Moisture-Curable Polyurethane Adhesion to Water-Repellent Fabrics
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Solution Overview
Problem
Current moisture-curable polyurethane resin compositions exhibit poor adhesion, particularly with water-repellent cloths, in the production of moisture-permeable waterproof functional clothing, and there is a need for environmentally friendly alternatives due to solvent emission regulations and marine plastic pollution concerns.
Innovation Solution
A moisture-curable polyurethane hot-melt resin composition using a urethane prepolymer derived from biomass-based polyols and polyisocyanates, specifically sebacic acid and 1,3-propanediol, with a high biomass content, which forms a crosslinked structure for enhanced adhesion with various cloths, including water-repellent ones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional moisture-curable polyurethane resin composition is used as adhesive, then the adhesive can be applied to general cloths, but it exhibits poor adhesion with water-repellent and super-water-repellent cloths
Solution Approach 1:
The patent modifies the chemical composition parameters of the adhesive by incorporating specific components (polyester resin with controlled molecular weight, silane coupling agent, titanate coupling agent) in optimized ratios. This changes the surface interaction properties of the adhesive, enabling it to bond effectively with water-repellent cloths that have low surface energy, thereby resolving the adhesion problem without sacrificing versatility
Solution Approach 2:
The patent creates a composite adhesive system by combining moisture-curable polyurethane resin with polyester resin, silane coupling agents, and titanate coupling agents. This composite formulation synergistically enhances adhesion to water-repellent surfaces while maintaining compatibility with general cloths, thus improving both adhesion strength and adaptability
2Strength
If solvent-based urethane adhesive is used, then excellent adhesion with both moisture permeable film and cloth is achieved, but solvent emission and residual solvent problems occur
Solution Approach 1:
The patent removes the harmful solvent component from the adhesive formulation, transitioning from a solvent-based system to a moisture-curable polyurethane resin composition. This extraction of the harmful element eliminates solvent emission and residual solvent issues while maintaining adhesion performance through the moisture-curing mechanism that forms crosslinked structures
Solution Approach 2:
The patent replaces the solvent evaporation mechanism with a moisture-curing chemical reaction mechanism. Instead of relying on solvent evaporation to achieve adhesion, the adhesive cures through reaction with atmospheric moisture, forming crosslinked polyurethane structures that provide strong bonding without harmful solvent emissions
3Adaptability or versatility
If cloth denier is reduced to improve water repellency function, then water repellency is improved, but adhesion with adhesive deteriorates
Solution Approach 1:
The patent adjusts the adhesive formulation parameters to match the reduced surface area and altered surface properties of low-denier cloths. By incorporating coupling agents and optimizing resin composition, the adhesive maintains effective bonding strength despite the reduced substrate area and improved water repellency of the cloth
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 demonstrates excellent adhesion with different types of cloths, including water-repellent and super-water-repellent cloths, while being environmentally friendly, making it suitable for producing moisture-permeable waterproof functional clothing.
Implementation Method 1
a moisture-curable polyurethane hot-melt resin composition which contains a urethane prepolymer (i) having isocyanate groups
Data Source
AI summary
In the present invention, there is provided a moisture-curable polyurethane hot-melt resin composition containing an urethane prepolymer (i) having an isocyanate group, which is a reaction product of a polyol (A) and a polyisocyanate (B), the polyol (A) comprising a polyester polyol (a1) which uses a polybasic acid (x) derived from biomass and a glycol (y) derived from biomass as raw materials. Further, the present invention provides an adhesive containing the moisture-curable polyurethane hot-melt resin composition. The biomass-derived polybasic acid (x) is preferably sebacic acid and/or succinic acid. The biomass-derived glycol (y) is preferably 1,3-propanediol and/or 1,4-butanediol. The moisture-curable polyurethane resin composition preferably has a biomass degree of 40% or more.