Processing Machinery
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ASA excessive melt temperature degradation
Fenómeno del problema
ASA product surface shows bubbles, silver streaks and burnt marks, color darkens, mechanical properties decrease by more than 20%, and the actual barrel temperature exceeds the upper limit.
Análisis de la causa
After ASA melt temperature exceeds 230℃, the acrylate rubber phase begins thermal degradation; temperature out of control decomposes the material to produce gas and carbonized spots; long-term high temperature residence aggravates molecular chain breakage.
Solución
①Control melt temperature at 190~230℃ and keep the 230℃ red line; ②calibrate the actual deviation of thermocouple and temperature controller; ③reduce screw speed and back pressure to reduce shear heat; ④purge the machine after degradation and resume production.
Conclusión clave
The 230℃ red line of ASA protects the rubber phase; rubber degradation directly destroys impact resistance and weather resistance; calibration of the difference between actual melt temperature and displayed temperature should be carried out regularly.
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