Multilayered Biodegradable Film Flexibility and Transparency
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Solution Overview
Problem
Conventional biodegradable films, such as polylactic acid films, face limitations in flexibility and transparency due to their inherent crystal structures and poor compatibility with aliphatic-aromatic copolymerized polyesters, which affects their mechanical strength and heat sealing properties, making them unsuitable for environmentally friendly packaging.
Innovation Solution
A multilayered biodegradable film comprising alternately layered polylactic acid-based polymer and aliphatic polyester or aliphatic-aromatic copolymerized polyester-based resin layers, with specific additives and processing techniques to enhance flexibility, transparency, and biodegradability, achieving a coloring peak value of 0.3 or less, haze of 10% or less, and an elastic modulus of 300 kgf/mm2 or less.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If polylactic acid films are used to achieve biodegradability, then environmental friendliness is improved, but flexibility is reduced due to inherent crystal structures
Solution Approach 1:
The patent employs a multilayered composite structure combining polylactic acid (PLA) layers with aliphatic polyester or aliphatic-aromatic copolymerized polyester layers. This composite approach allows the PLA to provide biodegradability while the polyester layers contribute flexibility and processability, resolving the contradiction between environmental friendliness and operational flexibility
Solution Approach 2:
Different layers of the film are assigned different functional properties: PLA layers provide biodegradability and mechanical strength, while polyester layers provide flexibility and ease of processing. This local differentiation of material properties within the composite structure allows each layer to optimize its specific function without compromising the overall film performance
2Ease of operation
If aliphatic-aromatic copolymerized polyesters are blended to enhance flexibility and heat sealing properties, then flexibility is improved, but transparency deteriorates due to poor compatibility
Solution Approach 1:
Instead of blending incompatible materials that reduce transparency, the patent segments the film into distinct alternating layers of PLA and polyester. This segmentation prevents the compatibility issues that arise from blending while still achieving the desired flexibility through the polyester layers, and maintains transparency by avoiding the formation of large-scale phase-separated structures that scatter light
3Object-generated harmful factors
If polylactic acid is used as the sole biodegradable resin, then biodegradability is maintained, but mechanical strength is reduced due to low glass transition temperature
Solution Approach 1:
The patent creates a composite multilayered film where PLA layers provide biodegradability and the polyester layers provide enhanced mechanical strength and heat resistance. The alternating layer structure ensures both material systems contribute their superior properties to the overall film performance
Solution Approach 2:
The patent modifies the structural parameters of the film by creating a multilayered architecture with specific layer thickness ratios and alternating patterns. This structural parameter change allows the film to achieve superior mechanical properties through the reinforcement effect of the polyester layers while maintaining the biodegradable character of the PLA components
Data Source
AI summary
A multilayered biodegradable film comprising at least one first resin layer and at least one second resin layer, wherein the first and second resin layers are alternately layered; the first resin layer comprises a polylactic acid-based polymer; the second resin layer comprises an aliphatic polyester-based resin or an aliphatic-aromatic copolymerized polyester-based resin; and the film has a coloring peak value of 0.3 or less, a haze of 10% or less, and an elastic modulus of 300 kgf/mm2 or less, exhibits improved flexibility and transparency, which is useful for environmentally friendly packaging.