AU2003299220A1

AU2003299220A1 - Urea grease composition

Info

Publication number: AU2003299220A1
Application number: AU2003299220A
Authority: AU
Inventors: Kouichi Numazawa; Kazushige Ohmura; Takahiro Ozaki; Keiji Tanaka
Original assignee: SHELL INT RESEARCH; Shell Internationale Research Maatschappij BV
Current assignee: Shell Internationale Research Maatschappij BV
Priority date: 2002-12-10
Filing date: 2003-12-10
Publication date: 2004-06-30
Anticipated expiration: 2023-12-10
Also published as: JP2004204218A; WO2004053032A1; PL375721A1; BR0317109A; JP4405202B2; US20040224859A1; BR0317109B1; KR20050085578A; EP1570034B1; CA2509235A1; AU2003299220B2; EP1570034A1

Description

WO 2004/053032 PCT/EP2003/050980 UREA GREASE COMPOSITION The present invention relates to a urea grease composition. Urea grease is known as heat-resistant grease because it generally has a higher dropping point and 5 superior thermal stability than general-purpose lithium soap grease containing lithium soap as a thickening agent. In recent years, it has been discovered that urea grease has superior wear resistance and lubricating 10 properties than greases in which various metal soap and inorganic materials have been used as thickening agents. It is thought that the superior wear resistance is because urea grease can form both a urea film and an oxide film on lubricated sliding surfaces. 15 Urea grease has achieved rapid growth as grease which may be conveniently applied to typical grease lubricated locations, including a wide variety of bearings for vehicle constant-velocity joints, ball joints, wheel bearings, alternators and cooling fans, 20 ball screws and linear guides of machine tools, a wide variety of sliding areas of construction equipment, and bearings and gears in steel equipment and various other industrial mechanical facilities. The usage of urea grease has been rising steadily in 25 particular applications, such as various kinds of vehicle parts including CVJs (constant-velocity joints) where there is a strong demand for durability and reduced friction and wear in sliding areas in response to the trend of the present times toward miniaturisation, weight 30 reduction and a hostile use environment, and in steel WO 2004/053032 PCT/EP2003/050980 -2 equipment which requires highly heat-resistant, wear resistant lubricating grease. Although developments are being made year by year in the properties of urea grease, the latest urea grease 5 still has some points to be improved upon, depending on the desired application. For instance, domestic electric appliances and office automation equipment in particular are required to have appropriate sound characteristics, whilst it is 10 becoming necessary for vehicle parts to have a low-noise characteristics, abrasion resistance and low friction characteristics which are indispensable thereto. Taking a vacuum cleaner as a familiar example of the noises produced by domestic electric appliances and 15 office automation equipment, noise reduction requirements are becoming increasingly severe because the bearings therein have come to revolve at a high speed of 30,000 to 40,000 rpm as the reduction in size and increase in suction in such equipment has progressed, thereby 20 resulting in high wind noise and tumbling noise. In addition, it is desirable to minimise noises produced by the bearings of video cameras, video tape recorders and electronic equipment as they act as error signals and adversely affect electronic components. 25 Therefore, it is very effective if a grease capable of ensuring low noise and high lubricity could be applied to those bearings, and so the development of a grease having improved properties is desired. Furthermore, the smoothness of vehicles is also 30 being improved year by year under circumstances where progression of energy savings and fuel economy is accelerated, and so quality levels required of individual parts making up vehicles is being raised year by year. To the sliding areas of these parts, therefore, WO 2004/053032 PCT/EP2003/050980 -3 application of a grease capable ensuring low noise and high lubricity is highly desirable, and it is required to develop a grease having improved properties. Examples of lubricated parts of vehicles include 5 various kinds of bearings, such as cooling fan bearings of a radiator, compressor bearings of an air conditioner and alternator bearings, constant-velocity joints, universal joints of a propeller shaft, gears and bearings of a steering unit, ball screws, sliding areas of rack 10 guides, and ball joints. Smooth lubrication.with low noise and low friction are directly linked to energy savings, fuel economy and smoothness of vehicles, and greases showing excellent properties in those applications are very useful. Hence, 15 more effective greases are required. On the other hand, examples of parts to be lubricated in other industries, which are limited in direct low-noise requirements as compared with vehicles, domestic electric appliances and office automation 20 equipment, include a wide variety of bearings of auto assembly robots, ball screws and linear guides of machine tools, various sliding areas of construction equipment, and various bearings of steel facilities. Although the direct low-noise requirements for, 25 greases is limited in such applications, the noise coming out of grease is ascribable not only to a physical noise caused by stirring and flow of grease but also to noises made at the interface between lubricated surfaces (noise caused by extraneous substances on the interface and 30 noises caused by metal-to-metal contact arising from breakage of oil film). As a matter of course, it can be said that a substandard grease inferior in lubricity and contaminated with extraneous substances is prone to cause breakage of WO 2004/053032 PCT/EP2003/050980 -4 oil film and abrasion at the interface and the generation of unacceptable noise. Accordingly, the sound characteristic thereof is not improved unless lubricity is enhanced. In other words, greases having favourable 5 sound characteristics mean that the lubricity thereof is also improved. The low-noise properties of greases are further explained by taking a bearing as an example. In general, the lubricating mechanism of a grease on a rolling 10 element bearing is such that the grease which has been packed in the bearing is temporarily swung and scattered by revolution, and thereafter a trace amount of grease or oil is fed to a sliding area as churning and channeling are repeated, thereby lubricating the sliding area. 15 Therein, a sound caused by vibrations occurring between a tumbling element- of the bearing and a rolling surface appears as a bearing noise. The working precision of the bearing and contamination of the grease with extraneous substances 20 and particles of thickening agent in the grease are factors which cause bearing noise. The sound characteristics vary considerably with the form and the type of not only dirt and dust intruding into grease but also of the thickening agent incorporated in the grease. 25 In addition, such substances tend to constitute an obstacle to smooth lubrication. In general, in the case of a urea grease, urea compounds which have been obtained by reacting amine and isocyanate are used as thickening agents and these are 30 dispersed in the oil and maintain the grease state. Urea grease is generally superior to soap grease in abrasion resistance because the urea compound(s) used therein as a thickening agent are likely to adsorb to metal surfaces. However, many of the urea compounds WO 2004/053032 PCT/EP2003/050980 obtained by the afore-mentioned reaction between amine and isocyanate are in a hard granular state, thereby impairing the sound characteristics and having an adverse effect on smooth lubrication. 5 JP-A-1-139696, JP-A-2-77494 and JP-A-6-17080 concern the acoustic properties of urea grease. JP-A-1-139696 discloses a thickening agent containing a mixture of diurea compounds (a) and (b) represented by the following formulae (a) and (b), 10 respectively: (a) RINHCONHR 2

NHCONHR

3 (b) R 4

NHCONHR

5

NHCONHR

6 wherein R 2 is a diphenylmethane group, RI and R 3 each represents a C8 linear or branched saturated alkyl group, 15 R 5 represents a tolylene group or a bitolylene group, and

R

4 and R 6 each represents an alkyl-substituted aromatic group or a halogen-substituted aromatic group. JP-A-2-77494 discloses a thickening agent containing a mixture of diurea compounds (a) and (b) represented by 20 the foregoing formulae (a) and (b) wherein, however, R 2 represents a bitolylene group, RI and R 3 each represent a C18 linear or branched saturated alkyl group or unsaturated alkyl group, R 5 represents a diphenylmethane group, and R 4 and R 6 represent C8 linear or branched 25 saturated alkyl groups. JP-A-6-17080 discloses a thickening agent containing a mixture of diurea compounds (a) and (b) represented by the foregoing formulae (a) and (b) wherein, however, R 2 represents a tolylene group, RI and R 3 represent C16-18 30 linear or branched saturated alkyl groups or unsaturated alkyl groups, R 5 represents a diphenylmethane group, and WO 2004/053032 PCT/EP2003/050980 -6

R

4 and R 6 represent C8 linear or branched saturated alkyl groups. The following are other examples of literature on acoustic properties. 5 JP-A-3-28299 discloses a grease composition wherein the base oil containing an alkyldiphenyl ether oil as an essential component is mixed with a thickening agent which is a diurea compound represented by the foregoing formula (a) wherein, however, R2 represents a C6-15 10 aromatic hydrocarbon group, and Ri and R3 represent C8-18 linear alkyl groups, provided that the proportion of C8 alkyl groups in the combination of R 1 and R 3 is from 60 to 100 mole %. Page 8, Table 2 of JP-A-2-80493 discloses a 15 composition for circular conical roller bearings which is prepared by admixing urea grease with 0.5 to 5 % by weight of oxidation-modified polyolefin and/or acid modified polyolefin, and further discloses in Table 2 the urea thickening agents prepared from C8 octylamine, C18 20 stearylamine (octadecylamine) and MDI (diphenylmethane 4,4'-diisocyanate) and demonstrates that these agents produce beneficial effects on machine stability, wet shear stability and pressure transferability. JP-A-3-243696 discloses a diurea compound 25 represented by the foregoing formula (a) wherein, however, R 2 is a 3,3'-dimethyl-4,4'-biphenylene group and

R

1 and R 3 are mixtures of C8-18 alkyl groups with an oleyl group. The art disclosed in this document has defects that the consistency yield is so low that grease 30 having a consistency of about 250 cannot be obtained without increasing the amount of the thickening agent and the degree of oil separation under high temperature conditions is great.

WO 2004/053032 PCT/EP2003/050980 JP-A-58-185693 discloses a diurea grease improved by incorporating therein one or more of an additive selected from alkenylsuccinic acid imides, metal salts of alkylbenzenesulfonic acids, or metal salts of petroleum 5 sulfonic acid. The document further discloses the use of diisocyanate and monoamines for the diurea grease, and recites aliphatic amines, such as stearylamine and oleylamine, and aromatic amines, such as cyclohexylamine, as examples of those monoamines. Said document indicates 10 that the sound characteristics of said grease were favourable. Further cases are cited below where production methods are examined in order to improve the sound characteristics of urea grease. 15 For instance, JP-A-2-4895 discloses a urea grease preparation method enabling improvement in sound characteristics, wherein an isocyanate and an amine are added to a base oil and reacted with each other at a temperature of 60 to 1200C, and then the mixture of a 20 urea compound produced and the base oil is subjected to dispersion treatment by use of a kneading apparatus and further heated up to 160 to 1800C at a temperature-rising speed of 0.5 to 2*C per minute. JP-A-3-190996 discloses a method of preparing 25 greases which are said to have good sound characteristics, wherein the isocyanate-dissolved or dispersed base oil and the amine-dissolved or dispersed base oil are mixed through collisions by pressurizing them in a reaction vessel to cause reaction with each 30 other, or they are pressurized and introduced to an revolving impeller, thereby causing reaction with each other.

WO 2004/053032 PCT/EP2003/050980 In addition, JP-A-3-231993 discloses a method of preparing low-noise urea grease, which includes the first step of heating the mixture constituted of 2 to 30 % by weight of a urea compound represented by the foregoing 5 formula (a), wherein Rl and R 3 are C8-18 saturated alkyl groups and R 2 is a tolylene group, a diphenylmethane group or a dimethylbiphenylene group, and 98 to 70 % by weight of a base oil up to 170 to 230'C to thoroughly dissolve the urea compound into the base oil, and the 10 second step of cooling the solution obtained in the first step at a speed of at least 5YC per second. As in the above documents, in many cases tolylenediisocyanate (TDI) or 3,3'-dimethyl-4,4' biphenylenediisocyanate (TODI) have been used as starting 15 materials for obtaining urea grease compositions having good sound characteristics. With respect to the preparation methods thereof, the agglomeration of urea compounds is avoided by using kneading apparatus, performing the reaction in a high 20 pressure vessel, or dissolving two or more kinds of grease by heating and then mixing them. As urea grease production rises and the demand for low noise greases grows, there is demand for a clean working environment for grease production and better 25 sound characteristics in the final products. Many users demand an inexpensive high-performance grease, and urea greases using high-cost TODI as a raw material and requiring a complicated production process will not be commercially competitive. 30 Furthermore, from a Health and Safety perspective, increase in grease production requires additional care with regard to the handling of TDI as a raw material and the installation of special equipment. As a result, it WO 2004/053032 PCT/EP2003/050980 is required to consider reinforcing production facilities for improvement in sound characteristics and extending production process time. There have now been found in the present invention 5 specific urea grease compositions having a satisfactory consistency yield, with little oil separation at high temperature and with outstanding sound properties and lubricating properties. In addition, said urea grease compositions may be produced in conventional grease-making 10 facilities without the need for specialised equipment such as high-pressure kettles or kneading machines in order to disperse the thickening agent. The urea grease compositions of the present invention have good lubrication capabilities and can 15 easily spread on and are strongly adsorbed to friction surfaces. In addition, the intervened thickening function of the urea compounds in said grease composition is not an obstacle therein as extraneous matter. Therefore, the urea grease composition of the present 20 invention causes no noise, and, in addition, can enhance the strength of oil film by its viscoelasticity and can form more effective lubrication film on sliding surfaces under a synergy with additives. Thus, favourable grease lubrication can be attained. 25 According to the present invention there is provided a urea grease composition comprising a lubricating base oil and from 2 to 30 wt.-% of a thickening agent, with respect to the total weight of the urea grease composition and wherein said thickening agent is selected from: 30 (1) a mixture comprising a compound (a) and a compound (b), containing compound (a) at 20 to 80 mol%, relative to the total amount of compound (a) and compound (b); WO 2004/053032 PCT/EP2003/050980 - 10 (2) a mixture formed by mixing a compound (c) with a mixture (1); or (3) a compound (c) alone, wherein the compounds are represented by the general 5 formulae (a) R 1

NHCONHR

2 NHCONHRl; (b) R 3

NHCONHR

2

NHCONHR

3 ; and (c) RINHCONHR 2

NHCONHR

3 , and wherein R 2 is a diphenylmethane group, R 1 is a 10 C6-10 saturated alkyl group and R 3 is a C14-20 saturated and/or unsaturated alkyl group, wherein unsaturated alkyl groups constitute at least 20 mol% of the R 3 alkyl group. Preferably, unsaturated alkyl groups constitute at 15 least 25 mol%, more preferably at least 30 mol% of the R 3 alkyl group. In a preferred embodiment of the present invention Rl is a saturated C8 alkyl group and/or R 3 is a C14-20 saturated and/or unsaturated alkyl group wherein 20 unsaturated alkyl groups constituting at least 20 mol% of the R 3 alkyl group are oleyl groups. In a preferred embodiment of the present invention there is provided a urea grease composition comprising a lubricating base oil and from 2 to 30 wt.% of a thickening 25 agent, with respect to the total weight of the urea grease composition and wherein said thickening agent is selected from: (1) a mixture comprising compound (a) and compound (b), containing compound (a) at 20 to 80 mol%, relative 30 to the total amount of compound (a) and compound (b); WO 2004/053032 PCT/EP2003/050980 - 11 (2) a mixture formed by mixing a compound (c) with a mixture (1); or (3) a compound (c) alone, wherein the compounds are represented by the general 5 formulae (a) RINHCONHR 2 NHCONHRI; (b) R 3

NHCONHR

2

NHCONHR

3 ; and (c) RlNHCONHR 2

NHCONHR

3 , and wherein R 2 is a diphenylmethane group, RI is a 10 C8 saturated alkyl group, R 3 is a C14-20 saturated and/or unsaturated alkyl group, with the alkyl groups being such that this constituent includes at least 20 mol% of an oleyl constituent. In the present invention, a urea grease having 15 outstanding characteristics and performance is obtained when a thickening agent as described above is incorporated into a lubricating base oil in an amount of from 2 to 30 wt%, preferably from 5 to 20 wt% with respect to the total weight of the urea grease composition. When the content 20 of urea compounds as thickening agent is less than 2 wt%, the thickening effect is small and it is impossible to form a grease. On the other hand, when the content of urea compounds as thickening agent exceeds 30 wt%, the grease becomes too stiff and no lubricating effect is obtained. 25 When the proportion of the urea grease composition constituted by compound (a) in mixture (1) is less than 20 mol% or exceeds 80 mol%, relative to the total amount of compound (a) and compound (b), there is little effect of using the mixture and there is no improvement in noise 30 performance or oil separation. The lubricating base oil used in the urea grease composition of the present invention, may conveniently be WO 2004/053032 PCT/EP2003/050980 - 12 one or more of a vegetable oil, a mineral oil, and/or a synthetic oil. Base oils of mineral origin may be mineral oils, for example those produced by solvent refining or 5 hydroprocessing. Base oils of synthetic origin may typically be hydocarbon oils such as C 10

-C

50 hydrocarbon polymers, for example liquid polymers of alpha-olefins (poly(a-olefin)), ester type synthetic oils, silicone oils and/or ether type 10 synthetic oils. They may also be a mixture of these oils. Examples of mineral oils that may conveniently be used include those sold by member companies of the Royal Dutch/Shell Group under the designations "HVI", "MVIN", or "HIMVIP". 15 Polyalphaolefins and base oils of the type manufactured by the hydroisomerisation of wax, such as those sold by member companies of the Royal Dutch/Shell Group under the designation 'XHVI" (trade mark), may also be used. 20 In a preferred embodiment, the urea grease composition of the present invention further includes a zinc compound as an additive. Specific examples of zinc compounds that may be conveniently employed in the urea grease composition of 25 the present invention include zinc dithiocarbamates such as zinc diethyldithiocarbamate, zinc dipropyl dithiocarbarnate, zinc dibutyldithiocarbamate, zinc dipentyldithiocarbamate, zinc dihexyldithiocarbamate, zinc didecyldithiocarbamater zinc diisobutyldithiocarbamate, 30 zinc di(2-ethylhexyl)dithiocarbamate, zinc diamyldithio carbamate, zinc dilauryldithiocarbamate, zinc distearyl dithiocarbamate and zinc diphenyldithiocarbamate, etc., and zinc ditolyldithiocarbamate, zinc dixylyldithio carbamate, zinc diethylphenyldithiocarbamate, zinc WO 2004/053032 PCT/EP2003/050980 - 13 dipropylphenyldithiocarbamate, zinc dibutylphenyldithio carbamate, zinc dipenylphenyldithiocarbamate, zinc dihexylphenyldithiocarbamate, zinc dioctylphenyldithio carbamate, zinc dinonylphenyldithiocarbamate, zinc 5 didecylphenyldithiocarbamate, zinc didccecylphenyldithiocarbamate, zinc ditetradecylphenyl dithiocarbamate and zinc dihexadecylphenyldithiocarbamate. Similarly, specific examples of zinc dithiophosphates include zinc diethyldithiophosphate, zinc dipropyldithio 10 phosphate, zinc dibutyldithiophosphate, zinc dipentyl dithiophosphate, zinc dihexyldithiophosphate, zinc didecyldithiophosphate, zinc diisobutyldithiophosphate, zinc di(2-ethylhexyl)dithiophosphate, zinc diamyldithio phosphate, zinc dilauryldithiophosphate, zinc distearyl 15 dithiophosphate, zinc diphenyldithiophosphate, zinc ditolyldithiophosphate, zinc dixylyldithiophosphate, zinc diethylphenyldithiophosphate, zinc dipropylphenyldithio' phosphate, zinc dibutylphenyldithiophosphate, zinc dipentylphenyldithiophosphate, zinc dihexylphenyldithio 20 phosphate, zinc diheptylphenyldithiophosphate, zinc dioctylphenyldithiophosphate, zinc dinonylphenyldithio phosphate, zinc didecylphenyldithiophosphate, zinc didodecylphenyldithiophosphate, zinc ditetradecylphenyl dithiophosphate and zinc dihexaphenyldithiophosphate. The 25 metallic elements such as S or P in these organometallic zinc compounds react with iron in frictional surfaces to form extreme pressure films of iron phosphide or iron sulphide, etc.; and the additive itself breaks down and inter-reacts with other additives to form a protective 30 film. Furthermore, surprisingly, the urea grease compositions of the present invention exhibit outstanding lubricating properties due to synergistic effects of such S-P type additives with the urea thickening agents of the WO 2004/053032 PCT/EP2003/050980 - 14 present invention, which have outstanding penetration into the interface and adsorption. The urea grease composition of the present invention may advantageously include a molybdenum compound therein 5 as an additive. Specific examples of molybdenum compounds that may be conveniently employed in the urea grease composition of the present invention include molybdenum dithiocarbamates such as molybdenum diethyldithiocarbamate, molybdenum 10 dipropyldithiocarbamate, molybdenum dibutyl dithiocarbamate, molybdenum dipentyldithiocarbamate, molybdenum dihexyldithiocarbamate, molybdenum didecyl dithiocarbamate, molybdenum diisobutyldithiocarbamate, molybdenum di(2-ethylhexyl)dithiocarbamate, molybdenum 15 diamyldithiocarbamate, molybdenum dilauryldithiocarbamate, molybdenum distearyldithiocarbamate and molybdenum diphenyldithiocarbamate, etc., and molybdenum ditolyl dithiocarbamate, molybdenum dixylyldithiocarbamate, molybdenum diethylphenyldithiocarbamate, molybdenum 20 dipropylphenyldithiocarbamate, molybdenum dibutylphenyl dithiocarbamate, molybdenum dipenylphenyldithiocarbamate, molybdenum dihexylphenyldithiocarbamate, molybdenum dioctylphenyldithiocarbamate, molybdenum dinonylphenyl dithiocarbamate, molybdenum didecylphenyldithiocarbamate, 25 molybdenum didodecylphenyldithiocarbamate, molybdenum ditetradecylphenyldithiocarbamate and molybdenum dihexadecylphenyldithiocarbamate, and molybdenum dithio phosphates such as molybdenum dipentyldithiophosphate, molybdenum dipropyl dithiophosphate, molybdenum dibutyl 30 dithiophosphate, molybdenum dipentyldithiophosphate, molybdenum dihexyldithiophosphate, molybdenum didecyldithiophosphate, molybdenum diisobutyldithio phosphate, molybdenum di(2-ethylhexyl)dithiophosphate, molybdenum diamyldithiophosphate, molybdenum dilauryl- WO 2004/053032 PCT/EP2003/050980 - 15 dithiophosphate, molybdenum distearyldithiophosphate, molybdenum diphenyldithiophosphate, molybdenum ditolyl dithiophosphate, molybdenum dixylyldithiophosphate, molybdenum diethylphenyldithiophosphate, molybdenum 5 dipropylphenyldithiophosphate, molybdenum dibutylphenyl dithiophosphate, molybdenum dipentylphenyldithiophosphate, molybdenum dihexylphenyldithiophosphate, molybdenum diheptylphenyldithiophosphate, molybdenum dioctylphenyl dithiophosphate, molybdenum dinonylphenyldithiophosphate, 10 molybdenum didecylphenyldithiophosphate, molybdenum didodecylphenyldithiophosphate, molybdenum ditetra decylphenyldithiophosphate and molybdenum dihexaphenyl dithiophosphate, and molybdenum compounds as described in JP 5-66435 Bl, that is to say molybdenum complexes that 15 are reaction products of a fatty oil, diethanolamine and a molybdenum source. These afore-mentioned molybdenum compounds readily adsorb positively to the metal surfaces which constitute sliding surfaces, and are decomposed by the heat produced 20 at the frictional surfaces to produce MoO 3 and MoS 2 , and this MoS 2 component diffuses into the metal and has a mechanism of action which protects the frictional surfaces. In addition, surprisingly, the urea grease 25 compositions of the present invention exhibit outstanding lubricating properties due to synergistic effects of the chemical properties of these molybdenum compounds and physical and chemical properties such as adsorption and penetration of the urea thickening agents of the present 30 invention. Additives such as antioxidants, corrosion protecting agents and extreme pressure agents may be conveniently added to urea grease of the present invention in order to further improve the performance thereof.

WO 2004/053032 PCT/EP2003/050980 - 16 For example, antioxidants including alkylphenol, hindered phenol, alkylamine, diphenylamine and triazine antioxidants; anticorrosion agents include calcium sulphonate, sodium sulphonate, barium sulphonate and amino 5 derivatives or metal salts of carboxylic acids; and extreme pressure agents including sulphurized oils or fats, sulphurized olefins, phosphoric acid esters, tricresyl phosphate, trialkyl thiophosphates and triphenyl phosphorothionates may be conveniently used. 10 Lubricants for bearing use may advantageously comprise the urea grease composition of the present invention. Accordingly, the present invention further provides a method of lubricating a bearing comprising packing the 15 bearing with the urea grease composition of the present invention. In addition, lubricants for application to a sliding surface of a machine in a relative motion may advantageously comprise the urea grease composition of the 20 present invention. Accordingly, the present invention further provides a method of lubricating the sliding surface of a machine in a relative motion comprising lubricating said sliding surface with the urea grese composition of the present 25 invention. The present invention further provides the use of the urea grease composition of the present invention as a noise-reducing grease composition and, in particular, the use of said grease composition to reduce noise in bearing 30 applications. The present invention is described below with reference to the following Examples, which are not intended to limit the scope of the present invention in any way.

WO 2004/053032 PCT/EP2003/050980 - 17 Examples Examples 1-5 MDI (diphenylmethane-4,4'-diisocyanate) in the compounding proportions indicated in Table 1 and 60 parts 5 by weight of base oil were introduced into a grease kettle and heated to approximately 50*C; and after dissolving the MDI, octylamine dispersed in 20 parts by weight of the base oil was slowly added with brisk stirring. After approximately 10 minutes, oleylamine dispersed in 20 parts 10 by weight of the base oil was added and stirring was continued. The temperature of the contents of the grease kettle were raised by the reaction of the diisocyanate and the amine, and the reaction was completed by heating to 168*C 15 and holding at this temperature for approximately 30 minutes, followed by cooling to room temperature and then treatment in a triple roll mill to obtain grease. Examples 6 and 7 MDI in the compounding proportions indicated in 20 Table 1 and 60 parts by weight of base oil were introduced into a grease kettle and heated to approximately 50*C, and after dissolving the MDI, a mixture of octylamine and oleylamine dissolved in 40 parts by weight of the base oil was slowly added to the solution and the mixture was 25 stirred vigorously. The contents of the grease kettle were heated to 168 0 C and held at this temperature for approximately 30 minutes to complete the reaction, and then cooled to room temperature and treated with a triple roll mill to obtain grease. 30 Examples 8-10 The compounding proportions are shown in Table 2. 50 parts by weight of the grease of Example 1 and 50 parts by weight of grease of Example 6 were mixed uniformly with a spatula to give the grease of Example 8.

WO 2004/053032 PCT/EP2003/050980 - 18 50 parts by weight of the grease of Example 2 and 50 parts by weight of grease of Example 6 were mixed uniformly with a spatula to give the grease of Example 9. 50 parts by weight of the grease of Example 3 and 50 5 parts by weight of grease of Example 6 were mixed uniformly with a spatula to give the grease of Example 10. Examples 11-16 MDI (diphenylmethane-4,4'-diisocyanate) in the compounding proportions indicated in Tables 3 and 4 and 60 10 parts by weight of base oil were introduced into a grease kettle and heated to approximately 50*C, and after dissolving the MDI, 20 parts by weight of octylamine dissolved in the base oil was slowly added with brisk stirring. After approximately 10 minutes, the amines other 15 than octylamine mixed in the composition shown in Table 3 with 20 parts by weight of base oil were added and stirring was continued. The temperature of the contents of the grease kettle were raised by the reaction of the diisocyanate and the 20 amine, and the reaction was completed by heating to 1680C and holding at this temperature for approximately 30 minutes, and then cooled to 801C, followed by addition of the additives listed in Table 3 and then treated with a triple roll mill to obtain grease. 25 Comparative Examples 1-15 Diisocyanates in the compounding proportions indicated in Tables 5-7 and 60 parts by weight of base oil were put into a grease kettle and after dissolving the diisocyanates at the temperatures below, amines dispersed 30 in 40 parts by weight of the base oil were slowly added with brisk stirring. The contents of the grease kettle were heated to 1680C and held at this temperature for approximately 30 minutes to complete the reaction, and then cooled to room WO 2004/053032 PCT/EP2003/050980 - 19 temperature and treated with a triple roll mill to obtain grease. In Comparative Examples 13-15 the additives shown in Table 7 were added after cooling to room temperature, 5 followed by treatment with the triple roll mill to give grease. In Table 1 and Tables 3-7, MDI is diphenylmethane-4,4'-diisocyanate; heating temperature approximately 50 0 C 10 TDI is 2,4/2,6 (80%/20%) trilene-4,4'-diisocyanate; heating temperature approximately 30*C TODI is 3,3'-bitrilene-4,4'-diisocyanate; heating temperature approximately 75'C. The viscosity at 100*C of the oils shown in the 15 examples and comparative examples was 10.12 mm 2 /s for mineral oil, 12.69 mm 2 /s for alkyl diphenyl ether oil and 12.70 mm 2 /s for poly(a-olefin) oil. In the thickener mol% column in Tables 1 and 2, (a) represents a compound RiNHCONHR 2 NHCONHRi; 20 (b) represents a compound R 3

NHCONHR

2

NHCONHR

3 ; and (c) represents a compound R 1

NHCONHR

2

NHCONHR

3 , wherein R 2 is a diphenylmethane group, RI is a C8 saturated alkyl group and R 3 is a C18 unsaturated alkyl group; 25 (1) indicates the diurea compound in Example 1, (2) indicates the diurea compound in Example 2, (3) indicates the diurea compound in Example 3, and (6) indicates the diurea compound in Example 6. The additives in Table 3, Table 4 and Table 7: 30 Additive A is a primary Zn-DTP (primary zinc dithio phosphate) with C4 and C5 alkyl groups, Additive B is secondary Zn-DTP (secondary zinc dithio phosphate) with C3 and C6 alkyl groups, WO 2004/053032 PCT/EP2003/050980 - 20 Additive C is Zn-DTC (zinc dithiocarbamate) with C5 alkyl groups, Additive D is Mo-DTC (molybdenum dithiocarbamate) with mainly C8 alkyl groups, 5 Additive E is a molybdenum complex compound as described in JP 5-66435 B1, Additive F is Mo-DTP (molybdenum dithiophosphate) with predominantly C8 alkyl groups, and Additive G is a slurry formed by compounding 2,4-bis(n 10 octylthio)-6-(4-hydroxy-3,5-di-t-butylamine)-1,3,5 triazine and octyldiphenylamine in a ratio 1:2 at a concentration of 50% with mineral oil.

WO 2004/053032 PCT/EP2003/050980 21 C) CD H 0) C to m- to -o N- tO N N '34 M I H - I N A cD N CD C:) CD Hi m CD r- CIA u C14 N'. (M m -4 H 1 H04' A (D N 00 C) C'q C) co H C C) LO to t CD to O W, 00' 1 H- I H- 11 C\I A C) OD Lto OD to H CD <D H ) D Lo N .) t v C) r- N C"] (O f() N' C) H d v H 11 H (N" A C) H1 Lto O~C) 0)" ~ C * CDj - N HI to N (n 14 H 1 H I H C"] A C] Hi XC. 00 C) C"] j- 0 00 H C) CD - C) H tO H m' C3 o mD C H I I H 11 C"] A H HI Lto CD Hn C)'- qC 00 1-4 CDt to tD H HH I H II C' A C) cAO 4-1 0 0) tD- S:4 0 4 H ) H>1 0 41-) I) 0) r. r.2 0)14Q 4-J *dI --- 4 H 0- (3) LO U (D) >1 >1 0w >1 >1 U u CI) 4 Cl) H) 4U H- -H Hl 0 .(2 r20 1 C 00 'iE~E' C WO 2004/053032 PCT/EP2003/050980 22 CD 0)- (D CN w~ 4- 0 (DC) N -4~ C,4 CH I -O LO HH m CD c p ) C to-~ CO U') 4W. . o (( N CO (NCD ClC H H N A C) C LO 10 H O LO rCO C) M) CD CD CD H m N .10 010 010 10) C) H FO 4-)N N CO N *N ) 0 C ) OP a) a) A1) 1-H H -H -,Ha aH ) 0) wD tyD d C) H a) v U2 -10) +0 H ) 0 i O 0 4 0 1 H .0 E-C N- 1 0 10 0I WO 2004/053032 PCT/EP2003/050980 23 10 (N () -1O *~C CDi CD0 (N .- c iiCD CO Lo CO CDD w0 0 i- (N O *** ~' ( (N (N (NN r- in ni -'- CD * ' 1 N 0-,0.0 C C) OCD C M T rH H ~ L (C 10 ( H r- 10L10O I1 1 1I CI I'. I (N I - A ( J A 2 ( N (Nj -o 0 ) n0 I- C, HC: T) C) 0- (N M~ Lo M ( CD C> 0 00 ul1 C' l *5: I 0( . c i 411 ( C) O (N C) a ) 0- - *1D( -P I- -0 r, 4 I ( N >, r 0. . . . . r HL r 0 Eim m C)M M r - ( (a 6 q) U W1 U) C) U4 (N r -P- o- N 00 4 ci) 0- : E- I-- p 3-0 ' WO 2004/053032 PCT/EP2003/050980 24 0 C C Lt) C C A C on CD ( U) C.) C) A C -W C3 4J - 0O aU Y) H M o 4~ WQI H u )4 -H 1-41V) -H 0) c-I r 4- 0 H a 0 4JI Co4 o a - 0 ) 0) Z 114 0 co~ b Q4 0. r)-0 a) OH WO 2004/053032 PCT/EP2003/050980 25 Table 4 Example 15 16 MDI (g) 9.00 9.43 Octylamine (g) 3.65 4.85 Tetradecylamine (g) 0.28 0.32 Hexadecylamine (g) 2.32 2.73 C16 amine (C16 amine with 1 double bond) (g) Stearylamine (g) 5.20 2.13 Oleylamine (g) 3.50 4.54 C20 amine (q) 0.05 Mineral oil (g) 176 -176 Poly (a-olef in) (g) _ _ _ Thickener content () 2 12 Thickener (mol%) (a)/(b) (c) =100 =30/70

R

3 unsaturated constituents (mol%) 30 45 Additive A (g) - 1.0 B(g) C (g) 2.0 1.0 D (g) - E (g) 4.0 3.0 F (g) - 1.0 G (g) 2.0 2.0 Consistency (dmm) 240 235 Dropping point (4C) >250 >250 Oil separation (mass%) 2.2 1.5 Noise test after 120 s 4 8 ASTMD2246 Shell 4 sphere impact 0.52 0.48 resistance test (120rpm, 40kg, 75 0 C, 1h) mm ASTMD3336 Bearing service life - >1000 test (150*C, No. 6204,deep groove ball bearings) h WO 2004/053032 PCT/EP2003/050980 26 - 26 Bowden friction test (room temp. 0.126 0.129 sliding speed l0mm/s, surface pressure 1000 Mpa) coeff. of friction p Table 5 Comparative Example 1 2 3 4 5 6 MDI (g) 11.80 7.95 12.93 11.88 - TODI (g) - - - - 12.13 12.27 TDI (g) - - Octylamine (g) 12.20 - - - 11.87 Oleylamine (g) - 16.05 - - - 11.73 p-Toluidine (g) - - 11.07 - p-Chloroaniline (g) - - - 12.12 - Mineral oil (g) 176 176 176 176 176 176 Thickener content (%) 12 12 12 12 12 12 Consistency (dmm) 279 258 326 400 325 372 Dropping point (*C) >250 185 >250 >250 >250 >250 oil separation (mass%) 1.2 3.9 2.2 7.6 6.6 3.1 Noise test after 120 s 52 56 2,229 >10,000 151 191 WO 2004/053032 PCT/EP2003/050980 27 H H i ;T N N LO A_ Q00 Q0 C O ;dl H- 0; (') r O N * co H I O A m 1 10 LO * O N O * I ~ ~ ' N - C) ON w co N n r- '0 CD N0 CD C 00 NO COo 0' 0) I i 0 I t I H H A w- 0 O w 0 H0) 40-P 4 N, 1- $ N H (- N O * H r0 -I 0 0 M No 0 H c 4J - 0 000 H o CO-r4 i - 0 4 -Y N O N 04 U) >1o\ >1 0 3 0 0 0 0 044 4)) 0)~ p l - l 0 rI o r)O O - 1 1t 0 4- 4 U~~~~ ~ ~ I EIPIp10- 0IQ XIPIUIr 01 Z WO 2004/053032 PCT/EP2003/050980 28 Table 7 Comparative Example 13 14 15 MDI (g) - - 11.88 TODI (g) 12.21 - TDI (g) - 9.74 p-Chloroaniline (g) 11.79 14.26 12.12 Mineral oil (g) 176 176 50 Poly(a-olefin) (g) - - 126 Thickener content (%) 12 12 12 Additive A (g) 1.0 1.0 B (g) - - 1.0 C (g) 1.0 1.0 1.0 D (g) - - 3.0 E (g) 3.,0 3.0 1.0 F (g) 1.0 1.0 G (g) 2.0 2.0 2.0 Consistency (dmm) 410 405 415 Dropping point (*C) >250 >250 >250 Oil separation (mass%) 3.6 5.8 10.1 Noise test after 120 s >10,000 >10,000 >10,000 ASTMD2246 Shell 4 sphere - - impact resistance test (120rpm, 40kg, 75'C, 1h) mm ASTMD3336 Bearing service 680 380 520 life test (150-C, No. 6204,deep groove ball bearings) h Bowden friction test (room Stick slip temp. sliding speed 10mm/s, (discontinuous oil film) surface pressure 1000 Mpa) coeff. of friction pt The properties of the examples and comparative examples in the tables were tested using the following 5 methods. Consistency JIS K2220 WO 2004/053032 PCT/EP2003/050980 29 Dropping point : JIS K2220 Oil separation : The JIS K2220 method was performed under -the conditions of 150"C temperature for 24 hours. 5 Noise test : Bearing noise was measured for each grease using an NSK Noise Tester (available from NSK Ltd) as described in JP 53 2357 B1. Bowden friction test: The coefficient of friction was 10 measured using a device with the specifications below, which evaluated friction in a frictional surface between a reciprocating bed and a pin receiving a load vertical to a plate 15 fitted to the bed, having a mechanism applying a load vertical to the bed. 1. Form: Reciprocal sliding friction tester 2. Test piece: Fixed side: steel sphere or rod Moving side: steel plate ca. 3 x 40 x 20 100 mm 3. Sliding speed: 0.05-20 mm/s 4. Sliding distance: 20-50 mm 5. Load: 0.1 kg to 10 kg 6. Temperature: Room temperature to 200*C 25 7. Drive method: Feed screw slide, lead 2 mm 8. Drive motor: AC servo motor 400 W The results of these experiments demonstrate the following. (1) It is possible to produce a urea grease composition 30 according to the present invention, which has outstanding noise and lubricating properties, by using conventional facilities for grease production without the need for special equipment such as a kneading machine or a high pressure kettle in order to bring about dispersion of the WO 2004/053032 PCT/EP2003/050980 30 thickening agent. (2) The urea grease composition of the present invention gives an outstanding consistency yield, with a small quantity of thickener giving stiff grease; and 5 (3) The urea grease of the present invention has a high dropping point and does not show oil separation at high temperatures.

Claims

1. A urea grease composition comprising a lubricating base oil and from 2 to 30 wt.% of a thickening agent, with respect to the total weight of the urea grease composition and wherein said thickening agent is selected 5 from: (1) a mixture of a compound (a) and a compound (b), containing compound (a) at 20 to 80 mol %, relative to the total amount of compound (a) and compound (b); 10 (2) a mixture formed by mixing with a compound (c) with a mixture (1) or (3) a compound (c) alone, wherein the compounds are represented by the general formulae 15 (a) RiNHCONHR 2 NHCONHRi; (b) R 3 NHCONHR 2 NHCONHR3; and (c) RlNHCONHR 2 NHCONHR 3 , and wherein R 2 is a diphenylmethane group, RI is a CG-10 saturated alkyl group and R 3 is a C14-40 saturated and/or 20 unsaturated alkyl group wherein unsaturated alkyl groups constitute at least 20 mol % of the R 3 alkyl group.

2. Urea grease composition according to Claim 1, wherein unsaturated alkyl groups constitute at least 30 mol% of the R 3 alkyl group 25

3. Urea grease composition according to Claim 1 or 2, wherein an oleyl component constitutes at least 20 mol % of the R 3 alkyl group.

4. Urea grease composition according to any one of Claims 1 to 3, wherein said composition further comprises WO 2004/053032 PCT/EP2003/050980 32 a zinc compound as an additive.

5. Urea grease composition according to Claim 4, wherein said zinc compound is selected from zinc dithiocarbamates and zinc dithiophosphates. 5

6. Urea grease composition according to any one of claims 1 to 5, wherein said composition further comprises a molybdenum compound as an additive.

7. Urea grease composition according to Claim 6, wherein said molybdenum compound is selected from 10 molybdenum dithiocarbamates, molybdenum dithiophosphates and molybdenum complexes that are reaction products of a fatty oil, diethanolamine and a molybdenum source.

8. Urea grease composition according to any one of Claims 1 to 7, wherein the thickening agent is present in 15 an amount of from 5 to 20 wt.%, with respect to the total weight of the urea grease composition.

9. A method of lubricating a bearing, comprising packing the bearing with the urea grease composition as described in any one of Claims 1 to 8. 20

10. A method of lubricating a sliding surface of a machine in a relative motion, comprising lubricating said sliding surface with the urea grease composition as described in any one of Claims 1 to 8