NPE: Sustainability steps up a level

While plastics have always been recognised as offering a more sustainable solution for some applications because of their light weight and strength, the industry continually seeks new ways to improve. This may be through the innovative use of renewable raw materials, changes to manufacturing processes and expansion of plastic recycling technologies. Public outreach and educational efforts are also aimed at increasing plastic recycling.

Discussing sustainability can be a challenge, because often there are various definitions. The very broadest definitions of sustainability consider the entire life cycle, including the raw materials and manufacturing processes to produce them and what happens to plastics products at their end of life. This addresses the use of hazardous chemicals, their carbon footprint and their recyclability and biodegradability.

“We are definitely seeing an increasing emphasis placed on, and demand for, metrics and data to indicate the level of sustainability of our plastics and production processes from a wide range of stakeholders, including customers, suppliers, non-governmental organizations (NGOs) and the public,” says Tim Watson, director of environmental, health and safety at Americas Styrenics (AmSty).

In addition to product design to meet intended performance targets, raw material ­selection is one of the earliest phases in the plastics life cycle and,as such, has received significant attention from a sustainability ­perspective.

Plastics have historically been manufactured from petroleum-based raw materials. The use of materials derived from various types of biomass provides the opportunity to develop sustainable solutions using bio-based polymers, says 
Marsha Craig, global venture leader – renewable performance polymers at DuPont.

“It is important, however, to provide performance and functionality equivalent to or better than today’s fully petroleum-based materials while reducing the environmental footprint. These new materials should make it possible for engineers to develop new components and systems that offer high performance with minimal environmental impact,” she says.

LANXESS is also committed to finding more sustainable raw materials, according to Jens Fischer, general manager Americas for LANXESS’ high performance materials business line advanced materials. It has invested in two startup companies that produce chemicals via the fermentation of sugars or other biomass.

To date, LANXESS has succeeded in producing polybutylene terephthalate (PBT) from bio-based butanediol (BDO) manufactured by Genomatica that has the same properties as PBT made from conventional BDO. The resin, used in connectors for the electronics industry and wire harnesses for automotive applications, is undergoing customer testing.

Bio-based plastics including bio-PBT, bio-PE (polyethylene), Bio-PET (polyethylene terephthalate), bio-PP (polypropylene) and PEF (polyethylene furanoate), plus many others, are being added to the list of more established products, including polylactic acid (PLA), polyhydroxyalkanoate (PHA), poly-hydroxyvalerate (PHV) and polyhydroxy-butyrate (PHB).

FOOD PACKAGING DOMINATES

One of the biggest applications for plastics is food packaging. “We believe that in the foreseeable future, the strongest contribution packaging can make to sustainability is to protect and preserve food, thus reducing food waste,” says Yasmin Siddiqi, DuPont packaging & industrial polymers leader. She notes that one third of the food the world produces is lost or wasted each year. “Feeding the world’s rapidly expanding population is one of the greatest moral and economic challenges of our time,” observes Siddiqi.

There are significant environmental consequences to food waste, because most ends in landfills and contributes to global warming by emitting methane, which, says Siddiqi, is 21 times more potent than carbon dioxide as a greenhouse gas.

“Couple that with the environmental impact of lost food in terms of wasted water and energy, and you start to see that 1lb of food saved has a significant human and environmental impact,” she notes.

As examples, she points to the use of high-performance resins that seal through contamination, such as grease, and plastic shrink films and barrier shrink bags as replacements for tray-and-lid solutions, which can keep meat fresher longer – improving colour, reducing odour and helping meat maintain its texture – as well as lowering overall costs and reducing packaging waste.

“Each pound of beef thrown away also wastes the 50lb of greenhouse gases that were generated to produce it. Improved plastic food packaging can therefore have a positive impact on the environment and help address one of the most challenging issues of our time – food waste,” Siddiqi asserts.

Innovations in plastic packaging for other applications outside the food industry are focused on reducing weight and material consumption while improving cost and performance to reduce the amount of packaging needed, she says.

“Active engagement in industry sustainability initiatives with brand owners that are driving the sustainable materials agenda, including recycling efforts, has enabled DuPont to focus on the development of high-performance packaging resins that allow for the use of less total material in lighter-weight, flexible packaging structures,” she says.

Collaboration with equipment manufacturers on technologies to enable further packaging weight reduction has also been important. “Close relationships with original equipment manufacturers are necessary for understanding their new developments and providing materials solutions that derive the greatest benefits from their new technologies,” comments Siddiqi.

Growing interest in packaging plastics based on renewably sourced raw materials and that are specially designed for the recycling of the post-converter waste stream, and even post-consumer waste streams, are also trends that have driven recent product introductions at DuPont, including new coupling agents.

“Advances in the properties of plastic materials and smart package design allow our customers to make more items out of every pound of plastic than ever before,” says Ian MacDougall, director of corporate planning at AmSty. “A container made from plastic uses three to four times less material than the same container made from ‘natural’ materials such as paper, metal or glass,” he adds. The result is substantial savings in energy, carbon dioxide and water consumption for society over the useful life of the container.

THE RECYCLING TREND CONTINUES

Although the challenges of post-consumer recycling can be significant, the industry is committed to increasing the recycling of plastics materials. “One of the most exciting things that is happening in recycling today is the industry-wide effort to improve recycling, which includes increasing collection rates, improving recyclability and broadening the types of plastics being collected for recycling,” says Holli Alexander, market development manager for sustainability with Eastman Chemical.

One of the major challenges, according to Watson, is the persistent conflict in expectations from communities that express interest in recycling activities and the lack of adequate funding of collection or separation facilities and operations. Alexander agrees many of the challenges facing recycling are systemic and large-scale, but increased industry collaboration to address them is a powerful trend.

With respect to post-industrial recycling, Fischer stresses the recycling of secondary materials will actually decline in the future because the industry is making significant progress in the reduction of waste and scrap production.

“Sustainability and recycling start with the producers, and preventing scrap and off-spec material can have a significant impact on lowering overall system costs while also reducing the environmental impact of plastic manufacturing,” he asserts.

Another key example of collaboration can be seen in the healthcare industry, according to Alexander. She notes that the Healthcare Plastics Recycling Council, comprised of key brands, package producers, and resin suppliers, is focused exclusively on improving the recycling of healthcare plastics. The group works closely with several large hospital systems and is preparing for a “regional pilot” in conjunction with SPI: The Plastics Industry Trade Association.

Some plastics, because of their properties, cannot be recycled. There is growing interest, according to MacDougall, in expanding the definition of end-of-life uses for plastics to include waste-to-energy or plastics-to-oil initiatives in order to make full use of these plastic materials.

“This re-use concept offers an alternative for disposal of non-recyclable plastics into landfills,” he says. For Alexander, the growth of compost or organic collection through municipalities is a very powerful movement for sustainability and recycling.

“As we begin to separate the wet or compostable materials from trash, we open up opportunities for better energy recovery for materials that may not be easily or economically recycled,” she says. MacDougal cautions, however, that the conversion of waste plastics to energy still requires their collection and accumulation at centralised processing areas, which presents supply chain challenges in the collection and separation of plastics streams.