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PVC frames offer a window into sustainability

Jun 21, 2023

Over the past 50 years, PVC window frames have become an extremely popular choice for homeowners. Prized for their minimal maintenance, energy efficiency and cost savings, today, this type of window frame accounts for nearly three out of every four residential replacement windows installed.

PVC is widely deployed elsewhere in the construction industry as well; in fact, it is by far the most-used plastic in the European building and construction market. It the third most widely used plastic in the world behind polyethylene and polypropylene. PVC is found in pipe, wire insulation, flooring, door frames, wallcoverings and carpet backing, to name but a few.

Its proponents praise its durability, abrasion resistance, light weight, good mechanical strength and toughness. Versatile and affordable, PVC is also easily recycled, even after decades of use. According to VinylPlus, the European PVC industry’s commitment to sustainable development, PVC has inherent sustainability characteristics. As it states on its website, ‘made from rock salt (57%) and oil (43%), it contains less carbon than most major thermoplastics’.

At the same time, PVC materials have increasingly fallen into public disfavour. PVC has been criticised for containing hazardous chemicals, such as phthalates that are classified as endocrine disruptors, and heavy-metal stabilisers; it can release carcinogenic dioxins and furans in the case of a fire or when incinerated. Exposure to vinyl chloride, a gas emitted during the production of PVC has been linked to an increased risk of various types of cancer.

It seems paradoxical: how can a single material be hailed on the one hand as inherently sustainable, and on the other be described as ‘the most environmentally damaging type of plastic’ there is?

Jelmer Bijlsma

Know your PVCSustainable Plastics talked to Jelmer Bijlsma, sustainability and innovation manager at the profine Group, a company that, as its website states has “made synthetics our art”. As a manufacturer of extruded profiles, profine has an expert knowledge of PVC. Bijlsma has served as sustainability manager at the company for almost three years. The role is a new one, created in response to the increasing focus on sustainability and related issues both in- and outside the company.

The profine Group, said Bijlsma, is an owner-managed company headquartered in Troisdorf, in Germany. The company manufactures and sells three different PVC profile brands worldwide: KBE, Kömmerling and TROCAL, each a premium product in their respective markets.Sustainability is an important theme for the Group, which takes what it calls a ‘holistic approach’ that goes beyond simply responsibility for the environment, to include social and economic aspects as well.This means the company is involved in various initiatives, such as the VinylPlus voluntary commitment and the Zero Pellet Loss scheme – becoming the first company in the window industry to be certified by the latter. Despite efforts such as these, not only on the part of profine, but by the PVC industry as a whole, various environmental organisations continue to qualify PVC as problematic and concerning and to lobby for bans on its use.Part of the problem is the fact that not all PVC types are created equal, Bijlsma noted.Plasticised PVC is one both of the most commonly used and one of the cheapest plastics available. The material is soft and flexible, due to the addition of plasticisers. The addition of plasticisers makes the material soft and flexible. Plasticisers are added to PVC in quantities of up to 60 percent of the final product by weight.However, because they are not chemically bonded to the plastic, those same plasticisers migrate out of the PVC to the surface as the material ages, leaving it hard and rigid. Commonly used plasticisers for PVC are phthalic acid esters – phthalates – and these are the chemicals that, once in the environment, have been associated with a plethora of health impacts. They are known carcinogens in laboratory animals.

Unplasticised PVC, which is what products such as window frames are made from, contains no phthalates or BPA. It is long-lasting, resistant to fading and offers excellent thermal efficiency.The profiles produced by the profine Group are all made from PVC-U, or unplasticised PVC.

The legacy of leadAnother issue is that PVC is extremely sensitive to thermal stress and can only be processed in the presence of heat-stabilising additives to avoid changes in the chemical structure. Lead compounds were long considered the most cost-effective and common form of stabiliser used for PVC. Because of concerns about lead exposure and the adverse effects this has on human health, use of these stabilisers was phased out voluntarily by the industry in 2015.The profine Group company was an early adopter, discontinuing the use of lead-based stabilisers in its PVC-U profiles in 2004 and replacing these with calcium-zinc-based stabilisers.Seeking to curb lead emissions from PVC by regulatory means as well, efforts soon got under way to include some lead compounds as substances of high concern in the EU’s REACH chemicals regulation.What then ensued was a tug-of-war at the European level. The PVC industry is committed to increasing in the volume of recycled post-consumer PVC waste to enhance the sustainability of PVC. A restriction on the lead content of the waste would put a brake on this ambition.

In the original draft of the proposal, derogations were included designed to allow waste PVC containing lead stabilisers - legacy materials - to be recycled. The lead content was subject to a certain limit, determined following careful consideration by the European Chemical Agency (ECHA)’s Committee for Risk Assessment (RAC). The RAC estimated that over a period of 15-20 years continual recycling dilutions would see lead concentrations in recycled PVC materials fall to a level of 0.1%. The proposed derogations, however, were rejected by the European Parliament due to concern over ‘carry-over’ and the ongoing risk of lead exposure over that period.

For the PVC industry, this was a considerable setback. It pointed out that most recycled PVC is sourced from long lifetime legacy products such as window profiles, cables and roofing membranes, which were in all likelihood produced before lead stabiliser use was phased out.The rejection of the proposal posed a potential challenge for profine as well, said Bijlsma, as not only does the company reprocess industrial waste - offcuts – but it also uses recycled materials from end-of-life window frames. The company is a founding member of the German Rewindo window frame recycling initiative, that has established a closed-loop recycling programme for PVC frames.“For example, we have customers who carry out renovation projects in which all the PVC window frames are replaced – and this is something we are seeing increasingly often, as these windows are now, say, 30 years old, or perhaps even more. They take back all the PVC frames, delivers them to one of our recycling partners who then takes them apart and shreds the PVC material. This comes back to our factory, where we reprocess it into new profiles,” Bijlsma explained.To the relief of profine and the rest of the industry, a modified version of the restriction proposal passed the scrutiny of the European parliament in March, was adopted under the REACH framework by the Commission and entered into force at the end of May.

Briefly, it states that items containing recycled rigid PVC can still be sold and used for a certain period, to promote recycling, save 1.5 million tonnes of CO2 emissions and up to 8.4 tonnes of lead emissions every year. To ensure recycling is safe, however, these items need to be completely covered by a lead-free layer, so people and the environment are protected from accidental exposure to lead. In addition, recovered rigid PVC can only be recycled back into the same application, for example window profile to window profile.The industry especially welcomed the restriction on the import of lead-containing PVC products from countries where lead is still used as a stabiliser, as this will help create a level-playing field between PVC products manufactured in the EU and imported articles.

A window into sustainabilityJust how important is sustainability in the window frame industry? According to Bijlsma, it’s crucial. “If we continue doing what we have always done, we are putting our survival at stake. I think we all now realise that finite resources such as fossil fuels are running out, and that the emissions associated with their use are causing our climate to change. It’s simple: we have to take care of our planet and improve our products,” he said.Bijlsma added that over the past several years, sustainability has therefore become a driver in product development. The goal is a sustainable cycle for high-quality synthetic materials, and the profine Group is striving to be a role model in this respect.With the way now open for the continued use of recycled material in its products, the company is working to increase its range of more eco-friendly products. In 2020, it launched its first window profile made from 100 % recycled PVC-U under the name Kömmerling ReFrame; it recently also launched a new product, called bio-attributed PVC profiles by Kömmerling. This latter profile is made with INEOS Inovyn’s Biovyn – the first commercial PVC incorporating renewable feedstock.

The new profiles are made with bio-attributed, not bio-based PVC, emphasised Bijlsma. Pine oil-based raw material replaces some of the petroleum in the cracker in producing the ethylene used to make the PVC, which allows a CO2 reduction of up to 90% compared to conventional PVC and corresponds to two kilograms of CO2 savings per kilogram of material used. profine is certified to the RSB - Roundtable on Sustainable Biomaterials- standard from the raw material to the finished profile. Customers are issued a project-related verification certificate for each product delivery.“It’s more expensive than conventional PVC, but the first project in the Netherlands is already in progress,” said Bijlsma. “For both the window manufacturer - Kumij - and the Royal BAM Group who are carrying it out, the sustainability benefits, plus the fact that the frames offer exactly the same performance as traditional ones, count for more than price.” The issue, he said, is that there is not a lot of this raw material. “Once production of the raw material is scaled up, the price will come down.”This first project involves 19 dwellings that are being renovated into net-zero-energy social housing. The project involves a total of 113 windows and doors from the Dutch K-VISION Trend profile series, with frames in a cream colour typical of the country, multiple dark green foiled casements and high-quality triple glazing. It is the first construction project in the world to use certified bio-attributed PVC window frames. The Group is justly proud of this product. “It is a first in our window industry and we consider it an important step in the development of sustainable building materials. This innovation alone saves around 6,000 kilograms of CO2 in the project,” said Bijlsma. “All in all, it is a tremendous step forward. Of course, there's still so much to do. But I think we're making progress in the whole building industry.”

Henri Victor Regnault

PVC- A brief historyLike most discoveries, the creation of PVC was more accidental than anything else – only in the case of PVC, it happened at least twice. It was first discovered in 1838 by a French physicist and chemist named Henri Victor Regnault. Regnault had left several flasks of the newly discovered vinyl chloride gas exposed to sunlight. To his surprise, he later found a white solid polymer inside the flasks. The material was brittle and hard, and Regnault, having no practical use for it, never patented the discovery.Almost forty years later, in 1872, a German chemist called Eugen Baumann did the exact same thing. He made mention of his discovery, but, like Regnault, could find no useful application for the polymer.The first patent for the production of the compound was awarded to the German chemist Friedrich Klatte in 1913. Klatte discovered how to polymerise vinyl chloride into PVC, but he, too, never marketed the product for commercial use.

It wasn’t until 1926, with the invention of plasticized polyvinyl chloride by Waldo Lonsbury Semon, a researcher working for the B.F. Goodrich Company in the United States that the true potential of PVC started to be understood. Semon had been trying to find a cheaper synthetic substitute for natural rubber, when he accidentally found a way to increase the plasticity of PVC to make it more elastic. He discovered that by heating the PVC polymer in a solvent that had a high boiling point, a gel-like substance was created that once cooled, was elastic in nature.

For his invention, Waldo Semon received United States patents #1,929,453 and #2,188,396 for the "Synthetic Rubber-like Composition and Method of Making Same; Method of Preparing Polyvinyl Halide Products."

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Know your PVCThe legacy of leadA window into sustainabilityPVC- A brief history