Curable Silicone Composition Flexural Strength Transparency
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Solution Overview
Problem
Cured silicone products obtained from existing curable silicone compositions are not flex-resistant and can be easily damaged during molding or assembly, lacking sufficient flexural strength for applications involving bending.
Innovation Solution
A curable silicone composition comprising an alkenyl-containing organopolysiloxane and an alkenyl-containing organopolysiloxane resin, with specific viscosities and alkenyl group content, along with an organopolysiloxane containing silicon-bonded hydrogen atoms, and a hydrosilylation catalyst, which forms a thermally cured product with JIS K6253 type-A durometer hardness of 77 to 95 and transmittance of 90% or greater.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If existing curable silicone compositions are used to obtain transparent cured silicone products, then transparency is achieved, but flex-resistant is poor and products are easily damaged during molding or assembly
Solution Approach 1:
The patent changes the chemical composition parameters by specifying precise ratios of component (A) alkenyl-containing organopolysiloxane (52-65 mass %) and component (B) organopolysiloxane resin (35-48 mass %), along with controlled content of silicon-bonded hydrogen atoms (0.5-5 mass %) and alkenyl groups (3.5-5.0 mass %). These parameter adjustments simultaneously achieve high transparency (≥90%) and improved flex-resistant properties without compromising either characteristic
Solution Approach 2:
The patent creates a composite silicone system by combining two distinct organopolysiloxane components with complementary properties. Component (A) provides the base silicone matrix with transparency, while component (B) contributes cross-linking functionality through silicon-bonded hydrogen atoms. The synergistic combination of these composite materials delivers both optical clarity and enhanced mechanical strength
2Illumination intensity
If existing curable silicone compositions are used, then transparency is achieved, but the cured products lack sufficient flexural strength for applications involving bending
Solution Approach 1:
The patent optimizes the content of alkenyl groups to 3.5-5.0 mass % and silicon-bonded hydrogen atoms to 0.5-5 mass %, creating a balanced cross-linking density that provides sufficient flexural strength for bending applications while preserving optical transparency. This precise parameter control enables the material to meet both optical and mechanical performance requirements
3Illumination intensity
If the composition is designed for high transparency, then optical properties are improved, but surface tackiness increases and durability decreases
Solution Approach 1:
The patent controls the ratio of component (A) to component (B) within specific ranges (52-65 mass % and 35-48 mass % respectively) to achieve optimal cross-linking. This parameter optimization ensures complete curing that eliminates surface tackiness while maintaining high transparency (≥90%), thereby improving both optical properties and surface durability simultaneously
Solution Approach 2:
The patent ensures sufficient cross-linking by controlling the content of silicon-bonded hydrogen atoms at 0.5-5 mass %, which is enough to achieve complete curing and non-tacky surfaces without over-cross-linking that would compromise transparency. This controlled excessive action guarantees complete reaction for improved reliability
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 produces a flex-resistant, highly transparent cured silicone product with improved durability and non-tacky surfaces, suitable for applications requiring flexibility and optical transparency, maintaining performance in high-temperature and high-humidity environments.
Implementation Method 1
a curable silicone composition comprising: an alkenyl-containing organopolysiloxane (A)... an organopolysiloxane (B)... and a hydrosilylation catalyst
Data Source
AI summary
A curable silicone composition comprising: an alkenyl-containing organopolysiloxane (A) that contains: a dialkylpolysiloxane (A-1) having on average at least 2 alkenyl groups in one molecule having a 25°C viscosity in the range of 5,000 to 35,000 mPa.s, and a alkenyl-containing organopolysiloxane resin (A-2) consisting of SiO 4/2 units, R1 2R2SiO1/2 units, and R1 3SiO1/2 units (where R1 designates alkyl groups with 1 to 10 carbon atoms, and R2 designates alkenyl groups) with the content of alkenyl groups ranging from 3.5 to 5.0 mass %, and with the ratio of the sum of the mole numbers of the R1 2R2SiO1/2 units and R1 3SiO1/2 units to 1 mole of the SiO4/2 units in the range from 0.5 to 1.4; an organopolysiloxane (B), wherein silicon-bonded hydrogen atoms are in an amount of at least 0.7 mass %; and a hydrosilylation catalyst (C). The composition is capable of forming a flex-resistant highly transparent cured silicone product with non-tacky surface.