Full definition
The art and science of formulating a rubber compound by selecting and combining raw polymer(s) with a precise recipe of additives to achieve target physical, chemical, and processing properties. A typical compound recipe includes: base polymer (NR, SBR, EPDM, etc.), reinforcing fillers (carbon black, silica — 30-80 phr), plasticizers/process oils (5-30 phr for flexibility and processability), vulcanization system (sulfur + accelerators + activators, or peroxide), antioxidants/antiozonants (1-5 phr for aging resistance), and special additives (flame retardants, colorants, blowing agents). Quantities expressed in phr (parts per hundred rubber). The compound recipe is the core intellectual property of rubber manufacturers — even 1 phr change in a single ingredient can significantly alter performance. Mixing: two-roll mill or internal mixer (Banbury) at controlled temperature, time, and sequence. Quality control: Mooney viscosity, rheometer (MDR) cure curve, and physical property testing of cured samples. Per ASTM D3182 for standard mixing procedures.