Moisture-Curable Membrane Intercoat Adhesion
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Solution Overview
Problem
Existing liquid applied polymer membranes for construction sealing face issues such as sensitivity to moisture and temperature, foam formation, short pot-life, high VOC emissions, and poor intercoat adhesion, particularly when applied in layers over extended periods.
Innovation Solution
A moisture-curable composition comprising 20-50 wt.% of organic polymers with reactive silane groups and 10-30 wt.% of polyether PE, free of hydroxyl groups, and a curing catalyst, which cures rapidly at ambient temperature, forming a high-grade, non-tacky material with excellent mechanical properties and intercoat adhesion even when applied over dried base layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If silane-functional polymers are used as isocyanate-free alternatives, then VOC emissions and odor are reduced, but intercoat adhesion deteriorates when layers are applied over extended periods
Solution Approach 1:
The patent changes the chemical composition parameters by introducing polyetherdiamines as a key component (10-30 wt% of total composition) alongside silane-functional polymers. This compositional parameter change enables the system to maintain low VOC emissions while achieving excellent intercoat adhesion through the synergistic interaction between polyetherdiamine and silane groups, resolving the contradiction between reduced harmful emissions and maintained reliability.
Solution Approach 2:
The patent creates a composite material system combining silane-functional polymers with polyetherdiamines and reactive diluents. This composite approach integrates the advantages of each component: silane groups provide water resistance and structural integrity, polyetherdiamines enhance adhesion and flexibility, and reactive diluents maintain low viscosity. The composite material achieves both low VOC emissions and superior intercoat adhesion that neither component could achieve alone.
2Ease of operation
If viscosity is reduced by adding low molecular mass silanes, then ease of application improves, but intercoat adhesion and structural integrity deteriorate
Solution Approach 1:
The patent changes the viscosity parameter by incorporating reactive diluents (10-30 wt%) that lower the composition's viscosity to improve applicability. Simultaneously, the patent maintains structural integrity and adhesion by including polyetherdiamines and silane groups that form strong crosslinked networks upon curing, ensuring that the lowered viscosity does not compromise the cured film's mechanical properties or intercoat adhesion.
Solution Approach 2:
The patent uses polyetherdiamines as an intermediary component that bridges the gap between low-viscosity requirements and high-strength requirements. The polyetherdiamine molecules interact with both the silane-functional polymers and reactive diluents, facilitating a balanced system where the diluents provide flowability while the polyetherdiamine ensures that the cured structure maintains excellent adhesion and mechanical strength.
3Strength
If isocyanate-containing polyurethanes are used, then mechanical strength and elasticity are improved, but EHS compliance and environmental impact deteriorate
Solution Approach 1:
The patent extracts and eliminates the harmful isocyanate component from the polymer system while maintaining the desired mechanical properties. By removing isocyanates (the harmful factor) and replacing them with silane-functional polymers and polyetherdiamines, the system achieves EHS compliance and reduced VOC emissions while preserving mechanical strength and elasticity through alternative crosslinking mechanisms.
Solution Approach 2:
The patent changes the chemical composition parameters by replacing isocyanate groups with silane groups and polyetherdiamine combinations. This parameter change fundamentally alters the curing mechanism from isocyanate-based to silane-polyetherdiamine-based crosslinking, thereby eliminating harmful emissions while maintaining or improving mechanical properties through the formation of robust siloxane and polyetherdiamine crosslinked networks.
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 provides a low-odor, low-toxicity, long-shelf-life sealing solution with rapid curing and superior intercoat adhesion, enabling flexible multi-layer application without loss of performance, and exhibits excellent water, heat, and UV resistance.
Implementation Method 1
moisture-curable composition comprises between 20 and 50 wt.-% of at least one organic polymer which is liquid at room temperature and contains reactive silane groups
Implementation Method 2
at least one curing catalyst for reactive silane groups
Implementation Method 3
between 10 and 30 wt.-% of at least one polyether PE having between 2 and 6 ether oxygen atoms
Implementation Method 4
provide constructions with reliable protection from water penetration
Data Source
AI summary
A method for coating a surface, including the steps: a) applying a first layer of a moisture-curable composition onto a surface, b) optionally letting the applied moisture-curable composition cure into a dried first layer, c) applying a second layer of the moisture-curable composition onto the optionally dried first layer, wherein the moisture-curable composition includes: between 20 and 50 wt.-%, preferably between 25 and 45 wt.-%, based on the total weight of the composition, of at least one organic polymer which is liquid at room temperature and contains reactive silane groups, and between 10 and 30 wt.-%, preferably between 15 and 25 wt.-%, based on the total weight of the composition, of at least one polyether PE having between 2 and 6 ether oxygen atoms and is free of hydroxyl groups; and at least one curing catalyst for reactive silane groups. The method yields a multilayer coating with high intercoat adhesion.