ULTRADUR® S 4090 G4 LS Black 15077 Polybutylene Terephthalate

Unnecessarily high melt temperatures and excessively long residence times of the melt in the cylinder and the hot runner can bring about molecular degradation. The figure shows an example (Ultradur® B4520) illustrating how the viscosity number acts as a measure of the molecular weight as a function of the melt temperature and residence time. Based on experience material degradation of less than 10 % based on the measured viscosity in solution of the granules and the molding is tolerable. In the event of values higher than this the processing and drying parameters should be checked.

Ultradur® melts are stable at temperatures up to 280°C and do not give rise to hazards due to molecular degradation or the evolution of gases and vapors.

Like all thermoplastic polymers, however, Ultradur decomposes on exposure to excessive thermal stresses, e.g. when it is overheated or as a result of cleaning by burning off.

At temperatures of > 290 °C can be emitted: carbon monoxide, tetrahydrofuran.

Under special fire conditions traces of other toxic substances are possible.

Formation of further decomposition and oxidation products depends upon the fire conditions.

When Ultradur® is properly processed and there is adequate suction at the die no risks to health are to be expected.

Standard packaging includes the 25-kg-bag, the 1000 kg octabin (octagonal container) or the 1000 kg big bag.

Other forms of packaging are possible subject to agreement. All containers are tightly sealed and should be opened only immediately prior to processing.

Further precautions for preliminary treatment and drying are described in the processing section of the brochure.

Ultradur® can be stored for a longer period of time in dry, well vented rooms without causing problems in processing.

Ultradur® should generally have a moisture content of less than 0,04% when being processed.

Pre-drying is also for the addition of batches, e.g. in the case of inhouse pigmentation. In order to prevent the formation of condensed water, containers stored in unheated rooms must only be opened when they have attained the temperature prevailing in the processing area.

This can possibly take a very long time. Measurements have shown that the interior of a 25-kg bag originally at 5°C had reached the temperature of 20°C in the processing area only after 48 hours.