With this concept, production waste from fiber, film and start-up lumps are placed into a shredder and are transported via a conveyor belt with metal separator into an intermediate container with an agitator. From there, the material is conveyed into the extruder by means of an auger and a crammer feeder.

Alternatively, size-reduced and agglomerated waste can be directly fed into the MRS extruder. The advantage of separating the processing steps of size reduction and extrusion is that the material feed (and therefore the throughput rate) can be equalized and metals can be reliably ejected from the material flow, which is far more difficult to achieve on integrated systems.

The extruder melts the polyester waste gently and cleans the polymer of volatiles such as surface or absorbed water, spin finish oils and other spinning aids or printing inks (film waste) in the MRS devolatilising section. The intensive and highly efficient surface area exchange under vacuum ensures excellent performance. Solid contaminants such as glass, paper and ceramic are removed by the automatic, self-cleaning Rotary screen changer and the finely-filtered polymer melt flows to a pelletising system (chip cutter).

Optionally (for example when higher IV material is required) the polymer melt can be fed directly into the IV boost system JUMP to achieve an exact IV increase before being pelletised.

The pelletising / chip cutting system can be specified as an underwater strand pelletising process for cylindrical chips with subsequent crystallisation or alternatively, as an underwater die face cutting system for spherical chips with residual heat crystallisation. In this way, a high quality pellet / chip can be manufactured from up to 100 % industrial waste.

Advantages of the Gneuss recycling concepts for pellet / chip manufacture

  • Wide spectrum of pellet properties can be selected
  • Exact, user-defined viscosity adjustment, matched to the requirements of the application
  • User-defined blends
  • Additives for a wide range of different applications are easily introduced into the melt
  • Exploitation of new markets with the sale of high quality chip made from production waste

Pellets for further processing

The light bulk density production waste from fibre, film and start up waste are taken in tangled, non-flowing form and fed into a shredder where they are size reduced to a form which can be fed to an extruder. The material is transported by means of a conveyor belt via a metal detector into an intermediate buffer container with an agitator. From there, the voluminous material is fed by means of a dosing auger and crammer feeder into the extruder. The material is melted, devolatilised and decontaminated in the extruder. Volatile contaminants such as water or oils are extracted. Solid contaminants are extracted from the melt by the Rotary Filtration System. After pelletizing, the pellets / chips which have been purified from volatile and solid contaminants, can be used to replace virgin material in the manufacture of film, sheet, fibre, strapping tape etc..

 

Pellets for high viscosity applications

The starting point is production waste from fibre, film and start-up lumps. These are size-reduced and if necessary agglomerated and fed to the MRS extruder through a metal detector where they are melted and devolatilised – volatile contaminants such as absorbed or surface water, spin finish oils or other processing oils are extracted. Solid contaminants are extracted with the Rotary Filtration System and by means of a booster pump, the melt PET is fed into the liquid phase IV boost system, JUMP. Agitating and mixing devices within the JUMP reactor also achieve – under a deep vacuum – high polymer melt surface exchange rates and so achieve a set IV. The viscosity is adjusted by means of the Online Viscometer in combination with the process control system. The polymer melt is pumped out of the vacuum, through a further Rotary Filtration System for fine filtration and is then pelletised.