US3255109A - Arylcarbamyl compounds and grease compositions containing the same - Google Patents

Description

tures of 600 F. and even higher.

United States Patent 3,255,109 ARYLCARBAMYL COMPOUNDS AND GREASE COMPOSITIONS CONTAINING THE SAME Helen M. Sellei Beretvas, Chicago, Ill., assignor to Standard Oil Company, Chicago, Ill., a corporation of Indiana No Drawing. Filed Apr. 29, 1964, Ser. No. 363,608

' 20 Claims. (Cl. 25233.6)

This is a continuation-in-part application of my application Serial No. 271,500, filed April 8, 1963, and now abandoned.

This .invention'relates to certain arylcarbamyl compounds and their use as thickeners for high temperature greases.

Lubricant greases, comprising a normally liquid lubricant vehicle thickened to grease consistency with normally solid thickening agents, are currently being required to serve under conditions of high temperature and high loads and speeds. Both the lubricant vehicle and the thickening agent must be capable of performing satisfactorily. Until recently, it was the thickening agent rather than the vehicle which had imposed limitations on the grease performance.

Recently, it has been discovered that' certain arylcarbamyl compounds are outstanding grease thickeners, particularly when used in conjunction with special lubricant vehicles such as the silicone oils (Swakon and Brannen, US. Patents 2,710,839, 2,710,840 and 2,710,841). Arylcarbamyl thickened greases have been widely accepted for high temperature and high load and speed service conditions.

A primary object of the invention is to provide novel arylcarbamyl compounds which are superior to the arylcarbamyl thickeners heretofore known and which permit greases thickened therewith to be employed at tempera- In accordance with the invention, it has now been discovered that superior arylcarbamyl greases may be prepared from a normally liquid lubricant vehicle containing a reaction product of a primary or secondary amine having an amino group connected to an aromatic ring, with the arylcarbamyl compound of one mole of bitolylene diisocyanate and two moles aof p-aminobenzoic acid. It is unnecessary to efiect complete neutralization of the carboxyl groups on the arylcarbamyl compound (provided by the p-aminobenzoic acid) with the amine, and it has been found that any reaction, or even an excess of amine, substantially improves the performance of the inventive greases.

Greases of the invention are advantageously prepared in two steps, by conducting the appropriate reactions in situ in the lubricant vehicle. The first reaction is the preparation of an arylcarbamyl compound of one molar proportion of the bitolylene diisocyanate and two molar proportions of the p-aminobenzoic acid; it is advantageous to pre-dissolve the p-aminobenzoic acid in about ten volumes of Warm isopropanol per volume of p-arninobenzoic acid. Formation of the arylcarbamyl compound occurs rapidly at room temperature, and the reaction mixture is advantageously heated to about 150 F. and stripped with vacuum to remove the isopropanol. Then the mixture may optionally be milled, heat treated at about 400-500" 'F., e.g., about 450 F., for from onehalf to about ten hours, e.g., about four hours, and then re-milled. Reaction with the amine is then effected, utilizing anywhere from about 0.1 to as much as 1.2 or more times the stoichiometric quantity of amine based on p-aminobenzoic acid. This latter reaction occurs at temperatures depending upon the particular nature of the amine, and may range from, say, 0 F., to 500 'F., or

even higher. The grease is then optionally heat treated, as above, and then re-milled.

An additionally effective method of preparing the above described reaction product comprises dissolving the aromatic diisocyanate in a silicone polymer fluid followed by heating until the result is'a thick, amber, fairly viscous liquid which sets to a soft greasy consistency at room temperature. This preparative method is advantageous in that a viscous material containing a polymerized diisocyanate which can be further reacted effectively, as described above, with a p-aminobenzoic acid. I

The aromatic diisocyanate reactantmay be any one of the diisocyanates having at least one aromatic ring in the molecule. Biphenylene disocyanates having the following structural formula:

NC o IF NC 0 c (a). I (R).

constitute particularly desirable aromatic diisocyanates. In the foregoing formula n is an integer of 0-4, R is hydrogen, an alkyl group of 1 to 18 carbon atoms, a phenyl group, halogen, or mixtures thereof, x is an integer from 0 to 4 and R is hydrogen or an alkyl group of 1-4 carbon atoms. Examples of biphenylene diisocyanates include'bitolylene diisocyanate (3,3-bitolyle ne-' These compounds have the general formula:

NCO

where R is an alkyl group of 1-4 carbon atomsand n is 0-4. The Rs may be the same or different alkyl groups. Examples of monophenylene diisocyanates include the tolylene diisocyanates, which are available as 65 percent of the 2,4 isomer and 35 percent of the 2,6 isomer, as percent of the 2,4 isomer and 20 percent of the 2,6 isomer, or percent ofthe 2,4 isomer. Other monophenylene diisocyanates include metaphenylene diisocyanate, 2,4-tolylene diisocyanate dimer, and xylylene diisocyanate. Substituted monophenylene diisocyanates are also suitable, and these include methoxyphenylene diisocyanate, phenoxyphenylene diisocyanate, and chloro phenylene diisocyanate.

Polynuclear aromatic diisocyanates such as naphthalene diisocyanates may also be employed.

Amines which are suitable for the present invention are primary and secondary amines having an amino group connected to an aromatic ring. The aromatic ring may be a six-membered carbocyclic or heterocyclic aromatic ring, e.g., as in .triazines. The amine may be mononuclear as in aniline or poly-nuclear as in diphenylamine and may be unsubstituted or substituted as in p-bromaniline or p-phenylazoaniline. Further, diamines' such as 2,6 diamino anthraquinone may be used. In addition, mixtures of more than one amine may be employed. Incorporated herein by reference, and to eliminate the need for extensive listings of suitable primary and secondary amines having an amino group connected to an aromatic 3,255,109 r Patented June 7, 1966 ring, is Brewsters text on Organic Chemistry (Prentice- Hall, 1948) Chapter 27, pages 545-574.

Additionally, the aforementioned products of the reaction of an arylcarbamyl compound with an aromatic primary or secondary amine may be modified advantageously by means of further reaction with an aromatic diisocyanate which may be the same as or different from that used in the primary reaction. Such further reaction provides a larger and structurally more rigid thickener molecule having characteristics enabling it to stand up better under severe test conditions. Grease composi tions thus modified have been demonstrated to be advantageous as a result of their excellent performance in bearing tests. Many aromatic diioscyanate materials, as described above, are suitable for this reaction. Especially preferred are bitolylene diisocyanate, p-phenylphenylisocyanate and dianisidine diisocyanate. The amount of diisocyanate, or mixtures thereof, to be used in this last described modifying reaction will broadly speaking be from about 0.1 to 2.1 moles and preferably 1.3 to 1.0 mole of aromatic diisocyanate for every mole of diisocyanate employed in the original reaction. In addition to the diisocyanates, mono-isocyanate may also be used in corresponding amounts. The reaction mixture may optionally be milled as described above.

Normally liquid lubricant vehicles, also termed oleaginous bases, etc. which are thickened with the foregoing arylcarbamyl compounds to form greases illustratively include the silicone polymer oils, mineral lubricating oils, synthetic hydrocarbon lubricating oils, synthetic lubricating oils such as polyalkylene glycols and their derivatives, high molecular weight esters of dicar boxylic acids, polyfiuoro derivatives of organic compounds such as the trifluorovinyl chloride polymers diesters of dicarboxylic acids such as the butyl, hexyl, 2-ethylhexyl, decyl, lauryl, etc., esters of sebacic acid, adipic acid, azelaic acid, etc., may be thickened to produce excellent greases. Polyfluoro derivatives of organic compounds, particularly hydrocarbons, and dibasic acid esters of H(CF ),,CH OH, in the lubricating oil viscosity range can also be thickened. Other synthetic oils, such as esters of aliphatic carboxylic acids and polyhydric alcohol, e.g., trimethylolpropane tripelargonate and pentaerythritol hexanoate, can be used as suitable oil vehicles.

Greases of the invention were tested on conventionalv MRC laboratory bearing test using L- bearings. The bearings were run at 10,000 revolutions per minute, and the temperature maintained at 600 F. Each bearing was fully packed with grease for the test. The test was run with a pound radial load and a 25 pound axial load. Hours to failure are reported as the test value.

Greases to illustrate the invention were prepared by the preferred technique set forth above, using Dow-Corning F67024 methylphenyl silicone base fluid. Extreme pressure additives were added where noted.

The following results were observed. It is particularly noted that the inventive greases are almost uniformly superior to the commercial aryloarbamyl grease of Run 1, and to the greases of Runs 2 through 4, in

known as Fluorolube and the trifluorochloroethylene 35 which no amine was employed.

GREASE PERFORMANCE TESTS Bitolyl- P-Amino- Approx- L-35 Run No. ene Diisobenzoie Amine imate Total Bearing cyanate, Acid, Thiekener, Test, wt. percent wt. percent wt. percent Hours 5 5 4% p-phenylaz0aniline 14 2 99 5 5 6% p-phenylazoaniline. 16 2 5 5 8% p-phenylazoaniline 18 5 5 4% p-brornaniline- 14 80 5 5 8% 2,4,6-trichloraniline. 18 00 4 4 1.5 p-phenylene diamine 9. 6 3 114 5 5 3% 1,5-diaminonaphtl1nlenc 13 3 175 4 4 8% l-aminoanthraquinone. 10 3 106 4 4 3% o-toluidine-.. 11 3G 5 5 2.5 amineline 15 G9 4 5 5 5% p-phenylazoa 20 108 5 5 5 4% p-phenylazoaniline 16 1 Commercial ASU Grease. I

2 Average of 2 or more runs.

3 Test conditions, 10,000 r.p.rn., 5 lbs. radial, 5 lbs. axial load, 000 F. 4 Plus an additional 5% dianisidine diisocyanate.

5 Plus an additional 2% p-phenylphenylisoeyanate.

polymers known as Kel-F, ammeline and other lubricant vehicles.

The silicone polymer oils which may be employed in conjunction with the represent invention are those falling substantially within the lubricating oil viscosity range, e.g., possessing a viscosity at 100 F. within the range of about 25 to about 3500 SSU. These silicone oils are polyalkyl or polyalkaryl siloxanes such as methyl siloxane or methyl phenyl siloxane. Mineral oils in the lubricating oil viscosity range, e.g., from about 50 SSU at 100 F. to about 300 SSU at 210 F., and preferably solvent extracted to substantially remove the low viscosity index constituents, are also suitable. Similarly, synthetic lubricating oils resulting from polymerization of unsaturated hydrocarbons or other oleaginous materials within the lubricating oil viscosity range such as high molecular weight polyoxyalkylene compounds typifled by polyalkylene glycols and esters thereof, aliphatic 1 The greases of the present invention may contain added oiliness agents, extreme pressure additives, etc., without 1. A new composition of matter, the product obtained by reacting at a temperature of from 0 F. to 500 F. (1) an amine selected from the group consisting of a primary amine and a secondary amine having an amino group connected to an aromatic ring and mixtures thereof with (2) an arylcarbamyl compound obtained by reacting 1 mole of an aromatic diisocyanate and 2 moles of p-aminobenzoic acid at a temperature of from about room temperature to about 150 F., the amount of said amine used being in the range of from about 0.1 to about 1.2 times the stoichiometric quantity of amine based on the p-aminobenzoic acid used.

2. A new composition of matter as described in claim 1 wherein the aromatic diisocyanate is first polymerized by heating in a solution of a silicone polymer fluid.

3. As a new composition of matter the product obtained by reacting at a temperature of from 0 F. to 500 F. (1) an amine selected from the group consisting of a primary amine and a secondary amine having an amino group connected to an aromatic ring, and mixtures thereof with (2) an arylcarbamyl compound obtained by reacting 1 mole of an aromatic diisocyanate and 2 moles of p-aminobenzoic acid at a temperature to about 150 F., the amount of said amine used being in the range of from about 0.1 to about 1.2 times the stoichiometric quantity of amine based on the p-aminobenzoic acid used, and (3) reacting at a temperature of from 0 F. to 500 F. the resultant product of (1) and (2) with from about 0.1 to about 2 moles of an aromatic diisocyanate per mole of the aromatic diisocyanate used in step (2).

4. The composition of claim 1 wherein said aromatic diisocyanate is bitolylene diisocyanate.

5. The composition of claim 1 wherein said amine is o-toluidine.

6. The composition of claim 1 wherein said amine is p-phenylazoaniline.

7. The composition of claim 1 wherein said amine is l-aminoanthraquinone.

8. The composition of claim 1 wherein said amine is a diamine.

9. The composition of claim 1 wherein said amine is a triazine.

10. The composition of claim 3 wherein said amine is p-phenylazoaniline and said aromatic diisocyanates in (1) and (2) are bitolylene diisocyanate.

11. A grease comprising an oleaginous lubricant vehicle thickened to grease consistency with the composition of claim 1.

12. A grease comprising an oleaginous lubricant vehicle thickened to grease consistency with the composition of claim 4.

13. A grease comprising an oleaginous lubricant vehicle thickened to grease consistency with the composition of claim 5. a

14. A grease comprising an oleaginous vehicle thickened to grease consistency with position of claim 6.

15. A grease comprising an oleaginous lubricant vehicle thickened to grease consistency with the composition of claim 7.

16. A grease comprising an oleaginous vehicle thickened to grease consistency with position of claim 8.

17. A grease comprising an oleaginous vehicle thickened to grease consistency with position of claim 9.

18. A grease comprising an oleaginous vehicle thickened to grease consistency with position of claim -3.

19. A grease comprising an oleaginous vehicle thickened to grease consistency with position of claim 10.

20. A grease comprising an oleaginous vehicle thickened to grease consistency with position of claim 2.

lubricant the comlubricant the comlubricant the comlubricant the comthe comlubricant thecom- References Cited by the Examiner UNITED STATES PATENTS DANIEL E. WYMAN, Primary Examiner.

lubricant I

Claims (2)

1. A NEW COMPOSITION OF MATTER, THE PRODUCT OBTAINED BY REACTING AT A TEMPERATURE OF FROMF 0*F. TO 500*F. (1) AN AMINE SELECTED FROM THE GROUP CONSISTING OF A PRIMARY AMINE AND A SECONDARY AMINE HAVING AN AMINO GROUP CONNECTED TO AN AROMATIC RING AND MIXTURES THEREOF WITH (2) AN ARYLCARBAMYL COMPOUND OBTAINED BY REACTING 1 MOLE OF AN AROMATIC DIISOCYANATE AND 2 MOLES OF P-AMINOBENZOIC ACID AT A TEMPERATURE OF FROM ABOUT ROOM TEMPERATURE TO ABOUT 150*F., THE AMOUNT OF SAID AMINE USED BEING IN THE RANGE OF FROM ABOUT 0.1 TO ABOUT 1.2 TIMES THE STOICHIOMETRIC QUANTITY OF AMINE BASED ON THE P-AMINOBENZOIC ACID USED.

11. A GREASE COMPRISING AN OLEAGINOUS LUBRICANT VEHICLE THICKENED TO GREASE CONSISTENCY WITH THE COMPOSITION OF CLAIM 1.