Supply Program Flame Retardants - HARKE Group

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Mode of Action
Phosphor compounds function in the gas phase by releasing
highly effective scavengers that act as flame retardants through
cutting-off the radical chain reaction. Furthermore, phosphoric
acid dehydrates the polymer surface to a charred layer. This
so-called carbon film prevents further feeding with oxygen, and
thus impedes the advancement of the oxidate corrosion.
The mechanism is especially effective with oxygenic polymers
because of the combination of phosphoric acid ester with fillers
like aluminium trihydrate a glassy slag is formed on the surface
during fire.
The organic trisphosphates can also be used in oxygen-free
polymeres.
The Chemical with a Double Effect
When adding plasticisers as for instance diethylhexal phthalate
(DEHP) the effect is that the combustibility of the plastic rises.
This makes the use of flame retardants indispensable, therefore,
diethylhexyl phthalate is often combined with inorganic flame
retardants.
Instead of using two chemicals you can change to only one.
The phosphor compounds feature both the retardant effect and
pasticising properties and thus counteract the brittleness of the
plastic.