US2781319A - Lubricating compositions - Google Patents

Description

LUBRICATING ooMPosITIoNs Emmett R. Barnum and Lyman E. Lorensen, Berkeley, Calif., assignors to Shell Development Company, New York, N. Y., a corporation of Delaware N Drawing. Application March 22, 1954, Serial No. 417,964

Claims. (Cl. 25.2-47.5)

This invention relates to lubricants and more particularly to new and improved lubricating compositions containing ashless polyfunctional additives which possess particularly pour point depressing and viscosity index improving properties.

Many lubricating oils, because of the nature of their source or methods of refining, contain substantial amounts of wax. Lubricating oils of this type are undesirable or unsuitable for many types oi operations, particularly under cold operating conditions such as encountered in cold climates. In order to overcome this defect in waxcontaining lubricating oils, pour point depressants and viscosity index irnprovers have been employed. Among the best known additives of this type are polymeric esters of the acrylic acid series and mixtures of said polymeric materials with other types of polymers such as polymerized olefins, including polyisobutylene, polystyrene, polyindene, polyisoprene and the like, as well as other types of polymeric compounds such as polyvinyl and polyallyl compounds.

Although the above-mentioned polymeric materials can eflectively reduce the pour point and improve the viscosity index of oils, they are corrosive; they have 'a tendency to form emulsions under conditions where water, steam, moisture and the like are encountered; and they possess a tendency to break down at elevated temperatures.

it has now been discoveredthat the above undesirable effects of polymeric pour point depressants on lubricating oil can be overcome by addition to lubricating oil compositions of from 0.01% to 5%, and preferably from about 0.05 to about 2%, of a highly branched oil-soluble organic compound having an essentially saturated linear hydrocarbon chain of from about 25 to 300 and preferably from S0 to 200 carbon atoms and containing at- 7 groups a portion of which'may be substituted for by R X polar groups wherein X1 and/or X2 is a chalcogen such as oxygen and/or sulfur, R and R can be the'same or difierent hydrocarbyl radicals, e. g., alkyl, alkaryl, aralkyl,

aryl, cycloalkyl radicals or hydrogen at least one of the Rs being non-aromatic and R -can be the sar'ne or I diiferent from eitherR or R these'Cs-Cm hydrocarbyl radicals and polar groups are suitably distributed either uniformly or randomly along the carbon chain, in general being randomly distributed. Preferred polar groups are the 2,781,319 Patented Feb. 12, 1957 and R O- wherein R is a CsC2'u alkyl (straight or branched) radical and R is the same as R or hydrogen. Other valences of the chain C-atom are satisfied prefer ably by hydrogen atoms, but may contain some lower alkyl radicals of 1-3 carbons. The ratio of the number of polar groups to the munber of non-polargroups can vary within relatively wide limits,fe. g., from 1/10 to 5/1 and preferably from 1/3 to 3/1." The compounds or mixtures of such compounds can have a molecular weight or average molecular weight of from about 2,000 to above. 100,000 andpreferably from 5,000 to 50,000.

Polymeric compounds of this invention can be prepared by hydrolyzing alpha-olefin-vinyl ester copolymers to form polyols and forming polycarbamates from said polyols by reacting them with organic isocyanate and/ or isothiocyanate compounds to form the carbamates and derivatives thereof. Another method of preparing polymers of this invention is to react alpha-olefins with a vinyl N or N,N-hydrocarbyl carbamate or thiocarbarnate or thiocarbamate such as vinyl N,N-dibutyl carbamate or vinyl N,N-dibutyl-dithiocarbamate. The vinyl carbamates such as vinyl N,N-dihydrocarbyl dithiocarbamate can be prepared by reacting acetylene with an amine and carbon disulfide under super-atmospheric pressure. Other compounds of this type include vinyl N,N-dioctyl dithiocarbamate, vinyl N,N-b utyl phenyl dithiocarbarnate, vinyl-N hexyl dithiocarbamate, methallyl carbamate, allyl carbamate and the like. The alpha-olefins used to'forrn copolymers with the carbamates include Ca-C-to alpha-olefins such as alpha-heptadecene, alpha octad'ecene, and the like. r

-The reaction conditions can be varied widely with respect to temperature time ratio of proportion of the reactants and selection of catalysts. Generally the temperature can vary from below room temperature to above C. for a' period of a fraction of an hour to over 48 hours, depending upon the reactants and the ratio of the reactants, and catalyst of which preferred are the organic peroxides such as benzoyl peroxide.

Thus, the polycarbamates as well as the polyol-polycarbamates and their thio derivatives used in compositions of this invention arepreparable.byreacting polyols produced by the method described in patent application Serial No. 357,374, filed May 25, .1953, now. abandoned, with organic isocyanates and/or isothiocyanates. Othermethods of producing polyols from which the polycarbamates or polythiocarbamates can be produced are described in U. S. Patents 2,421,971 and 2,467,774 or the polyols can be produced by the method described in U. S. Patent 2,551,643 followed'by hydrolyzing the copolymer by the method described in the first two patents. Still another method of preparing the polymers of this invention is by the method described in U. S. Patent 2,466,404 as well as by any other suitable means.

The following example illustrates a suitable method of preparing the intermediate product (alkanepolyols) from which the carbamate' derivatives can be produced by treating said alkaue'p olyols with organic isocyanate compound and analoguesthereof.

- Example I.Hy drolysis, product of alphactadecenevinyl acetate, copolymer terial and low molecular weight reaction products. The

residue by analysis had an ester value of 0.491 gramequivalent of ester groups per 100 grams of sample.

This product was alcoholized in about 1,800 ml. of methanol to which about 1 gram of metallic sodium was added. The mixture was distilled to remove the methyl acetate and theexcess methanol and the product was then dispersed in heptane and topped. The resulting residue product was an alkanepolyol (polyhydric alkanol) having a molecular weight of about 8,000 as determined by light scattering on the acetate. From the molecular weight and the aforesaid number of gram equivalents of ester groups of ester groups per 100 grams of the ester, it can be calculated that for the alkanepolyol there is a ratio of alcoholic hydroxyl groups to hydrocarbyl (hexadecyl) radicals of about 2.2. Furthermore, the average alkanepolyol molecule contains about 50 hydroxyethylene radicals and about 23 OctadecyIene-LZ radicals; there is a total of about 73 hydrocarbyl and hydroxyl radicals per molecule. In other words, the molecule is a chain of 146 C-atoms having 50 hydroxyl and 23 hexadecyl rad-icals attached to 73 different C-atoms of the chain throughout the chain length. Those 73 C-atoms having attached thereto 73 C-atoms being saturated with 2 H-atoms each. The molecule can be represented by the formula Example H.Hydrolysis product of alpha-hexadecenevinyl acetate copolymer Aflpha-heptadecene-vinyl acetate Alpha-tetradecene-vinylacetate Alpha-e-icosene-vinyl acetate Alpha-octadecene-vinyl propionate Alpha-octadecene-vinyl butyrate Alpha-octadecene-vinyl benzoate Mixtures of alpha-tetradecene and octad'ecene vinyl ace- V tate Cracked wax Cit-C14 alpha-olefin mixturevinyl' acetate Alpha-docosene-vinyl acetate Q The alkane' polyols can be prepared by any desired method such as, for example, as described specifically in 7 Examples I and II. V V p V The alkane polyols are converted to corresponding alkane polycarbarnates by reacting a plurality (part or I all) of the'alcoholic groupswith an organic isocy'anate of an organic isothiocyanate. These isocyanates and isothiocyanates are suitablyalkyl, alkenyl, aralliyl, al-

karyl,-cycloall yl isocyanates and :isothiocyanates illustrated by methyl,'propyl, butyl, octyl, Z-ethylhexyl, lauryl, cetyl, dodecyl, hexadecyl, octadecyl, oleyl, ricinoleyl isocyanates and isothiocyanates; phenyl, chlorophenyl, cetylphenyl iso-cyanates and isothiocyanates; phenethyl, naphthyl isocyanates and the like? 1 I V The following examples-are given asillustrative of suitable compounds and of their preparation:

Example III P0 ly' (octadecylcarba'mate 0 V alkane "polyol of Example I I 7 About one one-fiftieth of a'mol of the alkanepolyol product of Example I. was reacted with about one mol of voctadecylisocyanate in chlorobenzene for aperiod of about 10 to 24 hours and at refluxtemperatur e. There'action mixture was then dispersed in acetone and the VI using benzoyl peroxide as the catalysts.

resulting white precipitate which formed was filtered and dried. By analysis it was found that the average ratio of hydroxy units to carbamate units in the product was 1:1 and the chain length of the substance remained the The product was oil-soluble and had good pour point depressing properties.

Example I V.-P0ly octadecylcarbamate) of alkanepolyol of Example II About one-fiftieth of 21 mol of the hydrolysis product of alpha-hexadecene-vinyl acetate copolymer, Example II, was reacted with about one mol of octadecylisocyanate in chlorobenzene for a period of about 16 to 24 hours and at reflux temperature. The product was dispersed in acetone and the white precipitate formed was filtered and dried. The average ratio of hydroxy units and carbamate units in the molecule was 1:1. The product was oil-soluble and had good pour point depressing properties.

Example V A product was prepared by the method of Example III but in which the mol ratio of the copolymer to the isocyanate was in the ratio of 1 to 2, respectively. The product had good oil solubility and pour point depressing properties. i

Example VI A product similar to those described above was prepared by reacting alpha-octadecene with vinyl N,N-dibutyldithiocarbamate in the mol ratio of 1:1 and in the presence of alpha,alpha-azodiisobutyronitrile as a polymerization initiator for about 6 hours at 5580 C. The resulting copolymer had good oil-solubility.

Example VII A copolymer of alpha-octadecene and vinylmono-octyl dithiocar-bamate was prepared by the method of Example The copolymer had also good oil-solubility.

Example VIII A copolymer of alpha-octadecene and vinyl N-dodecyl carbamate was prepared'as described in Example VI but in which the mol ratio of the reactants was 1 to 2 respectively. The product had good oil-solubility.

Other products useful in lubricating compositions in accordance with this invention are illustrated by those listed below in which the various alkanepolyol compounds (A) are reacted with various isocyanate compounds, (B) the mol ratio of the (A) polyol to the (B) organic isocyanate can be selected to have various values, such as 111, 1:2, 1:4, 1:10; 2:1, 4:1, respectively, said poly- .eric compound having a high molecular weight and good oil solubility: (A):Hy drolized (alcoholized) copolymers of a lpha-heptadecene/vinyl acetate, alpha-tetradecene/ vinyl acetate, alpha-'eicosene/vinyl'acetate, alpha-octadecene/vinyl propionate, alpha-octadecene/vinyl butyrate, alpha-octadecene/vinyl benzoate; alpha-octadecene/ vinyljthioacetate';'(B) propyl isocyanate, butyl isocyanate, dodecylisocyanate, octadecyl isocyanate, oleyl isocyanate, .phenyl isocyanate, p-chlorophenylisocyanate, naphthyl isocyanate, lauryl thioisocyanate, octyldecyl thioisocyanate; and mixtures thereof. I

The base can be any natural or synthetic material havin lubricating properties. Thus, the base may be a hycarbon oil obtained from a paraffinic, naphthenic, Mid-Continent of Coastal stock and/ or mixtures thereof. The viscosity 10f these oils may vary over a wide range such as from 100 SUS at 100 F. to 100 SUS at 210 F. The hydrocarbon oils may be blended with fixed oils such as castor oil, lard oil and the like and/ or with synthetic lubricants such as polymerized olefins, copolymers of alkylene glycols and alkylene oxides, organic esters, e. g., Z-ethyl hexyl sebacate, dioctyl phthalate, trioctyl phos phate; polymeric tetrahydrofuran, polyalkyl silicone polymers, e. g., dimethyl silicone polymer and the like. If desired, the synthetic lubricants may be used as the sole base lubricant or admixed with fixed oils and derivatives thereof. In addition, the base can be gasoline, ethyl fluids, fuel oil, greases, etc.

The improved pour point properties which can be imparted to an undoped mineral oil as determined by ASTM procedure is evident from the data presented below.

Table [Basez Mineral oil] Compositions of this invention can be modified by addition thereto of minor amounts (0.01-2%) of blooming agents, corrosion inhibitors, oiliness agents, anti-wear agents solubilizers and the like. Among such materials can be included high molecular weight polymers, e. g., Acryloids, wax-naphthalene condensation products, isobutylene polymers, alkylstyrene polymers, organic nitrites such as diisopropylammonium nitrite or dicyclohexylammonium nitrite: organic phosphites, phosphates and phosphonates such as tn'chloroethyl phosphite, tricresyl phosphate, dilorol phosphate, phosphorus sulfide reaction products such as Pzss-terpene reaction products, metal organic phosphates, e. g., Zn dimethylcyclohexyl phosphate, organic sulfides, e. g., wax disulfide, ethylene bistolyl sulfide: amine, e. g., octadecylamine and the like. Solubilizers for some of the copolymers of this invention which lack desired oil-solubility include long chain aliphatic alcohols and fatty acids such as stearyl alcohol, oleic acid; partial esters such as sorbitan monoleate and the like.

We claim as our invention:

1. An improved mineral lubricating oil composition comprising a major amount of mineral lubricating oil and a minor amount, sufiicient to depress the pour point of the oil and to improve its viscosity index, of a reaction prod not obtained by treating (1) a hydrolyzed copolymer of an a-hydrocar'oon olefin of from 8 to 40 carbon atoms and a vinyl ester of a lower fatty acid of up to 5 carbon atoms with (2) an organic isocyanate, said final reaction product having a plurality of hydroxyl and carbamate radicals and the ratio of the number of polar groups to the nonpolar groups per molecule varying from 1:10 to 5:1 respectively.

2. A composition of claim 1 wherein the average molecule weight of the reaction product is from about 2000 to about 100,000.

3. A composition of claim 1 wherein the vinyl ester is vinyl acetate, the organic isocyanate is selected from the group consisting of alkyl isocyanate and alkylisothiocyanate, and said reaction product has an average molecnlar weight of from about 2,000 to about 100,000.

4. A composition of claim 1 wherein the e-hydrocarbon olefin is a-hexadecene, the vinyl ester is vinyl acetate, the organic isocyanate is octadecylisocyanate, and the average molecular weight of said reaction product is from about 2,000 to about 100,000.

5. A composition of claim 1 wherein the m-hydrocarbon olefin is a-octadecene, the vinyl ester is vinyl acetate, the organic isocyanate is octadecylisocyanate, and the average molecular weight of said reaction product is from about 2,000 to about 100,000.

References Cited in the file of this patent UNITED STATES PATENTS 2,466,404 Fowler Apr. 5, 1949 2,483,194 Gleim Sept. 27, 1949 2,660,563 Banes et al. Nov. 24, 1953 2,737,496 Catlin Mar. 6, 1956 OTHER REFERENCES A New Class of Polymeric Dispersants for Hydrocarbon Systems, presented at the National Meeting, Amer. Chem. Soc., March 23 to April 1, 1954, page 3 pertinent.

Claims (1)

1. AN IMPROVED MINERAL LUBRICATING OIL COMPOSITION COMPRISING A MAJOR AMOUNT OF MINERAL LUBRICATING OIL AND A MINOR AMOUNT, SUFFICIENT TO DEPRESS THE POUR POINT OF THE OIL AND TO IMPROVE ITS VISCOSITY INDEX, OF A REACTION PRODUCT OBTAINED BY TREATING (1) A HYDROLYZED COPOLYMER OF AN A-HYDROCARBON OLEFIN OF FROM 8 TO 40 CARBON ATOMS AND A VINYL ESTER OF A LOWER FATTY ACID OF UP TO 5 CARBON ATOMS WITH (2) AN ORGANIC ISOCYANATE, SAID FINAL REACTION PRODUCT HAVING APLURALITY OF HYDROXYL A ND CARBAMATE RADICALS AND THE RATIO OF THE NUMBER OF POLAR GROUPS TO THE NONPOLAR GROUPS PER MOLECULE VARYING FROM 1:10 TO 5:1 RESPECTIVELY.