A. Mixing process
Mixing time is not enough, discharge temperature is too high or too low; Acidic and alkaline compounds are added simultaneously (e.g. stearic acid and ESEN are added together with zinc oxide and magnesium oxide); Insufficient plasticizing; The order of adding the compound is not appropriate; The filler is added too late in the mixing cycle; At the same time add small particle size carbon black and resin or viscous oil; Metal oxide dispersion time is not enough; After the rubber has been torn or broken, add liquid growth agent; Batch size is too large or too small


B. technology
Did not follow established mixing procedures; The aggregates of oily material and dry material are glued to the top peg and the hopper side; Rotor speed is not appropriate; The rubber material is removed from the tablet press too fast; The folding device on the tablet press was not properly applied


C. equipment
Mixer temperature control failure; The top bolt pressure is not enough; Welding layer in mixing chamber wear transition; Press roll temperature control failure; The overhead turning device on the tablet press is out of order


D. Materials
Expired rubber and partial gelling; Epdm rubber or butyl rubber is too cold; Frozen natural rubber; Natural rubber preplasticizing is not sufficient; Excessive moisture in the filler (caking); The viscous compound is added at a temperature below the tipping point; Inappropriate use of the compound


E. Formula design
The viscosity of the elastomer Mooney used is too different; Plasticizer and rubber selection is not appropriate; Too much hard compound; Small particle size packing excess; Use resin with a high melting point; Liquid plasticizer is not enough; Excessive fillers and plasticizers