Cyclobutanediol Polyester Composition for Crystallization Control
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Solution Overview
Problem
Current polyester compositions face challenges in achieving a balance of high impact strength, glass transition temperature, hydrolytic stability, chemical resistance, and processability while maintaining thermoformability and clarity, often requiring modifications that compromise on one or more of these properties.
Innovation Solution
The development of polyester compositions comprising terephthalic acid, 1,4-cyclohexanedimethanol, and specific cis/trans ratios of 2,2,4,4-tetramethyl-1,3-cyclobutanediol, which offer a unique combination of properties such as high impact strength, toughness, and thermal stability, while being processable on standard industry equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If PCT crystallizes rapidly upon cooling from the melt to achieve high strength and stability, then the crystallization rate is improved, but it becomes very difficult to form amorphous articles by extrusion, injection molding, and other forming methods
Solution Approach 1:
The patent modifies the crystallization behavior by changing the chemical composition parameters - incorporating cyclobutanediol units (1-40 mol%) and controlling the cis/trans ratio (0.5-2.0) to adjust the crystallization half-time and enable amorphous article formation while maintaining stability
Solution Approach 2:
The patent creates a composite polyester structure combining terephthalic acid, cyclohexanedimethanol, and cyclobutanediol units with specific ratios to achieve both rapid crystallization and formability, resulting in a material with Tg of 80-150°C and crystallization half-time of 30-300 seconds
2Duration of action of moving object
If sufficient ethylene glycol is included in the formulation to provide long crystallization half-times for amorphous products, then the crystallization half-time is improved, but the glass transition temperature and impact strength become undesirably lower
Solution Approach 1:
The patent changes the chemical composition by replacing ethylene glycol with cyclobutanediol units and controlling the cis/trans ratio, achieving long crystallization half-times (30-300 seconds) while maintaining high impact strength through the unique molecular structure of the cyclobutanediol-containing polyester
3Strength
If polymers containing 2,2,4,4-tetramethyl-1,3-cyclobutanediol are used to achieve certain properties, then the inherent viscosity and melt viscosity become high, but the equipment used in industry becomes insufficient to manufacture or post polymerization process these materials
Solution Approach 1:
The patent optimizes the cyclobutanediol content (1-40 mol%) and cis/trans ratio (0.5-2.0) to achieve the desired inherent viscosity (0.6-1.3 dL/g) and melt viscosity while ensuring the material remains processable on standard industry equipment by controlling the glass transition temperature and crystallization behavior
Data Source
AI summary
Described are polyester compositions comprising (a) a dicarboxylic acid component comprising terephthalic acid residues; optionally, aromatic dicarboxylic acid or aliphatic dicarboxylic acid residues; 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues, wherein said 2,2,4,4-tetramethyl-1,3-cyclobutanediol contains certain cis to trans ratios; and 1,4-cyclohexanedimethanol residues.