HUNGARIAN JOURNAL OF INDUSTRIAL CHEMISTRY VESZPREM Vol. 29. pp. 139- 141 (2001) POSSIBILITIES OF THE APPLICATION OF POLYISOBUTENYL SUCCINIC ANHYDRIDE DERIVATIVES OF V ARlO US MOLECULAR STRUCTURES Z. KOCSIS, J. BALADINCZ, L. BARTHA1 and J. HANCS6K1 (MOL Co.Ltd., Lubricants Business Unit, Komarom Refinery, Komarom, HUNGARY 1 University ofVeszprem, Veszprem, P. 0. Box 158, H-8201, HUNGARY) Received: October 10, 2001 Detergent-dispersant (DD) effect is one of the most important properties of lubricants and fuels. To ensure these properties various types of additives are used in increasing amount in the performance additive packages. Among them ashless types and mostly polyalkenyl succinic anhydride derivatives are applied in high volumes. In this paper the main advantages of the ashless additives are presented showing the dependence of their properties on the molecule structure (monosuccinimides, bissuccinimides, mixtures thereof and polysuccinimide). Additionally, the interactions with other additives are shown which can determine the main tribological properties of the lubricants. Keywords: ashless dispersants, detergents, polyisobutenyl succinic anhydride derivatives, interactions of additives Introduction The first innovations about polyalkenyl succtmc anhydride derivatives, used as ashless DD additives in engine oils, were published in the 60's. Since, more than thousand patents have dealt with the alternatives of these additives and their syntheses. A wide group of them: the polyalkenyl succinimides and their derivatives are mainly used in engine oils and in fuels as detergent- dispersant additives. A classification of polyalkenyl succinimides of various molecular structures, based on their polyalkenyl chain, is the following: Polyisobutylene (PIB) based • monosuccinimides, • bissuccinimides, • high molecular weight succinimides (Mnpm>IOOO), • modified versions of the aboves, • ester, amide and imide derivatives of succinic acid, • polysuccinimides based on - maleic anhydride (MA) - polyisobutylene copolymer (1] - MA- PIB - a-olefin terpolymer [2] - MA- comonomer copolymer grafted on PIB [3]. a-olefin copolymer based • Ethylene - propylene copolymer based succinimides [4] and other succinic anhydride derivatives • ethylene - MA - a-olefin terpolymer I·"' j based succinimides • MA - methyl methacrylate copolymer grafted on ethylene- propylene copolymer (6]. In this paper the PIB based succinic anhydride derivatives are presented. The first step of the synthesis of polyisobutenyl succinimides is usually the production of polyisobutenyl succinic anhydride (PIBSA or PIBBSA depending on the number of succinic anhydride groups in one PIB chain). The synthesis can be carried out in different ways. initiating the process thermally, catalytically or radically. The quality of the PIB used for the synthesis (the percentage of terminal double bonds, average molecular weights etc.), the technological parameters, the active material content and the molecular structure of intermediate product can be different. These factors basically determine the molecular structure and performance of the end products in engine oils and fuels. The main types of the developed and studied polyisobutenyl succinimides are shown in Fig.J. New engine designs require high quality lubricating oils in order to maximally utilise their economical benefits in fuel efficiency (reduced consumption). in longer drain intervals and in lower emissiom.. Therefore the understanding of the properties and interactions of the additives working together in lubricating oils is of increasing importance. 140 0 R-CH-C.r 1 ~N-(C~-c~-NH)n-H CHz-C ~0 Polyisobutenyl monosuccinimide (MSI) lp 0~ R-CH-C, 1C-CHa /N-(CHz- CHz-NH)mCHz- CHz-N, I CHa-C C-CH-R ~0 ~ 0 Polyisobutenyl bisuccinimide (BSI) (CH- CH)n -(Y) I I c c -1' ..... / -::::- 0 N 0 I (U)tt I p General molecule structure of the polysuccinimide (PSI) Where: MSit BSI: R=polyisobutenyl group ( Nln = 300-30000)· n, m 2:: 1 (integer); ' PSI: R= polyolefin chain; U= -CH2-CHz-(NH-CH2-CH2- )"; n,p,g,r 2:: 1: Y= bifunctional hydrocarbon chain; x, m ~ 0. Fig.] Polyisobutenyl succinimides Experimental The interactions between performance additives were studied extensively [7]. The studies showed that the interactions are able to modify DD, extreme pressure and anti wear (EP/ A W) properties of individual additives. In order to examine the ability of interaction of the developed additives'. polyisobutenyl succinimides were synthesised having the main properties listed in Table 1. To investigate the properties of these succinimides in various mixtures containina performance additive, the blends represented in Table 2 were prepared (dispersant content 3.5.calcium pht!nate > calcium sulphonate. The polysucctmmtde sh:o\\"S the most significant VI Table 1 The properties of the synthesised polyisobutenyl succinimides T_xEe of additive MSI MBSI* BSI PSI PIB molecular weight 1000 1000 1000 2300 Kinematic viscosity at 230 70 50 510 100 oc, mm2 /s TBN, mgKOH/g 82 44 26 19 Nitrogen content, %rnlm 3.2 1.7 1.3 1.0 Base oil content, %rnlm 45 45 45 45 * Blend of mono-and bissucinimide Table 2 DD effects of performance additive blends Washing efficiency (WE) MSI+ZnDDP 0 + Ca-salycilate 0 +Ca-phenate 0 +Ca-sulphonate ++ MBSI+ZnDDP 0 + Ca-salycilate 0 +Ca-phenate 0 +Ca-sulphonate ++ BSl+ZnDDP 0 + Ca-salycilate + +Ca-phenate 0 +Ca-sulphonate +++ PSI+ZnDDP ++ + Ca-salycilate +++ +Ca-phenate +++ +Ca-sulphonate +++ ---... 0 ... +++: Strength of significance Detergent Index (DI) 0 0 0 0 0 PDDE 0 0 0 + 0 0 0 + 0 + 0 +++ 0 ++ ++ ++ increasing effect with calcium salicylate. In order to examine another very important effect of the interactions of these additives, polysuccinimide was used for me~s~ring the changes of EP/ A W property of the addtttve blends. Table 3 contains the main results of the standardised four ball tests (ASTM D 2783). As it can be seen in Table 3, polysuccinimide itself has EP/ A W effect and the best result was obtained when c~Icium salicylate or calcium phenate was used together With polysuccinimide and ZnDDP additive. Taking into consideration the presented results~ the synergy of the additives can be utilised in the formulation of engine oil compositions of high perform?nce leve~ with polysuccinimide, utilising its outstandmg DD, viscosity and viscosity index improving and EP/ A W effect whilst reducing the cost of formulation by reducing the conventionally required amount of rheological and EP/ A W additives. The formulation [9] meets the requirements of API SJ/CF, ACEA A-3/98, CCMC G5/CD2 and other OEM's (Ford, GM. Rover) specifications. Summary Various types of polyisobutenyl succinimides were examined regarding their properties and the effects of 141 Table 3 Data of four ball tests of different additive blends Scar diameter, mm Load,N Base oil SN-150 +PSI +PSI+ +PSI+ZnDD +PSI+ZnDDP+ +PSI+ZnDDP+ P+Ca- ZnDDP salicilate Ca-phenate Ca-sulphonate 1.965 2.637 2.800 Welding 1.941 2.398 2.564 3.186 Welding 0.341 0.735 2.278 2.413 0.312 0.311 0.312 0.728 0.394 0.379 2.106 2.047 2.226 2.294 2.275 2.240 600 800 1000 1260 1400 2000 2400 2.611 2.605 2.630 Welding Welding Welding Welding 18~·-··-··------... ---···--·-·-·~--···~-·--------·----·-------~ 016+-------------~------------~ ~14+-------------~~~----------i_ ~12+--------=~--~~~~r-------il ~10+-------1-r-~r-r ·~ 8 +---------l-\;;;;;:;---1-t--- c 6 +----------+- ~ : ++--IHEJ...d----t- 0 -1-l---'"'"~~_J...._ Ca-sulphonate Ca-salicilate Ca-phenate ZrtDDP Fig.2 Relative changes of kinematic viscosity at 40 oc by the interactions of the additives interactions, blended with performance additives of lubricating oils. Detergent-dispersant, extreme pressure/antiwear and rheological properties were shown which demonstrate that utilising the synergy among the additives, lubricants of the highest performance level can be formulated and the costs of formulation can be reduced. REFERENCES 1. PCT WO Pat. 90/03359 2. MACH H. and RATH P.: Highly reactive polyisobutene as a composition element for a new 130 +-----------------tl=!l---!l'oca-sulphonate ~ 120 tm Ca-salicilate > l!l1l Ca-phenate l•znDDP 100 MSI MBSI BSI PSI· Fig.3 Changes ofviscosityindexes (Vlex) of the additive blends generation of lubricant and fuel additives. Additives '97 Conference, Sopron, 52-66, 1997 3. HU Pat. 206,390, HU 214,439, EP 658,572, FP 677,572 and PCT WO 95/28460 4. US Pat. 4,089,794 and EP 0400866 5. US Pat. 5,205,949 6. US Pat. 4,161,452 7. RAMAKUMAR S. S. V., AGGARWAL N. and RAO M.: Lubrication Science, 1994, 7(1), 25-38 8. BARTHA L. and DEAK Gy.: Hung. J. Ind. Chern 1979 (7), 359-366 9. EP Pat. 0789069 Page 140 Page 141 Page 142