# US 11,078,303 B2 · Curable composition

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- Number: US 11,078,303 B2
- Document ID: US11078303B2
- Status: Granted
- Kind: B2
- Application number: 16/465,018
- Filed: 2017-11-28
- Published: 2019-09-26
- Granted: 2021-08-03
- Earliest claimed: 2016-12-01
- Assignees: Tokuyama Dental Corporation
- Applicants: Tokuyama Dental Corporation
- Inventors: Hironobu Akizumi; Takuma Matsuo
- Web page: https://patentgrep.com/patent/US11078303B2

## CPC

- C08F 2/48: by ultraviolet or visible light
- A61K 6/16: Refractive index
- A61K 6/17: Particle size
- A61K 6/62: Photochemical radical initiators
- A61K 6/71: Fillers
- A61K 6/76: comprising silicon-containing compounds
- A61K 6/884: comprising natural or synthetic resins
- A61K 6/887: Compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
- C08F 2/44: Polymerisation in the presence of compounding ingredients, e.g. plasticisers, dyestuffs, fillers
- C08F 20/18: with acrylic or methacrylic acids
- C08K 3/11: Compounds containing metals of Groups 4 to 10 or of Groups 14 to 16 of the Periodic Table
- C08K 7/18: inorganic
- C08K 2201/005: Additives being defined by their particle size in general
- C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- A61K: PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES (devices or methods specially adapted for bringing pharmaceutical products into particular physical or administering forms A61J3/00; chemical aspects of, or use of materials for deodorisation of air, for disinfection or sterilisation, or for bandages, dressings, absorbent pads or surgical articles A61L; soap compositions C11D)
- C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09)

## Abstract

Provided is a curable composition containing a polymerizable monomer (A), an organic-inorganic composite filler (B), and a polymerization initiator (C), wherein the organic-inorganic composite filler (B) includes an organic resin matrix (b1) and a spherical inorganic filler (b2) having an average primary particle size of 230-1000 nm, 90% or more of the number of individual particles constituting the spherical inorganic filler (b2) are present in a range of 5% greater or less than the average primary particle size, and the curable composition satisfies the following formulas (1) and (2): nP<nFb2 (formula 1) and nMb1<nFb2 (formula 2) In the formulas, nP represents the refractive index of the polymer of the polymerizable monomer (A) at 25° C., nFb2 represents the refractive index of the spherical inorganic filler (b2) at 25° C., and nMb1 represents the refractive index of the organic resin matrix (b1) at 25° C.

## Claims

### Claim 1

A curable composition comprising a polymerizable monomer (A), an organic-inorganic composite filler (B), and a polymerization initiator (C),
wherein the organic-inorganic composite filler (B) comprises an organic resin matrix (b1) and a spherical inorganic filler (b2) having an average primary particle size of 230 nm to 1,000 nm, 90% or more of the number of individual particles constituting the spherical inorganic filler (b2) are present in a range of 5% greater or less than the average primary particle size, and the following formulae (1) and (2) are satisfied:
nP<nFb2 (1)
wherein nP represents the refractive index of a polymer of the polymerizable monomer (A) at 25° C.; and nFb2 represents the refractive index of the spherical inorganic filler (b2) at 25° C.,
nMb1<nFb2 (2)
wherein nMb1 represents the refractive index of the organic resin matrix (b1) at 25° C.; and nFb2 represents the refractive index of the spherical inorganic filler (b2) at 25° C.; and
wherein when a spectral reflectance of a cured product having a thickness of 1 mm of the curable composition is measured using a color difference meter on a black background, the maximum point of the reflectance has a wavelength (peak wavelength) of 550 nm to 770 nm.

### Claim 2 (depends on 1)

The curable composition according to claim 1, wherein the difference between the refractive index nP of a polymer of the polymerizable monomer (A) at 25° C. and the refractive index nMb1 of the organic resin matrix (b1) at 25° C. is 0.005 or less.

### Claim 3 (depends on 2)

The curable composition according to claim 2, wherein the difference between the refractive index nP of a polymer of the polymerizable monomer (A) at 25° C. and the refractive index nMb1 of the organic resin matrix (b1) at 25° C. is 0.001 to 0.005.

### Claim 4 (depends on 1)

The curable composition according to claim 1, wherein the curable composition further comprises a spherical inorganic filler (D) having an average primary particle size of 230 nm to 1,000 nm, 90% or more of the number of individual particles constituting the spherical inorganic filler (D) are present in the range of 5% greater or less than the average primary particle size, and the following formulae (3) and (4) are satisfied:
nP<nFD (3)
wherein nP represents the refractive index of a polymer of the polymerizable monomer (A) at 25° C.; and nFD represents the refractive index of the spherical inorganic filler (D) at 25° C.,
nMb1<nFD (4)
wherein nMb1 represents the refractive index of the organic resin matrix (b1) at 25° C.; and nFD represents the refractive index of the spherical inorganic filler (D) at 25° C.

### Claim 5 (depends on 4)

The curable composition according to claim 4, wherein the difference between the filling ratio of the spherical inorganic filler (D) (weight of spherical inorganic filler (D)/(weight of polymerizable monomer (A)+weight of spherical inorganic filler (D))) and the filling ratio of the spherical inorganic filler (b2) in the organic-inorganic composite filler (B) (weight of spherical inorganic filler (b2)/weight of organic-inorganic composite filler (B)) is 0% to 35%.

### Claim 6 (depends on 1)

The curable composition according to claim 1, wherein the polymerizable monomer (A) comprises a (meth)acrylic compound, and the refractive index of the polymerizable monomer (A) at 25° C. is in the range of 1.38 to 1.55.

### Claim 7 (depends on 4)

The curable composition according to claim 4, wherein the spherical inorganic filler (b2) and the spherical inorganic filler (D) have substantially the same average primary particle size and substantially the same refractive index.

### Claim 8 (depends on 4)

The curable composition according to claim 4, wherein the spherical inorganic filler (b2) and/or the spherical inorganic filler (D) is spherical silica-titanium group element oxide-based composite oxide particles, and the refractive index (25° C.) thereof is in the range of 1.45 to 1.58.

### Claim 9

A curable composition comprising a polymerizable monomer (A), an organic-inorganic composite filler (B), and a polymerization initiator (C),
wherein the organic-inorganic composite filler (B) comprises an organic resin matrix (b1) and a spherical inorganic filler (b2) having an average primary particle size of 230 nm to 1,000 nm, 90% or more of the number of individual particles constituting the spherical inorganic filler (b2) are present in a range of 5% greater or less than the average primary particle size, the following formula (1) is satisfied:
nP<nFb2 (1)
wherein nP represents the refractive index of a polymer of the polymerizable monomer (A) at 25° C.; and nFb2 represents the refractive index of the spherical inorganic filler (b2) at 25° C., and
the maximum point of the reflectance obtainable at the time of measuring the spectral reflectance of a cured product having a thickness of 1 mm of the curable composition using a color difference meter on a black background has a wavelength of 550 nm to 770 nm.

### Claim 10 (depends on 1)

A dental curable composition consisting of the curable composition according to claim 1.

### Claim 11 (depends on 10)

A dental filling restorative material consisting of the dental curable composition according to claim 10.

### Claim 12 (depends on 9)

A dental curable composition consisting of the curable composition according to claim 9.

### Claim 13 (depends on 12)

A dental filling restorative material consisting of the dental curable composition according to claim 12.