Bio-based Reactive Polyurethane Hotmelt Adhesive Composition
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Solution Overview
Problem
There is a need for reactive polyurethane adhesives with increased bio-based content without compromising desired physical properties and performance, as traditional petrol-based materials lack suitable bio-based alternatives with identical chemical structures.
Innovation Solution
A moisture curable hotmelt adhesive composition is developed, comprising a polyurethane prepolymer obtained from the reaction of polyether, (meth)acrylic resin, crystalline polyester, amorphous polyester, and an isocyanate compound, with at least one of the polyether, crystalline polyester, or amorphous polyester being partially or completely bio-based, allowing for bio-based material replacement within a specific weight range without affecting performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If petrol-based polyurethane prepolymers are replaced by bio-based polyurethane prepolymers, then sustainability is improved, but physical properties and performance deteriorate due to different chemical structures
Solution Approach 1:
The patent uses a composite material system combining multiple polyurethane prepolymers with different functionalities. The composition includes at least two different polyurethane prepolymers where one provides structural integrity and the other adjusts flow and bonding characteristics. This composite approach allows tuning of physical properties to compensate for variations introduced by bio-based materials while maintaining sustainability goals.
Solution Approach 2:
The patent systematically varies key parameters including the ratio of different prepolymers (1:4 to 4:1), molecular weights (2000-10000 g/mol), and functional groups to optimize performance. By adjusting these parameters, the formulation achieves desired balance between sustainability requirements and physical performance characteristics such as fixture time, open time, and bond strength.
2Quantity of substance
If close alternative bio-based polyurethane prepolymers are used, then bio-based content is increased, but solidification behaviour and performance change due to slightly different chemical structures
Solution Approach 1:
The patent achieves compositional homogeneity by carefully selecting prepolymers with compatible molecular weight ranges (2000-10000 g/mol) and similar functional group distributions. The formulation ensures uniform mixing and consistent solidification behavior across different batches by maintaining narrow parameter tolerances for each component, thereby stabilizing the overall solidification profile despite using diverse bio-based feedstocks.
Solution Approach 2:
The patent introduces a coupling mechanism where at least one prepolymer contains both hydroxyl and isocyanate groups, acting as an intermediary that facilitates crosslinking and network formation. This intermediary component bridges the chemical structure differences between various bio-based prepolymers, ensuring consistent curing behavior and solidification characteristics across the composition.
3Object-affected harmful factors
If bio-based material replacement is increased, then sustainability is improved, but adhesive performance may be compromised
Solution Approach 1:
The patent optimizes adhesive performance by systematically adjusting critical parameters including the weight ratio of prepolymers (1:4 to 4:1), molecular weights (2000-10000 g/mol), and functional group concentrations. These parameter adjustments ensure that bond strength, fixture time, and open time meet performance specifications while maximizing the incorporation of bio-based materials to achieve sustainability targets.
Solution Approach 2:
The patent employs a composite prepolymer system where at least two different polyurethane prepolymers work synergistically. One prepolymer provides primary adhesion and structural strength, while the other enhances flow characteristics and bonding kinetics. This composite structure allows the formulation to achieve high adhesive performance metrics while incorporating significant bio-based content, thereby resolving the trade-off between sustainability and strength.
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 adhesive composition maintains desired physical properties and performance even with bio-based material replacement, as evidenced by consistent fixture strengths and cross tensile strengths across various examples, demonstrating the effectiveness of the bio-based material integration.
Implementation Method 1
Reactive polyurethane adhesives consist primarily of isocyanate terminated polyurethane prepolymers that react with surface or ambient moisture in order to chain-extend, forming a new polyurethane polymer
Implementation Method 2
Reactive polyurethane hot melt adhesives are solid at room temperature but, upon application of heat, melt to a liquid or fluid state
Implementation Method 3
During cooling, the hot melt adhesive regains its solid form
Data Source
AI summary
The present invention relates to a moisture curable hotmelt adhesive composition comprising at least one polyurethane prepolymer obtained from the reaction of a) at least one polyether; b) at least one (meth)acrylic resin; c) at least one crystalline polyester; d) at least one amorphous polyester; e) at least one isocyanate compound; in a presence of a catalyst, wherein at least one of said polyether, crystalline polyester and amorphous polyester is partially or completely bio-based material.