Moisture-Curing Polyurethane Adhesive Using Recycled PET Polyol
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Solution Overview
Problem
Current one-component polyurethane adhesives and hot melt adhesives face challenges with polyols from renewable sources due to their uneven hydroxyl functionality distribution, leading to unstable viscosity and storage stability, and recycled materials are often used as fillers rather than active components.
Innovation Solution
A solvent-free, moisture-curing polyurethane composition is developed using a polyurethane prepolymer with free isocyanate groups, where at least one polyol is recycled polyethylene terephthalate (PET) combined with polyisocyanate in stoichiometric excess, along with additives like catalysts, resins, and fillers, to create stable one-component adhesives or reactive hot melt adhesives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If polyols from renewable sources are used in one-component polyurethane adhesives, then sustainability is improved, but viscosity stability and storage stability deteriorate due to uneven hydroxyl functionality distribution
Solution Approach 1:
The patent changes the chemical parameters of the polyol by using recycled PET polyol with controlled molecular weight (1000-5000 g/mol) and hydroxyl number (50-200 mg KOH/g), achieving more uniform hydroxyl functionality distribution that stabilizes viscosity and storage properties while maintaining sustainability
Solution Approach 2:
The patent creates a composite polyol system by combining recycled PET polyol with conventional polyols in specific ratios (2-50 wt% recycled PET polyol), where the composite material exhibits improved viscosity stability and storage stability while maintaining the sustainability benefit of using renewable/recycled resources
2Ease of manufacture
If recycled materials are used as fillers rather than active components, then manufacturing cost is reduced, but adhesive performance deteriorates
Solution Approach 1:
The patent transforms recycled PET from a filler material into an active polyol component by controlling its molecular weight (1000-5000 g/mol) and hydroxyl number (50-200 mg KOH/g), enabling it to participate in polyurethane formation reactions and provide adhesive performance while maintaining cost benefits
Solution Approach 2:
The patent uses recycled PET polyol as an intermediary substance that bridges the gap between cost reduction and performance maintenance, where the polyol serves both as a reactive component for adhesive formation and as a sustainable material substitute, eliminating the need to use recycled materials merely as inert fillers
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 composition achieves stable viscosity and improved storage stability, enabling effective use of sustainable polyols as active components in one-component adhesives, particularly in reactive hot melt applications.
Implementation Method 1
the transesterification of native oils and fats or naturally occurring oils with triglycerides containing OH groups
Implementation Method 2
solvent-free, moisture-curing polyurethane compositions based on polyurethane prepolymer with free isocyanate groups
Data Source
AI summary
Solvent-free moisture-curing polyurethane compositions are described, containing 99.9% to 75% by weight of at least one polyurethane prepolymer having free isocyanate groups, prepared by reaction of at least one polyol selected from the group of the polyether polyols and polyester polyols, having at least one polyisocyanate in stoichiometric excess, at least one polyol being a recycled polyethylene terephthalate polyol. In addition, this composition contains 0.1% to 25% by weight of at least one additive selected from the group of the catalysts, resins, plasticizers, fillers, pigments, stabilizers, adhesion promoters and further polymers. The sum total of the aforementioned constituents is 100% by weight. These compositions can be used as a one-component adhesive, reactive hotmelt adhesive, coating material or sealant.