The Sustainable Choice: Why We Use Polypropylene in Our Bins

The "war against plastic" raises frequent questions about our use of Polypropylene (PP) in our bin manufacturing. The material selection wasn't taken lightly. In the design process, we considered all materials and production techniques, from stainless steel to bioplastics. We couldn't find a material that matched PP in strength, durability, recyclability, and its beautiful matte finish.

The concern over plastic is understandable; a major plastic problem undeniably exists. However, we believe in using plastic responsibly, focusing on circularity and moving away from single-use items.

Polypropylene: A Sustainable Choice?

PP is number 5 plastic; it is strong, durable, and resistant to fatigue and heat. As one of the few structurally stable plastics, it lacks the off-gassing and toxicity of others, leading to widespread use in the medical industry and food packaging (ice cream containers, medicine containers, and bottle lids). This explains the growing market value of PP and the increasing number of recyclers collecting it.

When properly treated, PP is fully recyclable. Broken parts, end-of-life stock, or production errors are chipped down and reused in production. This is why we use pure PP. By avoiding other plastics or excessive overlays, we ensure our bins remain fully recyclable.

Sourcing quality recycled PP in New Zealand in sufficient quantities proved challenging, especially with injection molding's complexities. However, with our manufacturing partners and recycling processors, we incorporated 50% recycled materials into our 60L bins.

This journey enabled us to make 100% of the black components of the Method Twenty from recycled materials. We maximized black components to increase recycled material use.

Our recycled materials are sourced locally, including curbside collections in Whanganui and Christchurch. Sources vary but often include:

• 1-liter yogurt containers

• 2-liter ice cream containers

• Car bumpers

• Buckets

• Car wheel covers

Challenges and Future Goals

Colored components present a greater challenge. Our team actively seeks onshore recycled PP sources in New Zealand or Australia for our lids. Usable material requires a clear or natural PP source. We are exploring a private collection scheme to validate market materials and enable large-scale, regular collection.

Durability and Performance

PP's strength and durability were key selection factors. A bin endures significant workplace use; flexible or low-quality materials necessitate frequent replacements. Injection molding allows for a relatively thin bin base while maintaining years of use under at least 20 kg of waste daily. Our confidence in the design is reflected in the 3-year warranty.

Maintaining Recyclability

Many organizations effectively use recycled materials, but mixed plastics often hinder recyclability. Our 60L and 20L bins are currently made from pure polypropylene (#5 plastic). We remain open to material changes if a more sustainable solution meets our criteria.

Product Stewardship

Method prioritizes product stewardship. The founders believed that addressing waste requires appropriate end-of-life solutions. Durable materials extend product life, emphasizing reuse before recycling. Usable returned bins are refurbished and donated; beyond repair bins are recycled.

We take design and sustainability seriously; each step is carefully considered for longevity and circularity.