A. Mixing process
The mixing time is not enough, the discharge temperature is too high or too low; acidic and alkaline compounding agents are added at the same time (such as adding stearic acid and anti-scorch agent ESEN together with zinc oxide and magnesium oxide); insufficient mastication; compounding agent addition The sequence is inappropriate; the filler is added too late in the mixing cycle; small particle size carbon black and resin or viscous oil are added at the same time; the metal oxide dispersion time is not enough; liquid accelerator is added after the rubber has been torn or broken agent; the batch size of the glue is too large or too small

B. Craftsmanship

Established mixing procedures were not followed; aggregates of oily and dry materials stuck to the upper ejector pin and sides of the feed hopper; improper rotor speed; compound was unloaded from the tablet press too quickly; the press was not applied correctly Turning device on film machine

C. equipment

The temperature control of the internal mixer failed; the pressure of the upper ejector bolt was insufficient; the welding layer in the mixing chamber was worn and excessive; the tablet press roller temperature control failed; the elevated turning device on the tablet press failed.

D． Material

Expired and partially gelled rubber; EPDM or butyl rubber too cold; Frozen natural rubber; Insufficient pre-moulding of natural rubber; Excessive filler moisture (caking); Adding viscosity at temperatures below the pour point Compounding agent; Improper use of compounding agent

E. Formulation design

The Mooney viscosity of the elastomer used is too different; inappropriate selection of plasticizer and rubber; too many hard particle compounding agents; excessive small particle size fillers; use of resins with too high melting points; not enough liquid plasticizer; fillers and Too much plasticizer