Study On Performance Optimization Of High Alkaline Complex Calcium Sulfonate Grease

Grease is widely used in a variety of industrial equipment to reduce the wear of mechanical equipment,automotive parts,etc.,and improve service life.As a kind of grease with good property,high alkaline complex calcium sulfonate grease can make the equipment operate normally under harsh working conditions,its excellent high temperature,anti-rust and extrusion anti-wear resistance has made it attract more and more attention.However,the preparation of high alkaline complex calcium sulfonate grease has problems,such as complex process and many control points,which urgently need to be optimized,and the research on the relationship between its properties and microstructure is not perfect.In order to solve these problems,the property of high alkaline complex calcium sulfonate grease was optimized by process optimization and raw material screening,and the relationship between its properties and structure was characterized by infrared spectroscopy(FT-IR),thermogravimetric analysis(TG),X-ray diffraction(XRD)and scanning electron microscopy(SEM).The specific work is as follows:(1)The effects of three feeding sequences,reaction temperature,time and stirring speed in the conversion stage on the properties and structure of high alkaline complex calcium sulfonate grease were discussed,and the relationship between properties and structure was analyzed.The optimum preparation process conditions were as follows:the feeding sequence 2 was selected,that is,the basic material,conversion agent and fatty acid Y were added to the system at the same time in the conversion stage,and the saponification agent Z was added in the saponification stage,the reaction time was 85℃,the reaction time was 3 h and the stirring speed was 200 rpm in the conversion stage.The high alkaline complex calcium sulfonate grease prepared under this process condition has excellent high temperature performance,and the dropping point is 360℃,the consistency grade is 3,and the working cone penetration is 251(0.1 mm),the low temperature performance is good,and the similar viscosity at-10℃ is 581.84Pa·s,the colloidal stability is good,and the oil separation amount of steel mesh is only 2.37%.The P_B value is 1098 N,P_D is as high as 4900 N,and the wear spot diameter is only 0.471 mm.The overall performance of the prepared grease meets the requirements of the national standard GB/T 33585-2017,and the properties are equivalent or better than the commercially available grease.By analyzing the structure-property relationship,it was found that the crystal form of calcium carbonate in the grease with better properties was more completely transformed,and the fiber structure of the grease was more compact and the pores were smaller.(2)The naphthenic base oil A(high viscosity),paraffin base oil B,naphthenic base oil C(low viscosity)and poly-α-olefin synthetic oil D were selected as the base oil.The effects of the above base oil and its blended base oil on the properties and structure of the grease were investigated,and the base oil most suitable for the preparation of high alkaline complex calcium sulfonate grease was selected.The results show that the grease prepared from naphthenic base oil A has better high temperature property,colloidal stability,tribological property and water resistance.The paraffin base oil B has poor fat-forming effect,and the naphthenic base oil C is not fat-forming.The grease prepared from poly-α-olefin synthetic oil D has good high temperature property,low temperature fluidity and friction reduction property,but the water spray resistance is as high as 69.88%,and the water resistance is poor.High alkaline complex calcium sulfonate grease can be successfully prepared by blending base oil A and B and blending base oil A and D,but the overall properties is not as good as that of base oil A.(3)In order to further improve the water resistance of high alkaline complex calcium sulfonate grease,the effects of ethylene propylene copolymer(OCP),polyisobutylene(PIB)and polymethacrylate(PMA)on the water resistance and other properties of high alkaline complex calcium sulfonate grease were investigated,and the relationship between property and structure was analyzed.The results show that the three tackifiers can improve the water resistance of the grease.OCP and PIB have a great influence on the water spray resistance of the grease,the addition of 4%(wt%)OPC can reduces the water spray resistance by 6.98%and 6.89%,respectively.The water spray resistance of the grease reaches below 15%.OCP has less negative impact on the low temperature fluidity and tribological properties of grease,and PMA has little effect on the water resistance of the grease.The tackifier is adsorbed on the surface of the grease fiber structure,which is agglomerated,increases the crystal plane spacing,and increases the soap fiber structure of the grease.