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Molding
Pre-drying
Modified PPE has the lowest moisture absorption of any engineering plastic and displays excellent hydrolysis
resistance. To help ensure against surface appearance faults such as silver streaks, it is nonetheless good
practice to predry the material. For applications where surface appearance is critical, always be sure to
predry the material. When using a PPE/PA grade, predrying is especially important due to the high moisture
absorption properties of PA.
Predrying should be done at the proper temperature range specified for each grade. A closed loop
dehumidifying/drying hopper system is the most efficient equipment for predrying Xyron. When using hot-air
circulating ovens, Xyron pellets will be efficiently predried when spread out in trays at a uniform depth of 20
to 30 mm.
Take care to ensure that Xyron is not predried for longer than 8 hours. Excessive predrying may result in
degradation of physical properties and color changes.
Regrind
Properly molded Xyron (sprues, runners, molded articles, etc.) may be reground, dried, and remolded
without adverse effects. It is essential that material to be reground be free from oil, grease, dirt, and foreign
substances, and shows no signs of degradation. Regrind levels up to 20% can be used successfully, but it is
not advisable to use reground material for applications where surface appearances are critical.
Purging
High viscosity GPPS and Asaclean SA™ (available from Asahi Kasei Corporation and
distributors) are recommended purging materials for all Xyron grades. Purging should be performed at
temperature ranges appropriate for each grade.
Downtime
In order to prevent polymer degradation when molding operation is stopped or interrupted, the following
measures are recommended.
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Up to 30 minutes:
Maintain cylinder temperature. Purge barrel using same material prior to the re-start of molding
operation.
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From 30 minutes to 12 hours:
Decrease cylinder temperature to 200・20°C. Purge barrel using high viscosity GPPS. Upon
commencement of molding operation, Purge barrel using material for molding after increasing cylinder
temperature to the required level.
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For downtime longer than 12 hours:
Purge barrel with high viscosity GPPS, and shut down machine.
Mold release
Generally, mold release agents are not required for molding Xyron resins. In cases where mold release agents
are needed due to the complex shape of the mold, minimal use is recommended. Silicone-based mold release
agents such as Pelicoat B™ (manufactured and sold by Chyukyo Kasei Kogyo Ltd., Japan) are
recommended, as the chemical ingredients do not react with Xyron.
NOTE:
The information provided here is accurate to the best of our knowledge, based on all information and data
available at this time, and is subject to change without notice. It is provided with no guarantee or assumption
of liability whatsoever. It applies only to the normal handling and use of Xyron as a molding material. Any
other use or application would necessitate additional, special safety precautions, and is not
recommended.
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