Siliceous materials
First Claim
1. In a process for the manufacture of a siliceous filler which comprises contacting a particulate siliceous filler with an organic compound at elevated temperature, whereby the organic compound is catalytically decomposed to form an adherent carbonaceous coating on the surface of the said particulate siliceous filler, the improvement which comprises treating the siliceous filler particles which contain alkali metal ions in a quantity sufficient to impede catalytic decomposition to form the carbonaceous coating first with a solution of an ammonium salt or a salt of an organic base so as to displace alkali metal ions therefrom and then removing the solution so as to leave the siliceous filler particles depleted of at least a portion of their alkali metal ion content.
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Abstract
The deposition of a carbonaceous coating on the surface of a particulate siliceous filler by catalytic thermal decompositon of an organic compound, to improve the value of the said filler in organic polymer compositions, is difficult with some varieties of siliceous filler. The invention is based on the treatment of the initial siliceous filler with a solution of an ammonium salt or a salt of an organic base to displace alkali metal ions, which are believed to inhibit the desired catalytic decomposition. The treatment is carried on to reduce the alkali metal ions (especially sodium) to an acceptably low level, preferably below about 500 ppm. The treatment is especially applicable to precipitated silica fillers.
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Citations
11 Claims
- 1. In a process for the manufacture of a siliceous filler which comprises contacting a particulate siliceous filler with an organic compound at elevated temperature, whereby the organic compound is catalytically decomposed to form an adherent carbonaceous coating on the surface of the said particulate siliceous filler, the improvement which comprises treating the siliceous filler particles which contain alkali metal ions in a quantity sufficient to impede catalytic decomposition to form the carbonaceous coating first with a solution of an ammonium salt or a salt of an organic base so as to displace alkali metal ions therefrom and then removing the solution so as to leave the siliceous filler particles depleted of at least a portion of their alkali metal ion content.
Specification