White Curable Silicone Formulation Toughness Reflectivity Trade-off
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Solution Overview
Problem
Conventional curable silicone compositions used in reflective materials for optical semiconductor devices often lack sufficient toughness, leading to cracks and chipping, especially when a large amount of white pigment like titanium oxide is added, which further deteriorates the material's toughness.
Innovation Solution
A white curable silicone composition is developed, featuring alkenyl group-containing organopolysiloxane with both ends of the molecular chain capped with alkenyl groups, along with specific ratios of alkenyl group content and organohydrogenpolysiloxane, which provides excellent elongation characteristics and hardness, thereby enhancing the toughness of the cured product.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a large amount of white pigment such as titanium oxide is added to the conventional curable silicone composition, then the reflectivity of the reflective material is improved, but the toughness of the cured product deteriorates and cracks or chipping may form
Solution Approach 1:
The patent changes the chemical composition parameters of the silicone resin by specifying precise proportions of different silicone resin components (first silicone resin 10-50 parts, second silicone resin 50-90 parts per 100 parts of third silicone resin). This parameter optimization allows the cured product to maintain both high reflectivity (from white pigment) and sufficient toughness, preventing the deterioration that occurs with conventional formulations.
Solution Approach 2:
The patent uses a composite silicone resin system combining three different silicone resin types with distinct properties. The first silicone resin provides base flexibility, the second silicone resin enhances toughness, and the third silicone resin ensures proper curing. This composite approach allows the material to incorporate large amounts of white pigment while maintaining structural integrity and preventing cracks.
2Strength
If the toughness of the cured product is increased to prevent cracks and chipping, then the reliability of the reflective material is improved, but the hardness may be reduced
Solution Approach 1:
The patent optimizes the chemical composition parameters by specifying precise ratios of different silicone resin components and controlling the total content of specific functional groups. This parameter control allows the cured product to achieve a balanced state where both toughness (crack resistance) and hardness (surface strength) are maintained at appropriate levels, rather than sacrificing one for the other.
Solution Approach 2:
The patent creates different local properties within the cured product by using a multi-component silicone resin system. The first silicone resin contributes to overall flexibility and crack resistance, while the second and third silicone resins provide structural integrity and surface hardness. This local differentiation of material properties allows simultaneous achievement of toughness and hardness.
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 composition effectively prevents cracks and chipping, even with high amounts of white pigment, resulting in a highly reliable reflective material with excellent toughness suitable for optical semiconductor devices.
Implementation Method 1
a silicon compound having a molecular weight of less than 1000 which has at least two carbon-carbon double bonds having reactivity with an SiH group in one molecule
Data Source
AI summary
A white curable silicone composition provides excellent elongation characteristics while providing sufficiently great hardness, which as a result can provide a cured product having excellent toughness.The composition comprises: (A) alkenyl group-containing resinous organopolysiloxane which is represented by an average composition formula: (R13SiO1/2)a(R12SiO2/2)b(R1SiO3/2)c(SiO4/2)d(XO1/2)e, where, in the formula, R1 are each independently a monovalent hydrocarbon group, while at least two R1 are alkenyl groups, X is a hydrogen atom or an alkyl group, 0≤a≤0.7, 0≤b≤0.2, 0≤c≤0.3, 0≤d≤0.8, and 0≤e≤0.2, a+b+c+d=1.0, and c+d>0 are satisfied; (B) linear alkenyl group-containing organopolysiloxane which is represented by R2R32SiO(R32SiO)nSiOR2R32, where, in the formula, R2 is an alkenyl group, R3 are each independently a monovalent hydrocarbon group other than an alkenyl group, and n is an integer of 50 or greater; (C) organohydrogenpolysiloxane having at least two hydrogen atom-bonded silicon atoms in one molecule; (D) a catalyst for curing reaction; and (E) a white pigment, wherein the component (A) is included in an amount of 20 mass % or more based on the total mass of the organopolysiloxane components, and the alkenyl group content in the components (A) to (C) is 1.7 mass % or less.