rPET FIBCs: from bottle to bag

Polyester is a widespread polymer: for decades, PES fibers have been used in textile production, PET for bottles and film in the packaging industry, and various specialty polyesters for engineering plastics. The outstanding mechanical and chemical properties of PET make it the material of choice for a wide variety of intermediate and final products. Recyclability and the possibility to produce PET in a closed loop to reduce emissions to the environment are other factors that helped PET gain importance in the past years.

Developments in technology allow the use of PET in new fields where it brings important advantages due to its material characteristics. One such field is heavy-duty fabric for applications such as big bags, geotextiles, carpet backing and tarpaulins. Austrian machinery producer Starlinger & Co. Ges.m.b.H. has developed the process technology for the production of tape fabric made of virgin and recycled PET. The engineering company has already invented a number of packaging solutions made of woven polypropylene tape fabric for dry bulk products. With the PET tape technology, Starlinger has now entered the territory of speciality fabrics for heavy duty applications. The exceptionally high strength and long-lasting form stability of PET tape fabric make it the perfect material for heavy-duty fabrics used e.g. for FIBCs (Flexible Intermediate Bulk Containers), geotextiles, carpet backing, or tarpaulins.

With Starlinger also producing technology for PET bottle-to-bottle recycling, the next logical step was to use rPET in the fabric production process. As stated before, PET is fully recyclable; quality losses such as IV decrease can be reversed by solid-state polycondensation, so that rPET achieves the same properties as virgin PET. In addition, customized UV protection can be added (for outdoor applications). Starlinger has successfully tested rPET in the tape and fabric production process and produced FIBCs from this material which show the same performance as FIBCs made from virgin PET. The used rPET tape fabric can be recycled again and reused in the same or different applications, which considerably reduces the carbon footprint. 

PET tape fabric – excellent performance, look, recyclability

The combination of high strength and a high melting point are the two main reasons why PET achieves a better performance and withstands higher working temperatures than other polymers used for fabric production: PET maintains its modulus and strength at temperatures up to 80°C and has excellent creep resistance. Creep is time-dependent strain or deformation due to stress; it occurs as a result of long term exposure to high levels of stress that are below the yield strength of the material.

A very visible feature of PET tape fabric is its high gloss that provides it with outstanding visual appeal. PET tape fabric can be produced transparent and in a wide variety of colours offering new possibilities for package style and design.

Another important characteristic in favour of PET as a packaging material is its excellent recyclability. As polycondensation is a repeatable reaction, the molecular weight of PET can be rebuilt, allowing converters to use recycled material to replace virgin resin. The possibility to recycle PET tape fabric to 100% and reuse it is an essential aspect for a sustainable future. 

Special material properties of PET:

• Increased stiffness due to higher tensile modulus combined with high surface resistivity
• Higher creep modulus and thus higher creep resistance
• Very good abrasion resistance
• The material of choice for hot fill applications
• Does not become brittle at temperatures below 0°C
• Lower residual shrinkage at high temperatures

A wide field of applications

Be it attractive packaging for consumer goods such as sugar, cereals or pet food, or geotextiles used for soil reinforcement and erosion control – PET tape fabric meets the requirements for various applications. The high working temperature, an eye-catching appearance, low weight and shrinkage combined with high tenacity and creep resistance are qualities that surpass those of other types of plastic fabric currently used for such applications and speak in favour of PET. But not only PET tape fabric offers many advantages; also the plain PET tapes can be employed for a variety of uses: tear tapes, filling yarn, concrete fibre, ropes, belts, to name a few. 

Starlinger comPETence Center

In the Starlinger comPETence Center, a special facility dedicated exclusively to the development of PET tape fabric for heavy-duty packaging applications, the correct equipment setup, the optimum parameter settings for extrusion and weaving have been tried and tested to achieve the desired results. Continuous laboratory analysis of the tape and fabric samples produced on the installed equipment ensures that all relevant criteria are met.

The Starlinger comPETence Center is also available for customer trials on the installed PET tape extrusion line and the circular looms, as well as for testing of customer materials.

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About Starlinger & Co. Ges.m.b.H.:

Starlinger is a Vienna-based engineering company with production sites in Weissenbach and St. Martin, Austria, as well as Taicang, China. As the world’s leading supplier of machinery and complete lines for woven plastic bag production and PET recycling and refinement, Starlinger & Co. Ges.m.b.H. is a synonym for leadership in quality and technology in over 130 countries. Founded in 1835, the family-owned business has been exporting machines worldwide for more than 45 years with an export quota of over 99.5 %. Branches in Brazil, China, India, Indonesia, Russia, South Africa, USA and Uzbekistan ensure quick and professional technical support and service.