US3891564A

US3891564A - Process for preparing mixed lithium-calcium soap thickened greases

Info

Publication number: US3891564A
Application number: US226304A
Authority: US
Inventors: Don A Carley; Fred T Crookshank
Original assignee: Texaco Inc
Current assignee: Texaco Inc
Priority date: 1972-02-14
Filing date: 1972-02-14
Publication date: 1975-06-24
Anticipated expiration: 1992-06-24

Abstract

This invention concerns a novel process for preparing mixed alkali metal-alkaline earth metal soap thickened greases of depressed yield by a one-stop, non-melt process in which the temperature does not exceed the melting point of the alkaline earth metal soap contained in the grease during the entire grease manufacturing cycle. This procedure is especially useful in the preparation of water-resistant greases.

Description

Q Umted States Patent 11 1 1111 3,891,564 Carley et a1. June 24, 1975 [54] PROCESS FOR PREPARING MIXED 2.929,?32 3/1960 Sproule et al 252 40 L|THIUM CALC|UM SOAP THICKENED 2,959,548 1 1/1960 OHalloran et a1. 252/40 GREASES 3,133,020 5/1964 Scott .1 252/405 3,139,405 6/1964 Farmer et a1. 252/405 [75] Inventors; Don A, Carley, Nederland; Fred T, 3,158,574 11/1964 Greenwood et al 252/4017 Crookshank, p Arthur, both f 3,171,812 3/1965 Horth et a1. 252/4045 3,242,082 3/1966 Badgett et a1 252/40 3,801,506 4/1974 Cross et a1. 252/40 [73] Assignee: Texaco Inc., New York, NY.

22 n Feb 14, 1972 Primary Examiner-Delbert E. Gantz Assistant Examinerl. Vaughn App! 226304 Attorney, Agent, or Firm--T. l-l. Whaley; C. G. Ries',

Bernard Marlowe [52] US. Cl. 252/40; 252/41; 252/52 A [51] Int. Cl..... Cl0m 5/16;C10m 5/14', C10m 5/12 [58] Field of Search 252/40, 33.6, 40.5, 40.7, [57] ABSTRACT 252 5 5 R, 39 37 7 4 52 A This invention concerns a novel process for preparing mixed alkali metal-alkaline earth metal soap thickened 5 References m greases of depressed yield by a one-stop. non-melt UNITED STATES PATENTS process in which the temperature does not exceed the melting point of the alkaline earth metal soap con- ?ggg igt;""'"""""' 2 tained in the grease during the entire grease manufac- 2475589 7/1949 Bondi ....:I. II II. III. 252/401 F proceiure especany usefu' 2:s45:190 3/1951 Bondi............ 252/407 Preparatlo" of waterreslstam greases- 2,588,556 3 1952 Moore et a1. 252 40.5 2,831,812 4/1958 North 25 2/40 5 Clams Drawmgs 1 PROCESS FOR PREPARING MIXED LITHIUM-CALCIUM SOAP TI-IICKENED GREASES BACKGROUND OF INVENTION The prolonged contact of greases containing hydrophilic components with an aqueous environment is usually detrimental to the grease. The reason for this is that hydrophilic components are attacked by water, especially at elevated temperatures. When the hydrophilic agent is the gelling agent, such as a lithium soap, sodium soap or a mixture of these alkali metal soaps with alkaline earth soaps, attack by water is particularly acute because these soaps are emulsifying agents and tend to leach out. As a result of this extraction or leaching that alkali metal soaps undergo, the structure of the grease is degraded and, because of deficient lubrication, the part to be protected can be damaged or can fail.

Another area of concern caused by the poor resistance of greases to the attack of water is the field of water pollution. For example, facilities such as foundries or steel mills which utilize large amounts of lubricants in processes requiring the use of large quantities of water for cooling or washing, frequently discharge huge quantities of soaps or other grease components into the waterways which cause undesirable changes in the life cycle and appearance of the waterways. While it is sometimes possible to remove the grease pollutants from the waterways, it almost always is costly and can be avoided by use of prophylactic methods; in this instance, utilizing greases possessing good water resistance.

Recently a grease formulation comprising a mixed alkaline earth metal soap-alkali metal soap grease was prepared which incorporated lithium and calcium soaps as gelling agents and certain polyoxylalkylated derivatives to further enhance the greases normal resistance to water. These novel greases were disclosed and claimed in co-pending Ser. No. 161,993 filed July l2, l97l, in the United States Patent Office. While these formulations of mixed soap greases possessed excellent resistance to water, and excellent appearance among other attributes, their method of preparation left something to be desired. That is, the preparative process requires a relatively tedious and complex twostep saponification for each soap. For example, in the preparation of a calcium-lithium soap based grease, the calcium soap is first made from l2hydroxystearic acid and calcium hydroxide. Then the lithium soap is prepared by saponifying l2-hydroxystearic acid and/or methyl-IZ-hydroxystearic acid with a premixed lithium hydroxide solution. Previous experimental work on mixed lithium-calcium soap greases indicate that the two-step saponification is necessary to obtain a grease with a satisfactory texture and appearance. Surprisingly enough good texture and appearance of a grease is a necessity in the successful marketing of a commercially acceptable product.

In view of the difficulties encountered in the attempts to produce mixed alkaline earth metal-alkali metal soap greases (such as calcium-lithium soap thickened greases) possessing good texture and good appearance through a onestep saponification procedure, it was quite unexpected and surprising to discover that a suitable mixed grease having satisfactory texture and appearance could be prepared in depressed yield primarily by utilizing reaction temperatures below the melting point of the alkaline earth metal soap or soaps contained in the mixed soap grease. When this critical temperature employed during manufacture is combined with a one-step saponification and utilizes a critical ratio of oil to fat in the charge especially useful mixed soap thickened greases are produced.

Thus, it is the broad object of this invention to provide a method for preparing alkaline earth metal soapalkali metal soap thickened greases which are equally recalcitrant to the attack by water as are comparable greases made by the two-step saponifications of the prior art.

Other objects will suggest themselves to those skilled in the lubrication art after a perusal of this disclosure.

DETAILED DESCRIPTION OF THE INVENTION In the broad practice of this invention, a mixture of alkaline earth metal soap-alkali metal soap thickened grease of depressed yield and possessing substantially increased resistance to water is prepared by a one-step, non-melt saponification of the saponifiable fats present while keeping the temperature of the grease during the entire manufacturing cycle below the melting point of the alkaline earth metal soap or soaps contained in the finished grease. As in the case in the conventional two-step saponification procedure, the formulation, including additives and grease adjuvants is virtually unchanged.

In the most favored contemplated practice, a grease thickened by a mixture of lithium soap-calcium soap having comparable improved resistance to water as to conventional greases gelled by mixtures of calcium soap and lithium soap is prepared by concurrent and in situ saponification of the calcium and lithium fatty components keeping the maximum temperature below the melting point of the calcium soap not only during saponification but throughout the entire grease manufacture cycle. Of secondary but significant importance is controlling the ratio of the oil present to the fat employed.

In order to aid in the understanding of the inventive concept, the following additional disclosure is submitted. Unless otherwise indicated, all parts and percentages are by weight rather than by volume and all temperatures are in degrees F rather than degrees C.

A. Alkoxylated additives imparting water-resistance to greases. These are selected from the group consisting of:

1. Polymeric Alkoxylated Derivatives of Alcohols.* Alcohols as used herein not only refer to aliphatic compounds containing at least one free-hydroxyl group but which as can be seen from supra also includes diols, trials and polyols.

These additives, which are used to impart increased water-resistance to greases thickened with alkali metal soaps, are known in the patent or technical literature. See, for example, the preparation of a copolymer of polyoxyethylene and polyoxypropylene glycol having a molecular weight from 300 to 15,000 as disclosed by Toussaint et al in US. Pat. No. 2,425,845 and Roberts et al in ()5. Pat No. 2,425,755, both assigned to Carbide & Carbon Chemicals Corp. These novel grease additives may be obtained among other preparative methods using the aforementioned process of Toussaint et al and Robert et al, by the alkaline catalyzed reaction in a substantially anhydrous environment of a mixture of ethylene and 1,2 propylene oxides with alcohols, diols and/or polyols, or their mixtures, at temperatures ranging from about C to C. Typical alcohols,

diols and polyols include methanol, n-butanol, noctanol, ethylene glycol. propylene glycol, glycerol and sorbitol, among others. The average molecular weights as measured by the ebullioscopic method or calculated from viscosity measurements or acetyl values are between about 300 to about 15,000. The favored copolymers usually contain from about 50 to 75 parts by weight of propoxy groups, and from about 25 to 50 parts by weight of ethoxy groups and have an average molecular weight of from about 1500 to about 10,000. One of the preferred copolymers is sold by Retzoloff Chemical Company of Houston, Texas, as DPB-15. 1t contains about 75 to 90 parts by weight of propoxy groups and from about 25 to 10 parts by weight of ethoxy groups.

The novel copolymer additives are employed in an amount effective to substantially increase the resistance of the alkali metal soap-alkaline earth metal soap-thickened grease to the attack by water. This amount will vary according to the additive employed, the degree of protection sought, the alkali metal soap contained in the grease, etc. However, when lithiumcalcium soaps are used to thicken a mineral oil base and the preferred copolymers are derived from alkoxylation of di-, tri-, or polyhydroxylated compounds, from about 0.1 parts by weight to 5.0 parts by weight of copolymer per hundred parts by weight of the finished grease represents the extremes of the polymer content. A more useful range of about 0.1 to 0.6 parts by weight of copolymer produces greases which have good properties and consistently pass water-resistance tests, and for this reason are preferred.

2. Alkoxylated Adducts of Alkylated Phenols.

The second class of additives employed to provide improved water-resistance to said greases, particularly calcium-lithium soap-thickened greases comprises alkylene oxide adducts of alkylated phenols. The favored alkylene oxides are ethylene oxide, propylene oxide and their mixtures. A favored group within the class are alkylated phenols wherein the alkyl group contains 5 to 15 carbon atoms, which have from 2 to 50 alkoxylate groups attached to the molecule. The preferred additives within this class are ethoxylated phenols whose alkyl groups contain 6 to 10 carbon atoms and an average of 5 to ethoxylate groups per molecule.

Two of the preferred ethoxylated alkylated phenols are commercially available. One of these is a nonyl phenol ethoxylated with an average of 9.5 moles of ethylene oxide per mole of nonyl phenol. The second phenolic adduct which is preferred is supplied by the Retzloff Chemical Company of Houston, Texas, and is designated as DRB-203.*

The properties of this additive are: Viscosity at 77F 575: 50 ctks, Form-liquid, Specific Gravity 1.02 at 60F, Pour Point, F -Below 5F, Mole Wt. 6000-8000.

3. Mixed Alkoxylated Products of Alkylene Diamines.

P (ocn cn (ocn cnh 11(0c1i cH -(ocn cah,

The third class of additives which impart substantially improved water-resistance to greases refers to products formed by initially adding an alkylene oxide such as ethylene or propylene oxide to an alkylene diamine such as ethylene diamine (H N-CH C- H H N) to give the symmetrical tetrapropoxylated derivative followed by subsequent oxyethylation to a structure shown below:

CH CH wherein x an integer ranging from 6 to 16.

These condensates are also available commercially from the Petrolite Company of Houston, Texas. A favored additive is referred to by the manufacturer at Tretolite Additive A-3089" whose active components structure appears above.

B. Lubricating Oils.

The lubricating oils employed as the base fluids in this invention of prime interest are the natural (mineral) oils, or mixtures of one or more of these oils. The mineral oils which can be used are those of paraffinic, naphthenic, asphaltic or paraffinic-asphaltic type derived from crude oils by refining processes including distillation, cracking and/or polymerization. These oils will have a gravity (APl) of about 10 to 35, a viscosity within the range of 100 to 2000 SUS at 100F and flash points within the range of about 275F to 650F. Generally a viscosity of from about 500 to 1400 SUS at 100F is favored.

The lubricating base oils preferred for the water resistant grease formulations are mineral oils of the paraffinic type having SUS viscosities at 210F in the range of about to and flash points in the range of about 450F to 600F. The above oils are preferred as bases for greases because they consistently produce greases having generally good characteristics and enhanced resistance to water.

C. Ratio of Oil to Fat.

For reasons presently unknown, the ratio of oil to fat plays an important role in the novel one-step saponification process to form mixtures of calcium and lithium soaps. Through experimentation it has been found that ratios of oil to fat ranging from 2:1 to 4:1 usually give good results but higher or lower ratios of oil to fat present problems. For example, higher ratios of 5:1 to 7:1 and higher cause poor appearance due to nonhomogenity, while lower ratios cause the formation of very heavy soap base which could overload the agitation means employed and unduly extend the processing cycle.

D. Optional Grease Adjuvants.

The term adjuvants" as used throughout this disclosure is used to describe any materials or agents (excluding the inventive additives imparting water-resistance and the alkali metal and alkaline earth metal soapthickeners) which are incorporated into the grease formulation to enhance desirable properties or to elimi' nate or minimize deleterious properties. These adjuvants can be of diverse structure or origin and are typified by the following: extreme pressure (E.P.) agents such as the metallic naphthenates and sulfurized sperm oil, fillers such as the metal oxides, oxidation inhibitors including phenyl-beta-naphthylamine and the diphenyl amines, corrosion inhibitors including alkali metal nitrites, and stabilizers such as the fatty acid esters. When these optional adjuvants are employed they are used in minor amounts, seldom totaling more than percent by weight of the finished grease. More usually these adjuvants comprise from about 0.5 to 7.0 parts by weight per hundred parts by weight of finished grease. Ordinarily, these adjuvants are added at the expense of the oil base, most often during the cooling step that takes place during the finishing of greases.

E. Mixed Alkali Metal Soaps and Alkaline Earth Metal Soaps.

The soap-thickeners of prime interest in the formulation of the water-resistance greases of this invention broadly include mixtures of alkali metal soaps and alkaline earth metal soaps. More narrowly the process relates to greases thickened by calcium and lithium soap mixtures. These latter greases are particularly useful because when combined with the additives disclosed in Ser. No. 161,993 not only do the greases exhibit good general lubrication properties, but they also exhibit far superior water resistance.

As will be disclosd infra, one of the salient advantages of the subject process is that it permits one-step saponification of the calcium soap-lithium soap mixture without compromising the general properties of the grease or its appearance. In short, this is accomplished by concurrently saponifying both the strongly alkaline form of both metals which can be saponified with saponifiable material. The terms strongly alkaline metal material or strongly alkaline metallic agent refers to basic forms of alkaline earth metals and alkali metals such as their hydroxides, oxides, alkoxides and the like and/or mixtures of these materials. As indicated previously in order to obtain the advantages of this invention at least one basic alkaline earth material and at least one basic alkali material must be employed. Illustrative basic alkaline earth materials include alkaline earth hydroxides, alkaline earth oxides among others. Preferred alkaline earth materials are calcium hydroxide, calcium oxide or mixtures of these calcium materials. Illustrative basic alkali metal materials include lithium hydroxide, sodium hydroxide, sodium methoxide as well as mixtures of these basic alkali metal materials. The preferred basic alkali metal material is lithium hydroxide. The term saponifiable material refers to fatty acids and hydroxy-substituted fatty acids and their esters containing 1 to 4 carbon atoms. Especially useful are those saponifiable materials containing from about 12 to 32 carbon atoms per molecule. Also included are glycerides or hydroxylated glycerides. Suitable saponifiable materials include the following illustrative materials: l2-hydroxystearic acid, stearic acid, hydrogenated castor oil, myristic acid and the like.

The preferred saponifiable materials in the order of preference are l2-hydroxystearic acid, stearic acid, hydrogenated castor oil and/or their mixtures. in the most favored composition, the saponifiable material is l2- hydroxystearic acid.

F. Novel Process for Preparing the Novel Low Water Absorbing Greases of this invention.

The novel process requires the temperature of the grease to be kept under the melting point of the alkaline earth metal soap or soaps used during the manufacturing cycle. In the continuous units temperatures are most conveniently controlled by the temperatures maintained in the reactor jacket, while in the case of batch precessed greases. adjusting the kettle jacket temperature affords the most practical means of controlling the temperature of the grease. Where calcium-l2-hydroxystearate is the alkaline earth metal of the mixed soap this requires maintaining the temperature below 293F. throughout the entire preparative process.

G. Consistency (Grades) of Greases Produced Using the Novel Process Because of their overall suitability as a lubricant in many applications, the mixed alkaline earth metalalkali metal soap thickened greases can be manufactured in at least three consistencies as defined by National Lubricating Grease Institute (N.L.G.l.) to be 0, 1 and 2 described in ASTM Method D-2l7 for Cone Penetration of Lubricating Greases. Adjusting the oil and additive content will permit the manufacture of various other grades of greases. For example, a typical grease of the NLG] 0 grade would be composed of 7 parts by weight of total soap, 88 parts by weight of oil and 5 parts by weight of additives. A typical grease of the NLGI 1 grade would be composed of l2 parts by weight of total soap, 83 parts by weight of oil and 5 parts by weight of additives; while a typical grease of the NLGI 2 grade would be composed of l6 parts by weight of total soap, 79 parts by weight of oil and 5 parts by weight of additives. Preparation of the other NLGI grades of grease can be readily accomplished by further adjustments in the concentrations of soap and oil present in the grease.

EXAMPLE 1 Preparation of a Lithium-Calcium Soap-Thickened Grease Having Both Enhanced Water Resistance and Good Appearance Using Concurrent In Situ Saponification and Control of Temperature of the Reaction Mixture I. A grease kettle equipped with heating, cooling and stirring means is charged with 156 pounds of lithium hydroxide monohydrate and 780 pounds (97 gallons) of water. The aqueous alkali mixture is stirred for about 15 minutes and 3200 pounds of mineral oil base A*, 1600 pounds of l2-hydroxystearic acid and 74 pounds of hydrated lime are added with continuous stirring.

Mineral oil base A used in this example and subsequent examples has the following properties:

API Gravity 26.5 Viscosity SUS at 100?. l20l Viscosity SUS at 210F. 93.8 Flash Point (COC) 520"F. Pour Point 0F.

ll. The stirred charge is then heated to between 180F. to 200F. to saponify the mixedlithium-calcium soap. The heating of the stirred saponification mixture is controlled carefully to assure that no part of the mixture exceeds 293F. during the batch cycle.

111. At the end of the saponification step the aqueous mixed soap solution is conditioned by heating to 270F. to 275F. It is stirred at 270F. to 275F. for 3 to 4 hours or until soap base has a very heavy, smooth texture and translucent appearance.

1V. At the end of this time an additional 439] pounds (589 gallons) of mineral oil base A* is added at a rate at which it will blend in smoothly (about 1 gallon per minute).

V. When the above oil addition is completed, 562 pounds (76.7 gallons) of base oil 8* is added at a blendable rate (at about 3 gallons per minute).

Vl. After the addition of base oil B*, the temperature of the stirred mixture is maintained between 180 and 220F. and the following additives** are blended in with stirring:

215 pounds of lead naphthenate 142 pounds of lead diamyldithiocarbamate 74 pounds of antimony dialkyldithiocarbamate 72 pounds of copolymer of polyoxyethylene and polyoxypropylene 145 pounds of a residuum oil**** 3,324 pounds of base oil A 260 pounds of base oil B "Mineral oil base B used in this example and subsequent examples has the following properties:

A?! Gravity 29.2 Viscosity SUS at 100F 335 Viscosity SUS at 210F 54.3 Flash Point (COC) 450F. Pour Point F.

"The quantities of additives blended in represent total amounts corrected to conform to specifications after testing.

""The copolymer has the following properties:

Vll. After the addition of the additives including additional oil is complete, stirring is continued at about 195F. for 1 hour to insure homogeneity, a sample is taken for testing. As the data in examples 1 to 3 (presented in Table l) indicate, not only are the general physical properties including water resistance good, but the appearance of the finished grease is smooth, not grainy as is the case in the preparations where the critical jacket temperature is not maintained and oil to fat ratio is greater than 4:1.

Equally suitable greases can be prepared by substituting either hydrogenated castor or methyl-l2- hydroxystearate for l2-hydroxystearic acid in the above process.

EXAMPLE 2 Preparation of a Lithium-Calcium Soap-Thickened Grease Having Both Enhanced Water Resistance and Good Lubricating Properties but Poor Appearance In this run the same reactants and general reaction procedure are employed as in Example 1 except that the jacket temperature is allowed to exceed the melting point of the calcium l2-hydroxystearate which is 293F. The procedure is as follows:

1. A grease kettle equipped with heating, cooling and stirring means is charged with 4.6 pounds of lithium hydroxide monohydrate and 23.4 pounds of water. The aqueous alkali mixture is stirred for about 15 minutes and 160.4 pounds of mineral oil base A, 47.32 pounds of l2-hydroxystearic acid and 2.25 pounds of hydrated lime are added with continuous stirring.

11. The stirred charge is then heated to between 180F. to 200F. to saponify the mixed lithium-calcium soap. During this heating period the kettle jacket reaches 350F. and the temperature of the saponification mixture touching the kettle wall is between 293 and 350F. to produce a bulk temperature between 180 to 200F.

111. At the end of the saponification step the aqueous mixed soap solution is conditioned by heating to 270F. During the heating period the kettle jacket reached 350F. and the temperature of the mixture touching the kettle wall is between 293 and 350F. to produce a bulk temperature between 270 to 275F. The batch is stirred at 270 to 275F. for 3 to 4 hours.

IV. At the end of this time an additional 104.6 pounds of mineral oil base A is added at a rate at which it will blend in smoothly (about 1.5 lbs. per minute), and the mixture is allowed to cool to 180 to 220F.

V. When the above oil addition is completed, 25.25 pounds of base oil B is added at a blendable rate.

Vl. After the addition of base oil 8, the temperature of the stirred mixture is maintained between 180 and 220F. and the following additives are blended in with stirring:

5.25 pounds of lead naphthenate 3.50 pounds of lead diamyldithiocarbamate 1.75 pounds of antimony dialkyldithiocarbamate 1.75 pounds of a copolymer of polyoxyethylene and polyoxypropylene 3.50 pounds of a residuum oil Vll. After the addition of the additives is complete the batch is stirred for an additional 30 minutes at 180-220F. to insure homogenity and a sample taken for testing. Although the resultant grease exhibits good test characteristics, its texture and appearance are at comparable to the smooth, buttery texture of the grease of Example 1. The test data appears in Table 1.

EXAMPLE 3 Preparation of Another Lithium-Calcium Soap Thickened Grease Having Poor Appearance in this run the procedure of Example 1 is followed but the oil to fat ratio is outside (in this instance higher) than the recommended 2:1 to 4:1 weight range. The procedure used appears below:

1. A grease kettle equipped with heating, cooling and stirring means is charged with 1.58 pounds of lithium hydroxide monohydrate and 7.9 pounds of water. The aqueous alkali mixture is stirred for about 15 minutes and 82.6 pounds of mineral oil base A, 16.22 pounds of l2-hydroxystearic acid and 0.76 pounds of hydrated lime are added with continuous stirring.

II. The stirred charge is then heated to between l80F to 200F to saponify the mixed lithium-calcium soap. The heating of the stirred saponification mixture is controlled carefully to assure that no part of the mixture exceeds 293F during the batch cycle.

lll. At the end of the spaonification step the aqueous mixed soap solution is conditioned by heatingto 270F to 275F. it is stirred at 270F to 275F for 3 to 4 hours.

IV. At the end of this time an additional 9.4 pounds of mineral oil base A is added at a rate at which it will blend in smoothly (about 0.5 lbs. per minute), and the mixture is allowed to cool to [80F to 220F;

added to the stirred charge. During the addition and after the addition the consistency of the batch increases substantially and stirring becomes very difficult. As a consequence the batch is not completely homogeneous and requires an inordinately long time to heat up. Samples of the grease batch when the grease is finally prepared contains undispersed soap lumps and both the grease appearance and properties are poor. Further the batch cycle (preparation time) is impractically long and for these reasons greases prepared with oil to fat weight ratios lower than 2:] are not practical to prepare.

TABLE 1 Example 1 Example 2 Example 3 Composition:

Lithium l2-Hydroxystearate 9.6 9.3 9.3 Calcium l2-Hydroxystearate 4.7 4.7 4.7 Mineral Base Oil A 75.5 75.8 75.8 Mineral Base Oil B 5.7 5.7 5.7 Lead Diamyldithiocarbamate [.0 1.0 L Antimony Dialkyldithiocarbamate 0.5 0.5 0.5 Copolymer of polyoxyethylene and polyoxypropylene 0.5 0.5 0.5 Residuum Oil 1.0 L0 1.0 Lead Naphthenate L L5 [.5

Total |00.0 100.0 I000 Tests;

Penetration at 77F Worked 60 strokes 332 333 322 Grease Water Absorption Test X Water Absorbed 100 90 85 Original Penetration 305 305 298 Penetration of Emulsion 287 287 294 ASTM D-l264 Water washout 1 Loss at [00F L4 3.5 2.7

Z Loss at |75F 2.2 3.7 3.8

V. When the above oil addition is completed, 6.8 pounds of base oil B is added at a blendable rate.

Vl. After the addition of base oil, the temperature of the stirred mixture is maintained between 180F and 220"] and the following additives are blended in with stirring:

l.8 pounds of lead naphthenate 1.2 pounds of lead diamyldithiocarbamate 0.6 pounds of antimony dialkyldithiocarbamate 0.6 pounds of a copolymer of polyoxyethylene and polyoxypropylene and polyoxypropylene 1.2 pounds of a residuum oil Vll. After the addition of the additives is complete the batch is stirred for an additional minutes at l80-220F to insure homogenity and a sample is taken for testing. Although the grease prepared in this example exhibits good test characteristics, its texture is mealy and its appearance is unacceptable.

Inasmuch as the heating temperatures are within the recommended limits, the poor texture and appearance can be attributed to the 5 to 1 weight ratio of the oil to fat used in the run.

EXAMPLE 4 Preparation of Another Lithium-Calcium Soap Thickened Grease Having Poor Appearance In this run a lower oil to fat ratio than the recommended 22] weight ratio is employed. Again the same procedure and the same components used in the grease prepared in Example I are employed.

To the grease kettle is charged 4.60 lbs. of lithium hydroxide and 23.4 lbs. water. After stirring for 15 minutes, 47.32 lbs. of Mineral Oil Base A, 47.32 lbs. of 12- hydroxystearic acid and 2.25 lbs. of hydrated lime are As the preceding examples and discussions have indicated, the novel preparation process of this invention offers several advantages over processes used to prepare comparable greases thickened by a mixture of both alkaline earth metal soaps and alkali metal soaps. For example, not only does this one-step saponification procedure reduce the time needed for the manufacturing cycle compared to processes employing two separate saponification steps but the resultant grease contains more soap than greases having comparable properties. These depressed yield greases will be more resistant to deterioration in service particularly under wet conditions.

Further, the above advantages are achieved without significantly affecting lubricating properties or the appearance of the grease. Surprisingly enough the latter factor (appearance) which is a very important consideration in commercial acceptance of a grease, is much superior compared to greases formerly prepared by simuitaneous saponification of the mixed soaps at tempertures exceeding the melting point of the alkaline earth soap contained in the grease. in addition, the novel process is equally applicable to both batch or continuous operation.

Finally, the invention process is relatively flexible insofar as the mineral base oil, the fatty acids and alkaline materials that may be employed. However, the metes and bounds of this invention are best ascertained by an examination of the claims which follow, read in conjuction with the preceding specification.

What is claimed is:

l. A nonmelt process for preparing mineral oil-based greases combining good lubrication properties, good resistance to water and a smooth nongrainy appear- 1 1 12 ance, said greases being thickened by a mixture of calexceeding the melting point of the calcium and cium soaps and lithium soaps, formed in situ through lithium soap until the calcium and lithium soap the saponification of a saponifiable fatty material with are formed; a mixture of calcium hydroxide and lithium hydroxide 3. adding from 5.0 to 0. 1 parts by weight ofa copolywith the provisos 5 mer of polyoxyethylene and poly-1,2-oxypropylene a. that during the in situ saponification step between having a molecular weight of from about 2300 to the fatty materials and the calcium and lithium hy- 2500 to said heated saponification mixture, and droxide materials said saponification always takes 4. adding to the heated mixture of mineral oil, calplace in the presence of excess mineral oil of lubricium and lithium soaps from 7.0 to 0.5 parts by eating viscosity, the excess of oil to fat not to ex weight of grease adjuvants while maintaining the ceed a ratio of 2:] to 4:] and temperature of the saponification mixture below b. that during said saponification step and throughout the elting POinl 0f aid lith um and Calcium the entire preparative process the saponification p While Optionally adding Sufficient mineral temperature shall not exceed the lti point f oil to said saponification mixture until a grease of the calcium and lithium soaps formed during the the desired consistency having good lubrication saponification process, said non-melt process conp p i g resistance Wale! and g 8P- sisting essentially of: pearance is produced. 1. admixing from about 4,5 parts b i h t 2. The process of claim 1 wherein the saponification parts by weight of the saponifiable fatty material temperature ranges from 230F to 293F. with from about 0.1 to L6 parts by weight of cal- 20 3. The process of claim 1 wherein the saponifiable cium hydroxide and from about 0.1 to 1.3 parts material is stearic acid. by weight of basic lithium hydroxide materials in 4. The process of claim 1 wherein the saponifiable the presence of sufficient mineral oil to maintain fatty material is l2-hydroxystearic acid. the ratio of said mineral oil to said fatty materials 5. The pr ess of laim 1 wherein he ponifiable ranging from 2:l to 4:]. and to form a saponififatty material is a mixture of stearic acid and 12- cation mixture; hydroxystearic acid. 2. heating said saponification mixture up to but not a

Claims

1. A NONMELT PROCESS FOR PREPARING MINERAL OIL-BASED GREASES COMBINING GOOD LUBRICATION PROPERTIES, GOOD RESISTANCE TO WATER AND A SMOOTH NONGRAINY APPEARANCE, SAID GREASES BEING THICKENED BY A MIXTURE OF CALCIUM SOAPS AND LITHIUM SOAPS, FORMED IN SITU THROUGH THE SAPONIFICATION OF A SOPONIFIABLE FATTY MATERIAL WITH A MIXTURE OF CALCIUM HYDROXIDE AND LITHIUM HYDROXIDE WITH THE PROVISOS A. THAT DURING THE IN SITU SAPONIFICATION STEP BETWEEN THE FATTY MATERIALS AND THE CALCIUM AND LITHIUM HYDROXIDE MATERIALS AND THE CALCIUM AND LITHIUM HYDROXIDE PRESENCE OF EXCESS MINERAL OIL OF LUBRICATING VISCOSITY, THE EXCESS OF OIL TO FAT NOT EXCEED A RATIO OF 2:1 TO 4:1 AND B. THAT DURING SAID SAPONIFICATION STEP AND THROUGHOUT THE ENTIRE PREPARATIVE PROCESS THE SAPONIFICATION TEMPERATURE SHALL NOT EXCEED THE MELTING POINT OF THE CALCIUM AND LITHIUM SOAPS FORMED DURING THE SAPONIFICATION PROCESS SAID NON-MELT PROCESS CONSISTING ESSENTIALLY OF:

1. ADMIXING FROM ABOUT 4.5 PARTS BY WEIGHT TO 20 PARTS BY WEIGHT OF THE SAPONIFIABLE FATTY MATERIAL WITH FORM ABOUT 0.1 TO 1.6 PARTS BY WEIGHT OF CALCIUM HYDROXIDE AND FROM ABOUT 0.1 TO 1.3 PARTS BY WEIGHT OF BASIC LITHIUM HYDROXIDE MATERIALS IN THE PRESENCE OF SUFFICIENT MINERAL OIL TO MAINTAIN THE RATIO OF SAID MINERAL OIL TO SAID FATTY MATERIALS RANGING FROM 2:1 TO 4:1, AND TO FORM A SAPONIFICATION MIXTURE;

2. HEATING SAID SAPONIFICATION MIXTURE UP TO BUT NOT EXCEEDING THE MELTING POINT OF THE CALCIUM AND LITHIUM SOAP UNTIL THE CC ALCIUM AND LITHIUM SOAP ARE FORMED;

2. The process of claim 1 wherein the saponification temperature ranges from 230*F to 293*F.

2. heating said saponification mixture up to but not exceeding the melting point of the calcium and lithium soap until the calcium and lithium soap are formed;

3. adding from 5.0 to 0.1 parts by weight of a copolymer of polyoxyethylene and poly-1,2-oxypropylene having a molecular weight of from about 2300 to 2500 to said heated saponification mixture, and

3. The process of claim 1 wherein the saponifiable material is stearic acid.

3. ADDING FORM 5.0 TO 0.1 PARTS BY WEIGHT OF A COPOLYMER OF POLOXYETHYLENE AND POLY-1,2-OXYPROPYLENE HAVING A MOLECULAR WEIGHT OF FROM ABOUT 2300 TO 2500 TO SAID HEATED SAPONIFICATION MIXTURE, AND

4. The process of claim 1 wherein the saponifiable fatty material is 12-hydroxystearic acid.

4. adding to the heated mixture of mineral oil, calcium and lithium soaps from 7.0 to 0.5 parts by weight of grEase adjuvants while maintaining the temperature of the saponification mixture below the melting point of said lithium and calcium soap while optionally adding sufficient mineral oil to said saponification mixture until a grease of the desired consistency having good lubrication properties, good resistance to water and good appearance is produced.

5. The process of claim 1 wherein the saponifiable fatty material is a mixture of stearic acid and 12-hydroxystearic acid.