Flame-retardant mineral fillers and flame-retardant polymer compositions

摘要

A powdery mineral filler comprising a calcium compound and a magnesium compound, comprising a semi-hydrated dolomite of general formula aCaCO3.bCa(OH)2.cMg(OH)2.dMg0.eCaO, a, b, c, d and e being molar fractions with (a+b+e)/(c+d) between 0.8 and 1.2, and comprising particle agglomerates, a flame-retardant polymer composition containing same, production methods and use of such mineral fillers.

主权项

1. A powdery mineral filler comprising a calcium compound and a magnesium compound, characterized in that said mineral filler comprises a semi-hydrated dolomite fitting the general formula aCaCO3.bCa(OH)2.cMg(OH)2.dMgO.eCaO, a, b, c, d and e being molar fractions with (a+b+e)/(c+d) being comprised between 0.8 and 1.2 and having values such that b represents the molar fraction corresponding to a weight proportion ≧15%, c represents the molar fraction corresponding to a weight proportion ≧1%, d represents the molar fraction corresponding to a weight proportion ≧1%, a and e respectively representing molar fractions corresponding to weight proportions being both ≧0%, said weight proportions being given based on the total weight of said semi-hydrated dolomite and in that said mineral filler comprises agglomerates of aggregates of particles, said aggregates of particles having a d97<30 μm, a d90<15 μm, a d50<5 μm, and a d3>0.3 μm, after suspension in methanol.