One-Part Polythiol Sealant with Dual-Cure Photolatent Base and Phase-Separated Amine
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Solution Overview
Problem
Current aerospace sealants face challenges in achieving a balance between long application life and short curing time, requiring multiple products for different applications and involving complex mixing steps or storage in freezers for one-part products.
Innovation Solution
A composition comprising a polythiol, a polyepoxide, a photolatent base that generates an amine upon light exposure, and a phase-separated second amine that can cure at elevated temperatures, providing a cure-on-demand feature with independent photochemical and thermal options.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a conventional two-part sealant system is used to achieve short curing time, then curing speed is improved, but application complexity increases due to mixing requirements
Solution Approach 1:
The patent combines multiple curing mechanisms (photochemical cure via photolatent base and thermal cure via phase-separated amine) into a single one-part composition. This allows the sealant to be applied without mixing while still enabling rapid curing through light exposure or heat activation, thus merging the benefits of fast curing with the simplicity of one-part application.
Solution Approach 2:
The patent introduces dynamic curing options where the same composition can be cured through different pathways (light or heat) depending on application requirements. The phase-separated amine provides thermal cure capability that activates when exposed to heat, while the photolatent base provides photochemical cure when exposed to light, allowing the system to adapt its curing mechanism dynamically.
2Ease of operation
If a one-part sealant is used to simplify application, then ease of operation is improved, but curing time increases
Solution Approach 1:
The patent changes the activation parameters of the curing agents. The photolatent base is activated by light exposure (optical parameter), and the phase-separated amine is activated by heat (thermal parameter). This allows a one-part composition to achieve fast curing by changing the activation method rather than requiring mixing, thus reducing curing time while maintaining application simplicity.
Solution Approach 2:
The phase-separated amine is pre-incorporated into the composition in a dormant, phase-separated state during manufacturing. This preliminary inclusion ensures that the thermal cure capability is already present in the one-part composition, ready to activate when heat is applied, eliminating the need for pre-mixing while maintaining fast cure potential.
3Adaptability or versatility
If multiple catalysts are included to provide curing options, then versatility is improved, but composition complexity increases
Solution Approach 1:
The patent segments the catalyst system into two distinct functional components: a photolatent base for photochemical cure and a phase-separated amine for thermal cure. The phase-separated amine exists as a distinct phase within the composition, physically separated from the main matrix. This segmentation allows each catalyst to function independently through different activation mechanisms, providing versatility while managing composition complexity through physical separation.
Solution Approach 2:
The phase-separated amine acts as an intermediary curing agent that bridges between the photolatent base system and thermal cure requirements. It provides a backup or alternative curing pathway that can be activated by heat, mediating between the primary photochemical cure and the need for thermal cure capability, thus adding versatility without requiring a completely separate catalyst system.
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
Enables a one-part sealant with a long application life that can be cured on demand, reducing inventory needs and eliminating the need for mixing, while ensuring efficient curing regardless of light exposure.
Implementation Method 1
a photolatent base that can photochemically generate a first amine
Implementation Method 2
The second amine can decrease the time to fully cure the composition, for example, once the light source is removed. This can be accomplished by increasing the temperature of the composition.
Data Source
AI summary
A composition including a polythiol having more than one thiol groups, a polyepoxide having more than one epoxide group, a photolatent base catalyst that can photochemically generate a first amine, and a second amine phase-separated within the composition. A polymer network preparable from the composition, and a method for making the polymer network are also disclosed.