JP2000512668A - Lubricants for diesel engines - Google Patents

Abstract

  (57) [Summary] The present invention relates to the use of a lubricant in a diesel engine to disperse soot generated from a diesel engine, which can disperse soot without adversely affecting the viscosity of the lubricant. Wherein the functionalized viscosity index improver has from 2 to about 50 carbon atoms and contains oxygen, nitrogen or an ethylene-based unsaturated It contains a high-functional graft copolymer reaction product obtained by grafting an aliphatic or aromatic monomer to a polyolefin copolymer.

Description

Description: The present invention relates to a lubricant for diesel engines, and in particular to a lubricant for passenger cars and for commercial diesel engines with strict obligations. Diesel engines produce soot as a by-product of the combustion process. Since soot increases the viscosity of the lubricant used in diesel engines, the lubricant eventually becomes too viscous to operate. Thus, soot reduces the useful life of the lubricant, so that money and time are wasted to replace the inoperable lubricant early. Smoke also causes the wear of the diesel engine, which reduces the useful life of the diesel engine. Currently available lubricants for diesel engines are typically 65-80% by weight base oil, 5-15% by weight viscosity index improver (VII), and 10-22% by weight detergent inhibitor (Detergent). Inhibitor (DI) package. The viscosity index improver (VII) may be a non-dispersible viscosity index improver (NDVII) and / or a dispersible viscosity index improver (DVII). One role of the Detergent Inhibitor (DI) package is to provide a dispersant to disperse soot and thereby prevent the viscosity increase associated with lubricant soot and engine wear. The choice and amount of viscosity index improver (VII) used in the lubricant depends on, for example, whether it is NDVII or DVII, the dispersant provided by the cleaning inhibitor package present in the lubricant. Affects the choice and quantity. In conventional formulations, the choice and amount of DI package is at least at least: a) 6% dispersant in the finished lubricant, if non-dispersible viscosity index improver (NDVII) is used, b) traditional When using a dispersant viscosity index improver, such as a lubricant used prior to about 1994, it is common practice to select such that 4% of the dispersant is present in the finished lubricant. is there. By increasing the amount of dispersant provided by the cleaning inhibitor (DI) package present in the lubricant, it is possible to increase the amount of soot that the lubricant can disperse, but the amount of dispersant Increasing has the following negative effects: That is, it increases the wear of the engine by interfering with the antiwear additives contained in the formulation, causes damage to the seals in contact with the lubricant, and has a negative effect on the low temperature viscometer. Impact and increase the price of lubricants. Accordingly, the inventor has increased the amount of soot that is dispersed by a lubricant without increasing the amount of dispersant normally provided by a detergent inhibitor (DI) package contained in the finished lubricant. It will be related to the problem. The inventor has also been concerned with the problem of controlling the viscosity increase associated with soot with a smaller amount of dispersant than is conventionally used by those skilled in the art, at the amount of dispersant normally provided by the DI package. Become. According to the present invention, there is provided a lubricant comprising a dispersant and a functionalized viscosity index improver, wherein the functionalized viscosity index improver has from 2 to about 50 carbon atoms, and comprises oxygen, A diesel engine containing a highly functional graft copolymer reaction product obtained by grafting an ethylenically unsaturated aliphatic or aromatic monomer containing nitrogen or oxygen and nitrogen onto a polyolefin copolymer The use of lubricants in diesel engines, characterized in that the soot generated from the oil is dispersed in the lubricant without adversely affecting the viscosity of the lubricant. According to the present invention, there is also provided a method for controlling a viscosity change of a lubricant in a diesel engine caused by the generation of soot, the method comprising using the above-described lubricant in a diesel engine. It is. The inventor has discovered a lubricant capable of dispersing an increased amount of soot without increasing the amount of dispersant normally provided by the detergent inhibitor (DI) present in the lubricant. Further, the present inventors have developed a high-performance graft copolymer which can disperse soot generated as a by-product of a diesel engine without adversely affecting the viscosity of the lubricant when added to the lubricant. Was found. The inventor has also disclosed that a lesser amount (eg, 4% or less) of the dispersant conventionally provided by the DI package can be combined with the above-described high performance graft copolymer. It has been found that, when used, the viscosity increase associated with soot can be controlled. Also, the inventor has noted that the lubricants of the present invention include a lesser amount (e.g., 4% or less) of the dispersant than conventional amounts of dispersant commonly provided by a detergent inhibitor (DI). And still pass recent industrial soot handling tests for passenger car diesel engines and strictly duty commercial diesel engines. A detrimental effect on the viscosity of a lubricant means that the viscosity of the lubricant is increased to an unacceptable degree, as specified in standard industry tests, such as the Mack T8 test. Highly functional graft copolymers suitable for use in the present invention can be made using solution or melt grafting methods. Preferred solution graft copolymers suitable for use in the present invention are disclosed in WO 96/12746, issued May 2, 1996. The entire content of WO 96/12746 is expressly incorporated into this patent application by reference. Other suitable graft copolymers can be made by grafting maleic anhydride onto a polyolefin copolymer and reacting the resulting succinic anhydride with a suitable nitrogen-containing component such as a polyamine. Polyolefins grafted to an appropriate degree are, for example, US-A-4,144,181, US-A-4,507,515, US-A-4,557,847, US-A-4,632, 769, U.S. Pat. No. 4,693,838, U.S. Pat. No. 4,707,285 and U.S. Pat. No. 5,350,532. A suitable solution graft copolymer is a Mannich base condensate. WO 96/12746 is hereby incorporated by reference in its entirety, which discloses the reactants and reaction conditions necessary to produce a preferred graft copolymer for use in the present invention. I have. In particular, this document discloses the graft copolymer reaction products that can be used in the preferred lubricants according to the present invention, and the reaction materials and reaction conditions required to make the viscosity index improver. . WO 96/12746 is hereby incorporated by reference in its entirety, which is an example of a preferred polyolefin suitable for use as the spine of a graft, and a preferred graftable suitable for grafting the polyolefin to the spine. Nos. 4,087,058, 4,078,086, 4,098,086, 4,078,086, 4,086,098, 4,098,098, 4,098,019, 3,067,098, 3,067,019, 3,984, and 3,984,098, and 5,953,088, and their preferred initiators, solvents, and inhibitors, respectively. WO 96/12746, the entire contents of which are incorporated herein by reference, also discloses suitable melt reaction conditions for producing the preferred grafted polyolefin in a melt reaction process. WO 96/12746, the entire contents of which are incorporated herein by reference, also discloses that nitrogen and solvent in the grafted copolymer (assuming that the reaction is performed in a solvent in some process). , The amount of unreacted graftable monomer remaining in the graft copolymer, the dispersibility of the graft copolymer, the UV / RI ratio, and the aroma of the solvent or process fluid used in the solution grafting reaction. A test method for determining group content is disclosed. WO 96/12746, the entire contents of which are incorporated herein by reference, also includes preferred base oils, graft copolymers, ungrafted polyolefins, other dispersants, detergents, antiwear agents. , Antioxidants, pour point depressants and minor components are disclosed in detail. A preferred melt-grafted copolymer for use in the present invention is Paratone 8500, commercially available from Exxon, Chemical, Company. US-A-5,427,702 also discloses melt-grafted copolymers suitable for use in the present invention. WO 96/12746 also discloses details of melt-grafted copolymers that can be used in the present invention. The high-functional graft copolymer reaction product is preferably a graft copolymer reaction product obtained by grafting at least 13 mol% (based on a polymer having a molecular weight of 100,000) of a monomer to a polyolefin copolymer. Means things. More preferably, about 20 to 30 mol% or more of the monomers are grafted to the polyolefin copolymer. The high-performance graft copolymer reaction product comprises: a) an ADT value of at least 8, more preferably at least 16, when it is prepared using a solution grafting process; When manufactured using the above, the ADT value is preferably at least 1. The ADT test is a method developed by Rohm and Haas to determine the dispersibility of the grafted dispersant polyolefin. Details of the test method can be found in WO 96/12746 published May 2, 1996. The high-performance graft copolymer preferably has the property of increasing the viscosity index of the lubricating base oil feedstock by at least 20 points when about 1% by weight of solids is present in the base oil feedstock. The high-performance graft copolymer preferably contains at least one of the following monomers in the spine of the polymer. N-vinylimidazole, 1-vinyl-2-pyrrolidinone, N-vinylimidazole, N-allylimidazole, 1-vinylpyrrolidone, 2-vinylpyridine, 4-vinylpyridine, N-methyl-N-vinylacetamide, diallylformamide, N-methyl-N-allylformamide, N-ethyl-N-allylformamide, N-cyclohexyl-N-allylformamide, 4-methyl-5-vinylthiazole, N-allyldiisooctylphenothiazine, 2-methyl-1- Vinylimidazole, 3-methyl-1-vinylpyrazole, N-vinylpurine, N-vinylpiperazine, N-vinylsuccinimide, vinylpiperidine, vinylmorpholine, and combinations of these materials. Preferably, the high-performance graft copolymer comprises at least 1.2% by weight of N-vinylimidazole grafted to the polymer spine. The high-performance graft copolymer preferably contains at least 1.2% by weight of a suitable grafted monomer, for example an acid function such as succinic anhydride or fumaric acid, wherein the acid function is After functionalization of the spine, it is derivatized with morpholine, tetrapentamine, triethyltetramine or other suitable amine or nitrogen containing compound. The highly functional graft copolymer reaction product preferably comprises a graft copolymer spine having a weight average molecular weight of 20,000 to 500,000 and a polydispersity of 10 or less. The lubricating oil preferably comprises a lubricating base oil (mineral oil, synthetic oil and mixtures thereof), a detergent inhibitor (DI) package and the above-described high-performance graft copolymer. The lubricant may also include some standard commercial viscosity index improvers (VII). This lubricating oil comprises: 75% by weight or more of a lubricating base oil; B. 0.1 to 2.5% by weight of the above-mentioned solid, high-performance graft copolymer; D. from 0 to 2.5% by weight of a solid, commercially available viscosity index improver; Preferably, it contains from 1 to 20% by weight of a detergent inhibitor (DI) package. The lubricant may comprise from 0.1% to 10% by weight, preferably from 0.2% to 7% by weight, more preferably from 0.2% to 4% by weight, more preferably from 0.1% to 4% by weight. It preferably contains from 2% to no more than 2% by weight of the dispersant, provided by the DI package. The lubricant includes optional conventional additives such as detergents, extreme pressure antiwear agents, antioxidants, rust inhibitors, friction modifiers, antifoams, and other minor additives. be able to. Suitable additives can be found in WO 96/12746. WO 96/12746, the entire contents of which are incorporated herein by reference, discloses in detail a high-performance graft copolymer suitable for use in the present invention to disperse soot in diesel engines. It is clear to a person skilled in the art. Therefore, those skilled in the art should read this application in connection with WO 96/12746, the entire contents of this document being incorporated into this patent application. The applicant hereby incorporates by reference the entire contents of WO 96/12746, so that any one feature described in WO 96/12746 may be incorporated into any claims pending during the examination of this application. It will be apparent to those skilled in the art that the claims can be explicitly inserted into any claims granted within the correction period after the patent is granted for this patent application. The invention will be further described with reference to the following examples. Example WO 96/12746, the entire contents of which are incorporated herein by reference, is a laboratory specific example of a preferred grafted polyolefin, a pilot plant specific preparation of a preferred graft copolymer. Examples, a special production example of a comparative graft copolymer by a pilot plant, a special production example of a preferred graft copolymer and a comparative graft copolymer, and a special production example of extrusion of a preferred graft copolymer. Has been disclosed. U.S. Pat. No. 5,427,702 also details extrusion-preferred production of preferred graft copolymers. Accordingly, those skilled in the art are taught in WO 96/12746 and US-A-5,427,702. The following tests were conducted to show that lubricants within the scope of this invention can disperse soot from diesel engines without adversely affecting the viscosity of the lubricant. All treat rates are stated as weight percent. Example of Passenger Diesel Engine Smoke Handling-BMW TDS Test Method-BMW TDS 80 Hour Test The BMW TDS test was performed for each series of tests using a new type of M51 engine. The engine was a 2.5 liter, 6 cylinder, turbocharged, indirect-injection diesel engine that was supercharged and cooled with an intercooler. This engine was suitable for engine testbed operation. Modifications have been made to the fuel, oil and engine cooling systems. After the engine was installed and ready for testing, a 7-hour test run was performed. After the commissioning operation, a reference test was performed for 80 hours using high quality commercially available fully synthetic engine oil. The BMW TDS test included 15 hours of increasing engine speed and load, after which the 15 hours were repeated twice, for a total of 45 hours of operating time. This was followed by a 5 hour low / medium speed operation with maximum load followed by a 5 hour medium speed operation with maximum load. This test was completed by 25 hours at maximum engine speed and load. The test conditions are as follows. After a reference test on the new engine, four candidate drivers drove. Before each candidate, a full engine flush was performed to remove all traces of old oil. Since the engine used in the test was not built for laboratory standards, the candidate was compared to a reference run. Each test was evaluated by sludge measurement, oil consumption, and analysis of the oil used. In the examples below, the Detergent (DI) package was constant except for the type and amount of dispersant present. Example A1 15W50 oil was mixed with NDVII (Unfunctionalized Olefin Copolymer, Paratone 8002 sold by Exxon, Chemical, Company) in an Exxon base stock. The amount of dispersant (Lubrizol, LZ6420 sold by Corporation) present in the lubricant preparation table was 6.5%. Example A2 Referring to Example A1, the amount of dispersant was reduced to 1.5% in the finished lubricant and more than half of the NDVII was replaced with a high performance graft copolymer (0.88% solids). Was. The high-performance graft copolymer was the graft copolymer made in Example 10 of WO 96/12746. Results These results are summarized in the table below. Results obtained from Examples A1 and A2, although the amount of dispersant in the finished lubricant is 6.5% in Example A1 but only 1.5% in Example A2. Are very similar. Conclusion These results indicate that the use of the high-performance graft copolymer as defined in this invention at 0.88% solids by weight, and the 5% dispersant It gives the same dispersibility as use. Thus, using a high-performance graft copolymer, it is possible to use a DI package containing much lower amounts of dispersant to control soot-related viscosity rise in lubricants in diesel engines. BMW TDS test BMW 2.5 TDS test BMW test conditions Speed and load position The test ends with 80 hours + power curve time (about 25 minutes) + oil leveling time. Oil samples to be taken at 50, 60, 70, 80 while the engine is running. Operating conditions The accompanying table shows the operating conditions for the last 25 hours of the BMW TDS oil concentration test. Another example of a soot processing passenger car diesel - "XUD11ATE" engine test XUD11ATE engine test (CEC L-56-T- 95) is a recent change in viscosity soot caused to occur as a by-product in the combustion process of the passenger car diesel engine A recently established European test to determine the ability of a lubricant to control. The XUD11ATE engine test is an integral part of Europe, oil and sequencing for light-effect diesel engines from Association, Des, Constorque Wool, Europuan, Dotmobile and European. This test also assesses the cleanliness of the sludge and piston. An important parameter is the viscosity increase in the lubricant at a soot concentration of 3.0%. Smoke requirements must be reached before the end of the test. Example B1 A formulation similar to formulation A2 was evaluated in the XUD11 ATE test as 15W50 of the BP raw material. The high-performance graft copolymer consists of 5% NDVII (Paratone 8002, unfunctionalized olefin copolymer) on Paratone 8500 (commercially available from Exxon, Chemical, Company) with a solids content of 0.88%. (Polymer) was added to adjust the viscosity. The DI package treat rate was 7.07%, which gave a dispersant loading of 1.75% in the finished lubricant. The dispersant used in this example was TLA1605X, which was commercially available from Texaco, Additive, and Company. The test results meet the requirements of European ACEA B2-96 in this engine test. At 3% soot, the viscosity increase was 182.8%, the piston merit was 43.2, and the sludge rating was 9.50. Example B2 The above test was repeated replacing TLA1605X with an alternative dispersant, 7.07% of OLOA 375C (commercially available from Chevron, Chemical, Company). Further, the amount of the dispersant in the lubricant was 1.75%. The test results meet the requirements of the European ACEA B2-96 for this engine test. The viscosity increase at 3% soot was 195.1%, the piston merit was 51.8, and the sludge rating was 9.57. Conclusion The use of high-performance graft copolymers can control smoke-related viscosity increases and meet industrial specifications with unexpectedly low dispersant treatment rates (1.75%). . Strictly Duty Commercial Diesel Smoke Handling Example-Mac T8 Test The Mac T8 engine test lubricates the viscosity changes caused by soot and by-products generated during the combustion of diesel engines in recently stern duty trucks. An established test to determine the ability of an agent to control. The Mac T8 engine test is an important part of truck CG4 lubricants on the American, Petroleum and Institute highways. This test also evaluates sludge and oil consumption. A key parameter is the viscosity increase at 3.8% soot in oil as measured by thermogravimetric analysis (TGA). The soot requirement is reached before the end of the test (250 hours). This measurement is used as a measure of oil performance. Mac T8 Test Details (ASTM 4485) Equipment: Mac E7-350, 6 cylinder, turbocharged, intercooled diesel engine, 12.0 liter, 350 BHP Purpose: Engine in turbocharged, intercooled diesel engine. Evaluation of oil viscosity behavior and smoke load Test conditions: Duration, time 250 hours at full load Speed, rpm 1800 torque, lb / ft 1010-1031 Oil sump temperature ℃ 102-107 Coolant outlet temperature 85 Fuel 0.03- 0.05% sulfur rating Method: The viscosity increase from the oil used was determined by analysis. The test method also specifies a maximum oil consumption of 0.0005 lbs / BHP / hr. In the following examples, the Mack T8 test (excluding the 3.8% requirement) was retested and the relative performance of Examples C1 and C2 was compared. In the examples below, the cleaning inhibitor package was constant and the amount of dispersant obtained from the cleaning inhibitor was varied. Example C1 In a Sun HPO Group 2 base stock, 15W40 was mixed with NDVII (Unfunctionalized Olefin Copolymer, Paratone 8011 available from Exxon, Chemical, Company). The amount of dispersant used in this lubricant formulation was 4%. Example C2 15W40 was mixed with a high-performance graft copolymer obtained by the additional test of Example 10 of WO 96/12746 in a Sun HPO Group 2 base stock. The amount of dispersant obtained from the DI package present in the lubricant formulation was 1%. The results are summarized in the table below. The results from Examples C1 and C2 are very different. With equal amounts of soot, there is a significant difference in viscosity increase and soot particle size. Example C2, which uses a high-performance graft copolymer within the scope of this invention (Example 10 of WO 96/12746), shows good control of the viscosity throughout the test. The average particle size of the soot is at a relatively low value, which can explain the relatively low increase in viscosity. Example C2 also shows good sludge suppression. Conclusion The use of a lubricant containing a high-performance graft copolymer as defined in this application results in a lubricant finished product recipe that shows a 3% more dispersant coming from the DI package compared to the conventional formulation. Excellent performance is obtained. Mac T8 results

────────────────────────────────────────────────── ─── Continuation of front page    (81) Designated countries EP (AT, BE, CH, DE, DK, ES, FI, FR, GB, GR, IE, IT, L U, MC, NL, PT, SE), OA (BF, BJ, CF) , CG, CI, CM, GA, GN, ML, MR, NE, SN, TD, TG), AP (GH, KE, LS, MW, S D, SZ, UG), EA (AM, AZ, BY, KG, KZ , MD, RU, TJ, TM), AL, AM, AT, AU , AZ, BA, BB, BG, BR, BY, CA, CH, CN, CU, CZ, DE, DK, EE, ES, FI, G B, GE, HU, IL, IS, JP, KE, KG, KP , KR, KZ, LC, LK, LR, LS, LT, LU, LV, MD, MG, MK, MN, MW, MX, NO, N Z, PL, PT, RO, RU, SD, SE, SG, SI , SK, TJ, TM, TR, TT, UA, UG, US, UZ, VN (72) Inventor Henderson, Kennes             United States, New Jersey             08876, Somerville, Baker Circle               41 (72) Inventors Carlyle, Danni             Berkshire Earlsey, United Kingdom             110 JR, Hungerford,             Chilton Way, Millstones             Ground) (72) Einskoff, Nyall             Nya Reading Earl, United Kingdom             G 80 Jetty, South Storm             C, Cross Keys Road Lyndon             Tory Cottage (unnumbered) (72) Inventor Brown, Mylon             United States, New Jersey             07090, Westfield, Tudor               Oval 136 (72) Inventor Tittel, Richard             United States, New Jersey             08831, Jamesburg, Earl Dee             Number 2 Box 300 Sea (No number)             Ground)

Claims (1)

[Claims] 1. A lubricant comprising a dispersant and a functionalized viscosity index improver, the lubricant having the above function   The modified viscosity index improver has from 2 to about 50 carbon atoms, and   , Nitrogen or ethylenically unsaturated aliphatic or aromatic monomers containing oxygen and nitrogen   Functional graft copolymer obtained by grafting polymer to polyolefin copolymer   Body reaction products, soot from diesel engines   Characterized by being dispersed in a lubricant without adversely affecting the viscosity of the   Use of lubricants in diesel engines. 2. The graft copolymer is based on a polymer having a molecular weight of 100,000.   At least 13 mol% of grafted polyolefin copolymer   Use according to claim 1, characterized in that it comprises a monomer. 3. The monomer according to claim 1, wherein the monomer is selected from the following table.   Use as described in.               N-vinylimidazole,               1-vinyl-2-pyrrolidinone,               N-vinylimidazole,               N-allylimidazole,               1-vinylpyrrolidone,               2-vinylpyridine,               4-vinylpyridine,               N-methyl-N-vinylacetamide,               Diallylformamide,               N-methyl-N-allylformamide,               N-ethyl-N-allylformamide,               N-cyclohexyl-N-allylformamide,               4-methyl-5-vinylthiazole,               N-allyldiisooctylphenothiazine,               2-methyl-1-vinylimidazole,               3-methyl-1-vinylpyrazole,               N-vinyl purine,               N-vinyl piperazine,               N-vinyl succinimide,               Vinylpiperidine,               Vinyl morpholine,               And combinations thereof. 4. The graft copolymer has at least 1.2% by weight of graft on the backbone of the polymer   4. The composition according to claim 3, wherein said N-vinylimidazole is used.   Use. 5. If the graft copolymer is a suitable monomer such as succinic anhydride or fumaric acid   At least 1.2% by weight of the acid function, the acid function comprising a polymer spine.   After functionalization, morpholine, tetrapentaamine, triethyltetramine   Or other suitable amine or nitrogen-containing component.   3. Use according to claim 1 or claim 2. 6. The reaction product of the graft copolymer is             a) When it is made using the solution grafting method,                 Have an ADT value of at least 8, preferably 16, or             b) when it is made using the melt grafting method,                 Has at least one ADT value   Use according to any one of the preceding clauses, characterized in that: 7. The graft copolymer spine has a weight average weight of 20,000 to 500,000.   Characterized in that it has a molecular weight and a polydispersity of 10 or less.   Use according to any one of the above. 8. Lubricant is normally provided by a detergent inhibitor (DI) package.   More preferred is 1 to 10% by weight, preferably 0.2 to 7% by weight.   Or from 0.2 to 4% by weight, more preferably from 0.2 to 2% by weight.   Use according to any one of the preceding clauses, characterized in that it comprises a dispersant.   . 9. The lubricant according to any one of claims 1 to 8, as a lubricant for a diesel engine.   It is characterized by the use of lubricants.   To control the change in viscosity of the lubricant caused by