Latent Epoxy Curing Catalyst for Low-Temperature Stability

The patent uses an adduct of triphenylphosphine and 1,4-benzoquinone as a latent curing catalyst that acts as an intermediary. This adduct remains stable during storage but decomposes at curing temperature to release the active catalyst, thereby mediating between storage stability requirements and low-temperature curability needs

The patent changes the chemical state of the curing catalyst by forming an adduct that is stable at storage temperature but decomposes at curing temperature. This parameter change (from stable adduct form to active catalyst form) allows the system to achieve both storage stability and low-temperature curability

The adduct serves as a controlled intermediary that releases the active catalyst at a specific temperature threshold, ensuring uniform decomposition and catalyst release throughout the composition, thereby achieving uniform curing even at low temperatures

The curing catalyst is pre-prepared as a stable adduct that will decompose at the desired curing temperature. This preliminary preparation ensures that the catalyst activates uniformly throughout the composition at the specified temperature, preventing non-uniform curing

The adduct acts as a stable intermediary during storage that prevents premature catalyst activation. Only at the desired curing temperature does the adduct decompose to release the active catalyst, thereby maintaining flowability during storage while achieving curability at low temperature

The stable adduct form preliminarily counteracts the catalytic activity that would otherwise occur at storage temperature. This preliminary anti-action prevents unwanted curing and viscosity increase during storage, while allowing curability when heated to the decomposition temperature