Photochromic Hydroxyurethane Compounds for Reduced Matrix Aggregation
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Solution Overview
Problem
Existing photochromic compounds face issues with aggregation in solid matrices, leading to white turbidity and reduced photo-responsiveness, and have difficulty dissolving in polymerizable compounds, necessitating improved dispersion stability and reduced matrix dependency.
Innovation Solution
A photochromic hydroxyurethane compound with a hydroxyurethane constitutional unit and at least one photochromic moiety, such as a naphthopyran skeleton, is developed to enhance dispersion in solid matrices, prevent aggregation, and improve solubility in polymerizable compounds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a low-molecular photochromic compound is used, then aggregation is reduced and transparency is improved, but matrix dependency increases and fading speed decreases
Solution Approach 1:
The patent uses a composite structure combining low-molecular photochromic compound (naphthopyran) with oligomer chain groups (polyalkylene glycol or polysiloxane). This composite approach allows the photochromic moiety to remain low-molecular for reduced aggregation while the oligomer chains provide encapsulation effect to reduce matrix dependency and improve fading speed.
Solution Approach 2:
The oligomer chain group acts as an intermediary between the photochromic compound and the solid matrix. It provides a flexible interface that reduces the restrictive effect of the solid matrix on the photochromic compound's structural change, thereby improving fading speed while maintaining transparency.
2Reliability
If a polymer photochromic compound with oligomer chain group is used, then matrix dependency is reduced and photo-responsiveness is improved, but aggregation occurs during curing causing white turbidity
Solution Approach 1:
The patent optimizes the molecular weight and structure parameters of the oligomer chain groups. By carefully selecting the oligomer chain length and composition (polyalkylene glycol or polysiloxane), the patent achieves a balance between providing sufficient encapsulation to prevent aggregation during curing and maintaining flexibility for photochromic activity.
Solution Approach 2:
The patent introduces polymerizable substituent groups at specific locations on the oligomer chain, allowing localized polymerization that locks the photochromic compound in place after curing. This local quality change prevents post-curing aggregation while maintaining the encapsulation effect during the curing process.
3Illumination intensity
If photochromic compound concentration is increased, then color optical density is improved, but dispersion difficulty increases and white turbidity occurs
Solution Approach 1:
The oligomer chain groups serve as solubilizing intermediaries that enhance the compatibility between the photochromic compound and the polymerizable matrix. This allows higher concentrations of photochromic compound to be dispersed uniformly without phase separation or aggregation, achieving high color optical density while maintaining ease of manufacture.
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 hydroxyurethane compound maintains excellent photochromic properties in solid matrices, prevents white turbidity, and ensures high solubility in polymerizable compounds, resulting in a transparent photochromic cured body.
Implementation Method 1
Photochromic compounds represented by chromene compounds, fulgide compounds, spirooxazine compounds and the like possess photochromic properties that allow these compounds to quickly change color when irradiated with light containing ultraviolet rays such as sunlight or light of a mercury lamp, and to get back their original color when kept dark by stopping the irradiation.
Data Source
AI summary
A photochromic hydroxyurethane compound of the present invention is characterized in that, on condition of having at least one photochromic moiety as the photochromic minimal unit in a molecule, it has a hydroxyurethane constitutional unit represented by Formula (1): -X-O-CO-NH- (1). In the formula, X is an oxygen-containing chain organic group having a hydroxyl group as a substituent, or a hydrogen atom in the hydroxyl group is substituted by any one of (A): a photochromic group having the photochromic moiety; (B): a polymerization reactive group having a polymerizable substituent; (C) an alkyl group having 1 to 10 carbon atoms; (D) a cycloalkyl group having 3 to 10 carbon atoms; or (E) : an aryl group having 6 to 14 carbon atoms (each of the groups (C)-(E) can be bonded to an oxygen atom derived from the hydroxyl group via the oxygen-containing chain organic group) .