and about 45% by weight based on the thinned product. However, we may use between about 5% and about 95% based on the nonvolatile constituents or between about 2.5% and 47.5% based on the thinned product.

Although the relative brittleness or tackiness of the applied and dried film may be controlled as indicated above, i. e., by varying the proportion of the two types of soaps employed, anadditional and desirable means of controlling brittleness of the applied film as well as viscosity and particularly pour point of a thinned rust preventive composition is to include in the rust preventive composition small percentages of a metal sulfonate, such as an alkali or alkaline earth or heavy metal salt of sulfonic' acids obtained by sulfonating petroleum hydrocarbons. Thus metals such as sodium, potassium, lithium, calcium, barium, strontium, magnesium, lead, zinc, etc., all produce sulfonates which may be used in our composition. Such sulfonates when employed in concentrations ranging from about 1% to about 5% or even'as high as 10% by weight of the thinned rust preventive have the efiect of reducing the pour point and the apparent viscosity of the thinned product. Moreover, rust preventi e compositions containing such sulfonates give even better protection against corrosion when applied to metal surfaces. Sulfonates which have been found to be particularly desirable include the so- 5 dium, barium, and lead salts of oil-soluble sulfonic acidsproduce'd by concentrated or fumin sulfuric acid treatment of lubricating oils. These oil-soluble sulfonic acids are usually referred to as mahogany acids. In those instances in which the indicated sulfonates are used the proportion of the oil-soluble soaps of synthetic acids may be correspondingly reduced or the sulfonates may be substituted for a portion or all of the lubricating oil which otherwise may be employed since the sulfonates have a plasticizing action on the resultant-dried film.

The paraffin wax is employed to render the composition more water resistant. This paraffin wax may be added as such, or in those instances in which a wax oxidate isemployed for the preparation of the lead soaps of synthetic acids, there may be suflic'ient parafiin wax or non-acidic partially oxidized paraffin wax present in the o'xi-' date to impart the desired waterresista'nce to the finished composition. In those cases in which the synthetic acids are separated from the wax oxidate before being converted into a usable oilsoluble soap such as a lead soap it may be desirable to add small proportions of paraffin wax to so the composition. Also in those cases in which the synthetic acids are produced by oxidizing highly paraflinic oils whether the acids are first purified or' not, 'itmay be desirable to include small proportions of paraiiin wax in the composition' While the wax is employed to render the composition more water resistant it has the effect of producing a'dull finish in the rust preventive film which eliminates light reflections from treated I surfaces. This effect appears to be due to a slight 40' incompatibility of the wax.

or less of the total composition, i. e., including thinner,'is parafiin wax the product is still very desirable but-the finish whendry tends to be shiny. If the proportion of'parafiin wax is increased above about 4% the pour point of the rust preventive solution in thinner is raised to an objectionable degree. Thus the 4% of paraffin wax based on the thinned product approaches the critical concentration. We prefer to use,

therefore, up to about 8% or 9% by weight of paraffin wax based on the non-volatile constituents and we may use as much as about 12% by weight of wax. The amount to be employed in any given case will, as indicated hereinabove, depend upon the utilization of the product and upon the purity, i.- e., the freedom from wax and/or oil of. the synthetic acids used in its preparation.

In place of the paraffin wax we may use petroiatum which is a micro-crystalline or amorphous wax' obtained by dewaxing paraflinic residual oils. The proportion of petrolatum which may be successfully employed is somewhat higher than the f limits indicated for parafiin wax because the petrolatum does not raise the pour point of the thinned rust preventive composition to as great an extent as does the paraflin wax. Thus we may use up to about 15% by weight of petrolatum based on the non-volatile constituents although '70 amounts less than about 10% by weight are.

generaly more desirable. The amount to be employed in any given case will depend upon the purity of the synthetic acids employed in the composition. u

The lubricating oil is employed to piasticize the When 2% to 3% composition and make the dried rust preventive film less brittle. Preferably the lubricating oil should be rather heavy, such as one having a viscosity of 150 seconds Saybolt Universal at 210 'F. corresponding with 70 SAE grade. Here again about 4% of oil based on the total composition approaches the critical, inasmuch as larger proportions of lubricating oil tend to retard the drying excessively and tend to make the dried film too soft. As in the case of the paraflln wax or the petrolatum, the amount of lubricating oil used will depend upon the character of synthetic acids, 1, e., whether they were prepared from a highly paramnic oil fraction or whether they were prepared from a parafiin wax, and also upon the degree of purity of the synthetic acids, 1. e., whether they were separated from unsaponifiable components present in the oxidate. Thus, if a parafilnic oil oxidatewere converted into the lead or other oil-soluble metal soap the purified rust preventive compositions prepared from such lead soaps, would be sufiiciently plastic in most instances without the addition of further quantities of lubricating oil. On the other hand, if the paraifinic oil oxidate was first separated into an acid fraction and a fraction comprising the unsaponifiable components and the thug separated acids converted into lead soaps it would usually be desirable to include small proportions of lubricating oil or its equivalent in rust preventive compositions containing these soaps. Thus it will be seen that we may prefer to use up to about 8% by weight of lubricating oil based on the non-volatile constituents, however, we may use as high as about 12% by weight of oil.

The amount of cobalt drier previously indicated, i. e., 0.01% based on the finished composition, is within the practical limits. If much less drier is used its efi'ectiveness is inconsequential, and if greater proportions than about 0.1% (metal content in thinned product) are employed no appreciable additional benefits appear to be obtained. The presence of the ,drier speeds up the drying of the applied film so that good drying may be obtained in as little as six to eight hours. It the time of drying is of no consequence, so'that a drying period of twenty to fifty hours or more is not objectionable, the drier may be eliminated. On the other hand, if drying within two or three hours is required, the cobalt content f the finished rust preventive may be increased to two or three times'the indicated 0.01%. The use of greater proportions than 0.1% is in no way'objectionable and amounts as large as 0.2% or even 0.3% of cobalt in the form of cobalt drier may be employed in certain instances.

In those cases 'in which extremely active drier rust preventive composition in the form of soaps of either the synthetic acids or the semidrying oils, it is usually not necessary to add additional drier. When less active drier metals, such as lead,

zinc, etc., are employed the cobalt or other drier is to be used when rapid drying of the applied film is desired.

Although in general we prefer to use about 50% by weight of an ordinary petroleum thinner, as indicated hereinabove, the proportion of thinner may be varied depending upon the use for which the rust preventive is intended. Desirable rust preventives have been prepared containing as in which it is desirable tha as mineral spirits or naphtha or equivalent thinner. I

In some instances, particularly in those cases t the finished rust preventive composition have a flash point above about 100 F. the thinner selected may be .one having a flash point slightly above the indicated value. In such cases it is preferable that the high flash point thinner have a relatively narrow boiling point range in order to avoid the presence of high boiling components which if present would retard the drying of the applied rust preventive film. Such a thinner would be a petroleum naphtha having a boiling point range of about 310 F. to about 375 F. or even as high as 400 F.

soluble metal soap to produce one component of our rust preventive composition may, for the purposes of this application, be consideredto be a semi-drying oil. Tall oil which consists chiefly of resin acids, fatty acids and unsaponifiable material is a by-product of wood pulp manufacture and is well known in commerce. We may use the unrefined tall oil or the refined tall oil depending upon the use to which the finished anti-rust composition is to be placed. Thus if a relatively light colored rust preventive film is desirable we may use a refined or a distilled tall oil, however, in those cases in which appearance is not important, we may prefer. to use the unrefined tall oil.

Other oils which are generally classified as semi-drying oil may be employed in place of all or part of the tall oil in any given case. Thus we may use an oil-soluble metal soap of rape seed oil, cotton seed oil, corn oil, rice oil, colza oil, mustard seed oil, sesame oil and like oils in place of the oil-soluble In those instances in which one of the last named group of semi-drying oils is used to replace all of thetall oil, the proportion of the oil-soluble will usually be reduced somewhat from the amount of oil-soluble metal soap of tall oil employed and the oil-soluble metal soap of synthetic acids will be correspondingly increased because most of these semi-drying oils produce a harder film and a film that is more difllcult to remove after exposure than does tall 011.

In some instances it may be desirable to use an oil-soluble metal soap of a drying oil such as linseed oil, China-wood oil, tung oil and the like. In general it .is not desirable to replace all of the tall oil or semi-drying oil with a drying metals, e, g., cobalt or manganese are used in the little as about 30% by weight of thinner and as high as about 70% by weight of thinner based upon the total composition. The thinner may be any readily volatile mineral oil fraction such oil, however, rust preventive compositions containing as much as 5% to 10% by'weight of an oil-soluble metal soap of a drying oil, based upon the non-volatile constituents, replacing an approximately equal quantity of an oil-soluble metal soap of tall oil have been found to be very good anti-rust agents.

Oil-soluble metal soaps of semi-drying oils and/0r acids The above semi-drying oils and/or acids may be converted into soaps such as, for example, lead soaps which are the preferred type of soaps, by saponifying the semi-drying oil with sodiumhydroxide to produce the sodium soap and then preparing the lead soap from the sodium soap by metathesis. The required quantity of semidrying oil is charged to a steam jacketed kettle equipped with an agitator and the theoretical metal soap of tall oil.

period.

should' be present as indicated by a quantity of caustic soda, indicated by the saponification number of "the oil, is added in the form of a to 50% NaOH solution in water. With the agitator in motion the batch is .heated slowly to the boiling point andheld at this temperature until analysis indicates that the reaction is comv plete and all of the caustic soda has been utilized. If necessary and particularly where concentrated NaOH solutions are used small additions of water may be made during the course of the saponification and if necessary, a small addition of fatty oil may be made to neutralize any free caustic soda present after a reasonable heating When 'sapon'fication iscomplete the with water to yield a soap by weight. To the dilute charge is diluted content of 10% to w soap, which should'be at a temperature between about-180 g retical quantity of lead acetate in the form'of a and 200 F.,is added the theosolution in water. The amount of leadacetate to be added is calculated from the methyl orange soap number of the dilute soap solution. The lead-acetate is added as rapidly as it will be taken up by the batch and during the addition the agitator is kept in motion. To complete the formation of the lead soap, the batch is maintained at a temperature of 180 F. to 200 F. for approximately one hour and at this time no more than a small amount of free lead ion test with potassium dichromate solution. The agitator is then stopped and the lead soap of the semidrying oil is allowed to separate from the aqueous phase. The separated water is drained from the kettle and the lead soap washed with hot water until free from lead ion. The batch is then dehydrated by heating to 325 F. to 340 F. with agitation. When dehydration is complete,thinner may be added at the lowest practical tem-' perature to yield a solution of lead soap containing approximately 50% by weight of the soap.

The soaps may also be prepared by heating the oil with the theoretical quantity of-litharge, the proportions of litharge to oil varying with the acid number or the saponification number of the oil and the purity of the litharge. Thus the oil is heated in'a steam jacketed kettle equipped with i an agitator, and when the temperature of the oil F. the litharge is added reaches 250 F. to 300 slowly. During the addition of litharge or after the addition of litharge has been completed the charge may be blown with steamto increase the rate of reaction. Steam blowing is particularly "desirable when fatty oils or other glycerides are employed as the soap stocks. In those cases in which the soap stocks are primarily free acids, e. g., tall oil, the use of steam is not required and care should be taken to prevent excessive foaming during the reaction which may result from the liberation of water. In any case temperatures should be maintained between about 300 F. and about 350 F. until reaction is complete. This will require from one to two hours or even longer in the case of some of the fatty oils. When the reaction is complete, the batch is cooled to about 250 F. and may then be thinned by the gradual addition of a thinner such as a mineral solvent having a boiling range of approximately 315 F. to'380 F. until the resulting solution of soap in thinner contains approximately 50% by weight fication. It is important that no free caustic shall be present at the completion of the saponi- 'litharge Or other insoluble impurities, and then decanted from. the ,settlings and run tostorage.

:= In those'cases in which a mixtureof semi-drying'oils or in which talloil and one of the other semi-drying oils is. to be employed in the rust preventive"v composition, the oil-soluble metal soap may be prepared from each oil alone orv from the mixture of-the two oils. Generally the first method of preparation, i.- e., the one involving saponiflcation followed bymetathesis is preferable for preparing. the mixed'soaps or for preparing the soaps of any of the glycerides.

In addition to lead, other metals may be employed to form desirable oil-soluble metal, soaps. Thus the alkaline earth metals, calcium, barium, strontium, and magnesium, maybe employed in place of partor all of the lead in the preparation ofthe above soaps. We may also use iron, cobalt,

manganese, zinc, tin, nickel, chromium, vanadium, copper, and other like heavy metals. A

more complete discussion'of the metals which i ,may be employedisgiven hereinbelow;

Synthetic-organic acids The second soap component of ourrust preventive composition referred to hereinabove as an oil-soluble metal soap of acids produced by acids which may be used in our ru stpreventive composition is that the acids from soaps with the .metals disclosed hereinabove which are suffiof soap. The finished batch is held at a temperature of about 100 F. for eighteen to twentyfour hours to permit settling of the unreacted ciently soluble in oil an'din mineral solvents or thinners to permit their use in. combination with the above described oil-soluble soaps of semidrying oils in a mineral thinner solution. Since oil solubility of such soaps depends upon the molecular weight of the acids from which they are produced, stocks employed for oxidation must be a composed of hydrocarbon molecules having relatively high molecular weights. Hydrocarbon fractions which have been found to be satisfactory Oxidationstocks include petroleum waxes such .asthose normally referred to as paraffin waxes, petrolatums, foots oil, which is. a highly parafl'inic high pour point oil separated from paraffn waxes during the final stages of their purification by means of cold pressing, etc., and highly paralfinic lubricating oils having viscosities greater than about 40 seconds Saybolt Universal at 210 F. Such parafilnic lubricating oils are those highly solvent treated lubricating oils having viscosity indices of about or above and viscosity gravity constants of about 0.82 or below.

In'preparing a satisfactory oxidate from a para melting point of about 120 F. and a small j quantity, i. e., about 0.75% by weight, based on the paraflin wax, of manganese naphthenates which acts as an oxidation catalyst. The vessel is pressured to about lbs/sq. in. gage and the wax heated to a temperature of approximately 250 F. Air is introduced into and finely dispersed in the molten wax until the oxidate hasan acidnumber of about 200 mg, KOI-I/g. requiring between about 35 and 50 hours of treatment depending upon the temperature, pressure, catalyst, etc. This oxidate may be used directly for conversion into the desired metal soap or may be first refined to separate the acidic constituents partial oxidation the non-acidic or unsais not limited; to that described above, for the.

oxidation has'been satisfactorily effected by air blowing this parafiin wax at ordinary atmosother hand, if a dark colored rust preventive is not objectionable iron:naphthenate may desirpheric pressures and'temperatures of about 250 F, in the presence of an oxidation catalyst and in 'fact in some instances atmospheric pressure oxidation results-in the production of a higher grade oxidate'than does pressure oxidation. Oxidates produced in-this manner and having acid numbers of 100 mg. KOH/g. or above, such as 120 mg. KOH/g. or higher are particularly desirable and have been prepared by air-blowing for periods of 40 to 75 hours. In those cases in which the acid number of the wax oxidate is below about 100 mg. KOH/g. it is usually desirable'to separate the acids from the oxidate for ifthe crude oxidate itself were used the proportion of unoxidized wax carried with the oil-soluble meta; soap into the rust preventive composition would be objectionably high. 7 V

Lubricating oil. such as one disclosed hereinabove may be oxidized by either processdescribed for the oxidation or paraflin wax. In this case,

however, the oxidation is preferably'continued until the oxidate has an acid number in the order 0:"40 to 60 mg. KOH/g. although in some instances it maybe desirable to produce oil oxidates having acid numbers as high as 100 mg. KOH/g. In those cases in which the acid numberof the KOH/g. acids from the oxidate before preparing the 'oilsoluble metal soap of the acids in order to eliminate the rather large proportions of unoxldized oil contained in such low acid number oxidates.

As is well known the controlled partial oxidation of hydrocarbon fractions such as those disclosed above results in theproduction of alcohols, ketones, esters and ucts along with the desired acids. The presence of these partial oxidation products in the soaps prepared from the synthetic acids is in no way undesirable or objectionable, unless, as indicated above, the proportion of unoxidized wax or oil and products is great enough that a dried film, produced by a rust preventive composition containing soaps having the high wax or oil content is too soft. Generally,

those cases. in which the oxidation is continued until the oxidatehaslan acid number of. about 100 mg. KOH/g. 50 or higher-for 'or higher for the wax or about the oil, the proportion of unoil oxidate is below about 50 mg. it is usually desirable to separate the other partial oxidation prodhowever, in

oxidized wax or .,oil and of partial oxidation products otherthanacidswill be sumciently reduced to permit the use or the oxidate without; separat ing the, synthetic acids therefrom. L 9 v 1 The oxidation ot the paraflin waxandoflubricating oil may beeil'ected without the use of a catalyst. However, in general we prefer to oxidize in the presence of a small proportion i. e., in the order of from about 0.5% to 1.0% 1 or even asmuch as. 2 to 3% of an'oil-solublesalt such as a naphs thenate, oleateor like salt masnesium, iron. cobalt or other like polyvalent metala Manganese lyst are dark in "color thus may objectionable in those cases in which light coloredrust preventive compositions are desired:

otmanganese, calcium,

is particularly desirableboth from the point-of view of catalytic activity and ably be used as a catalyst forthezoxidationuoiparaflin wax or lubricating oil .becauseof its extremely active catalyticefiectsa- Oil-soluble metal soap'sjor synthetic or anic acids Inpreparing oil -soluble metal soaps, :as forlexample, lead soapsof the synthetic organic acids either of the twoprocesses described for-prepare ing oil-soluble nietal soaps" of semi-drying oils may be employed. Thus the crude oxidate orthe crude oxidate after being water washed; to remove waterrsoluble acidic constituents may be treated directly with litharge at temperatures in the order F. until reaction, is completeand:

, produced lead soaps are separated from the aque ous layer containing sodium acetate, etc.,*-and washed-free from lead ion with hot water] The washed soaps are thendehydratedand may be thinned with mineral-solvent to produce a solution' containing approximately 50% by weight of a vIn those instances in whichit is desired to use a refined orsubstantially oilor wax-freesynthetic organic acid, the crude oxidate is saponified with sodium hydroxide at temperatures in the; order of 300 F. for a periodof two to three hours and the saponified mixture" allowed to separate into an aqueous sodium soapphase, and an oily phase comprising unoxidized oil and/onwax'andz non-acidic partial oxidation products. The aqueous soap phase is separated from the oil phase and then treated with the theoretical quantity of lead acetate (25% Metals The, metals which we may use for producing oil-soluble metal soaps of semi-drying oils and of, synthetic organic acids may be, classified {into two groups, i. e., those which may be considered as drier metals and those w ich, may be considered. as non-driers; The first eludes lead, cobalt,manganesejiron, vanadium,

active catalyst rortheoiddation, 4 v r v drying i'PF i= Ihen;

. to f be employed will ,dependr to a and; zinc, The second groupj' or 'thenoii-driers includes those metals which have little or no drying 1 ei fect. This-group includes calcium, barium; strontium, magnesiumpcopper, nickel, chromium,"

In selecting a metal for use in the preparation of' either or both typesof steps required in our rust preventive composition, it is important that ameast a portion of the total metal. employed a metal selected'froin thefi'rstzgroumi meme a g c rtain-extent u o the a ti y. ranes-ga iepts inma e t n M ss. b ie We ave mime ilis am aqueous solution) to convert the sodium soaps into lead soaps. The thus pro:

grou'plor' the driers 111;,

use at least 2 parts of a non-drying metal soapto 1 part of the cobalt soap. Thus, as the drying effectiveness of the drier metal selected increases, the proportion of that metal used in the finished rust preventive should be decreased. In this connectionit is generally understood that the eilectiveness as adrier of 1 weight of cobalt is approximately equivalent to 8 weights of manganese and to 40 weights of lead.

Finished rust preventive composition In preparing a finished rust preventive composition, we may simply combine the 50% thinner solutions of the two types of soaps, i. e., those of a semi-dry oil and those of synthetic acids, in the desired proportions and thus obtain a finished composition comprising about 50% by weight of a mixture of oil-soluble soaps and 50% by weight of thinner. To such a. mixture we may add a small percentage of a cobalt drier as indicated above, and/or small percentages of lubricating oil and/or paraflin wax as desired. In compounding these ingredients it is essential that thorough mixing be employed to produce a homogeneous product. This compounding may be efiected at ordinary atmospheric temperatures or at temperatures as high as 180 F. or 200 F.

. We may, however, prefer to prepare both soaps without-the addition of thinner to produce a solvent-free composition which may be subsequently diluted with thinner and in this case also, we may incorporate the cobalt drier, the paraflin wax and the lubricating oil in the solvent-free soap mixture by heating and agitating the mass, say at temperatures of 200 F. to about 300 F. to produce a homogeneous solvent-free mixture which may subsequently be thinned with a desired quantity of mineral solvent.

Examples of rust preventive compositions which we have found to be particularly efiective as anti-corrosive agentswhen applied in thin films to metal surfaces are given below.

Example I Per cent by weight Lead soap of tall oil 400 Lead soap of lubricating oil oxidate 15.0 Petrolatum 5.0 Cobalt drier (as metal) 0.01 Petroleum thinner 40.0

An oxidate produced by oxidizing a highly solvent treated paraflinic Western lubricating oil having a Saybolt Universal viscosity of 50 seconds at 210 F., a V. I. 01' 99 and a V. G. C. of 0.805. Thisoil was oxidized by blowing with air at 270 F. for 36 hours under a pressure of 90 lbs/sq. in. gage and the resulting oxldate had an acid This was the same lubricating oil oxidate as used in Example I.

' wax 122 F. to 125 F. M. P.)

Example III Per cent by weight Lead soap of tall oil 41.0 Calcium soap of wax oxidate Manganese soap of wax oxidate 4.0 Barium sulfonate 3.0 Petroleum thinner 44.0

The wax oxidate was prepared by oxidizing paraffin for a period of 49 hours at 250? F. and at a pressure of lbs./sq. in. gage. This oxldate hadan acid number of 195 Mg. KOH/g. and saponification number of 345 mg. KOH/g.

fdThe barium salt of oil-soluble (mahogany) sulionic aci Example IV Per cent by weight Lead soap of rape seed oil. 1. 20.0 Lead soap of tall oil 15.0 Lead soap of wax acids 14.0

Paramn wax 122 F. to 125 F. M. P.) Lubricating nil Cobalt drier (as metal) 0.01 Petroleum thinner 45.0

. The wax acids were obtained from the wax oxidatc used in Example III by sapouification with aqueous caustic and acidification of the thus formed calcium soaps with dilute mineral acid.

Example V Per cent by weight Lead soap of tall oil 39.0 Lead scan of wax acids 13.0 Sodium sulfonate 4.0 Petrolatum 4.0 Cobalt drier (as metal) 0.01 Thinner 40.0

Wax acids as used in Example IV. flhe sodium salt of oil-soluble (mahogany) sulfonu: an s.

Example VI Per cent by weight Cobalt soap of tall oil 5.0

1 Wax oxidate as used in Example III. I

= The lead salt of oil-soluble (mahogany) sulfonic acids.

The foregoing description and examples of our invention are not to be 7 for many variations may be made by those skilled in the art without departing from the spirit or the scope of the following claims.

We claim:

1. An anti-rust composition comprising between about 5% and by weight of an oilsoluble metal soap of a semi-drying oil, between about 3% and 85% by weight of an oil-soluble metal soap of synthetic organic acids produced by the liquid phase oxidation of a. petroleum hydrocarbon, less than about 12% by weight of paraflin wax and less thanabout 12% by weight of lubricating oil. I

- 2. An anti-rust composition comprising between about 5% and 95% by weight of an oilsoluble'metal soap of a semi-drying oil, between about 3% and 85% by weight of an oil-soluble metal soap of synthetic organic acids produced metal soap of synthetic organic acids .produced considered as limiting 13 by the liquid phase oxidation or a petroleum hydrocarbon, a small amount of petrolatum and a small amount of a drier.

4. An anti-rust composition comprising between about and 95% by weight of an oilsoluble metal soap of tall oil and between about 3% and 85% by weight of an oil-soluble metal soap of acids produced by the liquid phase oxidation of a highly parafiinic petroleum fraction.

5. An anti-rust composition comprising between about 5% and 95% by weight of an oilsoluble metal soap of tall oil, between about 3% and 85% by weight of an oil-soluble metal soap of acids produced by the liquid phase oxidation of a petroleum fraction, a small amount of an oil-soluble metal sulfonate, a small amount of parafiin wax and a drier.

6. An anti-rust composition as in claim 4 wherein said oil-soluble metal soaps are lead soaps.

7. An anti-rust composition comprising between about 5% and 95% by weight of an oilsoluble metal soap of a semi-drying oil and between about 3% and 85% by weight of an oilsoluble metal soap of synthetic organic acids produced by the liquid phase oxidation of a petroleum fraction wherein said oil-soluble metal soap of a semi-drying oil comprises a mixture of soluble metal soap of synthetic organic acids produced by the liquid. phase oxidation of a petroleum fraction wherein said oil-soluble metal soap of synthetic organic acids comprises a mixture of a drier metal soap and a non-drier metal soap of said synthetic organic acids.

9. An anti-rust composition comprising between about 5% and about 95% by weight of an oil-soluble metal soap of a semi-drying oil, between about 3% and about 85% by weight of an oil-soluble metal soap of synthetic organic acids produced by the liquid phase oxidation of a highly parafiinic petroleum fraction, less than about 8% by weight of parafiin wax, less than about 8% by weight of lubricating oil and a drier, said drier being an oil-soluble salt of a metal selected from the class consisting of cobalt and manganese.

, 10. An anti-rust composition comprising between about 2.5% and about 47.5% by weight of an oil-soluble metal soap of a semi-drying oil, between about 1.5% and about 42.5% by weight of an oil-soluble metal soap of synthetic acids produced by oxidizing a. hydrocarbon fraction, between about 1% and about 6% by weight of parafiin wax, between about 1% and about 6% by weight of lubricating oil, betweenabout 0.01% and about 0.2% by weight of cobalt in the form of an oil-soluble cobalt salt and between about 30% and about 70% by Weight of thinner.

11. An anti-rust composition comprising between about 25.0% and about 45.0% by weight of an oil-soluble metal soap of a semi-drying oil, between about 5.0% and about 20.0% by weight of an oil-soluble metal soap of synthetic acids producedby the liquid phase oxidation of a hydrocarbon fraction, between about 1.0% and about 5.0% by weight of an oil-soluble metal sulfonate,

between-about 1.0% and about 6.0% by weight of Paraffin wax, between about 0.01% and about.

0.1%. by weight of cobalt in the form of an oila 1'4 soluble cobalt salt and between about 30.0% and about 70.0% by weight of a thinner.

12. .An anti-rust composition comprising'about 40.0% by weight of lead tall oil soap, about 15.0% by weight of a. lead soap of a lubricating oil oxidate, about 5.0% by weight of petrolatum, about 0.01% by weight of cobalt drier as metal and [about 40.0% by weight of thinner, said oxidate being produced by oxidizing a highly solvent treated parafiinic Western lubricating oil.

13. An anti-rust composition comprising about 41.0% by weight of a lead soap of tall oil, about 8.0% by weight of a calclumsoap of paraflin wax oxidate, about 4.0% by Weight of a manganese soap of paramn wax oxidate, about 3.0% by weight of a barium soap of oil-soluble sulfonic acid and about 44.0% by weight of a thinner.

14. An anti-rust composition comprising about -of lubricating oil, about 0.01% by weight of cobalt drier as metal and of thinner.

15. An anti-rust composition comprising between about 5% and 95% by weight of an oil.- soluble metal soap of a semi-drying oil and beabout 45.0% by weight tween about 3% and 85% by weight of an oil-- soluble metal soap of synthetic organic acids produced by the liquid phase oxidation of a petroleum hydrocarbon.

16. An anti-rust composition according to claim 15 wherein one of said oil-soluble metal soaps is a drier metal soap.

17. An anti-rust composition according to claim 15 wherein one of said oil-soluble metal soaps is a, non-drier metal soap.

18. An anti-rust composition according to claim 7 wherein said drier metal is lead and said non-drier metal is calcium. 1

19. An anti-rust composition according to claim 7 wherein said drier metal is manganese and said non-drier metal is calcium 20. An anti-rust composition according to claim 8 wherein said drier metal is lead-and said non-drier metal is calcium.

21. An anti-rust composition according to claim 8 wherein said drier metal is manganese and said non-drier is calcium.

CHESTER E. WILSON. MARY LOUISE DODGE.

REFERENCES crrEn The following references are of record in the.

I file of thispatent:

UNITED STATES PATENTS Number Name Date 2,348,715 Adams et a1 May 16, 1944 2,306,352 Burrell Dec. 22, 1942 2,242,837 Shields May 2 1 2,184,952 Zimmer et al 26, 1939 2,175,491 Stresen-Reuter et al 0ct. 10, 1939 1,630,101 Wilkin May 24, 1927 1,364,134 Morgan Jan. 4, 1921 2,266,325 Lazar et al; Dec. 16, 1941 2,367,462 ,Farber Jan. 16, 1945 FOREIGN PATENTS Number Country Date 502,335 Great Britain Mar. 15, 1939 681,855 Germany Oct. 3, 1939 111.339 Australia Sept. 15. 194