Preparation And Performance Of Environment-friendly Extreme Pressure Additives

Sulfurized isobutylene(SIB)is a kind of widely used lubricating oil sulfur containing EP additive,its extreme pressure and anti wear performance is very good.But the traditional production process was not environmental-friendly,it generated lots of industrial wastes and the finial product was smelly.The application in lubricant oil of SIB was restricted by all these disadvantages.At present the main research on SIB is focused on the production process improvement and development on the SIB substitute.Based on this background,this thesis studied on the main production processes of sulfur containing EP additive;and finally choose the unsaturated olefin / sulfur / hydrogen sulfide as the raw materials,adopted a more environmental-friendly process,synthesized two kinds of sulfur containing EP additive as the substitute of SIB.The main research work included the following contents:(1)Di-tert-dodecyl trisulfide and di-alkyl pentasulfide was synthesized with unsaturated olefin/ sulfur /hydrogen sulfide under high pressure and catalyst.The sulfur containing EP additive was characterized by IR spectrometer,GC-MS,TGA,sulfur analyzer and so on.(2)A new test method of lubricant oil and additives odor was created,two sulfur containing EP additives were tested with this method.The results show that they have a much lower odor than SIB.Then the oil solubility,active sulfur content,copper corrosion and tribology performance was evaluated.Results show that the four ball weld load of di-tert-dodecyl trisulfide is 250 kg,the total sulfur content was 22%,the active sulfur content was 2.5%,it was a typically low activity and high EP sulfur carrier and was very suitable for the application of gear oil and grease.And results show that di-alkyl pentasulfide's four ball weld load was 250 kg,total sulfur content was 40%,active sulfur content was 35%,it was a typically high activity and high EP sulfur carrier,suitable for the application of metal working fluid.These two kinds of sulfur containing EP additives can be used as the substitute of SIB.(3)The performance of di-tert-dodecyl trisulfide in gear oil was evaluated by compound with phosphorus containing AW additives.The results show that the gear oil meet the L-CKD gear oil specification requirement,di-tert-dodecyl trisulfide can be used as EP additive in the gear oil.Di-tert-dodecyl trisulfide was compounded with ZDDP in grease,and the four ball weld load of grease can be promoted by 96%-98%,the grease oxidation pressure drop value was reduced by 68%,di-tert-dodecyl trisulfide can be used as EP additive in grease.The performance of di-alkyl pentasulfide in metal working fluid was studied.It was compounded with overbase sulfonates,the four ball weld load was boosted by 275%,wear scar was reduced by 24%.The di-alkyl pentasulfide showed obviously extreme pressure and anti wear performance.Then it was compounded with unsaturated polyester,the weld load was boosted by 212%,so it also show the EP proformance.In conclusion,di-alkyl pentasulfide can be used as EP additive in metal working fluid.