Moisture-Curable Coating Composition for Flexible Substrates
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Solution Overview
Problem
Low temperature, moisture-curable coating compositions often result in brittle films that are susceptible to cracking, making them unsuitable for flexible substrates like elastomeric automotive parts and consumer electronics, and they typically require energy-intensive curing processes or solvents.
Innovation Solution
Development of ungelled, secondary amine-containing Michael addition reaction products combining compounds with ethylenic unsaturation and aminofunctional silanes, along with moisture scavengers, to create flexible, crack-resistant coatings that can cure at low temperatures and are solvent-free, with a specific molar ratio of secondary amines to functional groups for optimal performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If silane-based coating compositions are used to form hard, highly crosslinked films, then coating hardness and crosslink density are improved, but coating flexibility and crack resistance deteriorate
Solution Approach 1:
The patent changes the chemical parameters of the coating composition by incorporating specific flexible polymer backbones and controlling the crosslink density through选择不同的 silane compounds and ratios. This allows the coating to maintain hardness while achieving the required flexibility for elastomeric substrates
Solution Approach 2:
The invention creates a composite coating system that combines silane-based crosslinked network with flexible polymer chains. The composite structure integrates the hardness and adhesion benefits of silane crosslinking with the flexibility of the polymer matrix, preventing crack formation on bending substrates
2Productivity
If thermal or radiation curing methods are used, then cure speed and crosslinking efficiency are improved, but energy consumption and equipment complexity increase
Solution Approach 1:
The coating composition is formulated to cure automatically upon exposure to moisture in the environment. The hydrolysis and condensation of silane groups proceed spontaneously without requiring external energy input, equipment, or controlled conditions, making the process self-sufficient and energy-free
Solution Approach 2:
The patent replaces the thermal or radiation-based curing mechanism with a chemical moisture-curing mechanism. Instead of using heat or electromagnetic radiation to drive the crosslinking reaction, the system utilizes ambient moisture to trigger hydrolysis and condensation of silane groups, eliminating the need for complex curing equipment
3Temperature
If conventional moisture curable coating compositions are used, then low temperature curing is achieved, but coating flexibility and crack resistance worsen
Solution Approach 1:
The patent modifies the chemical composition parameters by selecting specific silane compounds with appropriate functional groups and incorporating flexible polymer backbones. This composition design enables the coating to cure at low temperatures while maintaining the flexibility and crack resistance required for elastomeric substrates
Solution Approach 2:
The invention creates local flexibility within the coating matrix by incorporating flexible polymer chains between the crosslinked silane nodes. This local flexibility allows the coating to accommodate substrate deformation without cracking, even though the overall crosslinked network provides hardness and adhesion
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 coatings are resistant to cracking, achieve complete cure within 24 hours at low temperatures, and maintain flexibility, suitable for substrates that bend or flex, while being storage stable and free of solvents.
Implementation Method 1
Some coating compositions are based on the hydrolysis and condensation of silane based materials that form a crosslinked Si—O—Si matrix
Implementation Method 2
Some coating compositions are based on the hydrolysis and condensation of silane based materials that form a crosslinked Si—O—Si matrix
Implementation Method 3
an ungelled, secondary amine-containing, Michael addition reaction product of reactants comprising, or, in some cases, consisting essentially of: (a) a compound comprising more than one site of ethylenic unsaturation, and (b) an aminofunctional silane
Data Source
AI summary
Disclosed are low temperature, moisture curable coating compositions, related coated substrates, and methods for coating a substrate. The coating compositions include an ungelled, secondary amine-containing Michael addition reaction product of reactants including a compound comprising more than one site of ethylenic unsaturation, and an aminofunctional silane.