The Art of Designing Casing Film Dies for Degradable Plastics
Today's technology offers advantages to forward thinking processors who want the flexibility to run tomorrow's products. Over the last decade, we have heard enough of five layers. The trend does not stop at five layers. It continues to seven and nine layers for today's requirements.
Blown Film Technology is available to process barrier resins such as Nylon and EVOH. However, it is restricted by the die design because of the thermal sensitivity and short life of the die. In order to improve the thermal sensitivity and the short life of the die you have to design your equipment with very low residence time and no dead areas in the whole system. Macro's latest die design with new side-feed overlap channel (spiral or non-spiral mandrel) allows you to run degradable resins with the lowest residence time. This makes all degradable resins run through the die without degradation and extends the life of the die. This will not only allow you to run Nylon and EVOH but PVC, PLA, PVOH and PVDC resins as well. Macro currently has a five-layer shrink bag casing film line running in our R&D facility, which is available for customer's trials at request.
Blown and cast film producers would like to run almost anything and everything in the same line therefore it becomes very crucial how you design your equipment. Thanks to the today's technology you can machine almost anything as long as you provide proper machining coordinates or 3D surface to your CNC center. At Macro we have custom designed flow simulation software, which generates automatic coordinates as well as geometry for the 3D Pro/ENGINEER CAD system.
This minimizes the CNC programming time and helps you to customize your equipment as needed for versatility of production for existing or new film structures in order to stay ahead of the market.
Macro offers many different styles of dies according to the requirements: Conventional, TaperPack (Figure 4), Side-fed MacroPack, Center-fed MacroPack, ComboPack and even a FlatPack. The die design principle is the same for all types of dies but there are many different ways to bring the balanced flow to the die exit for the best possible film properties. We design our spirals without any restrictions keeping in mind that we must design the equipment for versatility in order to run more than one resin through the same spiral mandrel without sacrificing gauge uniformity.
Macro has already successfully supplied many single layers to nine layer dies in the industries for the degradable resins such as EVOH and even PVdC.
