WATERPROOF MEMBRANES | PROCESSING


in constant contact with aggressive, concentrated media. For the gold-processing plant in Kazakhstan – which also includes a grinding cleaning plant as well as a water reservoir – Agru supplied two types of HDPE geomembrane: 1mm-thick smooth sheet, measuring 7 x 200m, accounted for more than 900,000 sq m; and 2mm-thick smooth sheet, 7 x 100m in size, accounted for around 200,000 sq m.


Green roofing Roofing membranes are more sustainable than their image suggests, according to a European trade body. At the recent Waterproof Membranes conference


– organised by AMI – Massimo Cunegatti, of the European Single-ply Waterproofing Association (ESWA), said: “The green image of roofing mem- branes is often questioned by national or European regulations and international studies, for reasons such as leaching and microplastics. However, waterproofing sheets are greener than their image suggests.”


Many standards, including those covering CE marking and technical specifications, include details on design for recycling and the environ- mental impact of materials. He said that develop- ing legislation included a number of contradictions – such as prioritising recycling over long life, and not balancing leaching and microplastics genera- tion against long-term exposure. An example is where manufacturers are encour- aged to use recylate in their products – although this may affect its long-term durability. He pointed to a number of sustainable advan-


tages of membranes, including: they collect water on roofs; help to save dams in a flood; separate dirty water near motorways; and ensure clean storage of drinking water. In addition, he said that many synthetic mem-


branes are easy to disassemble at the end of life in single elements – such as membrane, fasteners and insulation – which makes for easier recyclability. “Regulations evaluate the potential negative


environmental effects,” he said. “Yet membranes are basic products that save water and create a greener environment.”


Flame retardance Italy-based Ipool – a spin-off of the Italian National Research Council – has developed a flame-retard- ant roofing membrane based on thermoplastic polyolefin (TPO). The formulation combines the base polymer and natural milled magnesium hydroxide (also


www.filmandsheet.com


known as MDH) – supplied by Europiren – in equal proportion of 49.5% each, plus a 1% loading of antioxidant and stabiliser. Prototypes were made in the laboratory on a twin-roll mixer.


“MDH has a very low carbon footprint compared to synthetic fillers,” said Camillo Cardelli, CEO of Ipool. “It is typically used in cable compounds and roofing membranes.” Ipool had a range of TPOs to choose from, and selected SB330CF from Borealis, which he said had superior softness and good heat seal proper- ties compared to other PP grades. The material is classified as a ‘random heterophasic copolymer’. Cardelli said the material had the right mix of


properties, such as flexibility (including at low temperature), melting point and both UV and thermal stability. It also compared well in cost and availability versus other materials, he said. One formulation blended 60% of this material


with 40% Vistamaxx 6102 from ExxonMobil. The resultant material showed a high flexural modulus: a 2.2mm thick film could still be bent at -33°C, he said. Other formulations added a polar wax called


Viscospeed – which imbues PP matrices with polarity, helping to enhance the flame-retarding effect of the filler particles.


n The next edition of Waterproof Membranes runs on 14-16 November 2023 in Cologne, Germany. For more details, contact Jolanda Tudgey (jolanda.tudgey@amiplastics.com) on +44 (0) 117 314 8111.


CLICK ON THE LINKS FOR MORE INFORMATION: � www.agru.at � www.solmax.com � www.ami.international � www.eswa-synthetics.org � www.europiren.com � www.borealisgroup.com


May 2023 | FILM & SHEET EXTRUSION 29


Left: HDPE membranes are commonly used in applica- tions such as reservoirs, to conserve water


IMAGE: SHUTTERSTOCK


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