Silane-Terminated Polythioether Sealant Ambient Stability
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Solution Overview
Problem
Existing one-part, moisture-curable sealants for aerospace applications have limited shelf life and require storage at very low temperatures, increasing manufacturing and transportation costs due to the need for freezing to slow down curing reactions.
Innovation Solution
A one-part moisture-curable sealant composition comprising a silane-terminated polythioether component, a filler, and a catalyst, packaged in a moisture-sealed container to prevent curing, which remains stable at ambient temperatures and only cures when exposed to moisture, eliminating the need for freezing and extending shelf life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the sealant is formulated as a one-part moisture-curable system, then ease of operation is improved by eliminating mixing requirements, but shelf life is reduced and freezing is required to slow curing
Solution Approach 1:
The patent changes the chemical parameters of the sealant system by using silane-terminated polythioether instead of conventional polysulfide polymers. This chemical modification allows the sealant to remain stable at ambient temperatures without freezing while maintaining moisture-curable properties, thus extending shelf life without sacrificing ease of operation.
Solution Approach 2:
The patent creates a composite material system combining silane-terminated polythioether with specific fillers and catalysts. This composite formulation achieves both long shelf life at ambient temperature and effective moisture curing, resolving the contradiction between ease of use and shelf life stability.
2Duration of action of stationary object
If freezing is used to slow down curing reaction, then shelf life is extended, but manufacturing cost increases due to additional labor and equipment
Solution Approach 1:
The patent fundamentally changes the storage temperature parameter from -40°C to -62°C (conventional) to ambient temperature (invention). This parameter change eliminates the need for expensive freezing infrastructure while maintaining extended shelf life through the inherent stability of silane-terminated polythioether at room temperature.
3Object-generated harmful factors
If freezing is required for storage, then curing reaction is slowed, but transportation cost increases due to low-temperature requirements
Solution Approach 1:
The patent changes the storage and transportation temperature parameter from cryogenic levels (-40°C to -62°C) to ambient temperature. The silane-terminated polythioether formulation maintains slow curing rates at ambient temperature through its chemical stability, eliminating expensive cold chain transportation requirements while still controlling the curing reaction.
4Ease of manufacture
If the sealant is stored at ambient temperature, then manufacturing and transportation costs are reduced, but curing reaction proceeds too quickly reducing shelf life
Solution Approach 1:
The patent modifies the chemical composition parameters by using silane-terminated polythioether instead of conventional polymers. This chemical change allows the sealant to maintain slow curing rates at ambient temperature, achieving both cost reduction and extended shelf life simultaneously.
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 solution provides a stable and cost-effective sealant with extended shelf life, eliminating the need for low-temperature storage and transportation, while ensuring effective curing when applied, making it suitable for aerospace and other applications.
Implementation Method 1
When the moisture sealed container is unsealed, and the composition exposed to moisture, the moisture promotes curing of the composition to form a sealant
Implementation Method 2
The silane-terminated polythioether component, filler and catalyst are combined and packaged in a moisture sealed container to substantially prevent curing
Data Source
AI summary
One-part moisture curable sealant compositions and methods of making the same are provided. The composition includes a silane-terminated polythioether component and a catalyst. The silane-terminated polythioether component and catalyst are isolated from moisture to prevent curing. The composition is stable against curing at ambient temperature and under conditions substantially free of moisture. When the composition is applied to a substrate and exposed to moisture, the composition cures to form a sealant. A method of making a sealant composition includes reacting a mercapto-terminated polythioether with a compound having a silane group to form a silane-terminated polythioether. The silane-terminated polythioether is then combined with a catalyst and isolated from moisture to prevent curing. Lastly, the composition is applied to a substrate and exposed to moisture which allows the composition to cure to form a sealant.