Amorphous Polyester Hollow Bodies Impact Resistance
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Solution Overview
Problem
Current thermoplastic polyesters containing 1,4:3,6-dianhydrohexitol units, such as isosorbide-based polyesters, face challenges with insufficient impact resistance and glass transition temperature, making them unsuitable for manufacturing hollow bodies with good chemical stability and high viscosity.
Innovation Solution
An amorphous thermoplastic polyester composition comprising at least one 1,4:3,6-dianhydrohexitol unit, an alicyclic diol unit, and terephthalic acid, with a specific molar ratio and reduced viscosity, is developed, eliminating the need for non-cyclic aliphatic diol units and achieving improved thermal and mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If 1,4:3,6-dianhydrohexitol units (isosorbide) are introduced into PET to improve thermal resistance, then glass transition temperature increases, but impact resistance becomes insufficient
Solution Approach 1:
The invention changes the chemical composition parameters by introducing specific alicyclic diol units (cyclohexane-1,3-dimethanol and cyclohexane-1,4-dimethanol) with controlled molar ratios. The alicyclic diol content is optimized at 5-50 mol% to balance thermal resistance (through isosorbide units) and impact resistance (through alicyclic diol units), resolving the contradiction between these two properties.
2Ease of manufacture
If non-cyclic aliphatic diol units (ethylene glycol) are used to improve processability and reduce viscosity, then manufacturing ease improves, but chemical stability of hollow bodies deteriorates
Solution Approach 1:
The invention extracts and eliminates non-cyclic aliphatic diol units (ethylene glycol) from the polyester composition. By removing these units that provide processability but compromise chemical stability, the patent achieves hollow bodies with excellent chemical resistance while maintaining adequate processability through alternative means (allylic diol units and controlled molecular weight).
Solution Approach 2:
The invention creates a composite polyester structure combining isosorbide units (for thermal resistance), alicyclic diol units (for impact resistance and processability), and terephthalic acid units (for structural integrity). This composite approach replaces the need for ethylene glycol while achieving both processability and chemical stability.
3Strength
If alicyclic diol units are introduced to improve impact resistance, then mechanical properties improve, but glass transition temperature may become too high for certain applications
Solution Approach 1:
The invention precisely controls the molar ratio of alicyclic diol units at 5-50 mol% to optimize the balance between impact resistance and glass transition temperature. This parameter optimization ensures that hollow bodies achieve sufficient mechanical strength while maintaining processability and suitability for various application temperatures.
Data Source
AI summary
The invention relates to the use of an amorphous thermoplastic polyester for the production of hollow articles, said amorphous thermoplastic polyester comprising at least one 1,4 : 3,6-dianhydrohexitol unit (A), at least one alicyclic diol unit (B) other than 1,4 : 3,6-dianhydrohexitol units (A), at least one terephthalic acid unit (C), the molar ratio (A)/[(A)+(B)] being at least 0.32 and at most 0.90 and said polyester being free of non-cyclic aliphatic diol units or comprising a molar amount of non-cyclic aliphatic diol units, relative to the total monomer units of the polyester, that is less than 5%, and having a reduced solution viscosity (25 °C; phenol (50%m) : ortho-dichlorobenzene (50%m); 5 g/L polyester) that is greater than 50 mL/g.