| 摘要 |
<p>The invention provides a composition comprising an intimate mixture of glass beads and finely divided material, characterized in that the glass beads have a mean diameter of not more than 80 micrometers and a size range spread which is at least half the mean diameter of the beads, and in that said finely divided material is hydrophobic, inorganic and substantially chemically inert with respect to the beads and has a specific surface of at least 50 m2/g, such material being present in said mixture in an amount not exceeding 5% by weight of the beads. The surfaces of the beads may be treated with an agent which improves adherence between the beads and a resin matrix, e.g. an agent such that the surfaces of the beads include organo-silane groups. The finely divided material preferably has a specific surface of at least 100 m2/g, and may substantially entirely consist of silica.</p> |
