Curable Composition Base Amplifier Thick Film Curing
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Solution Overview
Problem
Base generators in curable compositions have lower curing sensitivity compared to acid generators, making them less suitable for thick films, which is a limitation in applications such as concrete and other structural materials where high curability is required.
Innovation Solution
A curable composition comprising a polyfunctional isocyanate compound, a multivalent alcohol or epoxy compound, and a base amplifier, with a base generator that generates a base upon energy application, enhancing the urethane bond formation reaction sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If base generators are used in curable compositions, then polymerization inhibition by oxygen and corrosion/denaturation of resins are avoided, but curing sensitivity is lower compared to acid generators
Solution Approach 1:
The invention changes the chemical parameters of the base generator by using photobase generators that release strong bases (pKa > 11) upon light irradiation, combined with base amplifiers that undergo deprotonation to generate additional base species. This parameter change in base strength and generation mechanism achieves high curing sensitivity while maintaining the advantages of base-generated systems.
Solution Approach 2:
The invention introduces base amplifiers that are preliminarily incorporated into the curable composition alongside the photobase generator. When light irradiation occurs, the initially generated base immediately triggers the base amplifier to release additional base species, creating a cascading effect that amplifies the curing reaction speed and sensitivity before the reaction completes.
2Reliability
If base generators are used for curing thick films, then avoidance of oxygen inhibition is achieved, but poor curability in deep portions of thick films occurs due to low sensitivity
Solution Approach 1:
The invention changes the base generation parameters by using photobase generators with high quantum efficiency and strong base amplifiers with low pKa values for the conjugate acid. This enables sufficient base generation even in deep portions of thick films where light intensity is reduced, achieving uniform curability throughout the thickness.
Solution Approach 2:
The base amplifier mechanism provides continuous base generation throughout the curing process. As light irradiation proceeds and base is consumed in the curing reaction, the base amplifier continuously releases additional base species to maintain the reaction, ensuring complete curing even in thick film deep portions where initial base concentration might be insufficient.
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 achieves improved curing sensitivity and reactivity, enabling effective curing of thick films with enhanced urethane bond formation, even in deep portions of the film, thus expanding the applicability of anionic polymerization systems.
Implementation Method 1
base generator that releases bases by applying energy (see, for example, K. Arimitsu, R. Endo, Chem. Mater. 2013, 25, 4461-4463.)
Implementation Method 2
a base amplifier, with a base generator that generates a base upon energy application, enhancing the urethane bond formation reaction sensitivity
Data Source
AI summary
One embodiment of the present invention provides a curable composition, including a polyfunctional isocyanate compound, a compound selected from the group consisting of a multivalent alcohol and an epoxy compound, and a base amplifier.