Polyester Acrylate Resin from PET Depolymerization for UV Coatings
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Solution Overview
Problem
Current methods for recycling polyethylene terephthalate (PET) waste do not produce polyester resins with high enough molecular weight for effective use in energy curable coating compositions and inks, which require radical polymerization capabilities and sufficient molecular weight for high-speed printing applications.
Innovation Solution
A process involving the depolymerization of PET with polyhydric alcohols, esterification with polybasic carboxylic acids or anhydrides, and acrylation with acrylic acid to produce a polyester acrylate resin with a number average molecular weight of at least 800 Da, suitable for energy curable coating compositions and inks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If PET is depolymerized via alcoholysis reaction with polyhydric alcohols, then the molecular weight of the resulting polyester resin is increased, but the curing efficiency and speed of the energy curable coating composition deteriorates
Solution Approach 1:
The patent applies parameter changes by carefully controlling the molecular weight of the polyester polyol within a specific range (800-5000 Da) and adjusting the acrylate functionality (2-6) to optimize the balance between film formation and curing speed. This parameter optimization resolves the contradiction by finding the optimal point where sufficient molecular weight provides adequate film properties while maintaining adequate curing performance
Solution Approach 2:
The patent creates a composite resin system by combining polyester polyol derived from PET depolymerization with acrylic acid to form polyester acrylate resin. This composite approach integrates the benefits of both components: the polyester backbone provides molecular weight and film-forming capability, while the acrylate groups enable rapid UV curing, thus resolving the contradiction between molecular weight and curing speed
2Ease of manufacture
If PET waste is recycled through depolymerization, then environmental sustainability is improved, but the molecular weight of the resulting resin is insufficient for high-speed printing applications
Solution Approach 1:
The patent uses parameter changes by controlling the depolymerization conditions and selecting specific polyhydric alcohols to achieve the desired molecular weight range (800-5000 Da) in the polyester polyol. This controlled parameter adjustment ensures that recycled PET waste is converted into resin with sufficient molecular weight for high-speed printing while maintaining environmental sustainability
Solution Approach 2:
The patent employs polyhydric alcohols as intermediaries in the depolymerization process. These intermediaries facilitate the breakdown of PET waste into manageable oligomeric segments with controlled molecular weights, which can then be further processed into polyester acrylate resin suitable for high-speed printing applications
3Length of moving object
If the molecular weight of polyester resin is increased for better film formation, then the viscosity of the coating composition increases, but the processability and application performance deteriorates
Solution Approach 1:
The patent applies parameter changes by selecting a specific molecular weight range (800-5000 Da) for the polyester polyol that balances film-forming capability with processability. This optimized parameter range ensures that the resin has sufficient molecular weight for good film formation while maintaining adequate viscosity for easy application and processing
Solution Approach 2:
The patent applies local quality by ensuring that only specific portions of the polymer chain have the necessary molecular weight characteristics for film formation, while the overall resin system maintains low enough viscosity for processing. The acrylate modification allows different regions of the molecule to serve different functions: the polyester backbone provides film-forming quality while the acrylate end groups enable low viscosity and rapid curing
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 resulting polyester acrylate resin exhibits improved cure properties and deinking performance, enabling high-speed printing and enhanced solvent resistance in energy curable coating compositions and inks.
Implementation Method 1
depolymerizing virgin, scrap, recycled or reclaimed polyethylene terephthalate (PET) via an alcoholysis reaction with one or more polyhydric alcohols
Implementation Method 2
esterifying the depolymerization product with one or more polybasic carboxylic acids and/or anhydrides
Implementation Method 3
acrylated with acrylic acid to form a polyester acrylate resin
Implementation Method 4
Curing of energy curable coating compositions and inks predominantly proceeds via a radical polymerization mechanism
Data Source
AI summary
The present invention is directed to polyester resins which are prepared by depolymerizing virgin, scrap, recycled or reclaimed polyethylene terephthalate (PET) via an alcoholysis reaction with one or more polyhydric alcohols to form a depolymerization product and esterifying the depolymerization product with one or more polybasic carboxylic acids and/or anhydrides and optionally polyhydric alcohol to form a polyester polyol. The polyester may then be acrylated with acrylic acid to form a polyester acrylate resin. The polyester resins are then used in energy curable coating compositions or inks and in particular, the polyester acrylate resin is suitably used as a reactive binder/oligomer.