Study On Preparation And Grafting Reaction Of Large Particle Size Latex

ABS resin is a special structure toughening resin composed of dispersed butadiene rubber and continuous SAN resin.The impact resistance of ABS resin is determined by the particle size characteristics of butadiene rubber p Hase and its dispersion in SAN resin.The key to the production efficiency of ABS resin is how to produce large particle size polybutadiene latex with a relatively simple process in a short reaction time.The reaction time required to prepare large size butadiene latex by seed method and copolymerization method is long,most of which is more than 30 h,which seriously restricts the production capacity of ABS resin.In this paper,the large-size latex prepared by one-step method has good performance in all aspects,simple operation process and short reaction time.The optimized grafting process was used to graft the large-size latex with one-step method,and a higher graft rate was obtained.Furthermore,the grafted adhesive powder and SAN resin were fused and mixed to prepare ABS resin,and the ABS resin with high impact resistance was obtained.In this paper,on the basis of the high and low temperature butadiene latex technology developed by the research group,with butadiene as monomer,under the REDOX system,one step synthesis of large particle size latex.As a reference system,the similarities and differences of the seed method for the preparation of large size butadiene latex were compared.The effects of temperature,initiator dosage,emulsifier dosage and electrolyte dosage on polymerization kinetics,latex particle size and distribution and gel content were studied.One-step process was used to produce butadiene latex with conversion rate of over90%,particle size distribution of 58 nm,255 nm and gel content of 82%.It is superior to the large particle size and narrow distribution latex prepared by seed method.On the basis of the small scale test,the pilot scale test of one-step process was further carried out,which solved the temperature fluctuation and the low conversion rate in the test process,and obtained the large particle size latex with qualified conversion rate gel content.In this paper,the grafting polymerization of one-step and seed-method large particle size latex emulsion system was studied,and the effects of emulsifier dosage,initiator dosage,reductant type and dosage,reaction time,stirring speed and so on on grafting reaction were investigated,and the best grafting process was summarized.The results showed that the apparent grafting rate of ABS powder prepared by one-step butadiene latex was significantly higher than that of seed butadiene latex.The ABS resin was obtained by melting and mixing the grafted rubber powder and SAN resin,then extruded and granulated.The notch impact strength of the ABS resin toughened by the styrene-butadiene latex prepared by one step method was significantly higher than that of the ABS resin prepared by seed latex method,which could reach 247J/m.