Ultra-High IV Polyester Resin Solid-State Polymerization
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Solution Overview
Problem
Conventional polyester resin production methods face challenges in achieving high intrinsic viscosity (IV) levels efficiently and cost-effectively, leading to increased crystallinity and poor resin melting characteristics, which limits their use in extrusion blow molding applications.
Innovation Solution
A method for producing an ultra-high IV polyester resin through solid-state polymerization of a starting material with a specific IV range, using melt polymerization and latent heat crystallization to minimize crystallinity and enhance IV lift rates, allowing for the production of high melt strength resins suitable for extrusion blow molding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional melt-phase polycondensation is used to produce polyester resin, then the resin can be manufactured with standard IV levels, but the production time is extended and crystallinity increases, resulting in poor melting characteristics
Solution Approach 1:
The invention changes the fundamental parameter of polymerization phase from melt-phase to solid-state, enabling ultra-high IV achievement without extended production time. The solid-state polymerization allows molecular weight increase while maintaining low crystallinity and good melting characteristics, directly resolving the time-IV tradeoff contradiction.
Solution Approach 2:
The invention utilizes phase transition by conducting polymerization in the solid-state rather than melt-phase. This phase change enables the resin to achieve ultra-high IV levels while avoiding the crystallinity issues and time penalties associated with conventional melt-phase processes, thereby improving both production efficiency and product quality.
2Manufacturing precision
If solid-state polymerization is applied to increase IV levels, then ultra-high IV polyester can be achieved, but crystallinity increases leading to poor resin melting characteristics
Solution Approach 1:
The invention optimizes the crystallinity parameter by controlling it to remain below 50%, preferably below 40%, during solid-state polymerization. This parameter control enables achieving ultra-high IV levels while maintaining good melting characteristics and resin processability, directly resolving the IV-crystallinity contradiction.
Solution Approach 2:
The invention employs continuous solid-state polymerization processes that maintain optimal temperature and atmosphere conditions throughout the reaction. This continuous controlled environment prevents excessive crystallinity development while steadily increasing IV levels, thereby achieving ultra-high molecular weight without compromising melting characteristics.
3Manufacturing precision
If extended polycondensation reaction time is used to achieve high IV, then molecular weight increases, but production efficiency decreases and cost increases
Solution Approach 1:
The invention changes the reaction phase parameter from melt to solid-state, which fundamentally alters the kinetics and efficiency of the polycondensation reaction. This parameter change enables ultra-high IV achievement in a time-frame that maintains production efficiency, directly resolving the IV-production efficiency contradiction.
Solution Approach 2:
The invention substitutes the conventional melt-phase mechanical mixing system with a solid-state polymerization process that requires minimal mechanical intervention. This substitution eliminates the need for extended mixing and heating times associated with melt-phase processing, thereby achieving ultra-high IV levels while maintaining high production efficiency and reducing costs.
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 method achieves ultra-high IV polyester resins with reduced crystallinity, enabling the production of clear and colorless containers with improved melting characteristics and faster production times, suitable for high-end applications like handleware containers.
Implementation Method 1
having been subjected to latent heat crystallization upon formation of the resin particle
Implementation Method 2
forming a molten parison from solid polyester resin
Data Source
AI summary
A method for producing ultra-high intrinsic viscosity (IV) polyester resin pellets from a resin that contains one or more comonomers in an amount of up to 30 mol%. The method includes extruding a polyethylene terephthalate polyester starting material having a starting IV (IVst) meeting the following relationship: 0.65 dL/g <IVst <0.9 dL/g, to form resin particles having no more than 0.05 dL/g of IV lift due to solid-state polymerization, then latent heat crystallizing the resin particles to form crystallized particles having a variation of IV of no more than 0.05 dL/g across any dimension of the crystallized particles. The crystallized particles are then solid state polymerized to a final IV (IVf) of at least 0.9 dL/g to form the ultra-high intrinsic viscosity (IV) polyester resin pellets. During the solid state polymerizing the IV lift rate is at least 0.012 dL/g/hr.