PLA-PBSA Laminated Biodegradable Film for Flexibility and Processing
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Solution Overview
Problem
Existing biodegradable plastic films, such as PLA, suffer from limitations in flexibility, processability, and require specific conditions for biodegradation, while PBSA films are difficult to process due to low crystallization temperature, leading to challenges in manufacturing films with optimal biodegradability and mechanical properties.
Innovation Solution
A biodegradable film comprising an intermediate layer of PBSA resin and outer skin layers of PLA resin, optimized for composition, thickness ratio, and laminated structure, enhancing biodegradability, stretchability, and mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PLA resin is used to achieve biodegradability, then biodegradability is improved, but flexibility and processability deteriorate due to low flexibility from crystal structure
Solution Approach 1:
The patent uses a composite film structure combining PLA resin (for biodegradability) with PBSA resin (for flexibility and processability). The PLA/PBSA/PLA layered composite structure allows each material to contribute its advantageous properties: PLA provides biodegradability while PBSA provides flexibility and prevents excessive heat shrinkage, resolving the contradiction between biodegradability and flexibility.
2Ease of operation
If PBSA resin is used to improve flexibility, then flexibility is improved, but crystallization temperature becomes too low making film preparation difficult
Solution Approach 1:
The patent adjusts the composition ratios and processing parameters to optimize the balance between flexibility and crystallization temperature. By controlling the thickness ratio of layers (1:2:1 to 10:1:10) and processing conditions, the film achieves desired flexibility while maintaining suitable crystallization temperature for manufacturing.
3Strength
If conventional plastic films are used for packaging, then mechanical properties are improved, but biodegradability deteriorates as they accumulate in soil
Solution Approach 1:
The patent creates a composite biodegradable film using PLA and PBSA resins that combines the mechanical strength of conventional plastics with biodegradability. The layered structure provides tensile strength and elongation properties similar to conventional films while maintaining biodegradability in soil environments, resolving the contradiction between mechanical properties and biodegradability.
4Reliability
If PLA film is used for packaging, then biodegradability is improved, but heat shrinkage rate becomes high resulting in poor processability
Solution Approach 1:
The patent uses a PLA/PBSA/PLA composite structure where PBSA acts as a buffer to reduce heat shrinkage. The PBSA layer in the intermediate position prevents excessive shrinkage of the PLA skin layers during heating, improving processability while maintaining the biodegradability provided by the PLA outer layers.
Data Source
Figure 1~2
AI summary
An embodiment pertains to a biodegradable film and a biodegradable molded product manufactured using same. The biodegradable film comprises a middle layer containing polybutylene succinate adipate (PBSA) resin, and a first and a second skin layer on the respective outermost sides, each containing polylactic acid (PLA) resin, whereby excellent biodegradability can be ensured while maintaining optical properties such as haze and light transmittance, and mechanical properties such as tensile strength and modulus.