pu-schaum.center · Recycling

Recycling – a new lease of life for construction foam cans

"Cradle to cradle" is the aim of modern recycling systems. This means that, ideally, a product will be used over and over again - although perhaps in a different form. This vision is already reality for the 25 million PU foam cans used in Germany every year. A spent construction foam can is recycled to 95%; 80% of this in materials. This is made possible by the PDR industry solution.

PDR Recycling GmbH + Co KG — Products via Recycling

As early as 1993 the European manufacturers of PU foam cans set up an exemplary return and recycling solution for spent assembly foam cans in collaboration with PDR. Today, PDR is a sought-after recycling specialist for materials recycling of used products and production residues. It all started with the recycling of PU foam cans.

Step 1: Collection and return of spent construction foam cans

Anyone seeking a high-quality material-based recycling program first needs to sort the recycling products into their separate material components. PU foam cans are deemed special waste due to their MDI content. Therefore, the most important aspect when recycling PU foam cans is to establish a clever return system for spent construction foam cans - both for professional users and also the growing number of hobby users. Anyone who consumes boxes of assembly foam cans, can request for them to be picked up anywhere in Germany free-of-charge by PDR. Hobby users that only use PU foam cans occasionally can return these to a retail outlet or a municipal waste depot. PDR also takes back and recycles MDI-reduced and MDI-free PU foams via the PDR system.

To find out just how easy it is to make use of the PDR collection service, or where there is a return station close to you, please read here:

Do you know how to return used PU foam cans? Four funny animated mini-cartoons show you the best solution. Curious? Then click right here!

Step 2: Recycling of PU foam cans

Thanks to recycling technology that was specially designed for construction foam cans, PDR achieves very high recycling rates. The only system for recycling PU foam cans in the world is located at the site in Thurnau (Upper Franconia); this system chops the assembly foam cans mechanically without oxygen and the fluid residues and metal parts (aluminium and tin plate) fall into a solvent bath. Here, a washing screw removes the metal parts and washes them. This is followed by further washing and drying stages. The metal filter sorts the cleaned and dried aluminium and tinplate. 

The PU solvent mix that is created runs through a filter several times to separate the PU and solvent again. The solvent is added to a cycle for reuse in the next washing stages. The propellants are suctioned off and liquefied under pressure. The plastic caps are ground into granulate and used to make plastics.

Step 3: New products from old construction foam cans

From the recycling process PDR generates a series of new products that are sold again or returned to the raw material cycle.

PREPUR® is the pre-polymer that is recovered from the PU foam cans. It is then used again in various polyurethane applications such as adhesives, foams, paints, filling materials and binding agents.

PREMOD® is a blend of PREPUR® and MDI. As agreed with the customers, various mix ratios are possible depending on the specific purpose.

TRIGAS® is the propellant that PDR removes from the PU foam cans. The aerosol industry uses the fluid gas mix for technical aerosol products and cleaner sprays.

The ground plastic PE/PP is produced from the recycled caps of the spent PU foam cans. This is a colourful mix of PE/PP plastics and is used to make other plastics.


Also, there are scraps of tin plate and aluminium from the packaging material of the assembly foam cans. Both fractions are sold to the metal-working industry where they are smelted again.

Good service for excellent recycling rates

We can only recycle what is returned. Which is why, right from the start, PDR's recycling solution for spent PU foam cans focused on making it as easy as possible for tradesmen and women and DIY enthusiasts to return the cans. The idea of using the sales box as a return box was as easy as it was brilliant. It meant that tradesmen and women only had to put the empty cans back into the box and arrange for the box to be picked up once it was full. All the necessary contact data is stated on the box and on the can. This gives specialists in the trade an easy and automatic return system.

PDR has also established a widespread network of return stations for DIY enthusiasts that only use cans occasionally. Individual cans can be returned free-of-charge to more than 2500 DIY stores and communal recycling depots. These collection points are easy to find thanks to the search machine at www.pdr.de. Just enter the ZIP code and the system shows all return options.

Informing and motivating

Communication is just as important as creating these easy return options. This means: Informing tradesmen/women and DIY enthusiasts about the returns system, and motivating them to make use of it. For this reason, PDR has focused on a wide range of communication activities since its foundation. The most important element in this system is the company's own service centre that regularly calls tradesmen and women, retailers and communal offices to arrange pick-up appointments. In addition, there is free-of-charge information available for tradesmen/women and communal offices, who then inform the end consumers that only use cans occasionally. PDR also provides free return boxes and return stations for this target group. It also participates in exhibitions, issues press releases and maintains direct contact to professional user groups.

Own logistics service

A further challenge to implementing the recycling goals is the reverse logistics. One might think that only specialised freight haulage companies need to be contracted to complete the task inexpensively and reliably - but that proved not to be the case. Boxes containing spent PU foam cans do not weigh much. Transportation company employees, who are used to dealing with heavy weights, do not take them particularly seriously. Midway through the 90s PDR was finding that their orders were frequently not carried out because lorry drivers could not be bothered to take a detour for 'a few boxes'. This is why PDR set up its own logistics service that works with service providers. As a result, PDR can meet all pick-up orders and the return boxes can be collected directly from the various user companies. In addition, the drivers also help to pack the cans if necessary to ensure that all legal waste regulations are satisfied. This includes the necessary transportation permits and, more importantly, the take-over confirmation for the company so that it can prove to the authorities that it has disposed of its PU cans correctly.

Last but not least

Recycling is the final stage of this process that also includes packaging and all contents. Thanks to recycling technology that was specially designed for construction foam cans, PDR achieves very high recycling rates in excess of 95 percent - 80 percent of which is material based. From the recycling process PDR generates a series of new products that are sold again or returned to the raw material cycle. These exemplary recycling rates can only be achieved by sorting the PU foam cans separately.

A humorous explanation of the returns and recycling system for spent PU foam cans: