solid content of sbr latexes

The solids content is about 20 to 23% depending on conversion and the recipe ( typical SBR formulations have 180 phr water and conversion is 60-65%) FYI I worked in an SBR plant for 12 years before it closed down. terry

Interesting. My old copy of Billmeyer said the same thing. I would have thought that somebody would have increased these yields one way or another, as that is not a very high solids content nor a high reaction yield. But I suppose it is an old technology without a lot of money being made in it, and that means no/little R & D.

John Aspen Research, -

Opinions expressed herein are my own and may not represent those of my employer.

higher conversions the degree of crosslinking increases dramatically with consequent fall off in properties , particularly tensile strength, which is important to the main application ( tires). Increasing solids results in higher viscosity and heat transfer problems. Keeping the heat transfer surfaces clean in SBR polymerisation is a major and costly problem. High solids latex ( 65% solids) which is used for carpet backing etc is made post polymerisation by high pressure agglomeration to increase particle size which then lowers viscosity to allow evaporation to high solids. Very few new emuslion SBR plants are being built around the world as solution technology is taking over. terry