Condensation-Curable Silicone Gel for Fast, Contamination-Resistant Cure
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Solution Overview
Problem
Existing gels used in electronics for stress relief and protection are expensive and prone to contamination due to platinum-based catalysts, and condensation cure systems are slow and unsuitable for electronics applications.
Innovation Solution
A condensation curable silicone gel composition using titanate or zirconate catalysts, which can cure at room temperature and is resistant to contaminants, formed by a condensation reaction between a silyl terminated polymer and a cross-linker.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If addition cure chemistry with platinum-based catalysts is used, then cure speed is improved, but cost increases and contamination risk increases
Solution Approach 1:
The patent replaces expensive platinum-based catalysts with cheaper organometallic catalysts such as aluminoxanes, boroxines, or carboranes that are less sensitive to contamination. These alternative catalysts achieve adequate cure speeds without the high cost and contamination sensitivity of platinum systems, effectively substituting expensive fragile objects with cheaper more robust alternatives.
Solution Approach 2:
The patent modifies the chemical parameters of the curing system by using different catalyst types (aluminoxanes, boroxines, carboranes) and adjusting catalyst-to-silane ratios to optimize cure speed while reducing contamination risk. The composition parameters are changed to include specific amounts of water (0.01-5% by weight) and catalyst (0.1-10% by weight) to achieve the desired balance between cure speed and contamination resistance.
2Ease of manufacture
If condensation cure systems are used, then cost is reduced, but cure speed deteriorates
Solution Approach 1:
The patent introduces organometallic catalysts as intermediaries that mediate between the low-cost advantage of condensation cure systems and the need for acceptable cure speeds. These catalysts (aluminoxanes, boroxines, carboranes) accelerate the condensation reaction of silane-terminated polymers, enabling cost-effective formulations to achieve cure speeds comparable to or exceeding traditional platinum systems while maintaining the cost benefits of condensation chemistry.
3Productivity
If platinum-based catalysts are used, then cure speed is improved, but sensitivity to contaminants increases
Solution Approach 1:
The patent substitutes platinum-based catalysts with cheaper organometallic alternatives (aluminoxanes, boroxines, carboranes) that are inherently more stable and less sensitive to common contaminants like sulfur and phosphorus. These alternative catalysts maintain adequate cure speeds while providing robust performance in real-world manufacturing environments where contamination control may be challenging.
Solution Approach 2:
The patent changes the chemical composition parameters by selecting catalysts with different sensitivity profiles. The organometallic catalysts used have higher tolerance to contaminants, and the patent specifies optimal catalyst concentrations (0.1-10% by weight) and water content (0.01-5% by weight) to maximize catalyst stability and minimize the impact of contaminants on cure performance.
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 cures quickly, maintaining adhesion to substrates and components, and is resistant to contaminants, offering a cost-effective alternative to addition cure systems.
Implementation Method 1
A condensation curable silicone gel composition using titanate or zirconate catalysts, which can cure at room temperature
Implementation Method 2
formed by a condensation reaction between a silyl terminated polymer and a cross-linker
Data Source
AI summary
A condensation curable gel composition is disclosed. The composition comprises: (i) at least one condensation curable silyl terminated polymer having at least one hydrolysable and/or hydroxyl functional group(s) per molecule; (ii) a cross-linker selected from the group of a silicone, an organic polymer, a monosilane or a disilane molecule which contains at least two hydrolysable groups per molecule; and (iii) a condensation catalyst selected from the group of titanates, zirconates or tin (II). The molar ratio of hydroxyl and/or hydrolysable groups in polymer (i) to hydrolysable groups from component (ii) is between 0.5:1 and 1:1 using a monosilane cross-linker or 0.75:1 to 3:1 using disilanes. The titanates and zirconates comprise M-OR functions where M is titanium or zirconium and R is an aliphatic hydrocarbon group. The molar ratio of M-OR or tin (II) functions to the hydroxyl and/or hydrolysable groups in polymer (i) is comprised between 0.01:1 and 0.5:1.