Based on previous discussions regarding the structural characteristics and structure-activity relationships of flame retardants, the mainstream structures of novel flame retardants can be categorized as follows. All possess environmentally friendly attributes-such as low smoke emission, low toxicity, and halogen-free composition-making them suitable for the flame-retardant requirements of high-end materials:
Novel Phosphorus-Based Structures
DOPO and its derivative structures
The core features a phenanthrene-based heterocyclic structure (9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide). The molecule contains active P-H bonds and cyclic O=P-O bonds, offering thermal stability far superior to that of conventional non-cyclic organic phosphates. They achieve high-efficiency flame retardancy through a dual mechanism involving gas-phase free-radical quenching and condensed-phase char formation; adding even small amounts enables materials such as epoxy resins and PBT to meet the UL94 V-0 standard.
Cyclic phosphate structures
These are cyclic organic phosphorus structures with high phosphorus content. Compared to linear phosphates, they exhibit higher thermal decomposition temperatures and better resistance to migration (blooming). They are suitable for transparent flame-retardant applications-such as in PC and acrylic coatings-without compromising the transparency of the base material.
Low-acidity aluminum dialkylphosphinate composite structures
A novel structure disclosed in a 2026 patent, featuring aluminum dialkylphosphinate as the core component combined with a specific ratio of hindered amine light stabilizers (HALS). By adjusting the system's pH to a neutral range of 6.5–7, this structure significantly reduces corrosiveness toward resin matrices (such as polyamide) while simultaneously enhancing flame-retardant performance and oxygen barrier properties.
