Materials: Navigating the landscape of sustainable materials can be confusing and obscure. This section offers a point of view on the materials having an impact on sustainability right now, and some interesting innovations worth keeping tabs on.
A Perspective on Sustainable Materials
Sustainable materials should ultimately fall into two categories:
Products that have to be disposable (for health or safety reasons) should disappear immediately after they are used. Made from materials that can be replenished in nature with a neutral carbon impact.
Examples: paper pulps, plant based fibers, feedstock, algaenates.
Most packaging and product components can be kept in the loop (through refurbishment or recycling) provided they are made of materials that can be reprocessed into the same raw form as they began, or designed in such a way that they are useful for a life time (refill).
Examples: aluminum, copper, glass.
Materials that fall in-between are neither made to last or breakdown in an acceptable way, which is the definition of unsustainable. While down-cycling (processing a pure material into a lesser material) is a strategy for dealing with our current waste problem, it is not a sustainable strategy longterm.
Glossary of Terms for Sustainable Materials
Post-Consumer Recycled (PCR) Content – Made from a percentage of material that has been recycled from used products e.g. a PET milk bottle reground to make more bottles. Making products from PCR materials is ideal as it removes material from existing waste streams.
Pre Consumer Recycled Content – Made from material waste that is a by-product of the manufacturing process (off-cuts, rejects), and is a best practice for manufacturing. It does not remove waste already existing in the world and should be looked at as a lesser impact material than post-consumer recycled.
Bioplastics – A broad term for any plastics made from biomass (plant matter). Right now, the supply, processing, and recycling compatibility of these polymers would not be considered a truly sustainable option. We recommend doing a full material life cycle analysis before claiming anything with bioplastics.
PLA – Polylactic Acid, the most common family of bioplastic (identification code #7). Much more pervasive as a "biodegradable" replacement for disposable products, although generally requires an industrial facility to properly degrade.
Starch Based Polymers – Coming from the glucose monomer, starches have weaker environmental resistance (especially water) which makes them ideal for short-lifespan packaging that styrofoams are typically used for. They can also be safely consumed by humans!
Cellulose Based Polymers – Also from the glucose monomer, cellulose polymers cover a wide range of applications and degrees of degradability – from plant based fibers ("paper pulp") to to urethanes for adhesives and textiles.
BPA Free – BPA is found in polycarbonate plastics, and is a proven toxic resin that can seep into food. BPA free does not mean
Organic – Material that has been grown without chemicals or genetic modification.
Natural – A baseless term often used to greenwash.
Why Materials Matter
Wood Fiber Paper Pulp
One of the most simple and renewable forms of packaging. Cellulose fibers from wood are colored in a wet mixture, thermoformed and dried into shape. A high-resolution of detail can be achieved on consumer-facing surfaces.
Resistance to water is not ideal, but barrier coatings can be applied for limited resistance to oils and liquids (link to Kuraray's Exceval coating).
Similar to wood paper pulp, bagasse is a majority cellulose paper made from sugarcane that is a cheaper alternative to wood fibers.
The wet press application creates a smooth finish with fine detail for primary surfaces that can appear almost like plastic. It is a common material used as packaging trays, paper plates, and takeaway packages.
Often used by lower-cost vendors, we recommend analyzing manufacturing methods before claiming sustainability, as this can be a highly water-intensive process.
A bioplastic made from potato starch that is certified biodegradable and compostable according to the standards set by the European Union (EN 13432). The material can break down in greenhouse conditions, with a minimum lifespan of 6 months.
Aside from degradability, starch bioplastics are ideal as they process identically to comparable petro-plastics, making change over easy.
Visit Solanyl, a Canadian supplier of starch polymers
Injected Molded Starch Foam
Foamed potato starch is a lightweight, molded material that can replace plastic packaging parts that do not need moisture resistance. The texture is a matte, mottled finish which has a similar feel to styrofoam. A key advantage is that parts can be "glued" together using a small amount of water.
Its water solubility means it can be disposed of and broken down in minutes and is safe for human consumption. Barrier coatings are in development for limited resistance to liquid and fats.
Elephantgrass Cellulose Pulp and Plastic
Elephantgrass, a more efficient base material vs wood, is the base material processed into paper, pulp, and plastics.
For paper and pulp applications the material is similar to other molded fibers. The plastic alternative material requires industrial conditions to biodegrade, which should be considered as part of the end-of-life assessment of your part.
Another molded packaging alternative, mycelium is 100% at home compostable, making it a low impact option (select vendors are cradle2cradle gold certified).
Mycelium pulp has a large fiber size, giving the final molded part a rough textured finish. Much larger part tolerances are also required vs injected pulps or plastic parts.
An abundant resource that can be recycled infinitely, formed in a number of ways, with superior properties. Aluminum is primed to be the leading material in the circular economy!
Because of the high carbon footprint of extraction, aluminum CAN ONLY be considered a sustainable option if it is captured back. When using aluminum it is critical to understand what alloy is being used, and how that is reprocessed.
One of the oldest packaging materials, glass has many characteristics that make it ideal for circular products:
– It fits into a known recycling system.
– Detail can be molded to replace label materials & inks.
– It has an established value perception.
Glass is not recycled to its full potential in the US, and is energy intensive to produce. Any supply chain that relies on virgin glass is not a sustainable option. There is an opportunity for brands to take a bigger role in recapturing the material.
Watch a video from O.Berk explaining how glass bottles are made
Cork is waterproof, buoyant, elastic, fire-resistant, insulating and made from a regenerative source; a cork tree can be harvested for its bark roughly every 9yrs, and can live up to 300.
It comes in sheet form and can be molded, with various coloring options. A consideration for packaging is corks weight, which is a consideration for products that are shipped.
Like aluminum, steel alloys can be recaptured and recycled many times over if the material grade and processing conditions are factored into the design.
The benefits vs aluminum are strength, weldability, less conductivity, and more coating options. Circular products made from steel are likely to be highly returnable, lasting forever.
An introduction of stainless steel grades & applications
Polylactic Acid Plastic
A family of plastics that are commonly marketed as a sustainable alternative to petrochemical plastics. Extracted from natural products like corn, cassava, sugar cane or beets, these plants capture and sequester CO2 transforming it into long-chain sugar molecules. This is processed into PLA, which can be injection molded like traditional plastics.
While many PLA products are technically biodegradable, they require industrial composting conditions (chemical hydrolysis process, followed by the microbial digestion). As these are not yet widely available this material should not be considered a sustainable option.
Sulapac - Straw Based Polymer Replacement
Sulapac’s innovation is completely biodegradable and microplastic-free raw material. Plastic manufacturers can procure a licence to use the material and technologies in their existing equipment and plants without major capital investments. The solution has vast potential to reduce the amount of plastic waste that ends up in the sea.
Visit Sulapac, a vendor of straw based polymers
Post–Consumer Recycled Nylon
Nylon waste from landfills and oceans around the world is transformed and regenerated into nylon textiles. It offers a degree of circularity if the nylon is kept in a loop.
NewspaperWood is a company that reverses a traditional production process; not from wood to paper, but from (news)paper to wood. When a NewspaperWood log is cut, the layers of paper appear like wood grain or growth rings of a tree and therefore resemble the aesthetics of real wood.
A novel project looking at recycling paper. Not a long term sustainable option.
Textile Waste to New Textiles
A new technology that can turn textile, cardboard and agricultural waste to new natural fiber. Thus we can reduce the usage of new virgin materials. This fits any factory and is applicable to existing pulp and viscose fiber factories.
Because seaweed and algae are fast-growing and sequester CO2 out of the atmosphere, a number of new materials are being explored using these materials as the raw input.
We don't consider these to be advanced enough to claim renewability or circularity, but they could in the future with the right recapturing conditions.