The new Vacurema Inline Strapping System
Erema introduced the new Vacurema Inline Strapping System - from PET bottle flake to high-grade PET strapping band in just one production line.
The system has a throughput of up to 300 kg/h of high-strength strapping band of small cross-section, thus making for an extremely cost-efficient use of raw materials. In Compared to conventional extruder processing systems, the new Vacurema Inline Strapping System achieves both a saving in input material costs of 20 to 25% and a saving of approximately one third of the energy costs, and naturally without any loss of product quality: a strapping band extruded from 100% PCR-PET bottle flake and featuring a cross-section of only 15.75 mm x 0.8 mm has a tensile strength of 513 N/mm2.
The prerequisite for such lowcost, high-quality performance is met by Erema's compact Vacurema technology, which enables the processing of PET bottle flake in one process virtually without any loss of viscosity; the system eliminates the need for precrystallising or predrying.
Moreover, the Erema process has an approximately 30% lower power input requirement than a conventional extrusion line with an upstream crystalliser and drier. The system can also process virgin material or blends of virgin material, bottle flake and strapping scrap in any desired proportions. Conversion from one product to another is vastly facilitated by the fast and easy change-over of system components.
Erema's Vacurema technology works with a patented vacuum reactor featuring rotating tools and coupled with a sturdy single-screw extrusion system with high-performance degassing. The starting material, in this case PET bottle flake, is fed into the Vacurema reactor directly via a vacuum lock without any precrystallisation or predrying.
The material is then mixed, heated (through frictional heat alone) and, with the aid of the vacuum, dried, crystallised and freed from any volatile contaminants, all in a single pass. The single-screw extruder (screw diameter 80 mm), which is connected directly to the reactor, plasticises and homogenises the constantly dried material, degassing the melt where necessary (recommended option in the case of high-volatile extraneous polymers or other contaminants) and conveying it without the need for an additional melt pump into a fine filter with an integrated, fully automatic self-cleaning system.
The resulting finely filtered melt is then processed directly into PET strapping bands on the Techno Plastic strapping system, starting with the nozzle unit and proceeding through the stretching, embossing, stabilizing and cooling station to the winder.
The aim behind the development of an optimised system was to achieve the economical processing of PET bottle flake into a high-quality melt without any material degradation, i.e. without any loss of viscosity in comparison to the material fed into the extruder.
This way it is possible to achieve higher stretching levels without sacrificing strength. The result is a considerable reduction in material consumption. This was achieved through modifications carried out on the Vacurema Basic Reactor: compared to the standard version used previously, the volume of the vacuum reactor in the strapping system was doubled and at the same time rated for a vacuum of less than 10 mbar.
An increased reactor volume in conjunction with reduced feed intervals produced the desired positive effect: the extended pre-treatment of the material under high vacuum effectively removes contaminants and moisture, even in cases where there are fluctuating moisture contents up to 1.5%.
Moreover, the build-up of intrinsic viscosity (IV) in the reactor counteracts the loss of viscosity (material degradation) that normally occurs in the extruder.
Thus the viscosity of the product is comparable to that of the bottle flake fed into the reactor. The Techno Plastic Tight Strap 300 stretching system installed directly downstream of the Vacurema is based on the many years' experience of this Italian specialist manufacturer of extrusion systems for strapping bands and monofilaments. The melt from the Vacurema extruder enters the spinneret, which is equipped with a double melt pump, where it is divided into four band-shaped strands.
After initial cooling (solidification), the strands have a cross-section of 35.6 mm x 1.8 mm. They then pass through several temperature-controlled processing stages, in which they are stretched (in so-called godets), embossed and stabilised. Following this they pass via the final cooling station to the winding unit, with their final cross section measuring 15.75 mm x 0.8 mm. The overall length of the Tight Strap 300 stretching line is around 50 metres.
The use of PET strapping is currently growing worldwide at a rate of around 15%. Thus the production of high-quality PET strapping from washed PET bottle flake represents - both today and for the future - an attractive business opportunity. Turnkey production lines featuring the combined Vacurema Tight Strap Technology - this system configuration is also basically suitable for the production of PET filaments - will in future be offered by both partners - Erema and Techno Plastic.
Since it was founded in 1983 Erema has specialised in the development, manufacturing and worldwide distribution of plastic recycling systems and technologies for the plastics processing industry. With its own sales and service companies in the USA, China and Japan, plus around 50 local representatives in all five continents, Erema provides custom recycling solutions to match almost any individual application requirements.
Innovative, stable technology and global service support ensure that owners enjoy the maximum benefit from their machines. Erema's technology has become established as a global, leading standard for a wide variety of recycling tasks, ranging from the recycling of polyolefins to polyester (PET).