Recycled PET Transesterification for Polyurethane Production
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Solution Overview
Problem
The recycling of polyethylene terephthalate (PET) into valuable materials is economically unfeasible due to the high cost of reversing the polymerization process and the low price of petrochemical feedstocks, making it costly to produce aromatic polyester polyols for polyurethane production, which are desired for their fire/heat resistance and impact resistance properties.
Innovation Solution
The development of aromatic polyester polyether polyols through the transesterification of PET with ethoxylated glycerin or trimethylolpropane, allowing for the creation of polyurethanes with improved physical and chemical properties, such as low viscosity, fire resistance, and impact resistance, using recycled PET as a feedstock.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If PET is recycled through depolymerization to produce aromatic polyester polyols, then the environmental sustainability is improved, but the production cost increases significantly
Solution Approach 1:
The patent changes the chemical parameters of the polyol by incorporating ethoxylated glycerin or trimethylolpropane units into the polyester backbone. This parameter change allows the polyol to achieve desired molecular weight and viscosity without requiring complete depolymerization of PET, thereby reducing processing costs while maintaining environmental benefits
Solution Approach 2:
The patent creates a composite polyol structure combining PET-derived polyester segments with ethoxylated triol segments. This composite approach allows utilization of recycled PET content for environmental sustainability while the ethoxylated triol components adjust the physical properties to match performance requirements, avoiding the need for expensive complete depolymerization processes
2Ease of operation
If the degree of ethoxylation is increased to reduce polyol viscosity, then the processability is improved, but the molecular weight and structural integrity may be compromised
Solution Approach 1:
The patent systematically varies the degree of ethoxylation (n1, n2, n3) as a controllable parameter to achieve the target viscosity range of 5-500 Poise. By adjusting this parameter, the polyol's flow properties are optimized for coating applications while the overall molecular weight is maintained through controlled transesterification conditions and monomer selection
Solution Approach 2:
The patent applies partial ethoxylation rather than complete ethoxylation of all hydroxyl groups. This partial action approach provides sufficient viscosity reduction for processability while leaving enough unethoxylated segments to maintain molecular weight and structural integrity for achieving the desired gel time and crosslinking behavior
3Ease of manufacture
If aromatic polyester polyols are produced from petrochemical feedstocks, then the production cost is reduced, but the environmental sustainability deteriorates
Solution Approach 1:
The patent recovers and utilizes PET waste materials that would otherwise be discarded or landfilled. Through transesterification reactions, the recycled PET is converted into valuable aromatic polyester polyol components, reducing the need for virgin petrochemical feedstocks and thereby improving environmental sustainability while maintaining cost-effectiveness
Solution Approach 2:
The patent enables the recycled PET material to serve itself by converting waste PET directly into useful polyol components through transesterification with ethoxylated triols. This self-service approach transforms the waste stream into a valuable resource, eliminating the need for separate petrochemical synthesis and reducing environmental impact
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
This method enables the production of polyurethanes with enhanced properties while reducing costs by utilizing recycled PET, making them more economically viable and environmentally friendly, and providing 'green' characteristics.
Implementation Method 1
aromatic polyester polyether polyols derived from the transesterification of polyethylene terephthalate with either glycerin or trimethylolpropane
Data Source
AI summary
This abstract is intended as a scanning tool for purposes of searching in the particular art and is not intended to be limiting of the present disclosure. The disclosure provides aromatic polyester polyether polyols and compositions comprising such polyols. The disclosed aromatic polyester polyether polyols and compositions including same are the products of the transesterification reaction of polyethylene terephthalate (“PET”) and an ethoxylated triol, namely glycerin or trimethylolpropane, wherein the degree of ethoxylation is from 1 to 9 moles. At least some of the PET used to generate the aromatic polyester polyether polyols is derived from recycled PET. The disclosed aromatic polyester polyether polyols have utility in preparing polyurethane materials, for example.