Aluminum Hypophosphite (AHP)

Aluminum Hypophosphite(AHP),CAS,7784-22-7 is a white, crystalline powder. Its key characteristic is its role as a highly efficient, halogen-free flame retardant. It acts mainly in the condensed phase by promoting the formation of a protective char layer upon heating, which insulates the polymer and suppresses combustion. It is particularly effective in engineering plastics like polyesters and polyamides. A notable advantage is its high phosphorus content, providing excellent fire resistance at low loadings. It is a preferred eco-friendly alternative to brominated flame retardants.

Basic Information

Chemical Formula: Al(H2PO2)3

CAS NO.: 7784-22-7  

HS NO.: 28351000

EINECS No.: 479-150-8

Molecular weight: 221.96

Bulk density(20℃): 1.2 g/cm3

Aluminum hypophosphite%≥98.0

P%≥40.0

Particle size(D50)μm:3-5

Particle size (D98)μm≤20

Whiteness≥98

Cl%≤0.005

Moisture w%≤0.5

PH: 3-5

1% decomposition temperature(℃)≥300

Hazardous grade: 4.1 category

Execution standard: HG/T4833-2015

Appearance: Typically a white, free-flowing crystalline powder.

Mechanism of Action

It acts through a condensed phase mechanism. When exposed to heat, it decomposes and promotes the formation of a protective, carbonaceous char layer on the surface of the polymer. This char layer acts as a barrier, insulating the underlying material from heat and oxygen, and preventing the release of flammable gases.

Primary Use: Flame Retardant

Aluminum hypophosphite is primarily valued as an effective flame retardant, especially in polymers.

Polyesters (PBT, PET): Very effective, often used without the need for additional synergists.

Polyamides (Nylon 6, Nylon 66): A popular halogen-free flame retardant choice.

Epoxy Resins: Used in printed circuit boards and composites.

Polyolefins (PP, PE): Can be used, often with synergists.

Advantages as a Flame Retardant:

Halogen-Free: It is part of the environmentally friendly "halogen-free" flame retardant family, which is increasingly demanded due to regulations restricting brominated and chlorinated flame retardants.

High Efficiency: It has a high phosphorus content, making it very effective at low loadings.

Good Thermal Stability: It has a decomposition temperature suitable for processing many engineering plastics.

Other Properties

Solubility: Slightly soluble in water. Insoluble in most organic solvents.

Stability: Stable under normal conditions.

Toxicity: Generally considered to have low acute toxicity. However, like all hypophosphites, it should be handled with care as decomposition products can be hazardous.

Handling: Standard personal protective equipment (PPE) such as gloves and dust masks is recommended to avoid inhalation or skin contact.

Packaging, storage and transportation

25kg/bag, stored in dry and cool warehouse, avoiding fire, and stored separately from oxidizers and alkaline chemicals.