Apparatus and methods for manufacturing biodegradable, compostable, drink straws from polyhydroxyalkanoate material
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Solution Overview
Problem
There is a challenge in producing biodegradable and compostable drink straws with thermoplastic and mechanical properties suitable for consumer use, particularly with polyhydroxyalkanoate (PHA) material, which has different processing requirements than traditional polymer materials.
Innovation Solution
The development of an apparatus and method for manufacturing drink straws from PHA material involves a hopper for raw PHA, an extruder for melting and shaping the material, and a system of water baths for crystallization and shaping, including a pre-sizing water bath and a two-stage water bath, to produce straws with desired properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional polymer materials (e.g., polypropylene) are used to manufacture drink straws, then the straws have acceptable thermoplastic and mechanical properties for consumer use, but the straws are neither biodegradable nor compostable
Solution Approach 1:
The patent applies parameter changes by modifying the processing conditions for PHA material, specifically using temperature ranges of 250-350°F for extrusion and controlled cooling rates to achieve proper crystallization. The extrusion speed and die geometry are also adjusted to accommodate PHA's unique rheological properties, enabling successful manufacturing of biodegradable straws with acceptable mechanical properties
Solution Approach 2:
The patent utilizes phase transitions of PHA material during processing, including melting the material to 250-350°F for extrusion, controlling the crystallization phase transition during cooling in water baths, and managing the solidification phase to achieve the desired tubular straw structure with proper wall thickness and mechanical integrity
2Reliability
If PHA material is used to produce biodegradable and compostable straws, then the straws achieve marine-biodegradability and home-compostability, but the thermoplastic and mechanical properties differ from traditional materials requiring new processing methods
Solution Approach 1:
The patent segments the processing system into distinct functional zones: a hopper for material feeding, an extruder with heated barrel and screw for melting and mixing, a die assembly for shaping, water baths for controlled cooling and crystallization, and a puller for continuous production. This segmentation allows each component to be optimized for PHA's specific processing requirements
Solution Approach 2:
The patent uses water baths as intermediary cooling media between the hot extrusion process and the final solidified straw product. The water baths provide controlled thermal transition, allowing gradual cooling and crystallization of PHA material, which is essential for achieving the desired mechanical properties and structural integrity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method enables the production of PHA drink straws that are marine-biodegradable, soil-biodegradable, home-compostable, and industrial-compostable, with significant degradation (up to 88% in 97 days) in marine environments, meeting the requirements for biodegradability and compostability.
Implementation Method 1
an extruder that receives the raw PHA material from the hopper and produces extruded PHA material. Molten PHA material may be provided from the extruder through an extruder die
Implementation Method 2
One of the water baths may be a pre-sizing water bath that is configured to receive the extruded PHA material from the extruder, to cause the extruded PHA material to begin to crystallize to form crystalizing PHA material
Implementation Method 3
The extruded PHA material may be pulled through one or more water baths
Data Source
AI summary
Apparatus and methods for manufacturing compostable, biodegradable drink straws from polyhydroxyalkanoate (PHA) material are disclosed herein. Such apparatus may include a hopper that contains raw PHA material, an extruder that receives the raw PHA material from the hopper and produces extruded PHA material, one or more waters baths that cool the extruded PHA material, a puller that pulls a tubular stream of PHA material through the system, and a cutter that is configured to cut the stream of PHA material into finished straws. The finished straws may be soil- and marine-biodegradable, as well as home- and industrial-compostable.