Translucent Silicone Sealant Viscosity Stability
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Solution Overview
Problem
Current two-part RTV silicone sealants used in insulated glass units are opaque and suffer from viscosity issues due to the interaction of fumed silica with silanol-terminated diorganopolysiloxane, limiting their utility and requiring additional equipment for cleanup, which affects productivity and storage stability.
Innovation Solution
A translucent two-part RTV silicone rubber composition is developed, using a first part with silanol-terminated diorganopolysiloxane and a second part with a condensation catalyst, along with treated fumed silica to prevent viscosity structuring, and optionally including additional components for improved stability and adhesion, allowing for rapid primerless adhesion to various substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If fumed silica is used in two-part silanol terminated diorganopolysiloxane based sealants, then filler content and structural reinforcement are improved, but viscosity increases during storage due to interaction between free silanol groups and silanol terminated polymer
Solution Approach 1:
The patent introduces an intermediary substance - a silane-modified polymer - that mediates between the silanol-terminated diorganopolysiloxane and fumed silica. This modified polymer contains both silanol groups for crosslinking and silane groups that react with fumed silica, preventing direct interaction between free silanols and silica that would cause viscosity structuring, while still allowing the silica to provide structural reinforcement
Solution Approach 2:
The patent changes the chemical parameters of the silanol-terminated diorganopolysiloxane by modifying it with silane groups. This parameter change allows the polymer to simultaneously interact with both fumed silica (through silane groups) and maintain crosslinking capability (through silanol groups), preventing viscosity increase while preserving structural reinforcement benefits
2Reliability
If opaque two-part RTV silicone sealant compositions are used, then adhesion and sealing effectiveness are achieved, but productivity decreases due to visible squeeze out requiring clean up
Solution Approach 1:
The patent applies color/transparency changes by formulating the sealant composition to be translucent rather than opaque. This allows the sealant to maintain its adhesion effectiveness while becoming visually invisible when squeezed out during application, eliminating the need for cleanup operations and improving manufacturing productivity
3Reliability
If two-component sealing systems are used, then adhesion and sealing performance are improved, but device complexity increases due to requirement for set mix ratio and two-part mixing equipment
Solution Approach 1:
The patent maintains the beneficial two-component segmentation of the sealing system, separating the base polymer and curing agent into distinct components. This segmentation provides reliable adhesion and sealing performance while allowing each component to be optimized independently for its specific function
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 provides high bond strength, improved storage stability, and rapid adhesion, reducing the need for cleanup and enhancing productivity in the manufacturing of architectural elements like insulated glass units with excellent physical properties and translucency.
Implementation Method 1
a condensation catalyst
Implementation Method 2
a crosslinker in the first and/or second part
Implementation Method 3
fumed silica having surface silanol groups treated with a capping agent
Data Source
AI summary
The invention relates to architectural elements possessing at least two components bonded together employing a silicone rubber composition of high stability and translucency, which is useful for application as a bedding sealant in the manufacture of such architectural elements as window assemblies, door assemblies, structural glazing, curtainwall applications, and the like.