Particulate material, dental material, and method for producing particulate material

Claims

1. An aggregate of primary particles having a volume average particle size of 1 nm to 20 nm and containing two or more metal elements, the surface of which is made of silica, a portion of the primary particles has a core particle containing a heavy element having an atomic number of 38 or more as a metal oxide and a coating layer made of silica; at least a portion of the remainder of the primary particles are particles composed of silica, Specific surface area is 180m ２ / g or less, Unit volume (100 cm ３ ) Linseed oil absorption per 200g or less, Unit surface area (m ２ ) Linseed oil absorption per unit of paper is 0.02g or less, light transmittance is more than 20%, The mass of the heavy element is 4% to 60% based on the total mass; particle material.

2. A volume average particle size of 0.1 μm to 10 μm, The primary particles are bonded or fused together by dehydration condensation. The particulate material of claim 1 .

3. 2. The particulate material according to claim 1, comprising an inorganic particulate material having a volume average particle size of 1 nm to 200 nm and dispersed into primary particles.

4. The inorganic particle material is represented by the formula (1): —OSiX １ X ２ X ３ and a functional group represented by formula (2): -OSiY １ Y ２ Y ３ The particle material according to claim 3, wherein a functional group represented by the following formula (1) or (2) is bonded to the surface of the silica particle: X1 is a phenyl group, a vinyl group, an epoxy group, a methacryl group, an amino group, a ureido group, a mercapto group, an isocyanate group, or an acrylic group; and X ２ , X ３ Ha-OSiR ３ and -OSiY ４ Y ５ Y ６ are each independently selected from the group consisting of: Y １ is R; Y ２ , Y ３ is R and -OSiY ４ Y ５ Y ６ are independently selected from the following: ４ is R; Y ５ and Y ６ is R and -OSiR ３ and R is independently selected from alkyl groups having 1 to 3 carbon atoms. ２ , X ３ , Y ２ , Y ３ , Y ５ , and Y ６ Any of the adjacent functional groups X ２ , X ３ , Y ２ , Y ３ , Y ５ , and Y ６ may be bonded to either of the above via —O—.)

5. 2. The particulate material according to claim 1, which is dispersed in a transparent resin material and used as a dental material.

6. 6. The particulate material according to claim 5, wherein the difference in refractive index between the particulate material and the transparent resin material is −0.01 to 0.

01.

7. A particulate material according to any one of claims 1 to 6; a transparent resin material in which the particulate material is dispersed; and The dental material has a content of the particulate material of 10% to 80% based on the total volume.

8. A method for producing a particulate material according to claim 1, comprising: a dispersing step of dispersing the heavy element particle material in a liquid dispersion medium to form a dispersion; a coating step of adding a silica precursor to the dispersion liquid to coat the surfaces of the heavy element particle material with silica to form coated particles; an aggregating step of heating the coated particles to aggregate them; A method for producing a particulate material having the following structure: