Low Temperature Curable Coating Composition Using Unsaturated Anhydride Crosslinker
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Solution Overview
Problem
Current isocyanate-free ambient and low temperature cure coating compositions face challenges with high viscosity, leading to increased use of volatile organic compounds (VOCs) and inferior performance properties, while isocyanate-based coatings pose safety concerns and environmental issues.
Innovation Solution
The development of coating compositions comprising a polymer with functional groups reactive to anhydride groups and a crosslinking agent from an ungelled hydrosilylation reaction product of a silicon hydride and an unsaturated polycarboxylic acid anhydride, which are sprayable, low in VOC content, and provide good hardness and solvent resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If acrylic polyanhydrides are used as crosslinkers for hydroxyl functional compounds, then isocyanate-free ambient and low temperature cure is achieved, but viscosity increases significantly
Solution Approach 1:
The patent changes the chemical structure parameters of the crosslinking agent by using unsaturated polycarboxylic acid anhydrides with specific molecular weights and functional group configurations. This parameter optimization reduces the viscosity of the crosslinking agent compared to conventional acrylic polyanhydrides, while maintaining the isocyanate-free ambient and low temperature cure capability.
2Ease of operation
If higher amounts of VOCs are added to reduce viscosity, then sprayability is improved, but environmental performance deteriorates
Solution Approach 1:
The patent optimizes the viscosity parameter of the crosslinking agent through selective use of unsaturated polycarboxylic acid anhydrides with controlled molecular weights. This parameter change achieves a balance where the composition becomes sprayable at lower VOC levels, improving environmental performance while maintaining ease of application.
3Temperature
If conventional crosslinkers are used to achieve low temperature cure, then curing temperature is reduced, but performance properties such as hardness and solvent resistance become inferior
Solution Approach 1:
The patent creates a composite crosslinking system combining unsaturated polycarboxylic acid anhydrides with hydroxyl functional compounds. This composite approach enables low temperature curing while achieving superior performance properties including hardness and solvent resistance, overcoming the limitations of conventional single-component crosslinkers.
4Reliability
If isocyanate-based materials are used for ambient and low temperature cure, then curing capability is achieved, but safety and environmental concerns increase
Solution Approach 1:
The patent extracts and eliminates the isocyanate component from the crosslinking system, replacing it with unsaturated polycarboxylic acid anhydrides. This extraction removes the safety hazards and environmental concerns associated with isocyanates while preserving the ambient and low temperature cure capability through alternative chemistry.
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
These compositions are capable of curing at low temperatures, reducing VOC usage, and achieving superior performance characteristics such as hardness and solvent resistance without the safety hazards associated with isocyanates.
Implementation Method 1
a crosslinking agent comprising an ungelled hydrosilylation reaction product of a silicon hydride and an unsaturated polycarboxylic acid anhydride
Implementation Method 2
a polymer comprising functional groups reactive with anhydride groups
Implementation Method 3
Low temperature curable coating compositions
Data Source
AI summary
Disclosed are low temperature curable coating compositions that include a polymer comprising functional groups reactive with anhydride groups and a crosslinking agent that includes the ungelled hydrosilylation reaction product of a silicon hydride and an unsaturated polycarboxylic acid anhydride. Also disclosed are related coated substrates and methods for coating a substrate.