Post Holiday Subcontractor Moisture Degradation in Pearl River Factories
Unheated Pearl River sub-tier storage degrades unsealed damp resins during post-holiday spring restart; mandatory desiccation and humidity logging protect yield.
Polymer Melt Degradation
Meaning
Thermal decomposition alters the molecular structure of molten plastics during high-temperature processing. When polymer melt degradation occurs, the long-chain molecules break down into shorter fragments due to excessive heat, shear stress, or residence time in the extrusion barrel. This process reduces the mechanical properties of the final molded product.
Physical Cause
Thermal and mechanical inputs combine to accelerate the molecular breakdown. Excessive screw speed creates intense localized shear heating, which raises the temperature of the material far beyond the set point of the heating bands. In addition, any residual moisture in resins like nylon or polycarbonate causes hydrolysis at elevated temperatures, which rapidly reduces the molecular weight of the polymer melt degradation product.
This degradation lowers the melt viscosity, leading to inconsistent flow behavior during injection molding.
Operational Impact
Defects on the factory floor frequently originate from this material breakdown. Operators notice changes such as discoloration, splay marks, and a significant drop in the tensile strength of the finished parts. Furthermore, the degraded chains can release volatile compounds that corrode the expensive steel molds used in the production line.
Mitigation Strategy
Controlling the process variables prevents the material from breaking down. Production teams must dry the resin thoroughly and optimize the cycle times to keep the residence time within the safe threshold specified by the material supplier.