Molding process

  • Pre-drying
    VYLOPET® must be pre-dried prior to molding.
    It is recommended for pre-drying to use a hopper dryer, but alternatively, a shelf dryer may perform sufficient drying.
    For applicable drying conditions, please refer to the summary in Table 1.

    Table 1
    Drying temperature Drying time
    EMC series CA/FA series
    120°C Unsuitable 3~5 hours
    130°C 4~6 hours Unsuitable
    140°C 3~5 hours Unsuitable
    150°C 3~4 hours Unsuitable

      [Fig.1] shows the diagrams of drying time vs. water absorption when dried at 140°C.
    Please set appropriate drying conditions so as to keep the water absorption less than 0.025%.

    [Fig.2] shows the diagrams of pellets exposure time vs. water absorption. Pellets will absorb water when exposed in the air. For pellets exposed in the air for 30~40 minutes or more, please re-dry them prior to use.

    The longer pellets are exposed in the hot and high humidity air like the condition (A), the more they easily absorb water. Accordingly, during hot and high humidity time like the rainy or summer season, please treat pellets carefully to avoid their moisture re-absorbing.

  • [Fig.1] Drying time vs. water absorption at 140°C

    [Fig.2] Exposure time of pellets vs. water

    [Fig. 3] shows changes in the holding rate of solution viscosity when the water absorption in pellets changes.
    When the water absorption in pellets is high, resins will be hydrolyzed, and resultantly, the solution viscosity of moldings will be significantly decreased.

    [Fig.3] Holding rate of solution viscosity vs. water absorption

    Please remember to process moldings with the water absorption not more than 0.025 %.