Styrene Butadiene Rubber Processing
Duradene™ synthetic rubbers are typically used as
replacement for emulsion styrene butadiene rubber.
Because of the innate differences between emulsion and solution SBR, processing conditions are sometimes different. In general, Duradene-based compounds have higher Mooney viscosity than the corresponding emulsion SBRs.
Because solution styrene butadiene rubbers also have narrower molecular weight distribution, they tend to bag on the mill. To compensate for this, mill roll gaps should be tightened from 10 to 25 percent.
In addition, solution SBR compounds tend to go to the cold roll, so the front roll should be cooled to achieve a difference of 10 to 20 degree Fahrenheit difference. The stearic acid level can be increased to improve mill performance without adversely affecting other physical properties.
Since Duradene™ styrene butadiene rubbers have narrower molecular weight distribution and less branching, extrusion die swell is less, which may necessitate different extruder plates. Correspondingly, calender shrinkage also is less. In almost all cases, die swell and calender shrinkage will be noticeably more uniform once the corrections are completed.
Click here for non-tire application info and typical properties of our Duradene™ synthetic rubber or here for tire application details.
Looking for the right research and development partner for your styrene butadiene polymer needs? Contact our Akron Technical Service Group now.
Stereon® butadiene-styrene SB and SBS block copolymers – for grafting and melt blending plastic applications, as well as for non-woven hot melt adhesives, bookbinding adhesives, and roofing and paving asphalts.