Siloxane Composition for High Altitude Display Potting
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Solution Overview
Problem
Conventional silicone gel compositions exhibit high penetration values, leading to softness and low gel strength, which results in bubble formation and peeling under negative pressure environments, such as high altitudes, and reduced tackiness, making them unsuitable for applications like display potting and optical bonding.
Innovation Solution
A siloxane composition comprising an organopolysiloxane with two alkenyl groups, an organopolysiloxane with three alkenyl groups, and a hydrosilylation catalyst, with a specific viscosity range and component ratios, to achieve a silicone gel with improved elongation at break, tackiness, and resistance to high temperature and negative pressure, characterized by a low penetration value and enhanced mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the hardness of cured gels is increased to improve gel strength and prevent bubble formation under negative pressure, then the penetration value decreases and gel strength improves, but the elongation at break decreases and tackiness is reduced
Solution Approach 1:
The patent changes the chemical composition parameters of the silicone gel by incorporating vinyl MQ silicone resin and controlling the ratio of crosslinking agents to achieve optimal gel strength while maintaining elongation at break and tackiness. This resolves the contradiction by finding a specific compositional parameter range that satisfies both requirements.
Solution Approach 2:
The patent uses a composite silicone gel system combining multiple components: vinyl-terminated polydimethylsiloxane, vinyl MQ silicone resin, crosslinking agents, and catalysts. This composite approach allows simultaneous optimization of gel strength, elongation, and tackiness that cannot be achieved with single-component systems.
2Strength
If vinyl MQ silicone resin is used as a crosslinker to improve gel strength, then the penetration value decreases, but the gel still exhibits high penetration value and is not suitable for negative pressure environments
Solution Approach 1:
The patent optimizes the content ratio of vinyl MQ silicone resin to other components and controls the crosslinking density to achieve sufficient gel strength. By precisely controlling compositional parameters and crosslinking degree, the gel achieves low penetration value suitable for negative pressure environments while maintaining other required properties.
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 results in a silicone gel with increased elongation at break, better tackiness, and resistance to high temperature and negative pressure, preventing bubble formation and peeling, and maintaining effective adhesion and light transmittance, suitable for use in electronic components and displays at high altitudes.
Implementation Method 1
an addition reaction curable organopolysiloxane compositions which comprise i) an organopolysiloxane having at least two silicon-bonded alkenyl groups such as vinyl groups as a base polymer, ii) an organohydrogenpolysiloxane having at least three silicon-bonded hydrogen atoms (i.e. Si-H groups) as a crosslinker, and iii) a platinum-based catalyst, and which yield a cured product via an addition reaction of the Si-H groups to the alkenyl groups
Data Source
Figure 1
AI summary
Disclosed is a siloxane composition, comprising: (a) at least one organopolysiloxane containing two alkenyl groups bonded to silicon atoms at both ends of the chain per molecule, (b) at least one organopolysiloxane containing at least three alkenyl groups bonded to silicon atoms per molecule, (c) at least one organopolysiloxane containing two hydrogen atoms bonded to silicon atoms at both ends of the chain per molecule, and (d) at least one hydrosilylation catalyst, with the proviso that component (c) is in an amount of greater than or equal to 30 wt%based on the total weight of the composition, and component (e) at least one organopolysiloxane containing at least three hydrogen atoms bonded to silicon atoms per molecule is in an amount of less than or equal to 0.01 wt%based on the total weight of the composition. The silicone gel cured therefrom has a suitable low penetration, a higher elongation at break, a better gel tackiness and an excellent resistance to high temperature and negative pressure.