Nabaltec Gmbh

Nabaltec-nabwerk Aluminiumhydroxid Technologie Gmbh

Nabaltec Ag

Josef Brandl

Reiner Sauerwein

Dieter Prescher

Hans Gokorsch

Stefan Ross

Josef Fischer

Johann Trettenbach

Klaus-Dieter Prescher

A flame retardant polymer composition consists of A process of producing the flame retardant agent is characterised in that a filter-moist aluminum hydroxide obtained by precipitation and filtration with a mean grain size of 0.8 to 1.5 &#x3bc;m is subjected to mill drying in a turbulent hot air stream in such a way that, while the grain distribution is largely retained, the BET surface is increased by at least 20%.

Flame retardant polymer composition

A fire-retardant plastic mixture contains 55%-75% by weight of boehmite which has an orthorhombic crystal structure and has the general formula AlO.sub.x (OH).sub.3-2x with x-values ranging between 0.8 and 0.99, and has a mean grain diameter d.sub.50 ranging between 0.4 and 0.7 .mu.m, a d.sub.10 value ranging between 0.7 and 1.2 .mu.m and a d.sub.90 value ranging between 0.2 and 0.4 .mu.m. The filler material is used in the form of a finely-crystallized hydrargillite which is obtained during a precipitation process according to Bayer with a grain diameter of 0.5 to 3 .mu.m, which is suspended and which, without any mechanical working, is transformed directly in a hydro-thermal process at temperatures ranging between 220.degree. C. and 240.degree. C. under turbulent conditions into a boehmite of the general formula AlO.sub.x (OH).sub.3-2x with x-values ranging between 0.8 and 0.99. The phase transformation pressure amounts to at least 24 bar after a holding time of 1-15 minutes at the maximum temperature and then the pressure is reduced to ambient pressure.

Fire retardant plastic mixture and method of producing a filler material

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Teublitz, Germany

Josef Brandl