| 摘要 |
<p>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.</p> |
