ADVANCING 1-HEXENE-BASED PP-RCT: PIPE APPLICATION EXAMPLES AND NEXT CHALLENGES

Simona Africano, Emanuele Burgin, Thomas Boehm

# 2021 Amsterdam

Since the ‘80s, Polypropylene-Random (PP-R) has been a material of choice for producing plastic pipes for Hot & Cold water installations. Compared to other polyolefins, PP-R has higher stiffness and higher temperature resistance, along with the typical advantages of plastic pipes such as light weight, fast and reliable jointing by welding, and chemical and corrosion resistance. In the light weighing perspective (reducing wall thickness without compromising the mechanical properties), the way we have recently implemented is co-polymerization of propylene with a new monomer, 1-Hexene. The polymers produced with 1-Hexene as co-monomer in a new, LyondellBasell proprietary technology, show a long term pressure resistance so increased to achieve MRS classification 12.5, hence PP125. In the 2012 ISO 15874 and in the 2017 ASTM F2389 revisions, the new PP-RCT designations has been introduced to differentiate the outperforming properties offered by the new PP’s. The 1-Hexene co-polymers meet those long term pressure resistance requirements.

This presentation reports several commercial examples of 1-Hexene based PP-RCT in Hot & Cold installations and in other industrial applications. In case of restructuring or refurbishing, the presentation includes a reference to the pipe material previously used and the reason customers are now selecting PP-RCT piping instead. The examples will be about private and public buildings, such as hotels, commercial districts and hospitals, located in various countries (mainly Europe), where in most of the cases the PP has been the material of choice thanks to the thermal, chemical and corrosion resistance.

The market implementation of PP-RCT has also indicated new challenges, the first of which for PP is Chlorine resistance (NaClO or ClO 2 ).Therefore a number of studies has been implemented in that respect. The presentation includes our latest findings and achievements so far. The unique creep resistance offered by the 1-Hexene comonomer has also allowed a development activity in other piping system areas, like Under Floor Heating or fittings, and increased output rate in the conventional PP-R applications. The presentation finally reports also an update on these new developments and concludes that after less than 10 years from the first industrial implementation, there is a great potential for 1-Hexene co-polymers in many piping applications to ultimately outperform the traditional metal based systems.