PET strapping tape line

PET strapping tape replaces steel hoops

For the transport packaging and the strapping of heavy loads, steel hoops were previously due to its strength as the only reliable material. Not least through the steel crises, steel hoops are steadily replaced by polyester (PET) strapping tape.

• the strength of PET tapes is comparable to the steel tapes
• the elongation of 7 to 15 % is larger than that of steel; PET tape is more elastic and thus suitable for those packaging goods which change their volume by heat or vibration
• due to a higher resilience by use of PET tape there is no damage on the flange of the packaged product
• PET does not rust, a major advantage, especially in the packaging of chemical fibres and cotton bales
• the risk of injury compared to steel tapes is significantly lower. The handling of the coils is easier.
• the use of PET bottle waste for the production, PET tapes are now significantly cheaper than steel tapes

As flakes showing by the hydrolytic degradation during the first extrusion step a broad molecular weight distribution and a lower molecular weight as new, it was not possible in the past to produce high-quality strapping tapes made of 100 % bottle flakes.

The problem was solved by using additives or by mixing with virgin materials. However, a disadvantage is the increased raw material costs.
In 2001 REIMOTEC has developed and patented a technology, which allows to produce high quality strapping tape of 100 % bottle flakes.

Innovative twin-screw technology

The heart of these lines is a co rotating twin-screw extruder. In conjunction with the patented reactive extrusion, the twin-screw technology arrange for an excellent homogeneity of the melt of PET. In that way it can produce high quality PET strapping tape of bottle flakes.

Function of a co rotating twin-screw

• intensive material- and heat exchange at constant material handling
• almost complete self-cleaning effect and low residence time in cause of the screw geometry
• effective degassing of the melt along the partly filled screw output is decoupled of the screw speed (partly filled screws)
• excellent adaptation for the appropriate application by the modular screw design

Advantages of a co rotating twin-screw for the extrusion process:

Low degradation and minimal shear

• low screw speed (65 - 100 rpm)
• low back pressure ( 45 - 70 bar)
• high specific output

Blend

• mixtures of different PET qualities
• mixtures of PET with PP or PA are optimally mixed and result best melting qualities

Homogenization of impurities

• Polyolefin, PUR, PVC are mixed very well
• reduce the pulsation of stretching point
• greater stability of the stretching point reduce the variation of dimensions in the product

Cleaning of the melt

• the removal of low molecular components from the melt improves the product properties such as for example the strength and the splice behaviour

TriCo strapping tape, the 3-layer strapping tape

The success story of the plastic strapping tape is characterized by the presence of low cost PET recycling materials. Can be made high quality strapping tapes from inferior and less expensive PET grinding stock (bottle flakes), so the substitution potential rises and steel can be replaced by plastic. A technically interesting possibility is the production of 3-layer strapping tape (TriCo technology).

The core composed of inferior recycling material (for example PET multilayer-grinding stock). The upper and lower layer made of better quality recycled material ensures the good weld ability, the sufficient breaking resistance of the flange and the required mechanical properties.

The quality of the strapping tapes is substantially dependent on the stretching process. The patented stretching bar allows a reproducible accurate adjustable stretching point.

Tape Control System (TCS)

A more modern automation concept would include a continuous and automatic monitoring and logging of the width and the thickness of the tape.
For all standard tape types the width and the thickness of up to 16 tapes can monitored, statistically analyzed and logged inline and in real-time.

Performance spectrum of the strapping tape lines:

material:	PET IV = 0,65 - 1,15
material bulk weight:	Flakes 220 - 450 kg/m³
material bulk weight:	Virgin circa 800 kg/ m³
output:	up to 1200 kg/h
working width:	up to 1000 mm
dosing:	3 - 7 components
fixing/relaxation:	1 / 3 / 5 / 9 lead-through  up to 10 tapes

 

tape dimensions:	5 x 0,5 - 32 x 1,3 mm by maximum output
production speed:	up to 240 m/min

 

• single- or twin-screw extruder
• optional Inline width- and thickness- measurement system