Biodegradable Polyester Resin Processability and Strength
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Solution Overview
Problem
Biodegradable polyester films face challenges with stickiness, poor blow moldability, and compromised physical properties such as tensile strength and tear strength due to the limitations of existing biodegradable polymers like PBAT and PBS, which also require excessive inorganic additives to improve processability, leading to deteriorated physical properties.
Innovation Solution
A biodegradable polyester resin comprising a specific ratio of first and second repeat units, including 1,4-butanediol, terephthalic acid, and adipic acid residues, with a controlled softness index, is developed through a process involving pretreatment, esterification, and polycondensation, enhancing productivity, processability, and moldability while maintaining excellent biodegradability and water degradability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If biodegradable polymers like PBAT and PBS are used to replace conventional polymers, then environmental friendliness and biodegradability are improved, but processability and moldability deteriorate due to severe stickiness and easy stretching
Solution Approach 1:
The patent modifies the chemical composition parameters of the polyester resin by incorporating specific diol components (1,4-butanediol, 1,3-propanediol, 1,2-ethanediol) in controlled ratios, and adjusting the softness index to 80-140, which changes the physical properties to reduce stickiness while maintaining biodegradability
Solution Approach 2:
The patent creates a composite polyester resin system combining multiple diol components with dicarboxylic acids, where the synergistic interaction between different components (e.g., 1,4-butanediol providing flexibility and 1,3-propanediol providing structural integrity) achieves both processability and biodegradability
2Ease of manufacture
If inorganic substances such as silica or calcium carbonate are added to improve processability, then moldability is improved, but physical properties such as tensile strength and tear strength deteriorate due to excessive inorganic content forming voids
Solution Approach 1:
The patent removes the need for inorganic additives by extracting the stickiness problem to the molecular level, solving it through careful selection and ratio control of organic diol components in the polyester resin composition
Solution Approach 2:
The patent introduces specific diol components as intermediary substances that mediate between the conflicting requirements of processability and strength, where these organic intermediaries provide the necessary lubricity and flexibility without forming voids like inorganic fillers
3Ease of manufacture
If inorganic substances are added to reduce stickiness, then processability is improved, but productivity deteriorates due to excessive inorganic additive requirements
Solution Approach 1:
The patent changes the compositional parameters to use organic diol components instead of inorganic fillers, which provide processability improvements at much lower concentrations, thereby maintaining high productivity without the need for excessive additive amounts
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 solution achieves improved tensile strength, tear strength, and low friction coefficient, along with enhanced biodegradability and water degradability, allowing for diverse applications without the need for excessive inorganic additives, thereby improving the overall performance and usability of biodegradable polyester films.
Implementation Method 1
a process for preparing the biodegradable polyester resin, which comprises a first step of mixing a diol component and an aromatic dicarboxylic acid and pretreating it to obtain a slurry; a second step of subjecting a mixture comprising the slurry and an aliphatic dicarboxylic acid; or a mixture of a reaction product obtained by esterification of the slurry and an aliphatic dicarboxylic acid to an esterification reaction at least once to obtain a prepolymer
Implementation Method 2
a third step of subjecting the prepolymer to a polycondensation reaction, wherein the biodegradable polyester resin comprises a first repeat unit comprising a first diol residue and an aromatic dicarboxylic acid residue and a second repeat unit comprising a second diol residue and an aliphatic dicarboxylic acid residue
Implementation Method 3
studies on biodegradable polymers that can be decomposed in a much faster time are being actively conducted
Implementation Method 4
achieving excellent physical properties as described above while maintaining excellent biodegradability and water degradability
Data Source
AI summary
The present invention relates to a biodegradable polyester resin, in which the first repeat unit comprising a first diol residue and an aromatic dicarboxylic acid residue and the second repeat unit comprising a second diol residue and an aliphatic dicarboxylic acid residue satisfy a ratio of the number of repeat units in a specific range, and the softness index of the resin satisfies a specific range, and to a process for preparing the same. Since the biodegradable polyester resin can provide a biodegradable polyester sheet or film that can be simultaneously enhanced in productivity, processability, and moldability and is excellent in tensile strength, tear strength, and friction coefficient and excellent in biodegradability and water degradability, it can be utilized in more diverse fields.