| 摘要 |
<p>Dry-process fine silica particles which are produced with a burner of a multiannular structure by feeding a gas mixture comprising the gas of a siloxane compound containing no halogens in the molecule and oxygen gas in a specific proportion to a central tube of the burner, supplying a specific proportion of combustible gases to a first annular tube disposed on the outer side of the central tube, and burning them. These dry-process fine silica particles have a BET specific surface area of 20-55 m2/g. An aqueous suspension containing the fine silica particles in a concentration of 1.5 wt.% has an absorbance (d) as measured with a light having a wavelength of 700 nm satisfying the following relationship (1): d<=240S-1.4-0.07 (1) wherein S is the specific surface area of the dry-process fine silica particles (m2/g). These particles include almost no coarse particles or agglomerated particles and have a narrow particle size distribution. They have excellent dispersibility in resins, etc. The particles are inhibited from causing a viscosity increase when incorporated in a high proportion, and can impart a sufficient strength to a resin composition.</p> |
