Organic-inorganic composite filler, and method for producing the same

Patent metadata

Field	Value
Publication number	US-10004667-B2
Application number	US-201214343626-A
Country	US
Kind code	B2
Filing date	Sep 13, 2012
Priority date	Sep 15, 2011
Publication date	Jun 26, 2018
Grant date	Jun 26, 2018

Abstract

An organic-inorganic composite filler contains: inorganic aggregate particles formed by aggregation of inorganic primary particles with an average particle diameter of 10 to 1000 nm; an organic resin phase including a cured polymer of a polymerizable monomer covering surfaces of the inorganic primary particles and bonding the inorganic primary particles to each other, and a water absorbing resin; and aggregation gaps with a volume of micropores formed between parts of the organic resin phase of 0.01 to 0.30 cm 3 /g in pore volume measurement within a pore diameter range of 1 to 500 nm, as measured by a mercury intrusion technique. In a cross section passing through the centers of the inorganic aggregate particles, based on 100 measured inorganic particles, there are 10 or less inorganic aggregate particles having a macro void with a maximum width of at least 1 μm.

First claim

The invention claimed is:

1. An organic-inorganic composite filler for dental materials in the form of a powder, having an average composite particle diameter of 3 to 100 μm, comprising:
inorganic aggregate particles formed by aggregation of inorganic primary particles with an average particle diameter of 10 to 1000 nm;
an organic resin phase including a cured polymer of a polymerizable monomer covering surfaces of the inorganic primary particles and bonding the inorganic primary particles to each other, and 0.01 to 10 parts by mass of a water absorbing resin based on 100 parts by mass of the inorganic aggregate particles, wherein the water absorbing resin is selected from the group consisting of a polysaccharide based water absorbing resin, a polyvinyl alcohol based water absorbing resin, an acrylate based water absorbing resin, an acrylamide based water absorbing resin and a polyether based compound; and
aggregation gaps with a volume of micropores formed between parts of the organic resin phase of 0.01 to 0.30 cm 3 /g in pore volume measurement within a pore diameter range of 1 to 500 nm, as measured by a mercury intrusion technique,
wherein in a cross section passing through centers of the inorganic aggregate particles, based on 100 measured inorganic particles, there are 10 or less inorganic aggregate particles having a macro void with a maximum width of at least 1 μm.

2. The organic-inorganic composite filler according to claim 1 , wherein average degree of symmetry is at least 0.6.

3. The organic-inorganic composite filler according to claim 1 , wherein average particle diameter of the inorganic aggregate particles is from 3 to 100 μm.

4. The organic-inorganic composite filler according to claim 1 , wherein the water absorbing resin is an acrylate based water absorbing resin with a weight-average molecular weight of 2000 to 20000000 g/mol.

5. The organic-inorganic composite filler according to claim 1 , wherein the cured polymer of the polymerizable monomer included in the organic resin phase is a cured polymer of a (meth)acrylic polymerizable monomer.

6. The organic-inorganic composite filler according to claim 1 , wherein content of the cured polymer of the polymerizable monomer in the organic resin phase is, based on 100 parts by mass of the inorganic primary particles, from 1 to 40 parts by mass.

7. The organic-inorganic composite filler according to claim 1 , wherein the inorganic primary particles are silica-based complex oxide particles.

8. A method for producing the organic-inorganic composite filler according to claim 1 , comprising the steps of:
spray drying an aqueous suspension of the inorganic primary particles with an average particle diameter of 10 to 1000 nm containing the water absorbing resin to granulate the inorganic primary particles, so that the inorganic aggregate particles are formed in which the surfaces of the inorganic primary particles are attached with the water absorbing resin;
immersing the formed inorganic aggregate particles with a polymerizable monomer solution containing 100 parts by mass of an organic solvent, 3 to 70 parts by mass of the polymerizable monomer, and an effective amount of a polymerization initiator;
removing the organic solvent from the immersed inorganic aggregate particles; and
polymerizing and curing the polymerizable monomer with which the inorganic aggregate particles are impregnated.

9. The method for producing the organic-inorganic composite filler according to claim 8 , wherein the inorganic aggregate particles are inorganic aggregate particles with a volume of micropores of 0.015 to 0.35 cm 3 /g as measured by a mercury intrusion technique, wherein each of the micropores corresponds to a pore with a pore diameter in the range of 1 to 500 nm.

10. A dental curable composition, comprising: the organic-inorganic composite filler according to claim 1 ; a polymerizable monomer; and a polymerization initiator.

11. The organic-inorganic composite filler according to claim 1 , wherein the content of the water absorbing resin relative to the cured polymer of the polymerizable monomer is, based on 100 parts by mass of the cured polymer of the polymerizable monomer, from 0.05 to 50 parts by mass.

12. The organic-inorganic composite filler according to claim 1 , wherein
the polysaccharide based water absorbing resin is hyaluronic acid, a starch based water absorbing resin, or a cellulose based water absorbing resin;
the polyvinyl alcohol based water absorbing resin is polyvinyl alcohol or ethylene-vinyl alcohol copolymer;
the acrylate based water absorbing resin is sodium polyacrylate or sodium salt of acrylic acid-vinyl alcohol copolymer;
the acrylamide based water absorbing resin is polyacrylamide or N-substituted acrylamide; and
the polyether based compounds is polyethylene glycol or polyethylene oxide.

13. The organic-inorganic composite filler according to claim 12 , wherein
the starch based water absorbing resin is starch-acrylonitrile graft copolymer, starch-acrylic acid graft copolymer, or starch-acrylate salt graft copolymer; and
the cellulose based water absorbing resin is cellulose-acrylonitrile graft copolymer or carboxymethyl cellulose.

Assignees

• Yamazaki Tatsuya
• Akizumi Hironobu
• Tokuyama Dental Corp

Inventors

• Yamazaki Tatsuya
• Akizumi Hironobu

Classifications

• C08F2/44 Primary

  Polymerisation in the presence of compounding ingredients, e.g. plasticisers, dyestuffs, fillers · CPC title

• A61K6/71

  Fillers · CPC title

• C08K3/013

  Fillers, pigments or reinforcing additives · CPC title

• C08K9/08

  Ingredients agglomerated by treatment with a binding agent · CPC title

• C08F292/00

  Macromolecular compounds obtained by polymerising monomers on to inorganic materials · CPC title