Water-Based Polyester Resin Production from Recycled Material
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Solution Overview
Problem
Existing methods for producing water-based polyester resins using recycled polyesters result in products with low water dispersibility and stability, which is undesirable for environmental and performance reasons.
Innovation Solution
A method involving an ester formation reaction, depolymerization reaction, and polycondensation reaction using recycled polyester, divalent and trivalent polycarboxylic acid components, and a polyalcohol component, with specific proportions and processing conditions to achieve a water-based polyester resin with improved properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If recycled polyester is used to produce water-based polyester resin, then environmental friendliness is improved, but water dispersibility and stability deteriorate
Solution Approach 1:
The patent applies parameter changes by precisely controlling the compound ratio of recycled polyester (20-72% by mass) and adding specific amounts of surfactants (0.1-5.0 parts by mass per 100 parts resin). It also controls the acid value (30-120 mg KOH/g) and water content (5-50 parts by mass) to achieve optimal balance between environmental sustainability and water dispersibility/stability.
Solution Approach 2:
The patent uses surfactants as intermediary substances to bridge the hydrophobic recycled polyester and water. The surfactants act as mediators that enable the recycled polyester to disperse in water while maintaining stability, solving the incompatibility between environmental friendliness and water dispersibility.
2Object-affected harmful factors
If compound ratio of recycled polyester is increased, then environmental friendliness is improved, but water dispersibility deteriorates
Solution Approach 1:
The patent establishes an optimal parameter range where recycled polyester is used at 20-72% by mass. This controlled parameter change ensures that environmental friendliness is improved while water dispersibility is maintained through the synergistic effect of the resin composition and surfactant addition.
3Reliability
If surfactant is added to improve water dispersibility, then water dispersibility is improved, but physical properties of resin film and recyclability deteriorate
Solution Approach 1:
The patent optimizes the surfactant concentration parameter to 0.1-5.0 parts by mass per 100 parts resin, and controls the acid value (30-120 mg KOH/g) and water content (5-50 parts by mass). This precise parameter control ensures sufficient water dispersibility while minimizing the negative impact on resin film physical properties and recyclability.
Solution Approach 2:
The patent uses a controlled partial amount of surfactant (0.1-5.0 parts per 100 parts resin) rather than excessive amounts. This partial action is sufficient to achieve water dispersibility while avoiding the harmful effects of high surfactant concentrations on resin film quality and recyclability.
4Quantity of substance
If recycled polyester with varying molecular weight is used, then availability of material is improved, but uniformity of resin properties deteriorates
Solution Approach 1:
The patent controls the acid value parameter (30-120 mg KOH/g) and water content (5-50 parts by mass) to ensure uniform resin properties even when using recycled polyester with varying molecular weights. This parameter control compensates for the variability in recycled material.
Solution Approach 2:
The patent introduces surfactants with specific local properties that can adapt to different molecular weight distributions in recycled polyester. The surfactants provide localized stabilization that ensures uniform resin properties throughout the mixture despite variations in the recycled material.
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 produces a water-based polyester resin with excellent water resistance, dispersibility, and stability, while maintaining good adhesion and transparency, and reducing environmental impact by maximizing the use of recycled materials.
Implementation Method 1
performing an ester formation reaction and a depolymerization reaction using the recycled polyester
Implementation Method 2
performing an ester formation reaction and a depolymerization reaction using the recycled polyester
Implementation Method 3
performing a polycondensation reaction by reducing pressure
Data Source
AI summary
A method for producing a water-based polyester resin includes a first step, a second step, and a third step. The first step includes performing an ester formation reaction and a depolymerization reaction using a recycled polyester, a first polycarboxylic acid component, and a polyalcohol component. The second step includes performing an ester formation reaction using a reaction product of the first step and a second polycarboxylic acid component. The third step includes performing a polycondensation reaction by reducing pressure. The first step includes using the recycled polyester to such an amount that makes proportion of a terephthalic acid residue equal to or greater than 20% by mass and equal to or less than 72% by mass. The water-based polyester resin thus produced has an acid value equal to or greater than 30 mgKOH/g and equal to or less than 120 mgKOH/g.