Photochromic Materials Migration Control via Hyperbranched Bonding
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Solution Overview
Problem
Photochromic materials incorporated into soft polymeric materials tend to migrate into hard coatings, leading to deteriorated performance due to environmental hardness effects, and existing methods either slow down coloration/fade rates or cause phase separation and haze issues.
Innovation Solution
Development of photochromic materials comprising hyperbranched polyester and indeno-fused naphthopyran groups, bonded through specific reactive functionalities to reduce migration and maintain optimal performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If photochromic materials are incorporated into soft polymeric materials, then photochromic performance is achieved, but migration into hard coatings occurs leading to performance deterioration
Solution Approach 1:
The patent combines the photochromic material with the polymeric material through covalent bonding, merging two previously separate components into a unified structure. This bonding prevents migration while maintaining photochromic performance, resolving the contradiction between achieving photochromic functionality and preventing material migration.
Solution Approach 2:
The patent introduces a bonding mechanism as an intermediary between the photochromic material and the polymeric material. This intermediary connection (covalent bond) serves as a bridge that anchors the photochromic material within the polymer matrix, preventing migration into hard coatings while preserving optical properties.
2Stability of the object's composition
If photochromic materials are bonded to polymeric materials, then migration is reduced, but coloration and fade rates slow down
Solution Approach 1:
The patent changes the parameters of the bonding system by using short organic chain segments with specific molecular weights and flexibilities. By optimizing these parameters, the bonding provides sufficient anchoring to prevent migration while maintaining chain mobility necessary for rapid coloration and fading responses.
Solution Approach 2:
The patent creates a composite material system where the photochromic material and polymeric material are chemically integrated. This composite structure combines the migration resistance of bonded systems with the fast response characteristics of flexible polymer matrices, achieving both stability and speed.
3Stability of the object's composition
If short organic chain segments are used to bond photochromic materials, then migration is reduced, but photochromic performance diminishes when chain segments are placed too close to the active portion
Solution Approach 1:
The patent applies local quality by placing the bonding chain segments at specific locations distant from the active portion of the photochromic material. This spatial differentiation ensures that the bonding function is performed away from the photochromic active site, preventing interference with the coloration mechanism while maintaining migration resistance.
Solution Approach 2:
The patent segments the photochromic material structure into distinct functional regions: the active photochromic portion and the bonding chain segment portion. This segmentation allows each region to perform its specific function independently—the active portion responds to light while the chain segment provides anchoring—without mutual interference.
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 reduces migration and maintains favorable coloration and fade rates, preventing performance deterioration while ensuring compatibility and transparency in polymeric materials.
Implementation Method 1
the ability of the photochromic material to transform may be impeded... that portion of the photochromic material that undergoes reversible transformation from one state to another on exposure to actinic radiation
Implementation Method 2
a photochromic compound comprising a group that is adapted to react with a hydroxyl group of the hyperbranched polyester polyol, wherein the group that is adapted to react with the hydroxyl group is an isocyanate (—NCO)
Implementation Method 3
reaction product of a hyperbranched polyester polyol comprising, on average, more than two hydroxyl groups, and a photochromic compound comprising a group that is adapted to react with a hydroxyl group
Data Source
AI summary
Photochromic materials and photochromic compositions and articles including the photochromic materials are disclosed. The photochromic materials may be the reaction product of a hyperbranched polyester polyol having, on average, at least two reactive hydroxyl groups, and at least one photochromic indeno-fused naphthopyran.