Could milk casein one day replace plastic?

Machined to make buttons, jewels, trinkets, and light switches, Galalith, an early 20^th century material invention, had the appearance of horn and offered significant mechanical strength. "The material was gradually phased out in favor of plastic. At the time there were already two strikes against it: the formula incorporated formaldehyde to ensure that the objects wouldn’t be altered when in contact with water, and it was produced from milk fit for consumption," explains Marion Seignan, now a Designer at Frog Design (Capgemini Invent).

With investors behind the project, could milk casein be a viable alternative to plastic? ©Véronique Huyghe

During her studies at ENSCI (France’s National School for Industrial Creation), Seignan, began looking into Galalith’s potential. "In France, nearly 500 million liters of milk are destroyed every year and in Europe, a total of 11 billion liters a year," remarks Seignan. "It can’t be sold, thrown away or even dispersed as legislation prohibits it for health reasons," she adds.

Objective: upcycling dairy waste

She began experimenting in the kitchen: "At first, I made quite a lot of... cheese!” (The first stage of the process consists in transforming casein from a liquid to a solid state.) She then molded the casein and gave it color. "Depending on whether the pigments are integrated directly into the milk or added to the casein after extraction, the results are very different, ranging from homogeneous to marbled color effects."

Working in collaboration with researchers and engineers at French institutes CNRS and INRAE, Seignan developed a polymer whose physical properties resemble plastic, but with an appearance closer to ivory or stone than a conventional bioplastic. The material has the bonus of being weighty in hand.

Casein’s technical and aesthetic potential is very real. "Depending on the process used, the source material can be transformed into flexible, rigid, translucent, opaque, smooth, or textured materials, which can be machined, molded, thermoformed, thermo-welded or laser-cut and engraved." With the help of a doctoral student at French university Jussieu, she hit on a method that results in a material that is at once porous, lightweight, and extremely resistant. It is also 100% biodegradable, a non-negligeable selling point in today’s market.

Casein can be formed into a high-strength material or alternately one that is water-soluble ©Véronique Huyghe

Flexibility: casein’s strong selling point

What's is particularly interesting about this material, points out Seignan, is its flexibility. "Casein can be modulated from the most water-soluble to the most durable, allowing it to correlate the lifespan of the objects it holds. This means that with one material, we can address several different time frames. From simple consumables – water-soluble components that give users the freedom to manage their end-of-life – to more enduring objects. This means containers and packaging elements like jars, caps, cases and boxes that are more or less water-soluble, but also decorative elements for interior design: the potential appears without limits.

Billions of liters of milk are destroyed every year in Europe, making a strong case for upcycling. ©Marion Seignan

Seignan has designed debut product ranges for two very different markets: a line of funeral urns (in extra-hard, extra-dense casein) and one for perfume diffusers: "Casein has a real affinity with perfume. First because proteins encapsulate odors well and secondly, casein is resistant to alcohol while remaining water-soluble, which opens new potential for recycling perfume testers."

Seignan has been approached by architectural firms, agro-industrialists and companies looking to alternatives to plastics; she is currently seeking partners to deploy her industrial processes and scale up.