Infrared Light Reflector Coating Cissing Defect Resolution
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Solution Overview
Problem
Infrared light reflectors with cholesteric liquid crystal compounds face issues with cissing failure during coating, particularly when a fluorine-containing alignment controlling agent is added, leading to surface defects and poor surface conditions.
Innovation Solution
Incorporating a polyfunctional polymerizable compound with a fluorine-containing alignment controlling agent in a specific amount within the cholesteric liquid crystal compound, forming a laminate configuration that reduces cissing defects and enhances surface properties by controlling the distribution of the alignment controlling agent and surface energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a fluorine-containing alignment controlling agent is added to the cholesteric liquid crystal compound, then the alignment control is improved, but cissing failure occurs during coating
Solution Approach 1:
A silane coupling agent is introduced as an intermediary substance between the fluorine-containing alignment controlling agent and the cholesteric liquid crystal compound. The silane coupling agent contains both silane groups that react with the liquid crystal compound and fluorine-containing groups that provide alignment control, thereby mediating the conflict between achieving good alignment control and preventing cissing failure during coating
Solution Approach 2:
The invention creates a composite material system where the silane coupling agent forms a hybrid structure combining the properties of both the liquid crystal compound and the fluorine-containing alignment controlling agent. This composite approach allows the material to exhibit both good alignment control and coating stability simultaneously
2Reliability
If multiple cholesteric liquid crystal layers are laminated to broaden the reflected wavelength range, then the heat shieldability is improved, but the coating process becomes more complex and prone to cissing defects
Solution Approach 1:
The broad wavelength range heat shield is achieved by segmenting the structure into multiple cholesteric liquid crystal layers, each layer reflecting a specific wavelength band. The silane coupling agent enables each layer to be coated independently without cissing defects, making the segmented structure feasible
Solution Approach 2:
The invention changes the chemical composition parameters of the coating by introducing the silane coupling agent, which modifies the surface properties and reactivity of the cholesteric liquid crystal compound, thereby enabling successful coating of multiple layers without cissing failure
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 solution effectively minimizes cissing failures and improves the surface condition of the infrared light reflective layer, increasing film strength and reducing brittleness while maintaining heat shieldability.
Implementation Method 1
by forming one cholesteric liquid crystal layer on both sides of a λ/2 plate, a light circularly-polarized in one direction can be selectively and efficiently reflected within a range of from 700 to 1200 nm of the sunlight spectrum
Implementation Method 2
Infrared light reflectors with cholesteric liquid crystal compounds face issues with cissing failure during coating, particularly when a fluorine-containing alignment controlling agent is added
Data Source
AI summary
An infrared light reflector having an infrared light reflective layer formed by polymerizing an infrared light reflective layer composition that contains a polyfunctional polymerizable compound, a cholesteric liquid crystal compound and a fluorine-containing alignment controlling agent in an amount of at least 60 ppm relative to the liquid crystal compound, wherein when a functional layer composition is applied onto at least one surface of the infrared light reflective layer, the number of the coating liquid cissing defects having a diameter of at least 5 μm is at most 10/m2.