Keep your Elastomers flexible

Flame Retardants
Due to the chemical constitution TPU’s
are easy to ignite and are therefore
difficult to flame retard. By adding a
metal phosphinate (Exolit OP 1230) in
combination with additional flame
retardants the desired classification
UL 94 V-0 is achieved. But only with
the addition of a further ingredient
(antidrip, e.g. talc) the dripping of the
specimen in the UL 94 test could be
prevented, which is required for some
test in the cable industry (Chart 1).
Graph 2 shows, that the mechanical
properties in this case elongation at
break are maintained on an acceptable
value.
Chart 1:
Phosphinate in Polyether-TPU
Flammability Results – UL 94
TPU 100 64 64
Exolit OP 1230 15 15
Melamine cyanurate 7.5 7.5
Melamine polyphosphate 7.5 7.5
Talc (ultrafine) 6
UL 94 (1.6 mm) V-2/n.c. V-0* (V-2) V-0*
Burning time [s] 47 25 9
Number of specimen dripping 5 5 1
* = non-burning dripping
> Reduction of dripping possible by adding talc
Graph 2:
Phosphinate in Polyether-TPU
Physical Properties – Elongation at Break
Elongation at break [%]
800
700
600
500
400
300
200
100
0
= TPU, = with FR, = with FR + antidrip
* = Storage in water at 80 °C for 42 d
after water storage*
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