Manufacturing solid surfaces with RIM – Arfinio makes it possible

Something is only impossible as long as you don't try. Covestro has tried - and succeeded. The company has developed the new Arfinio manufacturing technology, the first application to allow reaction injection molding of aliphatic polyurethanes. This represents a breakthrough for the manufacture of solid surfaces. Joan Miquel Garcia Martinez explains in an interview why this was previously considered unthinkable and why it now works after all.

Mr. Garcia Martinez, please explain briefly what the breakthrough in this research was.

Joan Miquel Garcia Martinez: Arfinio® is a new breakthrough material and manufacturing technology: a solid-surface or artificial stone-like material made of a combination of unique minerals and aliphatic polyurethane (ALI PUR) polymers, manufactured using Reaction Injection Molding (RIM). It is lightweight, yet highly resistant (with all the benefits of PUR chemistry, such as light-fastness), repairable, and recyclable. Arfinio® is the first lightweight material of its kind, the first material of its kind to be manufactured with ALI PUR polymers, and the first instance of ALI PUR being processed by RIM.

Why was the RIM process considered impossible with ALI PUR until now?

Garcia Martinez: RIM has been used for decades with aromatic polyurethanes (ARO PUR), which have a much faster reaction time than ALI PUR. The reduced reactivity of ALI PUR leads to severe issues with surface defects, due to the shrinking of the material during the reaction.

For decades, different companies – including Covestro – unsuccessfully tried to find a way to process ALI PUR with RIM, so the industry assumed it was impossible to combine them. Thanks to our partnership with Arcesso Dynamics, we have now been able to find a way to use RIM with an ALI PUR system without surface defects. It is a modified process that also enables a faster cycle (demolding) time.

How were you able to overcome this challenge?

Garcia Martinez: We cannot provide specific details of the manufacturing process, since this constitutes sensitive manufacturing details. But the greatest challenge was that we had to forget everything we previously knew about RIM and completely rediscover the technology.

We had a set of challenges and a toolbox of technology, and we challenged every single belief in order to find out what about the technology was relevant and what needed to be different. At a certain point, we understood what was going on in the mold, as well as how and why, and we developed the concept. Then we started to play with all the relevant elements, not just the formulation, in order to further master and control the process.

One additional challenge was that the current way of working with ARO PUR takes into account that surface defects can be plastered and hidden during painting. In our case, to produce a mono-material, we needed perfect pieces. This also awakened our ambition to bring control of the process to an unprecedented level.

What makes the Arfinio® material special?

Garcia Martinez: I have mentioned lightness already. This is quite a relevant characteristic, as reducing the amount of material used to produce a piece is the most effective way to reduce its carbon footprint. This does not mean that Arfinio® is a weak material – quite the opposite. It has very high chemical and mechanical resistance, including abrasion and impact resistance, which have a direct relationship with its durability.

Besides that, Arfinio® can be repaired and recycled through milling at the end of its service life and being added to formulations as a replacement for mineral filler. The other properties that make it special depend on the application. For example, Arfinio®’s slip resistance is relevant in shower plates or bathtubs, as is the good insulating capacity that we can achieve thanks to its double structure. Arfinio® parts have two different densities: they consist of a lightweight core and a two-millimeter-thick non-porous skin, both made in a single step from the same material.

What does the new material make possible that was not possible before?

Garcia Martinez: We believe that Arfinio® opens possibilities to industrialize designs that, until now, were too complex to be produced in series. One of the benefits of the Arfinio® technology is that any detail added to a design is simply taken into account in the mold design, so the complexity of a piece does not add additional processing steps or translate to longer lead times for production.

The material can also be used in applications where a low weight is very important. It is also suitable for applications where a truly seamless part is needed to avoid structural weaknesses: to date, most parts have joints that weaken the structure, even if they are not visible.

What do you think is the future potential for solid surfaces through Arfinio®?

Garcia Martinez: In the future, I believe that we will see these kinds of solid surfaces used more often in applications where they are not used today, and that their presence will increase in some existing applications. Arfinio® enables designers, architects, and brands to aim for applications and designs that were not possible before.

To take one example: in mobility, there is a trend toward vehicles becoming an extension of our living rooms, but it will be important to minimize weight in order to reduce energy consumption. I would expect Arfinio® and other smart, sustainable materials to be part of these 'living rooms on wheels'. And in the very near future, I'm pretty sure you'll be surprised about the new applications for solid surfaces that we are developing with Arfinio®!