PHA Straw Extrusion with Two-Stage Cooling for Marine Biodegradability
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Solution Overview
Problem
Traditional drink straws made from plastic or thermoplastic polymers are not biodegradable or compostable, and there is a challenge in producing straws from polyhydroxyalkanoate (PHA) material that possess both biodegradable and compostable properties while maintaining acceptable thermoplastic and mechanical properties for consumer use.
Innovation Solution
An apparatus and method for manufacturing drink straws from PHA material using a hopper, extruder with a temperature profile, and a two-stage water bath to produce a tubular straw that is marine-biodegradable, soil-biodegradable, home-compostable, and industrial-compostable, with the extruder increasing temperature from the raw material end to the die end and the water bath having different temperature stages to crystallize and cool the PHA material effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional plastic or thermoplastic polymer materials are used to make 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 implementing a specific temperature profile in the extruder (increasing temperature from feed end to die end) and using a two-stage water bath with specific temperature ranges (first chamber: 125-175°F, second chamber: 70-90°F). These parameter adjustments enable proper processing of PHA material to achieve both biodegradability and acceptable mechanical properties for consumer use.
Solution Approach 2:
The patent utilizes phase transitions by controlling the melting and crystallization of PHA material through the temperature profile in the extruder and the two-stage water bath cooling process. The material transitions from solid to molten state during extrusion, then crystallizes in the water bath to achieve the desired mechanical properties while maintaining biodegradability.
2Reliability
If PHA material is used to produce biodegradable and compostable straws, then the straws achieve marine-biodegradability and home-compostability, but the PHA material has different thermoplastic and mechanical properties that challenge processing into straws
Solution Approach 1:
The patent implements parameter changes through a temperature profile in the extruder that increases from the feed end to the die end, and through a two-stage water bath with controlled temperature ranges (first chamber: 125-175°F, second chamber: 70-90°F). These parameter adjustments enable proper processing of PHA material to achieve both biodegradability and acceptable mechanical properties for consumer use.
Solution Approach 2:
The patent utilizes phase transitions by controlling the melting and crystallization of PHA material through the temperature profile in the extruder and the two-stage water bath cooling process. The material transitions from solid to molten state during extrusion, then crystallizes in the water bath to achieve the desired mechanical properties while maintaining biodegradability.
3Ease of manufacture
If a single-stage water bath is used to cool extruded PHA material, then the cooling process is simple, but it cannot effectively crystallize and cool the PHA material to achieve desired mechanical properties
Solution Approach 1:
The patent applies segmentation by dividing the cooling process into two distinct stages with different temperature ranges. The first chamber maintains water at 125-175°F for initial cooling and crystallization, while the second chamber uses 70-90°F water for final cooling. This segmentation enables effective crystallization and cooling to achieve desired mechanical properties.
Solution Approach 2:
The patent implements local quality by providing different temperature conditions in different sections of the water bath system. The first chamber provides warmer conditions suitable for initial crystallization, while the second chamber provides cooler conditions for final setting, optimizing the cooling and crystallization process at each stage.
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 results in PHA straws that degrade by up to 88% in a marine environment within 97 days, meeting biodegradability and compostability requirements while maintaining mechanical integrity, making them suitable for consumer use.
Implementation Method 1
The extruder may have a temperature profile, such that the temperature within the extruder increases from the end of the extruder that receives the raw PHA material from the hopper to the end of the extruder that provides the extruded PHA material to a die
Implementation Method 2
The first chamber may contain water having a first temperature, while the second chamber contains water having a second temperature that is lower than the first temperature
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.