Phosphoric Acid Esters for Halogen-Free Epoxy Flame Retardancy
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Solution Overview
Problem
Current epoxy resin formulations face challenges in achieving halogen-free flame retardancy, as existing halogen-free hardeners and curing accelerators do not provide a flame retardant effect integrated into the polymer network, and existing alternatives have environmental and health concerns.
Innovation Solution
Development of esters of phosphorus-containing acids, specifically phosphoric acid esters and thiophosphoric acid esters, which act as both hardeners and curing accelerators, providing a flame retardant effect while maintaining high storage stability and reactivity, thus becoming part of the cured epoxy resin's polymer network.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bromine-containing flame retardants are used to achieve flame retardancy, then flame retardancy is improved, but environmental and health harm increases
Solution Approach 1:
The patent changes the chemical composition parameter by replacing bromine-containing compounds with phosphorus-containing compounds (phosphoric acid esters and thiophosphoric acid esters). This substitution maintains flame retardancy while eliminating the environmental and health hazards associated with bromine, directly resolving the contradiction between flame retardancy and harmful effects
Solution Approach 2:
The patent converts the previously harmful bromine-based flame retardants into beneficial phosphorus-based alternatives. The phosphorus-containing compounds not only provide flame retardancy but also do so without the toxic effects, effectively transforming the harmful approach into a beneficial one
2Object-affected harmful factors
If halogen-free alternatives like melamine phosphate or DOPO are used, then environmental harm is reduced, but flame retardancy effectiveness decreases
Solution Approach 1:
The patent optimizes the phosphorus compound structure by selecting specific phosphoric acid esters and thiophosphoric acid esters with particular molecular configurations. This structural parameter change enhances the flame retardancy effectiveness compared to previous halogen-free alternatives like melamine phosphate or DOPO, while maintaining the environmental benefits
Solution Approach 2:
The patent uses composite epoxy resin formulations containing the phosphorus-containing compounds combined with appropriate hardeners and curing accelerators. This composite approach creates a synergistic effect that improves flame retardancy effectiveness beyond what simple phosphorus compounds alone could achieve
3Stability of the object's composition
If latent hardener systems are used for one-component formulations, then storage stability is improved, but reactivity at room temperature decreases
Solution Approach 1:
The patent selects phosphorus-containing compounds with specific molecular structures and functional groups that balance latency and reactivity. The ester structures of phosphoric and thiophosphoric acids provide appropriate steric and electronic properties, enabling the hardener to remain stable during storage yet react efficiently when curing is initiated
Solution Approach 2:
The patent designs the phosphorus-containing hardeners to be pre-formulated in one-component systems where they remain dormant during storage but become reactive under curing conditions. This preliminary preparation allows the material to be stored ready-to-use while maintaining the ability to cure effectively when needed
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
These phosphorus-containing compounds effectively enhance the flame retardancy of epoxy resins, offering excellent storage stability and reactivity, making them suitable for use in various applications without the environmental and health hazards associated with halogenated compounds.
Implementation Method 1
esters of phosphorus-containing acids, specifically phosphoric acid esters and thiophosphoric acid esters, which act as both hardeners and curing accelerators, providing a flame retardant effect while maintaining high storage stability and reactivity, thus becoming part of the cured epoxy resin's polymer network
Data Source
AI summary
The present invention relates to innovative hardeners for curing epoxy resins, and cure accelerants for accelerated curing of epoxy resins, comprising in both cases at least one compound from the group of the esters of phosphorus-containing acids of formula (I), where for formula (I), for the radicals R1, R2, R3, R6, X and indices m, n and p, simultaneously or independently of one another: R1, R2 = simultaneously or independently of one another hydrogen or alkyl, R3 = alkyl, aryl, -O-alkyl, -O-aryl, -O-alkylaryl or -O-arylalkyl, R6 = hydrogen, alkyl or -NHC(O)NR1R2, X = oxygen or sulphur, m = 1, 2 or 3, n = 0, 1 or 2, and m + n = 3, p = 0, 1 or 2.