Diarylpolysiloxane Silicone for High Refractive Index and Elasticity
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Solution Overview
Problem
Existing addition-curable silicone compositions struggle to produce cured products with high transparency, refractive index, and strength, particularly in optical applications, as branched polysiloxanes with phenyl groups result in hard, non-elastic materials, while linear polysiloxanes fail to meet transparency and refractive index requirements.
Innovation Solution
A diorganopolysiloxane with a diarylpolysiloxane backbone, combined with an organosilicon compound containing SiH groups and a platinum group metal-based hydrosilylation catalyst, undergoes an addition curing reaction to produce a transparent, high refractive index, and elastic silicone rubber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If branched polysiloxanes containing phenyl groups are used to increase refractive index, then refractive index is improved, but elasticity deteriorates (cured product becomes hard resin-like)
Solution Approach 1:
The patent changes the chemical structure parameter from branched polysiloxane to linear polysiloxane backbone, while controlling the phenyl group content at 10-50 mol%. This parameter optimization allows achieving refractive index of 1.53 or higher while maintaining rubber-like elasticity, resolving the contradiction between refractive index improvement and elasticity preservation
Solution Approach 2:
The patent creates a composite structure by combining linear polysiloxane backbone with controlled amounts of phenyl groups (10-50 mol%), achieving a balance between the optical properties provided by phenyl groups and the elastic properties provided by the linear backbone structure
2Illumination intensity
If dimethylsiloxane-diphenylsiloxane copolymer is used to achieve high refractive index, then refractive index is improved, but transparency deteriorates
Solution Approach 1:
The patent optimizes the compositional parameters by using linear polysiloxane as backbone and controlling phenyl group content within 10-50 mol%, which achieves refractive index of 1.53 or higher while maintaining excellent transparency, overcoming the transparency deterioration issue of conventional copolymers
3Ease of operation
If linear polysiloxane is used to maintain elasticity, then elasticity is preserved, but refractive index and transparency requirements are not met
Solution Approach 1:
The patent modifies the linear polysiloxane by introducing controlled amounts of phenyl groups (10-50 mol%) while maintaining the linear backbone structure, thereby achieving both rubber-like elasticity and high refractive index of 1.53 or greater, resolving the contradiction between elasticity preservation and refractive index improvement
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 resulting cured product exhibits excellent transparency, high refractive index, and favorable strength properties, making it suitable for optical element encapsulation with improved heat resistance and insulation.
Implementation Method 1
an addition-curable silicone composition comprises an organopolysiloxane containing aliphatic unsaturated groups such as alkenyl groups, and cures via a hydrosilylation reaction
Implementation Method 2
a platinum group metal-based hydrosilylation catalyst
Data Source
AI summary
Provided is an addition-curable silicone composition including A: a diorganopolysiloxane having a structure represented by a formula (1): (R1)(R2)2SiO((Ar)2SiO)nSi(R2)2(R1) (where R1 represents an aliphatic unsaturated group, R2 represents identical or different, unsubstituted or substituted monovalent hydrocarbon groups, Ar represents identical or different, unsubstituted or substituted aryl groups that may or may not contain a hetero atom, and n represents an integer of 1 or greater), B: an organosilicon compound containing at least two hydrogen atoms bonded to silicon atoms per molecule, and containing no aliphatic unsaturated groups, in an amount that is sufficient to cure the composition in the presence of the hydrosilylation catalyst described below, and C: a platinum group metal-based hydrosilylation catalyst. A cured product of this addition-curable silicone composition has superior transparency, a high refractive index, and favorable strength properties, and the composition can therefore be used as an optical element encapsulating material.