Provided is a method for preparing a modified filler. The method includes in sequence providing an acidified aqueous slurry of an untreated inorganic filler which has not been previously dried; an emulsifier material; and a hydrophobating agent having the following structural formula (I): (I) R.sub.a-M-X.sub.(4-a) wherein: R is C.sub.6 to C.sub.22 alkyl, M is silicon, titanium or zirconium, X is OR′ or N halogen, R′ is C.sub.1 to C.sub.4 alkyl, and a is 1; washing and/or filtering the acidified aqueous slurry to obtain a modified filler, and, optionally, drying the modified filler. Polymeric compositions and articles also are provided.

An oil-in-water type emulsion is characterized in that a fumed silica particle group in which lower order aggregates are aggregated with each other to form a higher order aggregate by a non-chemical bond forms a network-like surrounding structure including an oil inside the network-like surrounding structure.

A preparation method for a spherical silica powder filler comprises the following steps: S1, providing spherical polysiloxane comprising a T unit by means of a hydrolysis condensation reaction of R.sub.1SiX.sub.3, wherein R.sub.1 is hydrogen atom or an organic group having independently selectable 1 to 18 carbon atoms, X is a hydrolyzable group, and T unit is R.sub.1SiO.sub.3—; and S2, calcining the spherical polysiloxane under the condition of a dry oxidizing gas atmosphere, the calcining temperature being between 850° C. and 1200° C., so as to obtain the spherical silica powder filler which does not contain silica particles of which the diameter is less than 50 nanometers. The spherical silica powder filler does not contain silica particles of which the diameter is less than 50 nanometers, has a low dielectric loss and a low thermal expansion coefficient, and is suitable for high-frequency high-speed circuit boards, prepregs or copper clad laminates, etc.

A method for manufacturing granulated silica. The method includes granulating silica powders each having a primary particle size of 5 to 50 nm by use of water, and hydrophobizing each surface of the silica powders with a silicon atom-containing hydrophobizing agent before or simultaneously with the granulation step.

Provided is a method for producing surface-treated silica powder that has excellent gap permeability and that allows a resin composition to have low viscosity in a case where the surface-treated silica powder is used as a resin filler, for example, for a semiconductor sealant. A surface treatment agent is brought into contact with silica powder such that: (1) a cumulative 50 mass % diameter D.sub.50 of a mass-based particle size distribution obtained by a centrifugal sedimentation method is 300 nm to 500 nm (preferably 330 nm to 400 nm); (2) a loose bulk density is 250 kg/m.sup.3 to 400 kg/m.sup.3 (preferably 270 kg/m.sup.3 to 350 kg/m.sup.3); and (3) {(D.sub.90−D.sub.50)/D.sub.50}×100 is 30% to 45% (preferably 33% to 42%), to modify the surface of the silica powder, so that surface-treated silica powder is produced.

An aqueous, particle-stabilized Pickering emulsion along with methods or processes for producing the same and particles produced therefrom.

Fumed silica powder, surface treated with a surface treatment agent selected from the group consisting of organosilanes, silazanes, acyclic polysiloxanes, cyclic polysiloxanes, and mixtures thereof, wherein the powder has: a) a number of silanol groups relative to BET surface area d.sub.SiOH of at least 0.85 SiOH/nm.sup.2, as determined by reaction with lithium aluminium hydride; b) a methanol wettability of more than 40% by volume of methanol in methanol-water mixture; c) a tamped density of not more than 200 g/L.

A sol of inorganic oxide particles is stably dispersed in a hydrophilic organic solvent containing a hydrocarbon such as a paraffinic hydrocarbon or a naphthenic hydrocarbon. The sol contains a dispersion medium containing an organic solvent containing a C.sub.6-18 paraffinic hydrocarbon, a C.sub.6-18 naphthenic hydrocarbon, or a mixture of these, a C.sub.4-8 alcohol having a carbon chain with a carbon-carbon bond in the molecule in an amount of 0.1 to 5% by mass in the entire dispersion medium, and inorganic oxide particles having an average particle diameter of 5 to 200 nm as measured by dynamic light scattering as a dispersoid, wherein the inorganic oxide particles contain a C.sub.1-3 alkyl group bonded to a silicon atom and a C.sub.4-18 alkyl group. The paraffinic hydrocarbon is a normal paraffinic hydrocarbon or an isoparaffinic hydrocarbon. The naphthenic hydrocarbon is a saturated aliphatic cyclic hydrocarbon substitutable with a C.sub.1-10 alkyl group.

A preparation method for a spherical silica powder filler, comprises the following steps: S1, providing spherical polysiloxane comprising T units by means of a hydrolysis condensation reaction of R.sub.1SiX.sub.3, wherein R.sub.1 is hydrogen atom or an independently selectable organic group having 1 to 18 carbon atoms, X is a hydrolyzable group, and the T unit is R.sub.1SiO.sub.3—; and S2, calcining the spherical polysiloxane under the condition of a dry oxidizing gas atmosphere at a calcining temperature between 850° C. and 1200° C., so as to obtain a spherical silica powder filler having a low hydroxyl content. The spherical silica powder filler is composed of at least one selected from Q.sub.1 unit, Q.sub.2 unit, Q.sub.3 unit and Q.sub.4 unit, wherein Q.sub.1 unit is Si(OH).sub.3O—, Q.sub.2 unit is Si(OH).sub.2O.sub.2—,Q.sub.3 unit is SiOHO.sub.3—, Q.sub.4 unit is SiO.sub.4—, and the content of Q.sub.4 unit is greater than or equal to 95%.

A method for preparing a composition including mineral particles functionalized by at least one organic group and having a specific surface defined according to the BET method greater than 500 m.sup.2/g, involves: —choosing a phyllosilicate composition, including mineral particles having a thickness of less than 100 nm, a largest dimension of less than 10 μm and belonging to the family of lamellar silicates; —choosing at least one functionalizing agent, from the group formed from the oxysilanes and oxygermanes having at least one organic group, —bringing the phyllosilicate composition into contact with a functionalizing solution including the functionalizing agent, so as to obtain a phyllosilicate composition including mineral particles functionalized by the organic group, while choosing the organic group from the group formed from the cationic heteroaryl groups, the quaternary ammonium groups and the salts of same. The phyllosilicate composition obtained by the method is also described.