Manufacturing processes of bottle caps and tear away tubs rely on the use of non-renewable resources for production. The production of these materials creates large amounts of effluent during the manufacturing process. End of life for these products generally cannot be recycled or are left in landfills, degrading not as quickly as the world would like. For the purposes is this project Sunstrand is proposing to introduce natural bast hurd such as hemp, flax, and kenaf into the production process. These materials would not replace the entire Polyethylene/Polypropylene cap/tub but rather offset a significant fraction of the polymer material with biodegradable micronized hurd filler. Bast hurd is comprised of cellulose, hemicellulose and lignin; 100% biodegradable and can be easily introduced into composite/plastic component manufacturing techniques with little to no modification required by the manufacturer. The small step of replacing some of a widely mass produced item with biomaterials will be an evolutionary step towards less plastic waste generation, easily adoptable by current manufacturing processes.
Compounding of thermoplastics is a common practice whereby virgin polymers are mixed with a variety of additives to yield variations to the performance of manufacturability of plastic parts. Incorporating biomaterials such as hurd particulates or natural fibers inconveniences manufacturers very little allowing for an easier transition more environmentally friendly products. The increase of filler composition will decrease the amount of matrix material, polymers such as high density polyethylene (HDPE), low density polyethylene (LDPE) and polypropylene (PP). All these types of polymers are used for cap/tub production and require a significant amount of energy for production, See table in visuals. Sunstrand’s analysis of its own production practices uses only 0.670 MMBtu/ton of energy and not reflecting the carbon sequestered during the plant growth cycle. Chemical and petroleum based products cannot sequester carbon out of the air, unlike bast plants which absorb roughly 0.79 kg of CO2 for every kilogram of fiber grown. Although there will be less matrix material the caps and tubs will maintain strength properties as the bio-filler material can impart beneficial mechanical properties.
Sunstrand is currently on track to become the Sustainable Materials Company, suppling biomaterials for advanced applications in North America. With connections to upstream manufacturers that produce polymer products and a team made of engineers researching new ways to implement their products into end user products to mitigate environmentally negative effect composite part production practices.