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Home » TPX™ Polymethylpentene (PMP) Processing Method
TPX™ Polymethylpentene (PMP) Processing Method
  • TPX™ is available in pellet form.
  • Since TPX™ does not absorb water / moisture, it is not necessary to dry TPX™ before processing provided that it has been stored under normal conditions.
  • Because of its high melting point TPX™ is normally processed at high temperatures in a range of ± 300°C. Molding equipment which can be set to such temperatures is therefore a basic requirement.
  • To control / minimize the decomposition of TPX™, it is recommended to apply nitrogen-feeding at the hopper during molding process.
  • Unlike PC, PMMA and other amorphous resins TPX™ is crystalline and therefore shows bigger mold shrinkage. Due to this fact, special attention has to be paid in case an existing mold which has been designed for any other resin, will be used for the processing of TPX™.
  • Before starting to process TPX™, please be sure that no other resin is remaining in your machine. Particularly in the case of injection molding; even a small amount of foreign resin will result in an impair appearance of the product due to contamination. It is generally recommended to purge the equipment first with PP of low MFR and afterwards with TPX™.

Injection Molding
When TPX™ is in a melted state its viscosity declines drastically. Because of this, a pin gate is the most suitable gate for injection molding. This will help to minimize deformation and stress in the gate area. Particularly for shallow products, an off-center gate is highly recommended to avoid warpage. Injection molding of TPX™ is normally done within a range of 290°C and 310°C where 280°C and 320°C have to be regarded as lower and upper limits. For good controlling it is generally recommended to measure the actual resin temperature. Because of the very low viscosity of TPX™ at the melted state, it is also strongly recommended to inject at very low speed and very low pressure to minimize stress. The mold temperature is normally set within a range of 20°C and 60°C.

Extrusion
Because TPX™ needs a lot of energy to melt an extruder with an L/D ratio of at least 28, preferable 30 or 32, and with minimum 4 heating zones is strongly recommended. Also a special screw-design will allow you to easily process TPX™. If desired, we will help you to find the optimum screw-design for your machine. Sometimes a preheating of TPX™ pellets can be helpful.

Blow Molding
Because the viscosity of TPX™ declines sharply after it is melted, the blow molding of TPX™ is rather difficult and limited to the direct blow molding process. For the same reason the injection blow molding process does not work!
It should be noted that the transparency of blow molded TPX™-products is inferior to those made by injection molding.

Post-processing and Coloring
Because of its very low surface tension TPX™ has to be pre-treated with e.g. corona, flame, plasma, etc., for printing, painting or bonding it. Moreover, since TPX™ is low in mechanical strength, it is unsuitable for cutting manufacturing. TPX™ can be colored by dry blending and the most suitable way is to use a color masterbatch based on TPX™. However, please be sure to select pigments with high heat resistance, exceeding the molding temperature of TPX™.

 

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