Biodegradable Polyester Composition for Low-Migration Packaging Film
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Solution Overview
Problem
Biodegradable polyesters used in packaging face issues of high migration, low adhesion, and poor transparency, which are critical for food contact applications.
Innovation Solution
A biodegradable aliphatic polyester composition comprising specific ratios of succinic and adipic acids, 1,4-butanediol, and cyclic esters, with controlled volatile organic compounds (TVOC) and chain extenders, is developed to enhance adhesion and transparency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If biodegradable polyesters are synthesized from monomeric diacid and monomeric diol, then the material can be processed on common molding equipment, but small molecule compounds (cyclic esters or polyester oligomers) are generated and prone to migration
Solution Approach 1:
The patent changes the chemical composition parameters by introducing specific cyclic esters (gamma-butyrolactone and delta-valerolactone) in controlled amounts (538-1100 ppm) to modify the polymer structure. This compositional parameter change reduces the migration tendency of small molecules while maintaining processability on common molding equipment
Solution Approach 2:
The patent creates a composite material system by combining biodegradable aliphatic polyester with specific cyclic esters and chain extenders. This composite approach allows the material to simultaneously achieve low migration, high adhesion, and high transparency while remaining processable
2Strength
If packaging films are designed for good adhesive properties, then the film can adhere to itself and other surfaces, but the transparency of the film is compromised
Solution Approach 1:
The patent optimizes the chemical composition parameters by controlling the content of cyclic esters (538-1100 ppm) and TVOC (≤157 ppm), and by specifying the molar ratio of dicarboxylic acid components (65-95 mol% succinic acid + 5-35 mol% adipic acid). These parameter changes enable the film to achieve both high adhesion and high transparency simultaneously
Solution Approach 2:
The patent applies local quality by introducing specific functional components (cyclic esters and chain extenders) in precise amounts to achieve adhesion enhancement in specific regions of the film structure, while maintaining overall transparency. The cyclic esters are positioned to provide adhesion at the molecular level without affecting the bulk optical properties
3Strength
If the content of cyclic esters is increased to improve adhesion, then adhesion capability is enhanced, but migration and unpleasant odors increase
Solution Approach 1:
The patent precisely optimizes the cyclic ester content parameter to the range of 538-1100 ppm, which is sufficient to provide high adhesion capability while remaining below the threshold for significant migration and odor generation. The TVOC content is simultaneously controlled to ≤157 ppm to further minimize unpleasant odors
Solution Approach 2:
The patent employs feedback control by monitoring and adjusting the cyclic ester content within the specific range of 538-1100 ppm. This feedback mechanism ensures that the adhesion capability is maximized while migration and odor generation are kept at acceptable levels, achieving an optimal balance between competing requirements
Data Source
AI summary
The present disclosure relates to a biodegradable aliphatic polyester composition, a preparation method thereof, and a use as a packaging film, belonging to the technical field of biodegradable materials. The biodegradable aliphatic polyester composition of this disclosure comprises a biodegradable aliphatic polyester and a cyclic ester, wherein the biodegradable aliphatic polyester comprises: Component A, a dicarboxylic acid, based on a total molar amount of the component A, comprising: a1, 65-95 mol% of succinic acid, or an ester derivative of the succinic acid, or a mixture thereof; and a2, 5-35 mol% of adipic acid, or an ester derivative of the adipic acid, or a mixture thereof; Component B, 1,4-butanediol, at least in an equimolar amount to that of the Component A; the cyclic ester comprises compounds shown in formula (I) and formula (II), based on a total weight of the biodegradable aliphatic polyester composition, a total content of the cyclic ester with structures shown in formula (I) and formula (II) is 538-1100 ppm; a content of total volatile organic compounds (TVOC) in the biodegradable aliphatic polyester composition is no more than 157 ppm.