Xyron™ molding conditions

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.

• Up to 30 minutes:
  Maintain cylinder temperature. Purge barrel using same material prior to the re-start of molding operation.
• 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.
• For downtime longer than 12 hours:
  Purge barrel with high viscosity GPPS, and shut down machine.

Mold release

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.