Study On The Preparation Of Latex Of Polyisoprene Rubber Catalyzed By Rare Earth

The process for the preparation of Li-Polyisoprene Rubber Latex had been studied, and it was treated as the basis of the process for the preparation of rare earth-Polyisoprene Rubber Latex. The conditions of the emulsification and getting rid of the solvent were primarily discussed and the whole process was improved because of the recycle of the emulsifier. The impact of the rubber’s micro-structure on the process for the preparation of the latex was also researched by setting up ralated theory and model. The conclusions are as belows:1)The key emulsifier for the emulsification of rare earth-Polyisoprene Rubber contains agent A(A) and agent B(B), and it is compounded with the ratio of 1:4 by weight. Span-80 is used as the co-emulsifier, and PAAS is the stabilizer for the emulsifying system.2)The formula of the emulsification: a oil-water ratio of 1:1 by weight and key emulsifier of 1.5%～2.5% by weight of water phase. Span-80 is used as the co-emulsifier and its dosage is 0.15%～0.25% by weight of water phase. PAAS is used as the stabilizer and its dosage is 0.02% by weight of water phase.3)The conditions of emulsifying process: the temperature of the water phase is 45 ℃, and it is 50 ℃ in oil phase. The shear force is 3750 rpm for 2 minutes, and homogenize the system at 5000 rpm for 5 to 10 minutes.4)The conditions of getting rid of the solvent: the coarse emulsion is distiled with a stirring speed of 150 rpm at 72℃～74℃ under normal pressure, high molecular weight PAAS is added when 2/3 of the solvent is distiled, then slight vacuum to remove the remaining solvent. The impeller is always in the liquid level.5)The conditions of concentration: The dilute latex is centrifuged on 2000-3000rpm for 20-40 minutes and its solid content is 50%-60%.6)The emulsifier from the substratum of the centrifuged latex can be reuse after analysising.7)The rubber with high cis content or narrow range or topological structure is beneficial for the preparation of the latex.