Aqueous Polyester Resin Redispersion at High Solids Without VOC Solvents
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Solution Overview
Problem
Existing polyester resin adhesives use petroleum-derived organic solvents like xylene or ethyl acetate, leading to environmental pollution, increased transportation emissions, and reduced storage stability due to solvent content.
Innovation Solution
A method for producing a redispersed aqueous polyester resin dispersion with a solid content concentration of 70% or more, using biomass-derived materials and self-emulsifiable resins, and incorporating a crosslinking agent to enhance film formability and adhesive properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If polyester resin is diluted with organic solvent to adjust viscosity for easy application, then ease of operation is improved, but environmental pollution increases due to VOC emissions
Solution Approach 1:
The invention changes the parameter of dispersion medium from organic solvent to water, creating an aqueous dispersion system. This allows the adhesive to maintain ease of application while eliminating VOC emissions, as water is not classified as a harmful VOC substance
Solution Approach 2:
The invention uses water as a replacement for expensive organic solvents like xylene or ethyl acetate. Water is inexpensive, environmentally friendly, and can be easily evaporated during the drying process, leaving no harmful residues
2Ease of operation
If product is shipped containing diluent solvent, then ease of operation is improved, but energy consumption increases due to increased transportation mass
Solution Approach 1:
The invention changes the dispersion medium to water, which has lower molecular weight and can be more efficiently removed during drying. This reduces the energy required for both transportation and subsequent drying processes compared to heavier organic solvents
3Ease of operation
If polyester resin is stored with diluent solvent, then ease of operation is improved, but storage stability deteriorates due to resin degradation
Solution Approach 1:
The invention replaces stable organic solvents with water as the dispersion medium. Water-based dispersions provide excellent storage stability because water does not cause resin degradation, whereas organic solvents can lead to resin deterioration over time, affecting product performance
4Loss of energy
If solid content concentration is increased to 70% or more, then CO2 emissions are reduced, but dispersion stability may deteriorate
Solution Approach 1:
The invention changes the chemical composition and physical properties of the aqueous dispersion system to accommodate high solid content (70% or more). This includes optimizing the resin structure and dispersion characteristics to maintain stability at high concentrations, which enables reduced CO2 emissions during drying while preventing precipitation or aggregation
Solution Approach 2:
The invention creates a composite aqueous dispersion system that combines polyester resin particles with water and auxiliary agents. This composite structure allows the system to maintain dispersion stability even at very high solid content levels, enabling both environmental benefits and product performance
Data Source
AI summary
One aspect of the present invention relates to a method for producing a redispersed aqueous polyester resin dispersion for an adhesive, and the production method includes a solid content increasing step of setting a solid content concentration of a polyester resin aqueous dispersion for an adhesive containing a polyester resin and water to 70 mass% or more, and a step of redispersing a high-solid-content product obtained by the solid content increasing step in an aqueous medium.