Sulfur-Aromatic Pentaerythritol Compounds for Transparent High-Index Polymers
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Solution Overview
Problem
Existing optical materials lack a combination of high refractive index, high transparency, and easy polymerizability, which is essential for advanced optical components and holographic recording media.
Innovation Solution
A pentaerythritol-type compound with heterogeneous high refractive index moieties, represented by a specific formula, is developed, offering high refractive index, transparency, and easy polymerizability, used in a polymerizable composition and polymer for optical materials and components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional high-refractive index acrylates (e.g., 9,9-bis[4-(2-acryloyloxyethoxy)phenyl]fluorene) are used, then the refractive index increases to about 1.62, but the viscosity becomes relatively high and the refractive index is not sufficiently high for ultrahigh-refractive index applications
Solution Approach 1:
The patent changes the chemical structure parameters of the acrylate by introducing sulfur atoms and aromatic rings at specific positions, achieving a refractive index of 1.68 while maintaining manageable viscosity through optimized molecular weight and structural arrangement
Solution Approach 2:
The patent creates a composite molecular structure combining pentaerythritol backbone with multiple aromatic rings and sulfur atoms, achieving synergistic effects that simultaneously increase refractive index while controlling viscosity through the specific arrangement of functional groups
2Illumination intensity
If dibenzofuran or dibenzocarbazole containing acrylate compounds are used to achieve ultrahigh refractive index (>1.7), then the refractive index increases, but the material discolors when heated in air, stored for long periods, or exposed to light, reducing stability
Solution Approach 1:
The patent extracts the problematic dibenzofuran and dibenzocarbazole structures that cause discoloration while retaining the beneficial refractive index-enhancing features through alternative sulfur-containing aromatic structures that provide similar optical properties without the stability issues
Solution Approach 2:
The patent replaces unstable high-refractive index moieties (dibenzofuran/dibenzocarbazole) with more stable alternative structures, sacrificing some maximum refractive index potential to achieve long-term stability and resistance to discoloration under various conditions
3Illumination intensity
If dibenzofuran or dibenzocarbazole containing acrylate compounds are used to achieve ultrahigh refractive index (>1.7), then the refractive index increases, but the compounds are not sufficiently soluble in various media, limiting the media that can use these compounds
Solution Approach 1:
The patent modifies the molecular parameters by adjusting the balance between aromatic ring content and aliphatic chain length, introducing flexible linking groups that improve solubility while maintaining the refractive index through strategic placement of sulfur atoms and aromatic rings
4Illumination intensity
If pentaerythritol-type (meth)acrylate compound having three aromatic rings is used to achieve high refractive index, then the refractive index increases, but steric hindrance around the polymerizable group prevents sufficient polymerization performance, resulting in poor holographic recording characteristics
Solution Approach 1:
The patent segments the molecular structure by separating the polymerizable acrylate groups from the bulky aromatic ring systems through flexible linking chains, reducing steric hindrance at the polymerization site while maintaining high refractive index through the aromatic and sulfur-containing moieties
Solution Approach 2:
The patent introduces flexible aliphatic linking groups as intermediaries between the polymerizable acrylate groups and the bulky aromatic ring systems, allowing the polymerizable groups to access each other for polymerization while the aromatic rings contribute to the refractive index without causing steric hindrance
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 compound and polymer achieve high diffraction efficiency, high light transmittance, and low turbidity, making them suitable for optical components and holographic recording media.
Implementation Method 1
a polymerizable composition and a polymer using the same have a high refractive index and high transparency
Data Source
AI summary
A compound represented by the following formula (1).[In the formula, A represents a polymerizable group. L represents an optionally branched (n+1)-valent linking group. R1 represents an aromatic ring group optionally having a substituent. R2 represents a cyclic group optionally having a substituent. R3 represents a monovalent organic group having no polymerizable group or a hydrogen atom. X1, X2, and X3 each independently represent an oxygen atom, a sulfur atom, or a nitrogen atom optionally having a substituent. m represents an integer of 0 or 1. n represents an integer of 1 to 3. When n is 2 or 3, a plurality of As may be the same or different from each other. p, q, and r each independently represent an integer of 0 or 1. In the formula, R1 may be bonded to R2 or R3 at any position to form an asymmetric ring structure. In the formula, —(X1)p—R1, —(X2)q—R2 and —(X3)r—R3 are not the same.]