Magnesium process
AssigneeFlamemag International Gie
InventorsDagwin Elsner, Roger Rothon
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Abstract
The present invention relates to a flame retardant quality magnesium hydroxide having a BET surface area of less than approximately 10 m.sup.2 per gram (uncoated), an average particle size of approximately 0.5 to 10.0 micron, and less than approximately 0.5% of particles over 10 micron (average particle size measured by laserlight scattering method), and a substantial number of crystals which are generally ovoid in cross section. A process for producing a flame retardant quality magnesium hydroxide is also described.
Claims32
A flame retardant quality magnesium hydroxide having
- a BET specific surface area of less than approximately 10 m.sup.2 per gram (uncoated),
- an average particle size of approximately 0.5 to 10.0 micron, and less than approximately 0.5% of particles over 10 micron (average particle size measured by laserlight scattering method), and
- a substantial number of crystals which are generally ovoid in cross section.
A coated magnesium hydroxide product including
- a flame retardant quality magnesium hydroxide containing crystals being generally ovoid in cross-section, with a low BET specific surface area less than approximately 10 m.sup.2 /g, a median particle size of approximately 0.5 to 10.0 micron and an oil absorption less than approximately 70 mL/100 g (oil absorption measured under International Standard ISO 787/5-1980(E))
- an anionic surface active agent selected from the group consisting of stearic acid, oleic acid, lauric acid, palmitic acid, sodium stearate, potassium behenate, sodium montanate, potassium stearate, sodium oleate, potassium oleate, sodium palmitate, potassium palmitate, sodium laurate, potassium laurate, sodium dilauryl benzenesulfonate, potassium octadecylfsulfate, sodium laurylsulfonate, disodium 2-sulfoethyl .alpha.-sulfostearate and ammonium salts of fatty acids, and mixtures thereof coated on the magnesium hydroxide.
A polymeric composition including
- a thermoplastic polymer, thermoset or elastomer;
- and
- a magnesium hydroxide component containing a substantial number of crystals being generally ovoid in cross section with a low BET specific surface area less than 10 m.sup.2 /g, a median particle size of approximately 0.5 to 10.0 micron and an oil absorption less than approximately 70 mL/100 g (oil absorption measured under International Standard ISO 787/5-1980(E)).
A process for preparing a flame retardant quality magnesium hydroxide which includes
- providing
- a magnesium chloride solution;
- and
- a source of ammonia;
- adding a stoichiometric excess of ammonia to the solution to form a magnesium hydroxide precipitate;
- and
- subjecting the magnesium hydroxide to a hydrothermal recrystallisation.
Dependencies are inferred from the claim text.