Process for preparing carboxylic acrylonitrile butadiene rubber through emulsion polymerization method

The invention relates to a process for preparing carboxylic acrylonitrile butadiene rubber through an emulsion polymerization method. An emulsifier and an adjusting agent are added in batch, and a crosslinking agent and a pre-crosslinking agent titanate are added at different times, so the carboxylic acrylonitrile butadiene rubber has the characteristics of high content of a microgel, low content of a gel, controllable combined acid index, easy formation of a stereo netted structure in the processing process, uniform distribution of carboxylic groups on a molecular chain, uniform structure formed in the vulcanizing and product processing processes, slight stress relax phenomenon, and good dimension stability. The rubber obtained through adopting the method has good physical and mechanical properties and an improved Mooney viscosity, and has corresponding better compression set, Shore A hardness, tearing strength, tensile strength, elongation at break and 100% stress at definite elongation than common carboxyl