FR-Flame Retardants / (нг)

Additives used in FR polymer formulations.
Current Practice and Trends.

Limiting Oxygen Index
(LOI) ASTM 2863

A higher LOI indicates a lower flamability.
ABS - 18.5
PET - 22.0
PP - 17.6
PE - 17.3
F-PVC - 24.5
R-PVC - 42.5
PTFE - 95.0

Всего изобретено более 200 видов FR формул.

BROMINE is extremely efficient, meaning that a relatevely small amount is needed to achive FR.
CHLORINE. Chlorinated paraffins and chlorinated phosphates are used whole range of materials from cathing fire.
INORGANICS and MINERALS. Based on nitrogen (melamine compounds). Based on graphite, silica (glass/sand) and inorganic phosphates (ammonium phosphates and polyphosphates). Mineral compounds include certain phosphates, metal oxydes, hydroxides and and other metal products: aluminum, magnesium, mlybdenum, boron, antimony.

PHOSPHORUS is used to produce liquid and solid or inorganic flame retardants which are used in INTUMESCENT or FR coatings, as well as flexible PNC of cables.
NITROGEN compounds comprise a relatively small group of FRs. Application: Nylons, Polyolefins, PUR (as intumescents), paints.

<<MARKET>> 2,5 mln ton/year

> ATH Aluminum Hydroxide - 38%
> Haloginated and Chlorinated products which are commonly used with synergist Antimony Trioxide - 31%
> OrganoPhosphorus and other FRs like inorganic phosphorus compounds, nitrogen and zinc based FRs make rest 31%;

ATH - 38%
ORGANO-P - 18%
OTHER -13%


FRs may slow down or even interrupt the combustion process by physical or chemical action in the solid, liquid or gas phase.

@ PHYSICAL ACTION by cooling or diluting the substrate in gas phase (i.e. formation of water) and the solid phase (ATH, DTH, MDH), or by coating the substrate (shieldening it against the attack of oxygen and heat) with P and N compounds. 

@ CHEMICAL ACTION in gas phase inerferes with combustion process by eliminating the high energy H and OH radicals by halogen halides from halogenated FRs, metal halogen compounds from antimony trioxide, and P containig fragments from P FRs (flame poisoning). In solid phase, the FRs forms a carbonaceous layer on the surface of the polymer by dehydration, formation of double bonds thus initiating cyclization and cross-linking (P, N compounds, intumescent systems).

@ SYNERGISM. Today, FRs are mostly used as system consisting of several components. Synergism means that the overall FR effect is higher than  the sum of single component effect. 

ATO. ANTYIMONY TRIOXIDE (Sb2O3) with brominated or chlorinated compounds . ATO alone has no Fr effect; with Br/Cl compounds, however, it is higher than the sum of single effects.