APPARATUS AND METHODS FOR MANUFACTURING BIODEGRADABLE, COMPOSTABLE, DRINK STRAWS FROM POLYHYDROXYALKANOATE MATERIAL

Smart overview of the Invention

An innovative method for producing biodegradable and compostable drink straws using polyhydroxyalkanoate (PHA) material has been developed. The manufacturing apparatus consists of several key components, including a hopper for raw PHA, an extruder that melts and shapes the material, water baths for cooling, a puller to guide the material, and a cutter to finalize the straw lengths. These straws are designed to break down in soil and marine environments, as well as in home and industrial composting systems.

Challenges with Traditional Straws

Conventional drink straws are typically made from non-biodegradable plastics like polypropylene. As environmental concerns grow, there is an increasing demand for alternatives that can decompose naturally. PHA offers superior biodegradability compared to traditional materials; however, processing it into straws presents unique challenges due to its distinct thermoplastic and mechanical properties.

Apparatus Components

The manufacturing system includes a hopper that feeds raw PHA pellets into a screw-and-barrel extruder. The extruder is designed with a specific temperature profile to melt the PHA efficiently before it is shaped into a tubular form through a specialized die. The die features an internal pin that helps define the straw's dimensions while allowing for air to be introduced into the hollow tube as it exits.

Cooling and Shaping Process

After extrusion, the PHA material is passed through one or more water baths to cool and crystallize, which is essential for achieving the desired mechanical properties. A pre-sizing water bath initiates crystallization, followed by a sizing tube that ensures uniformity in the straw's shape. The puller system is carefully designed to avoid damaging the delicate PHA structure while maintaining a consistent flow through the cooling process.

Environmental Benefits

The resulting drink straws made from this process are not only functional but also environmentally friendly. They are capable of degrading significantly within marine environments—up to 80% degradation within one to two years, with some tests indicating up to 88% degradation in just 97 days. This advancement represents a significant step towards reducing plastic waste and promoting sustainable alternatives in everyday products.