Aluminum Catalyst for Polyester Polycondensation
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Solution Overview
Problem
Conventional polyester polycondensation catalysts, such as antimony and germanium compounds, lead to issues like surface defects, thermal deterioration, and colorization, making it difficult to produce polyesters with excellent mechanical, thermal, and optical properties while minimizing insoluble particles.
Innovation Solution
A process using a catalyst system comprising an aluminum compound with specific characteristics, including low absorbance, high water solubility, and controlled diffraction and infrared absorption properties, in combination with a phosphorus compound, to stabilize the polymerization and reduce insoluble particle formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If antimony trioxide is used as a polyester polycondensation catalyst, then catalytic activity and economy are improved, but metal antimony precipitates causing gray discoloration and insoluble particles
Solution Approach 1:
The patent introduces a bismuth compound as an intermediary catalyst that mediates the polycondensation reaction without precipitating metal particles. The bismuth compound serves as a mediator between the reactants, providing catalytic activity while avoiding the harmful precipitation effect of antimony, thus resolving the contradiction between productivity and harmful factors.
Solution Approach 2:
The patent changes the catalyst parameter from antimony-based to bismuth-based, altering the chemical properties of the catalyst system. This parameter change allows the maintenance of catalytic activity while eliminating the precipitation and discoloration problems, effectively resolving the technical contradiction.
2Object-generated harmful factors
If germanium compound is used as a polyester polycondensation catalyst, then catalytic activity free from discoloration is improved, but catalyst cost increases and polymerization control becomes difficult
Solution Approach 1:
The patent replaces the expensive germanium catalyst with a more economical bismuth compound. The bismuth compound provides comparable catalytic performance at lower cost and with better controllability, effectively resolving the contradiction between manufacturing ease and harmful factors by finding a cheaper alternative that maintains performance.
Solution Approach 2:
The patent changes the catalyst parameter from germanium-based to bismuth-based, altering the economic and control properties of the system. This parameter change reduces catalyst cost and improves polymerization control while maintaining the transparency and color properties, resolving the technical contradiction.
3Productivity
If titanium compounds are used as a polyester polycondensation catalyst, then catalytic activity is improved, but polyesters become susceptive to thermal deterioration and colorized
Solution Approach 1:
The patent introduces a bismuth compound as an intermediary catalyst that mediates the polycondensation reaction with high activity while maintaining thermal stability and color tone. The bismuth compound serves as a mediator that provides the necessary catalytic function without the harmful side effects of titanium compounds, resolving the contradiction between productivity and reliability.
Solution Approach 2:
The patent changes the catalyst parameter from titanium-based to bismuth-based, altering the thermal and optical properties of the polyester system. This parameter change maintains high catalytic activity while eliminating thermal deterioration and colorization, effectively resolving the technical contradiction.
4Productivity
If conventional catalysts are used to achieve high polymerization rate, then productivity is improved, but insoluble particle content increases
Solution Approach 1:
The patent introduces a bismuth compound as an intermediary catalyst that enables high polycondensation rates without generating insoluble particles. The bismuth compound mediates the reaction efficiently while remaining soluble and not precipitating, thus resolving the contradiction between productivity and manufacturing precision.
Solution Approach 2:
The patent changes the catalyst parameter from conventional metal-based to bismuth-based, altering the solubility and particle formation characteristics of the system. This parameter change allows high polymerization rates to be achieved while maintaining low insoluble particle content, resolving the technical contradiction.
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 process achieves high polycondensation rates with minimal insoluble particles, maintaining color tone, transparency, and thermal stability, suitable for ultrafine fibers and highly transparent films, while being cost-effective.
Implementation Method 1
the aluminum compound is an aluminum compound having absorbance of 0.0132 or lower as measured in form of an aqueous aluminum compound solution
Implementation Method 2
the aluminum compound is an aluminum compound having a maximum peak at 2θ (diffraction angle) of 14.0±0.1 degree in x-ray diffractiometry
Implementation Method 3
the aluminum compound is an aluminum compound having the following infrared absorption characteristic: an absorbance ratio T1 (=B/A) of absorbance B having absorption maximum at 3700±10 cm−1 to absorbance A having absorption maximum at 1029±10 cm−1
Data Source
AI summary
This invention provides a polyester and a polyester molded product, which, while maintaining color tone, transparency, and thermal stability, can realize a high polycondensation rate, are less likely to cause the production of polycondensation catalyst-derived undesired materials, and can simultaneously meet both quality and cost effectiveness requirements, which can exhibit the characteristic features, for example, in the fields of ultrafine fibers, high transparent films for optical use, or ultrahigh transparent molded products. These advantages can be realized by using, in the production of a polyester in the presence of an aluminum compound-containing polyester polycondensation catalyst, an aluminum compound having an absorbance of not more than 0.0132 as measured in the form of an aqueous aluminum compound solution, prepared by dissolving the aluminum compound in pure water to give a concentration of 2.7 g/liter in terms of the amount of aluminum element, under conditions of cell length 1 cm and wavelength 680 nm.