JP2019183111A - Organic inorganic composite filler, and curable composition containing the same - Google Patents

Abstract

To provide an organic inorganic composite filler capable of being used as a filler blended in a polymerizable monomer and a resin or the like, capable of forming a high strength material by dispersing the same in a resin becoming a matrix, and therefore capable of being suitably used as a dental material.SOLUTION: There is provided an organic inorganic composite filler by coating a surface of an inorganic particle with a polymerized cured article layer manufactured by polymerizing a polymerizable monomer, in which the polymerized cured article contains unpolymerized article of the polymerizable monomer of 0.1 mass% to 5.0 mass%.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a novel organic-inorganic composite filler. Specifically, the present invention relates to a novel organic-inorganic composite filler that can be used in combination with a polymerizable monomer so that the obtained cured product can exhibit excellent mechanical properties.

  Inorganic particles serve to increase the mechanical strength of articles obtained by mixing with a base resin or articles made of a curable composition mixed with a polymerizable monomer forming the base resin. Various studies have been made to improve the dispersibility of the mixing partner, that is, the base resin or the polymerizable monomer.

  As an article requiring such mechanical strength, there is a dental material. Among them, particularly high mechanical strength is required for a dental composite restorative material. Dental composite restorative materials are representative of dental curable compositions. For example, in a dental clinic, a dental composite restorative material is filled in a cavity of a tooth to be repaired and formed into a tooth shape, and then irradiated with active light using a special light irradiator and polymerized and cured. It is done. This restores the damaged tooth.

  In a dental laboratory, a dental composite restorative material is built up in the form of a tooth to be repaired on a plaster model and then polymerized and cured by light irradiation. This is a dental clinic using a dental adhesive and a tooth. Bonded to quality. This restores the damaged tooth.

  The dental composite restorative material is excellent in that a color tone equivalent to that of a natural tooth can be imparted and the operability is good. As a result, dental composite restorative materials have become rapidly popular in recent years and are now being applied in most anterior tooth treatments. Furthermore, dental composite restorative materials have also been developed that have considerably high mechanical strength, and dental composite restorative materials are beginning to be applied to the restoration of molars to which strong occlusal pressure is applied. .

  As described above, dental restorative materials are required to have mechanical strength equivalent to that of teeth, and various studies have been made. A dental composite restorative material is generally composed of a polymerizable monomer (monomer), a filler, and a polymerization initiator as main components. The dental composite restorative material is configured by selecting the type, shape, particle diameter, filling amount, and the like of the filler to be used. By appropriately selecting these, the operability of the paste-like dental composite restorative material, and various properties such as aesthetics and mechanical strength of the cured body are optimally adjusted.

  An organic-inorganic composite in which a surface of inorganic particles is coated with an organic resin layer (polymerized cured product layer) obtained by curing a polymerizable monomer in a dental curable composition containing a polymerizable monomer and a filler. Many attempts have been made to use fillers. The reason is as follows. That is, the organic-inorganic composite filler having the polymerization cured product layer on the surface has good affinity with the polymerizable monomer. As a result, the mechanical strength of the cured body can be improved (see, for example, Patent Documents 1, 2, and 3). According to these patent documents, by using this organic-inorganic composite filler, a paste-like composite restorative material having excellent operability while maintaining excellent surface smoothness and wear resistance when using fine inorganic particles. It can be seen that the polymerization shrinkage of the cured product is small.

  As described above, the organic-inorganic composite filler is obtained by coating the surface of fine inorganic particles with a polymerized cured product layer. And this organic inorganic composite filler has a small surface area compared with the said fine inorganic particle. Therefore, a paste-like composite restorative material can also be produced by blending a sufficient amount of this organic-inorganic composite filler without developing a thickening action.

  As a method for producing the organic-inorganic composite filler, a method is generally used in which a curable composition obtained by kneading fine inorganic particles and a polymerizable monomer in advance is polymerized to obtain a cured product, and then the cured product is pulverized. Yes (see Patent Document 1). It has also been shown that an organic solvent is used when mixing fine inorganic particles and a polymerizable monomer. By using an organic solvent, a large amount of polymerizable monomer can be introduced into the inorganic particles (see Patent Document 2). And after distilling off the organic solvent, an organic-inorganic composite filler having pores formed from the polymerized and cured product layer is produced by curing the polymerizable monomer to form a polymerized and cured product layer. (See Patent Document 3). Usually, the polymerizable monomer covering the surface of these fine inorganic particles is generally polymerized and cured under conditions where the polymerization proceeds sufficiently (no unpolymerized product remains).

JP 2000-80013 A JP 2008-37952 A International Publication No. WO2011-115007 Pamphlet

  The mechanical strength of the dental composite restorative material blended with the organic-inorganic composite filler obtained by the conventional method is considerably high. However, in recent years, increasing the strength of materials has been demanded in many applications, and in a resin blended with an organic-inorganic composite filler, it is also necessary to improve the strength accompanying the improvement of the organic-inorganic composite filler. In particular, in dental materials, fillers are often included in high-strength materials, and it has been desired to develop organic-inorganic composite fillers that can be made to have higher-strength materials than conventional techniques.

  Accordingly, an object of the present invention is to provide a novel organic-inorganic composite filler that can be made of a material having higher strength in the organic-inorganic composite filler that can be used for the purpose of improving the strength.

  In order to solve the above-mentioned problems, the present inventors have conducted intensive studies. As a result, in the organic-inorganic composite filler, it was found that the above-mentioned problems can be solved by leaving a certain amount of unpolymerized material in the polymerized cured product layer covering the inorganic particles, and the present invention has been completed.

That is, the present invention
(1) An organic-inorganic composite filler in which the surface of inorganic particles is covered with a polymerized cured product layer obtained by polymerizing a polymerizable monomer,
The organic cured composite filler is characterized in that the cured polymer layer contains 0.1% by mass or more and 5.0% by mass or less of an unpolymerized product of the polymerizable monomer.

  The present invention can take the following aspects.

(2) The inorganic particles are aggregated particles obtained by agglomerating inorganic primary particles having an average particle diameter of 10 to 1000 nm,
The polymerized cured product layer is a layer that covers at least a part of the surface of each inorganic primary particle and is a layer that binds each inorganic primary particle to each other;
A pore volume formed by the mercury intrusion method formed between the polymerized cured product layers covering at least a part of the surface of each inorganic primary particle (wherein the pore is a pore diameter in the range of 1 to 500 nm) The organic-inorganic composite filler according to the above (1), which has an agglomerated gap whose pores are 0.01 to ³⁰ cm ³ / g.

  (3) The organic-inorganic composite filler according to (1) or (2), wherein the content of the polymerized cured product layer is 1 to 40 parts by mass with respect to 100 parts by mass of the inorganic particles.

(4) The inorganic particles have a pore volume measured by mercury porosimetry (herein, the pore refers to a pore having a pore diameter in the range of 1 to 500 nm) of 0.015 to 0.35 cm ³ / g. The organic-inorganic composite filler according to any one of (1) to (3), which is an aggregated particle.

(5) A method for producing the organic-inorganic composite filler according to any one of (1) to (4),
The organic solvent is removed while contacting the polymerizable monomer solution obtained by diluting the polymerizable monomer with the organic solvent and the inorganic particles, and a predetermined amount of the polymerizable monomer is attached to the surface of the inorganic particles. A polymerizable monomer adhering step; and the polymerizable monomer adhering to the surface of the inorganic particles in the polymerizable monomer adhering step is polymerized to polymerize the surface of the inorganic particles. Including a polymerization step of coating with a polymerized cured product layer,
Based on at least one relationship shown in the following 1), 2), 3) and 4) separately confirmed in advance, the unpolymerized polymerizable monomer contained in the polymerized cured product layer obtained in the polymerization step Is expressed by the unpolymerized monomer total content defined by the concentration (mass%) of the unpolymerized polymerizable monomer based on the mass of the entire polymerization cured product layer, and 0.1 mass % To 5.0% by mass or more, and the polymerizable monomer adhesion step and / or the polymerization step are performed under the determined conditions.
1) The polymerization in the case where a polymerization inhibitor is blended in the polymerizable monomer solution and the polymerization inhibitor is contained in a polymer to be adhered to the surface of the inorganic particles, and the polymerization is performed under predetermined conditions. Between the polymerization inhibitor concentration in the polymerizable monomer preparation and the unpolymerized monomer total content.
2) In the polymerization step, the relationship between the polymerization time and the unpolymerized monomer content when the polymerization is carried out by changing only the polymerization time under conditions other than the polymerization time as predetermined conditions.
3) The relationship between the polymerization temperature and the unpolymerized monomer content when the polymerization is carried out by changing only the polymerization temperature under a predetermined condition other than the polymerization temperature in the polymerization step.
4) In the polymerization step, the oxygen concentration and the unpolymerized monomer mixture when the polymerization is performed by changing only the oxygen concentration under conditions other than the oxygen concentration in the atmosphere in which the polymerization is performed as a predetermined condition. Relationship with content.

  (6) The curable composition which further contains the organic inorganic composite filler in any one of said (1)-(4), and a polymerizable monomer.

  (7) A dental curable composition comprising the curable composition of (6).

  If it is normal, when manufacturing an organic inorganic composite filler, it will be preferable to polymerize the polymerizable monomer which exists on the surface of an inorganic particle almost completely. Actually, according to the study by the present inventors, in the organic-inorganic composite filler described in Patent Documents 2 and 3, the unpolymerized material in the organic resin layer (polymerized cured product layer) is less than 0.1% by mass. I understood.

  On the other hand, the organic-inorganic composite filler of the present invention is characterized in that a specific amount of unpolymerized material remains in the polymerization cured product layer existing on the surface. And although it is only an estimate, the unpolymerized material contained in the polymerized cured product layer covering the inorganic particles and the polymerizable monomer of the curable composition are intimately blended to cure the curable composition. By doing so, it is considered that the organic-inorganic composite filler can be strongly bonded to the organic resin component comprising the polymerizable monomer (the organic resin component obtained by polymerizing and curing the polymerizable monomer in the curable composition). It is done. As a result, it is presumed that the cured product obtained by curing the curable composition containing the organic-inorganic composite filler of the present invention and further a polymerizable monomer has improved mechanical strength.

  Therefore, the organic-inorganic composite filler of the present invention can be used not only as a dental material but also as a filler in various fields.

FIG. 1 is a schematic cross-sectional view showing a typical embodiment of a suitable organic-inorganic composite filler of the present invention.

  The present invention relates to an organic-inorganic composite filler in which the surface of inorganic particles is coated with a polymerized cured product layer formed by polymerizing a polymerizable monomer, and the polymerized cured product layer is not coated with the polymerizable monomer. An organic-inorganic composite filler comprising 0.1% by mass or more and 5.0% by mass or less of a polymer. In the following, description will be given in order.

<Organic inorganic composite filler>
The organic-inorganic composite filler of the present invention is characterized in that the surface of inorganic particles is coated with a polymerized cured product layer, and a specific amount of unpolymerized material is contained in the polymerized cured product layer. The polymerization cured product layer is not particularly limited as long as it contains a specific amount of unpolymerized product. For example, a method of adding an unpolymerized product to a polymerized cured product obtained by polymerizing and curing a polymerizable monomer in advance and coating the resulting mixture on the surface of the inorganic particles can be employed. Further, after coating (adsorbing) a polymerizable monomer capable of forming a polymerized cured product layer on the surface of the inorganic particles, the polymerized cured product layer obtained by controlling the polymerization rate of the polymerizable monomer A specific amount of unpolymerized material may be contained therein. Among these, considering the operability and the effect of the obtained organic-inorganic composite filler, it is preferable to employ a method of controlling the polymerization rate using a polymerizable monomer.

<Inorganic particles; inorganic particles constituting the organic-inorganic composite filler>
In the present invention, the material of the inorganic particles that form the organic-inorganic composite filler is not particularly limited, and any material that has been conventionally used as a filler can be used. Specifically, simple metals selected from Group I, II, III, IV, and transition metals; oxides and composite oxides of these metals; fluorides, carbonates, sulfates, and silicic acids of these metals Metal salts composed of salts, hydroxides, chlorides, sulfites, phosphates and the like; and composites of these metal salts. Suitable metal oxides such as amorphous silica, quartz, alumina, titania, zirconia, barium oxide, yttrium oxide, lanthanum oxide, ytterbium oxide; silica-zirconia, silica-titania, silica-titania-barium oxide, silica -Silica-based composite oxides such as titania-zirconia, borosilicate glass, aluminosilicate glass, fluoroaluminosilicate glass, etc .; metals such as barium fluoride, strontium fluoride, yttrium fluoride, lanthanum fluoride, ytterbium fluoride Fluorides; inorganic carbonates such as calcium carbonate, magnesium carbonate, strontium carbonate, barium carbonate; metal sulfates such as magnesium sulfate and barium sulfate.

  The inorganic particles made of the material may be subjected to surface modification (surface treatment) using a hydrophobizing agent such as a silane coupling agent. A conventionally well-known thing is used without a restriction | limiting as a hydrophobizing agent. Examples of suitable hydrophobizing agents are vinyltriethoxysilane, vinyltrimethoxysilane, vinyl-tris (β-methoxyethoxy) silane, γ-methacryloyloxypropyltrimethoxysilane, κ-methacryloyloxidedecyltrimethoxysilane, β -(3,4-epoxycyclohexyl) -ethyltrimethoxysilane, γ-glycidoxypropyl-trimethoxysilane, N-β- (aminoethyl) -γ-aminopropyl-trimethoxysilane, γ-ureidopropyl-tri Examples include silane coupling agents such as ethoxysilane, γ-chloropropyltrimethoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, and methyltriethoxysilane, and titanate coupling agents.

  There is no restriction | limiting in particular in the usage-amount of the hydrophobizing agent used for the hydrophobization of an inorganic particle, What is necessary is just to determine the optimal value, after confirming experimentally the mechanical physical property etc. of the organic inorganic composite filler obtained. If the usage-amount of a suitable hydrophobizing agent is illustrated, it will be 1-30 mass parts of said hydrophobizing agents with respect to 100 mass parts of inorganic particles.

  The surface treatment method is not particularly limited, and a known method is adopted without limitation. To illustrate a typical treatment method, inorganic particles and a hydrophobizing agent are dispersed and mixed in a suitable solvent using a ball mill or the like, the solvent is dried by an evaporator or air drying, and then heated to 50 to 150 ° C. There is a way. Furthermore, there is a method in which the inorganic particles and the hydrophobizing agent are heated and distilled for several hours in a solvent such as alcohol. Furthermore, there is a method of graft polymerization of a hydrophobizing agent on the particle surface.

  The inorganic particles may be a mixture of a plurality of inorganic particles having different average particle diameters, materials, and shapes.

  The inorganic particles may be inorganic particles produced by any known method. For example, as long as it is an inorganic oxide particle, a composite oxide particle, etc., it may be produced by any method of a wet method, a dry method, and a sol-gel method. Considering that it is advantageous to industrially produce fine particles having a spherical shape and excellent monodispersibility, and that it is easy to adjust refractive index and impart X-ray contrast properties, The inorganic particles are preferably produced by a sol-gel method.

  The method for producing spherical silica-based composite oxide particles by the sol-gel method is disclosed in, for example, JP-A Nos. 58-110414, 58-151321, 58-156524, 58-156. It is described in Japanese Patent No. 156526 and so on. In this method, first, a hydrolyzable organosilicon compound, or a mixed solution in which another hydrolyzable organometallic compound is added is prepared. Next, the mixed solution is added to an alkaline solvent in which these organic compounds are dissolved but the product inorganic oxide is not substantially dissolved, and hydrolysis is performed. Since the inorganic oxide is precipitated by hydrolysis, the precipitate is filtered and then dried. The inorganic particles obtained by such a method may be baked at a temperature of 500 to 1000 ° C. after drying in order to impart surface stability. During firing, some of the inorganic particles may aggregate. In this case, it is preferable to use after agglomerated particles are unwound using a jet mill, a vibration ball mill or the like, and the particle size is adjusted to a predetermined range. By treating in this way, the abrasiveness when used as a dental composite restorative material is improved.

  In the present invention, a polymerized cured product layer is formed on the surface of the inorganic particles as described above. The polymerized and cured product layer is characterized by containing a specific amount of unpolymerized material.

<Organic inorganic composite filler; unpolymerized>
In the organic-inorganic composite filler of the present invention, the surface of inorganic particles (inorganic particles) is covered with a polymerized cured product layer. And in this superposition | polymerization hardened | cured material layer, 0.1 mass% or more and 5.0 mass% or less of unpolymerized substances must be contained with respect to all the polymeric hardened | cured material layers. As described above, this unpolymerized material makes the familiarity between the polymerizable monomer and the organic-inorganic composite filler blended in the curable composition dense. That is, the bond between the organic-inorganic composite filler and the curable composition becomes strong, and the cured product of the curable composition containing the organic-inorganic composite filler of the present invention has high mechanical strength. When the amount of the unpolymerized product is less than 0.1% by mass, the bond reinforcement between the organic-inorganic composite filler and the organic resin component composed of the polymerizable monomer is slight, and the resulting cured product has a mechanical strength. The strength decreases. On the other hand, when the amount of the unpolymerized product exceeds 5% by mass, the organic-inorganic composite filler itself becomes brittle, and the mechanical strength of the obtained cured product is lowered. Moreover, it becomes difficult to coat the inorganic particles with the polymerized cured product layer, and the productivity of the organic-inorganic composite filler itself is lowered. From the viewpoint that the productivity of the organic-inorganic composite filler itself and the mechanical strength of the resulting cured product can be further improved, the amount of the unpolymerized product is preferably 0.2 to 4.0% by mass.

  This unpolymerized product is contained in a polymerized cured product layer covering the surface of the inorganic particles, and the unpolymerized monomer (polymerized and cured to form a polymerized cured product layer) that forms the polymerized cured product layer It is a thing. The amount of this unpolymerized product can be measured as follows. Specifically, the organic-inorganic composite filler is dispersed in an organic solvent capable of dissolving the polymerizable monomer that forms the polymerized cured product layer of the organic-inorganic composite filler. Then, the unpolymerized product extracted in the organic solvent is analyzed by high performance liquid chromatography. If a calibration curve for the polymerizable monomer (determining the relationship between mass and peak area) is prepared in advance using high performance liquid chromatography, the actual amount of the unpolymerized product extracted can be confirmed. . Further, the total amount of the polymerized cured product layer is the same as the total amount of the polymerizable monomer used during production. However, if the total amount of the polymerizable monomer is unknown, suggestive simultaneous heat-caloric measurement of the organic-inorganic composite filler after extracting the unpolymerized product or the organic-inorganic composite filler from which the unpolymerized product has not been extracted. It is sufficient to confirm the amount of mass reduction. In the case of the organic-inorganic composite filler from which the unpolymerized product has been extracted, the total amount of the mass reduction amount and the amount of the unpolymerized product is equivalent to the amount of the entire polymerized cured product layer. Moreover, the mass reduction | decrease amount of the organic inorganic composite filler which has not extracted the unpolymerized substance becomes equivalent to the quantity of all the polymerization hardened | cured material layers. In the present invention, the amount of unpolymerized product was determined by the method shown in the examples.

<Polymerizable monomer forming polymerized cured product layer; organic-inorganic composite filler>
In the organic-inorganic composite filler of the present invention, the type (molecular structure) of the polymerized cured product layer may be appropriately determined according to the use of the organic-inorganic composite filler and the polymerizable monomer to be mixed. Therefore, the polymerizable monomer that forms the polymerized cured product layer may be appropriately selected according to the purpose. Especially, it is preferable to use what is soluble in the organic solvent for the polymerizable monomer which forms a polymerization hardened | cured material layer.

  As the polymerizable monomer forming the polymerized cured product layer, those having a radical polymerizable group as the polymerizable group are preferable. A polymerizable monomer having one or two or more polymerizable groups can be used. And among others, A: a monofunctional vinyl monomer having one polymerizable group, B: a bifunctional vinyl monomer having two polymerizable groups, C: a trifunctional vinyl monomer having three polymerizable groups, and D: It is preferable to use a polymerizable monomer selected from tetrafunctional vinyl monomers having four polymerizable groups.

<A; Monofunctional vinyl monomer (polymerizable monomer forming a polymerized cured product layer)>
Methacrylates such as methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, hydroxyethyl methacrylate, tetrahydrofurfuryl methacrylate, glycidyl methacrylate, and acrylates corresponding to these methacrylates; or acrylic acid, methacrylic acid, p-methacryloyloxybenzoic acid, N-2 -Hydroxy-3-methacryloyloxypropyl-N-phenylglycine, 4-methacryloyloxyethyl trimellitic acid and its anhydride, 6-methacryloyloxyhexamethylenemalonic acid, 10-methacryloyloxydecamethylenemalonic acid, 2-methacryloyloxy Ethyl dihydrogen phosphate, 10-methacryloyloxydecamethylene dihydrogen phosphate DOO, 2-hydroxyethyl hydrogen phenyl phosphonate or the like.

<B; Bifunctional vinyl monomer (polymerizable monomer forming a polymerized cured product layer)>
<B-1 Aromatic Compound Monomer>
2,2-bis (methacryloyloxyphenyl) propane, 2,2-bis [4- (3-methacryloyloxy) -2-hydroxypropoxyphenyl] propane, 2,2-bis (4-methacryloyloxyphenyl) propane, 2 , 2-bis (4-methacryloyloxypolyethoxyphenyl) propane, 2,2-bis (4-methacryloyloxydiethoxyphenyl) propane), 2,2-bis (4-methacryloyloxytetraethoxyphenyl) propane, 2, 2-bis (4-methacryloyloxypentaethoxyphenyl) propane, 2,2-bis (4-methacryloyloxydipropoxyphenyl) propane, 2 (4-methacryloyloxydiethoxyphenyl) -2 (4-methacryloyloxydiethoxyphenyl) )propane, (4-methacryloyloxydiethoxyphenyl) -2 (4-methacryloyloxyditriethoxyphenyl) propane, 2 (4-methacryloyloxydipropoxyphenyl) -2- (4-methacryloyloxytriethoxyphenyl) propane, 2,2- Bis (4-methacryloyloxypropoxyphenyl) propane, 2,2-bis (4-methacryloyloxyisopropoxyphenyl) propane, and acrylates corresponding to these methacrylates;
Methacrylates such as 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 3-chloro-2-hydroxypropyl methacrylate, or vinyl monomers having —OH groups such as acrylates corresponding to these methacrylates; Diaducts obtained from addition with a diisocyanate compound having an aromatic group such as 4′-diphenylmethane diisocyanate.

<B-2 Aliphatic Compound Monomer>
Ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, butylene glycol dimethacrylate, neopentyl glycol dimethacrylate, propylene glycol dimethacrylate, 1,3-butanediol dimethacrylate, 1,4-butanediol dimethacrylate, 1 , 6-hexanediol dimethacrylate and acrylates corresponding to these methacrylates;
Methacrylates such as 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 3-chloro-2-hydroxypropyl methacrylate, etc., or vinyl monomers having —OH groups such as acrylates corresponding to these methacrylates, hexamethylene diisocyanate, trimethylhexamethylene Diadducts obtained by addition reaction with diisocyanate compounds such as diisocyanate, diisocyanate methylcyclohexane, isophorone diisocyanate, methylenebis (4-cyclohexylisocyanate);
Acrylic anhydride, methacrylic anhydride, 1,2-bis (3-methacryloyloxy-2-hydroxypropoxy) ethyl, di (2-methacryloyloxypropyl) phosphate, and the like.

<C; Trifunctional vinyl monomer (polymerizable monomer forming a polymerized cured product layer)>
Methacrylates such as trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, pentaerythritol trimethacrylate, trimethylolmethane trimethacrylate, and acrylates corresponding to these methacrylates;

<D: Tetrafunctional vinyl monomer (polymerizable monomer forming a polymerized cured product layer)>
Pentaerythritol tetramethacrylate, pentaerythritol tetraacrylate;
Diisocyanate compounds such as diisocyanate methylbenzene, diisocyanate methylcyclohexane, isophorone diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, methylenebis (4-cyclohexylisocyanate), 4,4-diphenylmethane diisocyanate, tolylene-2,4-diisocyanate, and glycidol Diaducts obtained by addition reaction with dimethacrylate.

  The polymerizable single-use substances (A) to (D) above may be used alone or in combination with different kinds.

<Combination of polymerizable monomers that form a polymerized cured product layer; composition (polymerizable monomer solution)>
Among the above monomers, a (meth) acrylic polymerizable monomer is preferable because the obtained polymer has good mechanical strength, biosafety, and the like. Moreover, bifunctional or more, more preferably bifunctional to tetrafunctional polymerizable monomers are preferred because of high polymerizability and particularly high mechanical properties of the cured product. Among them, (B) a polymerizable monomer containing 0 to 50 parts by mass of a trifunctional vinyl monomer and (D) 0 to 25 parts by mass of a tetrafunctional vinyl monomer with respect to 100 parts by mass of a bifunctional vinyl monomer. It is preferred to use a composition.

  When forming a polymerized cured product layer, when adopting a method of coating (adsorbing) a polymerizable monomer on the surface of inorganic particles, a composition containing the polymerizable monomer used for coating (or The polymerizable monomer solution described in detail below preferably contains a polymerization initiator. The polymerization initiator is not particularly limited, and the initiator exemplified in the following <Method for producing organic-inorganic composite filler> can be used. Further, the composition (or the polymerizable monomer solution described in detail below) can also contain a polymerization inhibitor for the purpose of controlling the polymerization rate. A known substance can be used as the polymerization inhibitor.

<Average particle size of organic-inorganic composite filler>
In this invention, 1-100 micrometers is preferable, as for the average particle diameter (particle size) of an organic inorganic composite filler, 3-100 micrometers is more preferable, and 5-70 micrometers is more preferable. When the average particle size is less than 1 μm, the filling rate of the filler that can be filled in the dental curable composition tends to decrease. As a result, the mechanical strength of the cured product is lowered, the adhesiveness of the dental curable composition is increased, and the operability during dental treatment tends to be deteriorated. On the other hand, when the average particle diameter exceeds 100 μm, the fluidity of the dental curable composition tends to decrease. As a result, the operability during tooth treatment tends to deteriorate.

  In addition, in order to adjust the average particle diameter of the organic-inorganic composite filler to 1 to 100 μm, the average particle diameter of the inorganic particles to be used, the polymerizable monomer (polymerized cured product layer) covering the surface of the inorganic particles, Adjust the amount. In particular, it is preferable to appropriately select the average particle size of the inorganic particles so that the finally obtained organic-inorganic composite filler satisfies the average particle size of 1 to 100 μm.

  The average particle size of the organic / inorganic composite filler indicates the median size obtained based on the particle size distribution by the laser diffraction-scattering method. The sample used for the measurement was prepared by uniformly dispersing 0.1 g of an organic-inorganic composite filler in 10 ml of ethanol.

<Amount of polymerization cured product layer in organic-inorganic composite filler>
In the present invention, the amount of the polymerized cured product layer, that is, the total amount of the polymerized cured product layer covering the surface of the inorganic particles (the amount of the total polymerized cured product layer) is determined from the curable composition combined with the polymerizable monomer. In order for the hardened | cured body obtained to exhibit the more excellent effect, it is 1-40 mass parts with respect to 100 mass parts of inorganic particles, and 5-25 mass parts is preferable.

  As a matter of course, the amount of the total polymerization cured product layer includes the amount of unpolymerized material.

  The organic-inorganic composite filler has been described above, but the organic-inorganic composite filler of the present invention preferably has the following shape. This suitable organic-inorganic composite filler will be described.

<Preferred organic-inorganic composite filler>
Since the organic-inorganic composite filler of the present invention has an appropriate pore volume, the strength of the curable composition is further improved.

That is,
The inorganic particles in the organic-inorganic composite filler are aggregated particles obtained by agglomerating inorganic primary particles having an average particle size of 10 to 1000 nm,
The polymerized cured product layer is a layer that covers at least a part of the surface of each inorganic primary particle and is a layer that binds each inorganic primary particle to each other;
A pore volume formed by the mercury intrusion method formed between the polymerized cured product layers covering at least a part of the surface of each inorganic primary particle (wherein the pore is a pore diameter in the range of 1 to 500 nm) It is preferable that the organic-inorganic composite filler has an agglomeration gap of 0.01 to ³⁰ cm ³ / g.

  By setting it as the organic inorganic composite filler which has the above pores, the improvement of the mechanical strength of the hardened | cured material obtained can be brought about. That is, it is considered that the anchor effect occurs when the polymerizable monomer of the curable composition penetrates into the pores formed between the polymerized cured product layers by capillary action and cures. And since an organic inorganic composite filler is hold | maintained with the organic resin component which consists of this polymeric monomer with high fitting force, it is guessed that the mechanical strength of the obtained hardening body improves further.

  Such a characteristic pore structure of the preferred organic-inorganic composite filler will be described with reference to the schematic diagram showing the particle cross section of FIG. The organic-inorganic composite filler 1 has an aggregate of a plurality of inorganic primary particles 2 having an average particle diameter of 10 to 1000 nm. Each of the plurality of inorganic primary particles 2 is at least partially covered with the surface of the polymerized cured product layer 3, and these polymerized cured product layers 3 are melted together and solidified in an integrated state, They are firmly connected to each other. And in this invention, this polymeric hardened | cured material layer 3 contains 0.1 to 5 mass% unpolymerized substance.

<Pore in preferred organic-inorganic composite filler>
In the preferred organic-inorganic composite filler, the polymerized cured product layer 3 does not fill the entire space formed by the aggregation of the plurality of inorganic primary particles 2, and the aggregation gap 4 remains. Among all the pores formed by the aggregation gap 4, the total volume of pores in the pore diameter range of 1 to 500 nm by the mercury intrusion method described below is preferably 0.01 to 0.30 cm ³ / g, preferably It is 0.03-0.20 cm < ³ > / g.

  When a suitable organic-inorganic composite filler has large pores having a pore diameter of more than 500 nm, the capillary phenomenon tends not to sufficiently act on the pores having such a large pore diameter. In this case, the polymerizable monomer contained in the curable composition tends not to sufficiently enter the pores, and as a result, the anchor effect does not tend to act sufficiently. Alternatively, when the pores are huge, even if the polymerizable monomer is filled inside, voids remain, and as a result, the anchor effect tends not to sufficiently act. The presence of such large pores in a suitable organic-inorganic composite filler is permissible. However, in the present invention, the giant pores are not included in the pores to be measured when determining the pore volume.

  On the other hand, pores having a pore diameter of less than 1 nm tend to make it difficult to measure the pore volume by mercury porosimetry. Furthermore, when forming the polymerized cured product layer, pores with small pore diameters are blocked, so that they are unlikely to exist as pores, and even if they exist, it is considered that the anchor effect tends not to be sufficiently exhibited. Therefore, in the present invention, pores having pore diameters other than the pore diameter range are not included in the pores whose pore volume is to be measured.

  The pore volume of the organic-inorganic composite filler is a value measured by a mercury intrusion method. The measurement of the pore volume by the mercury intrusion method is as described below. First, a predetermined amount of the organic-inorganic composite filler is placed in a measurement cell. Next, using a mercury porosimeter, the amount of mercury injected at a pressure corresponding to the diameter of each pore formed in the aggregation gap of the organic-inorganic composite filler is measured. Then, the pore volume is obtained by integrating the amount of mercury injected into each pore. In addition, the pore diameter of the measurement object pore at the time of measuring pore volume exists in the range of 1-500 nm as mentioned above.

  For the reasons as described above, the average pore diameter of the pores composed of the aggregation gaps of the organic-inorganic composite filler is preferably 3 to 300 nm, and more preferably 10 to 200 nm. In the case of this average pore diameter range, the agglomeration gap having the pore volume can be easily formed. In addition, the average pore diameter of the pores formed by the aggregation gap indicates a median pore diameter obtained based on the pore volume distribution of pores in the pore diameter range of 1 to 500 nm measured by a mercury intrusion method.

Further, when the total pore volume in pores having a pore diameter in the range of 1 to 500 nm is less than 0.01 cm ³ / g, a curable composition containing a suitable organic-inorganic composite filler and a polymerizable monomer In this case, the amount of the polymerizable monomer penetrating into the pores tends to decrease. As a result, a sufficient anchor effect tends not to be exhibited, and the mechanical strength of the obtained cured body tends to be small.

On the other hand, when the total pore volume exceeds 0.30 cm ³ / g, the organic-inorganic composite filler itself tends to be brittle, and the production thereof tends to be difficult. Therefore, from the viewpoint of making the productivity of the suitable organic-inorganic composite filler and the effect exerted more advanced, the total pore volume of the organic-inorganic composite filler is 0.03 to 0.20 cm ³ / g. Is particularly preferred.

<Other characteristics of suitable organic-inorganic composite filler>
In this invention, 1-100 micrometers is preferable, as for the average particle diameter (particle size) of a suitable organic inorganic composite filler, 3-100 micrometers is more preferable, and 5-70 micrometers is more preferable. In addition, in a suitable organic-inorganic composite filler, the amount of the total polymerization cured product layer is such that the cured product obtained from the curable composition combined with the polymerizable monomer exhibits an excellent effect. (Agglomerated particles formed by agglomerating inorganic primary particles) 1 to 40 parts by mass, preferably 5 to 25 parts by mass with respect to 100 parts by mass. These reasons are the same reasons as explained in the above <Average particle diameter of organic-inorganic composite filler> and <Amount of polymerized cured product layer in organic-inorganic composite filler>. Naturally, for the same reason as described in <Organic inorganic composite filler; unpolymerized product>, the polymerized cured product layer contains 0.1% by mass or more of the unpolymerized polymerizable monomer. It must be contained in an amount of 0% by mass or less and preferably contains 0.2% by mass or more and 4.0% by mass or less of an unpolymerized product.

  In the preferred organic-inorganic composite filler, the polymerizable monomer that forms the polymerized cured product layer is <polymerizable monomer that forms the polymerized cured product layer; organic-inorganic composite filler>, and <polymerized cured product layer It is preferable to use the same polymerizable monomer for the same reason as described in the combination of polymerizable monomers forming the composition; composition (polymerizable monomer solution)>.

  In addition, as described above, unless otherwise specified, naturally, a suitable organic-inorganic composite filler is the same or the same conditions for the same reason as described in <Organic-inorganic composite filler>. Can be adopted.

<Preferable organic-inorganic composite filler; inorganic primary particles>
Inorganic particles for forming a suitable organic-inorganic composite filler are aggregated particles formed by agglomerating inorganic primary particles having an average particle diameter of 10 to 1000 nm. When the average particle diameter of the inorganic primary particles is less than 10 nm, it tends to be difficult to form pores having the pore volume. Furthermore, when producing a suitable organic-inorganic composite filler, the pore openings tend to be easily closed by the polymerized cured product layer. As a result, air bubbles tend to be included in the resulting filler. When air bubbles are included in the organic-inorganic composite filler, the cured product of the curable composition containing the organic-inorganic composite filler is transparent. Tend to decrease.

  On the other hand, when the average particle size of the inorganic primary particles exceeds 1000 nm, if this is used for a dental composite restorative material, etc., the resulting hardened body tends to be less abrasive and a smooth surface hardened body is obtained. It tends to be difficult.

  For the above reasons, the inorganic particles for forming a suitable organic-inorganic composite filler are preferably aggregated particles formed by agglomerating inorganic primary particles having an average particle size of 40 to 800 nm, and inorganic particles having an average particle size of 50 to 600 nm. Aggregated particles obtained by aggregating primary particles are more preferable.

  In addition, the shape of the inorganic primary particles is not particularly limited, and spherical, substantially spherical, or amorphous particles can be used. Inorganic because it has excellent wear resistance and surface smoothness, and the organic-inorganic composite filler has uniform pores, and the pore openings are closed by the polymerized cured product layer, making it difficult to enclose air bubbles. The shape of the primary particles is preferably spherical or substantially spherical. In addition, a substantially spherical shape means that whose average uniformity is 0.6 or more. The average uniformity is more preferably 0.7 or more, and particularly preferably 0.8 or more.

  The particle diameter of the inorganic primary particles is measured using a scanning or transmission electron microscope. Specifically, the image equivalent of the photographed image of the organic-inorganic composite filler is analyzed to determine the equivalent circle diameter of the inorganic particles (the diameter of a circle having the same area as the target particle area). As an image taken with an electron microscope, an image that is clear in brightness and capable of discriminating the particle outline is used.

  The image analysis is performed using image analysis software capable of measuring at least the particle area, the maximum particle length, and the minimum particle width. With respect to 100 randomly selected inorganic particles, the particle diameter (equivalent circle diameter), the maximum amount of particles and the minimum width are obtained by the above method, and the average particle diameter and average uniformity of the inorganic particles are calculated by the following formulas.

  In the above formula, the number of particles is defined as (n), the maximum length of the i-th particle is defined as the major axis (Li), and the diameter in the direction perpendicular to the major axis is defined as the minimum width (Bi). In addition, the method of patent document 3 can be used for the method of calculating | requiring the average particle diameter and average uniformity of an inorganic primary particle by the above method.

  As the inorganic particles (aggregated particles) forming a suitable organic-inorganic composite filler, the same materials as described in (Inorganic particles; inorganic particles constituting the organic-inorganic composite filler) can be used. Among these, in a suitable organic-inorganic composite filler, it is preferable to use inorganic particles fired at a high temperature in order to make the metal oxide and the silica-based composite oxide a dense material. In order to improve the firing effect, it is preferable that the metal oxide and the silica-based composite oxide contain a small amount of Group I metal oxide such as sodium. Of these, the refractive index of the silica-based composite oxide particles is easy to adjust. Furthermore, since it has a large amount of silanol groups on the particle surface, it is particularly preferable because surface modification (surface treatment) can be easily performed using a hydrophobizing agent such as a silane coupling agent. As the hydrophobizing agent and the surface treatment method, the same hydrophobizing agent and the same method as those described in <Inorganic particles; inorganic particles constituting the organic-inorganic composite filler> can be adopted.

  Further, as the silica-based composite oxide particles, silica-zirconia, silica-titania, silica-titania-barium oxide, silica-titania-zirconia and the like have strong X-ray contrast properties, so that It is particularly suitable when used as an application material. Furthermore, silica-zirconia particles are preferred in that a cured product having more excellent wear resistance can be obtained.

The inorganic particles (aggregated particles) have a pore volume measured by mercury porosimetry (herein, the pore means a pore having a pore diameter in the range of 1 to 500 nm) of 0.015 to 0.35 cm ^3. / G aggregated particles are preferable in that a suitable organic-inorganic composite filler can be easily produced.

  A suitable organic-inorganic composite filler can be produced by using aggregated particles formed by agglomerating inorganic primary particles having an average particle size of 10 to 1000 nm as inorganic particles. Next, the manufacturing method of an organic inorganic composite filler is demonstrated.

<Method for producing organic-inorganic composite filler>
Hereinafter, the manufacturing method of the organic inorganic composite filler of this invention containing an unpolymerized material is demonstrated. The method for producing the organic-inorganic composite filler of the present invention is not limited to a specific method. An example of the organic-inorganic composite filler production method of the present invention is shown below.

  That is, when a suitable production method is described, it is preferable to employ a method in which inorganic particles are immersed in a polymerizable monomer solution containing a polymerizable monomer and then polymerized. As the inorganic particles to be used, those described above can be used.

  When the polymerizable monomer is a solution, the polymerizable monomer solution does not need to contain an organic solvent, but a polymerizable monomer solution obtained by diluting the polymerizable monomer with an organic solvent may be used. Can be used. When a polymerizable monomer solution containing an organic solvent is used, the inorganic particles are immersed in the polymerizable monomer solution containing the polymerizable monomer, and then once removed from the organic solvent, It is preferable to polymerize and cure the polymerizable monomer coated on the particles.

  In this invention, the polymerization rate of the polymerizable monomer coat | covered with the inorganic particle can be adjusted, and the quantity of an unpolymerized substance can be 0.1 mass% or more and 5 mass% or less. In order to adjust the polymerization rate, the polymerization rate may be appropriately adjusted by controlling the polymerization temperature, adding a polymerization inhibitor to the polymerizable monomer solution, controlling the polymerization time, or the like. These conditions can be prepared by conducting various experiments and setting optimum conditions. The simplest method includes a method of shortening the polymerization time. This will be described in detail below.

<Method for producing organic-inorganic composite filler; polymerizable monomer solution containing polymerizable monomer>
The method of coating the particle surface of the inorganic particles with the polymerizable monomer is not particularly limited, but generally the polymerizable monomer has a high viscosity, and it is difficult to coat the particle surface uniformly with a single monomer. It is. Therefore, it is preferable to coat the surface of the inorganic particles using a polymerizable monomer solution in which the polymerizable monomer is dissolved in an organic solvent.

  The concentration of the polymerizable monomer in the polymerizable monomer solution is not particularly limited, but it is necessary that the surface of the inorganic particles can be uniformly coated. That is, the organic solvent contained in the polymerizable monomer solution immersed in the inorganic particles is removed before polymerization and curing of the polymerizable monomer. When removing the solvent, if the concentration of the polymerizable monomer solution is not appropriate, the polymerizable monomer phase on the surface of the inorganic particles may become non-uniform. Therefore, if a suitable polymerizable monomer solution concentration is illustrated, it will be 3 to 70 mass parts of polymerizable monomers with respect to 100 mass parts of organic solvents.

<Method for producing organic-inorganic composite filler; organic solvent for polymerizable monomer solution>
As an organic solvent contained in the polymerizable monomer solution, a known solvent can be used without limitation. For example, halogen-type organic solvents, such as perchloroethylene, trichloroethylene, dichloromethane, chloroform, are mentioned. Furthermore, hydrocarbon compounds such as hexane, heptane and pentane; aromatic compounds such as benzene, toluene and xylene; alcohol compounds such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol and 2-butanol; diethyl Ether compounds such as ether, tetrahydrofuran and t-butyl methyl ether; ketone compounds such as acetone, methyl ethyl ketone and methyl isobutyl ketone; non-halogen compounds such as ester compounds such as ethyl formate, methyl acetate, ethyl acetate, propyl acetate and isopropyl acetate Organic solvents are examples. Among these solvents, from the viewpoints of having high volatility that enables the solvent removal process to be shortened, easy to obtain and inexpensive, and highly safe to the human body during production. More preferred are methanol, ethanol, acetone, dichloromethane and the like.

<Method for producing organic-inorganic composite filler; blending of polymerizable monomer solution / polymerization initiator>
The polymerizable monomer solution may contain an effective amount of a polymerization initiator. The polymerization initiator contained in the polymerizable monomer solution may be any of a photopolymerization initiator, a chemical polymerization initiator, and a thermal polymerization initiator. A photopolymerization initiator or a thermal polymerization initiator is preferable from the viewpoint that the timing of polymerization can be arbitrarily selected by energy applied from the outside such as light and heat, and the production operation is simple. A thermal polymerization initiator is more preferable in that it can be used without restriction of a working environment such as light shielding or red light.

  Examples of the thermal polymerization initiator include peroxidation such as benzoyl peroxide, p-chlorobenzoyl peroxide, tert-butyl peroxy-2-ethylhexanoate, tert-butyl peroxydicarbonate, and diisopropyl peroxydicarbonate. Azo compounds such as azobisisobutyronitrile, tributylborane, tributylborane partial oxide, sodium tetraphenylborate, sodium tetrakis (p-fluorophenyl) borate, triphenylamine tetraphenylborate, etc. Examples thereof include boron compounds, barbituric acids such as 5-butyl barbituric acid and 1-benzyl-5-phenylbarbituric acid, and sulfinates such as sodium benzenesulfinate and sodium p-toluenesulfinate. Among the above-mentioned thermal polymerization initiators, azo compounds such as azobisisobutyronitrile, which have high operational safety and are less affected by coloring on the organic-inorganic composite filler, are preferably used.

  These polymerization initiators may be used alone or in combination of two or more. The addition of a polymerization initiator is not essential. When added, the blending amount may be an effective amount sufficient to cause the polymerization to proceed. Generally, it is 0.01-30 mass parts with respect to 100 mass parts of polymerizable monomers (total amount of polymerizable monomers), more preferably 0.1-5 mass parts.

<Method for Producing Organic Inorganic Composite Filler Polymeric Monomer Solution Formulation / Polymerizable Monomer, Other Compounding Agents>
In producing the organic-inorganic composite filler of the present invention, the polymerizable monomer that forms the polymerized cured product layer is <polymerizable monomer that forms the polymerized cured product layer; organic-inorganic composite filler>, and <polymerization cured> It is preferable to use the same polymerizable monomer for the same reason as described in the combination of polymerizable monomers forming a physical layer; composition (polymerizable monomer solution)>. Moreover, the quantity of a polymerizable monomer is 1-40 mass parts with respect to 100 mass parts of inorganic particles, and 5-25 mass parts is preferable. These reasons are the same as described in the above <Organic inorganic composite filler>.

  Furthermore, in order to impart various functions to the organic-inorganic composite filler, the polymerizable monomer solution may be mixed with additives such as ultraviolet absorbers, pigments, dyes, polymerization inhibitors, and fluorescent agents.

<Method for producing organic-inorganic composite filler> Method for immersing inorganic particles in polymerizable monomer solution>
The method for immersing the inorganic particles in the polymerizable monomer solution is not particularly limited, but it is usually preferable to carry out the method at normal temperature and pressure. The mixing ratio of the inorganic particles and the polymerizable monomer solution is preferably 30 to 500 parts by mass, more preferably 50 to 200 parts by mass with respect to 100 parts by mass of the inorganic particles. After mixing, in the case of standing still, it is preferably left for 30 minutes or more, and more preferably left for 1 hour or more. In order to shorten the coating time, the mixture may be shaken, stirred, pressurized, decompressed, or heated. In addition, as a matter of course, the inorganic particles used can be those described in <Inorganic particles; Inorganic particles constituting the organic-inorganic composite filler>.

<Method for producing organic-inorganic composite filler> Method for removing organic solvent>
After immersing the inorganic particles in the polymerizable monomer solution, the organic solvent is removed from the polymerizable monomer solution before polymerizing and curing the polymerizable monomer. In the removal of the organic solvent, substantially the entire amount of the organic solvent in which the inorganic particles are immersed (usually 95% by mass or more) is removed. Visually, the removal may be performed until there is no coagulum adhering to each other and a powder in a fluid state is obtained.

  The operation of removing the organic solvent may be performed by any known drying method. For example, heating system drying such as convection heat transfer drying, radiant heat transfer drying, conduction heat transfer drying, internal heat generation drying, vacuum drying, vacuum freeze drying, centrifugal drying, absorbent drying, suction drying, pressure drying, Non-heating system drying such as sonic drying is exemplified. Of these, heating system drying, vacuum drying, vacuum freeze drying and the like are preferable.

  When vacuum drying is performed, the degree of reduced pressure may be appropriately selected in consideration of the boiling point and volatility of the organic solvent. Generally, the degree of vacuum is 100 hectopascals or less, preferably 0.01 to 50 hectopascals, and most preferably 0.1 to 10 hectopascals.

  When carrying out heating system drying, the heating temperature may be appropriately selected according to the boiling point of the organic solvent. When a thermal polymerization initiator is contained as a polymerization initiator in the organic solution, it is necessary to operate at or below the polymerization start temperature.

  The drying method may be a combination of the above methods. In order to shorten the drying time, it is particularly preferable to combine vacuum drying and heating system drying such as conductive heat transfer drying. The removal operation of the organic solvent may be performed under stirring as long as the characteristics of the organic-inorganic composite filler are not impaired.

<Method for Producing Organic-Inorganic Composite Filler Method for Forming Polymerized Cured Product Layer; Polymerization Conditions, Other Treatments>
After removing the organic solvent, the polymerizable monomer is polymerized and cured. The polymerization curing method to be employed varies depending on the polymerizable monomer and polymerization initiator to be used, and therefore an optimal method may be selected as appropriate. When a thermal polymerization initiator is used, the polymerization is performed by heating, and when a photopolymerization initiator is used, the polymerization is performed by irradiating light of a corresponding wavelength.

  When performing thermal polymerization, the polymerization temperature varies depending on the polymerization initiator used, and therefore an optimal temperature may be selected as appropriate. In general, the polymerization temperature is 30 to 170 ° C, preferably 50 to 150 ° C.

  When performing photopolymerization, the light source to be used varies depending on the type of polymerization initiator, and therefore an optimal light source may be selected as appropriate. As a light source, generally, a halogen lamp, LED, xenon lamp, high pressure mercury lamp, metal halide lamp, carbon arc lamp, tungsten lamp, helium cadmium laser, argon laser, or other visible light source, low pressure mercury lamp, xenon arc lamp, Examples include an ultraviolet light source such as a deuterium arc lamp, a mercury xenon arc lamp, a tungsten halogen incandescent lamp, a UV-LED, and a xenon plasma discharge tube.

The method for adjusting the content of the unpolymerized product is not particularly limited, and examples thereof include adjustment of polymerization temperature, adjustment of polymerization time, addition of a polymerization inhibitor, and polymerization in the presence of oxygen. Specifically, based on at least one relationship shown in the following (1), (2), (3) and (4) confirmed separately in advance, it is contained in the polymerization cured product layer obtained in the polymerization step. The unpolymerized monomer content is defined by the concentration (% by mass) of the unpolymerized monomer based on the mass of the entire polymerized cured product layer. It is preferable to determine a condition that is in a range of 0.1% by mass or more and 5.0% by mass or less, and perform the immersion and / or polymerization according to the determined condition.
(1) When the polymerization inhibitor is blended in the polymerizable monomer solution, the polymerization inhibitor is contained in the polymer to be adhered to the surface of the inorganic particles, and polymerization is performed under predetermined conditions, The relationship between the polymerization inhibitor concentration in the polymerizable monomer preparation and the unpolymerized monomer total content.
(2) In the polymerization step, the relationship between the polymerization time and the unpolymerized monomer content when the polymerization is carried out by changing only the polymerization time under conditions other than the polymerization time as predetermined conditions.

(3) The relationship between the polymerization temperature and the unpolymerized monomer content when the polymerization is carried out by changing only the polymerization temperature under conditions other than the polymerization temperature as predetermined conditions in the polymerization step.
(4) In the polymerization step, the oxygen concentration and the unpolymerized monomer when the polymerization is performed by changing only the oxygen concentration under conditions other than the oxygen concentration in the atmosphere in which the polymerization is performed. Relationship with total content.

  At this time, when separately confirming the above relationship in advance, it is preferable to confirm by performing a preliminary experiment in an actually used apparatus.

  Among these, the method of adjusting the unpolymerized content most simply includes adjusting the polymerization time. The polymerization time here refers to the time after the polymerizable monomer reaches a predetermined temperature or is exposed to irradiation light. However, since the adjustment of the polymerization time is affected by the scale of the apparatus used and other polymerization conditions, etc., as described above, a preliminary experiment should be performed in the apparatus used to confirm the polymerization rate relative to the polymerization time in advance. Is preferred.

  By the above method, an organic-inorganic composite filler containing a specific amount of an unpolymerized monomer can be efficiently produced.

As described above, the organic-inorganic composite filler of the present invention can be produced. The obtained organic-inorganic composite filler may be subjected to a surface treatment. By performing the surface treatment, higher mechanical strength is imparted to the cured body of the dental curable composition containing the organic-inorganic composite filler. The surface treatment agent and the surface treatment method are the same as the surface treatment of the inorganic primary particles described above.
Next, the manufacturing method of the suitable organic inorganic composite filler is demonstrated.

<The manufacturing method of a suitable organic inorganic double filler>
Hereinafter, a suitable method for producing an organic-inorganic composite filler of the present invention having an aggregation gap will be described. As a suitable method for producing an organic-inorganic composite filler, basically, the conditions described in the above-mentioned <Method for producing organic-inorganic composite filler> can be employed. That is, unless otherwise specified, <Method for producing organic-inorganic composite filler>, <Method for producing organic-inorganic composite filler; Polymerizable monomer solution containing polymerizable monomer>, <Organic-inorganic composite Manufacturing method of filler; Organic solvent of polymerizable monomer solution>, <Method of manufacturing organic-inorganic composite filler; Compounding of polymerizable monomer solution / polymerization initiator>, <Method of manufacturing organic-inorganic composite filler Blending of monomer solution / polymerizable monomer, other compounding agent>, <method for producing organic-inorganic composite filler> Method for immersing inorganic particles in polymerizable monomer solution>, <method for producing organic-inorganic composite filler Organic Solvent Removal Method><Method for Producing Organic-Inorganic Composite Filler Polymerization Cured Product Layer Formation Method; Polymerization Conditions, Other Treatment> For the same reasons as described above, the same conditions and the same conditions can be adopted.

  Specifically, the suitable organic-inorganic composite filler is preferably produced by the method described below. In this method, it is preferable to use aggregated particles obtained by aggregating inorganic primary particles having an average particle diameter of 10 to 1000 nm described in <Preferred organic-inorganic composite filler; inorganic primary particles> as a starting material.

And
(I) Polymerizable monomer containing 3 to 70 parts by mass of a polymerizable monomer with respect to 100 parts by mass of an organic solvent, inorganic particles which are aggregated particles formed by agglomerating inorganic primary particles having an average particle diameter of 10 to 1000 nm After soaking in body solution
(Ii) after removing the organic solvent from the immersed inorganic particles,
(Iii) By polymerizing the polymerizable monomer impregnated in the inorganic particles,
It is preferable to employ the manufacturing method.

<Preparation method of suitable organic-inorganic double filler> Preparation of aggregated particles>
Aggregated particles formed by aggregating a plurality of inorganic primary particles having an average particle diameter of 10 to 1000 nm as a starting material are preferably prepared by the following method. As the aggregated particles, those obtained by aggregating the inorganic primary particles described in <Preferred organic-inorganic composite filler; inorganic primary particles> can be used.

  Inorganic primary particles are obtained, for example, as agglomerated particles that agglomerate vigorously when produced by a wet process. Even when it is produced by a dry method, it can be obtained as agglomerated particles that agglomerate gently. Even in the case of producing by the sol-gel method, the inorganic primary particles are usually agglomerated in the drying step or the firing step.

  In the present invention, the inorganic agglomerated particles obtained in this way may be used after being pulverized if necessary. However, when pulverizing, it is difficult to control the particle size of the obtained inorganic aggregated particles, and as a result, inorganic aggregated particles having a wide particle size distribution can be obtained. In order to avoid this unsuitability, it is preferable to produce an organic-inorganic composite filler by using inorganic aggregated particles obtained by granulation by a spray drying method as a starting material.

  Here, in the spray drying method, a slurry in which inorganic primary particles are dispersed in a volatile liquid medium such as water is prepared into fine mist droplets using, for example, a high-speed air flow, and the mist droplets are prepared. It refers to a method of making inorganic aggregated particles by volatilizing a liquid medium by contacting with a high-temperature gas and collecting a large number of inorganic primary particles dispersed in droplets into substantially one aggregated particle. The particle size and particle size distribution of the agglomerated particles are controlled depending on the spray format and spray conditions.

The granulation method by the spray drying method is an advantageous method because inorganic aggregated particles having an average particle size of 1 to 100 μm desired as the particle size of the organic-inorganic composite filler can be obtained with a narrow particle size distribution. . Further, the inorganic agglomerated particles naturally have an agglomerated gap with a pore volume measured by the mercury intrusion method of 0.015 to 0.35 cm ³ / g, more preferably 0.15 to 0.30 cm ³ / g. It is formed. In the case of producing an organic-inorganic composite filler using the aggregated inorganic aggregated particles, usually 0.01 to 0.30 cm ³ / g, more preferably 0.03, is provided inside the obtained organic-inorganic composite filler. Agglomerated gaps with pore volumes of ˜0.20 cm ³ / g are formed. Therefore, when the inorganic agglomerated particles produced by the above production method are used as a starting material, a suitable organic-inorganic composite filler of the present invention can be obtained efficiently.

  In general, the pore volume of the inorganic aggregated particles is large when the size of the inorganic primary particles constituting the inorganic aggregated particles is narrow, while it is small when the size of the inorganic primary particles is wide. Furthermore, the pore volume of the inorganic aggregated particles can be further reduced by combining a plurality of types of inorganic primary particles having different average particle sizes. Furthermore, the pore volume of the inorganic agglomerated particles can be further reduced by combining a plurality of types of inorganic primary particles in such a ratio that the closest packing state is achieved.

  The spray-drying method used suitably is demonstrated concretely. As this method, there is a method in which a slurry in which inorganic particles are dispersed in an appropriate solvent such as water is prepared, and the slurry is finely sprayed by a high-speed air stream and dried. Furthermore, there is a method in which the slurry is dropped onto a disk-shaped rotating body, and the slurry is blown off in a mist shape by centrifugal force and dried. Examples of the solvent include water, ethanol, isopropyl alcohol, chloroform, dimethylformamide and the like.

  Although the density | concentration of the inorganic particle in a slurry does not have a restriction | limiting as long as it can atomize with a high-speed airflow or a disk shaped rotary body, Generally it is 5-50 mass%, Preferably it is 10-45 mass%. Moreover, the rotational speed of the disk-shaped rotating body is generally 1000 to 50000 rpm. The diameter of the droplets is adjusted so that inorganic aggregate particles having the desired average particle diameter can be obtained in consideration of the inorganic primary particle diameter.

  If the sprayed slurry is immediately dried with high-temperature air, inert gas, or the like, inorganic agglomerated particles having a uniform particle size can be obtained. The temperature of the gas used for drying is generally 60 to 300 ° C, preferably 80 to 250 ° C.

  In addition, although it is slight, the solvent used for preparing a slurry may remain in the inorganic aggregated particles obtained by the spray drying. For this reason, it is preferable to vacuum dry the resulting inorganic aggregated particles after spray drying. The time for vacuum drying is generally 1 to 48 hours, the temperature is 20 to 150 ° C., and the degree of vacuum is generally 0.01 to 100 hectopascals or less.

  The shape of the inorganic agglomerated particles obtained by spray drying is usually spherical, substantially spherical, donut-shaped, or dimple-shaped with a dent formed on the surface of the particles. The inorganic aggregated particles are generally obtained in a state where a plurality of inorganic aggregated particles having these shapes are mixed. Therefore, the organic-inorganic composite filler produced using the mixed inorganic aggregated particles is generally an organic-inorganic composite filler having a corresponding shape.

  The above-mentioned spherical, substantially spherical, etc. inorganic agglomerated particles can easily be produced with a hollow structure. A cured product of a curable composition containing a hollow-structure organic-inorganic composite filler tends to have a somewhat low mechanical strength. However, at the time of producing the curable composition, a large amount of the polymerizable monomer can selectively enter and fill the hollow portion, so that the light diffusibility can be changed. This effect can be advantageously used in dental applications.

  In general, when the slurry concentration used for spray drying is increased and the sprayed slurry droplets are dried with hot air within a relatively short time, a large amount of spherical or substantially spherical inorganic aggregated particles are generated, and the hollow contained therein The proportion of structured inorganic aggregated particles tends to decrease. On the other hand, as the slurry concentration is lowered, the generation ratio of doughnut-shaped or dimple-shaped inorganic aggregated particles increases, and in the spherical or substantially spherical inorganic aggregated particles, the content ratio of the inorganic aggregated particles having the hollow structure tends to increase. There is. In addition, the method of patent document 3 is employable as such spray-drying conditions.

By granulating inorganic primary particles having an average particle diameter of 10 to 1000 nm by a spray drying method, 0.015 to 0.35 cm ³ / g, more preferably 0.15 to 0.30 cm ³ / g. It is possible to produce inorganic aggregated particles having a pore volume and having an aggregation gap formed therein. In these inorganic agglomerated particles, the inorganic primary particles agglomerated in the vicinity of the surface are usually arranged close to a hexagonal close-packed structure. The inorganic primary particles having an average particle diameter of 10 to 1000 nm are arranged along the surface of the inorganic agglomerated particles in a state close to a hexagonal close-packed structure, thereby forming an agglomerated gap formed between adjacent inorganic primary particles. A pore is formed. The average pore diameter of these pores is usually 5 to 330 nm, more generally 20 to 300 nm. By using the aggregated particles (inorganic particles), a suitable organic-inorganic composite filler can be easily produced.

  In addition, the pore volume and average pore diameter formed in the inorganic aggregated particles are obtained by the same measurement method as that for the above-mentioned preferred organic-inorganic composite filler.

  The inorganic agglomerated particles used for the production of a suitable organic-inorganic composite filler are preferably surface-treated with a hydrophobizing agent in order to improve the wettability with respect to the polymerizable monomer. As the hydrophobizing agent, the silane coupling agent described in <Inorganic particles; Inorganic particles constituting the organic-inorganic composite filler> can be used.

  The surface treatment may be performed on the inorganic primary particles or the inorganic aggregated particles. When producing inorganic agglomerated particles by spray drying, it is efficient to perform a surface treatment simultaneously with this treatment.

<Production method of suitable organic-inorganic composite filler; production conditions>
The inorganic agglomerated particles produced as described above are then a polymerizable monomer solution containing 3 to 70 parts by weight of a polymerizable monomer and an effective amount of a polymerization initiator with respect to 100 parts by weight of an organic solvent. Soaked in. As a result, the polymerizable monomer solution enters the inside of the inorganic aggregated particles through the aggregation gap of the inorganic aggregated particles due to capillary action. In this case, since the polymerizable monomer is diluted with an organic solvent, the liquid infiltration due to capillary action is high. As a result, the polymerizable monomer solution is filled to the deep part of the aggregation gap.

In the polymerizable monomer solution, the content of the polymerizable monomer with respect to the organic solvent is preferably controlled within the above range. By controlling the content of the polymerizable monomer within this range, the pore volume formed by the aggregation gap of the obtained organic-inorganic composite filler can be controlled within the specific range. That is, the organic solvent contained in the polymerizable monomer solution that has entered the aggregation gap of the inorganic aggregated particles is removed before the polymerization and curing of the polymerizable monomer. Volume pores corresponding to the volume reduction caused by the removal of the solvent are formed in the aggregation gaps of the inorganic primary particles. For the above reason, in order to make the pore volume of the organic-inorganic composite filler within the above range (0.01 to 0.30 cm ³ / g), the polymerizable monomer contained in the polymerizable monomer solution The concentration needs to be the above content.

  When the content of the polymerizable monomer is outside the above range, the amount of the polymerizable monomer filled in the pores is excessive or insufficient. Moreover, when there is too much content of a polymerizable monomer, an air bubble may be formed in a filler. Furthermore, the excess polymerizable monomer adheres to the outer periphery of the inorganic agglomerated particles, which tends to cause a disadvantage that the inorganic agglomerated particles are bonded together to form a lump. Considering these disadvantages, the content of the polymerizable monomer in the polymerizable monomer solution is more preferably 10 to 50 parts by mass with respect to 100 parts by mass of the organic solvent.

  As for other conditions, the same thing and the same conditions can be employ | adopted as the reason demonstrated by <the manufacturing method of an organic inorganic composite filler> as above-mentioned.

  By the above method, the organic-inorganic composite filler having pores inside can be efficiently produced. These operations may be repeated a plurality of times depending on the concentration of the polymerizable monomer solution. By repeating these operations a plurality of times, the amount of organic resin covering the surface of the inorganic primary particles can be increased, and the amount of pore volume formed can be adjusted.

<Curable composition containing organic-inorganic composite filler and its use>
The organic-inorganic composite filler of the present invention can be used without limitation for ordinary filler applications. Especially, it can be used for various uses by setting it as the curable composition combined with the polymerizable monomer. In particular, the curable composition can be suitably used as a dental material.

<Dental curable composition>
As already explained, the organic-inorganic composite filler of the present invention is particularly useful as a dental filler to be blended in a dental curable composition. In addition to the organic-inorganic composite filler, a polymerizable monomer and a polymerization initiator are blended in the dental curable composition.

  As the polymerizable monomer, known monomers used for the application can be used without limitation. Usually, it may be selected from the same category as the polymerizable monomer exemplified for the production of the organic-inorganic composite filler. The compounding quantity of a polymerizable monomer is 10-100 mass parts with respect to 100 mass parts of organic-inorganic composite fillers, and 20-90 mass parts is preferable. As the polymerizable monomer, the same monomers as those described in <Polymerizable monomer forming polymerized cured product layer; organic-inorganic composite filler> can be used without any limitation.

  Any known polymerization initiator can be used without limitation. For example, the thermal polymerization initiator explained in <Method for producing organic-inorganic composite filler; blending of polymerizable monomer solution / polymerization initiator> can be used. In general, a photopolymerization method is often employed as a means for curing (polymerizing) a dental curable composition because of its ease of operation during use. For the above reason, it is preferable to use a photopolymerization initiator as a polymerization initiator also in the dental curable composition of the present invention.

  Preferred photopolymerization initiators include, for example, benzoin alkyl ethers, benzyl ketals, benzophenones, α-diketones, thioxanthone compounds, bisacylphosphine oxides, and the like. In addition, a reducing agent is often added to the photopolymerization initiator. Examples of the reducing agent include aromatic amines, aliphatic amines, aldehydes, sulfur-containing compounds and the like. Furthermore, a trihalomethyltriazine compound, an aryl iodonium salt, etc. can also be added as needed.

  The polymerization initiator is generally blended in the range of 0.01 to 10 parts by mass with respect to 100 parts by mass of the polymerizable monomer.

  Other inorganic particles can be added to the dental curable composition as long as the effects of the present invention are not impaired. As the other inorganic particles, known fillers used for the application can be used without limitation. For example, as other inorganic particles, inorganic particles made of the same material as the inorganic primary particles can be exemplified.

  Furthermore, in the dental curable composition of this invention, a well-known additive can be mix | blended in the range which does not inhibit the effect remarkably. Examples of such additives include polymerization inhibitors, pigments, ultraviolet absorbers, and fluorescent agents.

  In the present invention, the dental curable composition is generally obtained by sufficiently kneading a predetermined amount of each of the above essential components and each optional component to be added as necessary, and further defoaming the paste under reduced pressure. Can be produced by removing bubbles. The use of the dental curable composition is not particularly limited, but a particularly suitable use is a dental composite restorative material such as a dental filling restorative material and an indirect dental restorative material.

  When the organic-inorganic composite filler of the present invention is used as a filler for a dental curable composition, the polymerizable monomer has a difference between the refractive index of the polymer and the refractive index of the inorganic particles of 0.1. It is preferable to select so as to be as follows. Thus, by selecting a monomer, sufficient transparency can be provided to the obtained organic-inorganic composite filler. Further, when the obtained organic-inorganic composite filler is used in a dental curable composition, the difference in refractive index between the organic-inorganic composite filler and a polymer of a polymerizable monomer constituting the dental curable composition is determined. It is preferable to select it to be 0.1 or less. By selecting the monomer in this way, a cured body of a transparent dental curable composition can be obtained.

  Next, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples. Abbreviations of compounds such as polymerizable monomers, inorganic particles, and polymerization initiators used in the following Examples and Comparative Examples are shown below.

Polymerizable monomer 3G: triethylene glycol dimethacrylate.
UDMA: 1,6-bis (methacrylethyloxycarbonylamino) -2,2-4-
Trimethylhexane.
BisGMA: 2,2-bis [4- (2-hydroxy-3-methacryloxypropoxy) phenyl] propaneNBM80: BisGMA / 3G = 60/40 mixture Inorganic particles (aggregated particles)
F-1: Spherical silica (average homogeneity of 0.95) manufactured by a sol-gel method with an average primary particle size of 200 nm.
F-2: F-1 aggregated particles (average uniformity 0.95, pore volume 0.28 cm ³ / g). Example 4 describes the production method.

Polymerization initiator AIBN: azobisisobutyronitrile.
CQ: camphorquinone.
DMBE: ethyl N, N-dimethyl-p-benzoate.

  Average particle size and average uniformity of inorganic particles, characteristics of inorganic particles / organic-inorganic composite filler (average particle size, pore volume, average pore size), amount of polymerized cured product layer in organic-inorganic composite filler, unpolymerized amount The bending strength (mechanical strength) of the obtained cured product was measured according to the following method.

(1) Average particle diameter and average uniformity of inorganic particles constituting the organic-inorganic composite filler
Using a scanning electron microscope (XL-30S FEG, manufactured by PHILIPS), photographs of the organic-inorganic composite filler were taken at a magnification of 5,000 to 100,000. Using image analysis software (IP-1000PC, manufactured by Asahi Kasei Engineering Co., Ltd.), the captured image is processed to obtain the equivalent circle diameter (particle diameter), maximum length, minimum width, and number of particles in the unit field of view. It was. The number of particles to be observed was 100 or more. The average volume diameter of the particles was determined by the following formula, and this was defined as the average particle diameter.

Further, the number of primary particles observed in the unit visual field (n), the maximum length of the primary particles as the major axis (Li), and the diameter perpendicular to the major axis as the minimum width (Bi), n, Li, Bi Asked. The average uniformity of the inorganic primary particles was calculated by the following formula.

(2) Average particle size (particle size) of inorganic particles
0.1 g of inorganic agglomerated particles were dispersed in 10 ml of ethanol and sufficiently shaken by hand. Using a particle size distribution meter (“LS230”, manufactured by Beckman Coulter) using a laser diffraction-scattering method, an optical model “Fraunhofer” (Fraunhofer) was applied to determine the median diameter of volume statistics.

(3) Average particle size (particle size) of organic-inorganic composite filler
When dispersing the organic-inorganic composite filler in ethanol, the operation was performed in the same manner as in the case of (2) inorganic agglomerated particles except that ultrasonic waves were applied for 20 minutes, and the particle size was determined.

(4) The pore volume of the aggregation gap and the average pore diameter of the pores in the inorganic aggregated particles and the organic-inorganic composite filler, using a mercury porosimeter (“Pore Master”, manufactured by Quantachrome) The pore volume distribution was measured. 0.2 g of inorganic agglomerated particles or organic-inorganic composite filler was put in a measurement cell and measured. Pore volume distribution The pore volumes in the range of pore diameters of 1 to 500 nm were integrated to obtain the pore volume. Further, for the pores in this range, the median pore diameter determined from the pore volume distribution was used as the average pore diameter of the aggregation gap.

(5) Polymerized cured product layer amount in organic-inorganic composite filler (total amount of all polymerized cured product layer)
Using the differential thermal-thermogravimetric simultaneous measurement apparatus “TG / DTA6300” (manufactured by SII Nano Technology), the amount of the total polymerization cured product layer was measured by the following procedure. 0.03 g of organic-inorganic composite filler was put in an aluminum pan to prepare a sample. Heating was performed at a rate of temperature increase of 5 ° C./min, an upper limit temperature of 500 ° C., and an upper limit temperature mooring time of 30 minutes, and the mass loss was measured. Using the obtained mass reduction amount, the ratio between the inorganic particles and the polymerized cured product layer was determined, and the polymerized cured product layer (parts by mass) relative to 100 parts by mass of the inorganic particles was calculated. Further, 0.03 g of aluminum oxide was used as a reference for simultaneous differential thermal-thermogravimetric measurement.

(6) Amount of unpolymerized material in organic / inorganic composite filler High performance liquid chromatography (column: ODS-II, 4.6 nmφ × 250 nm, manufactured by GL Science, liquid feeding unit: LC-20AD, manufactured by Shimadzu Corporation, degasser: Using Shimadzu Corporation, DGU-20A, detector: Shimadzu Corporation, SPD-M20A), the amount of unpolymerized product was measured by the following procedure. 0.1 g of the organic-inorganic composite filler was dispersed in 0.9 g of acetone, and irradiated with ultrasonic waves for 10 minutes to obtain a filler dispersion. This dispersion was centrifuged (3000 rpm, 10 minutes), and the supernatant was filtered through a 0.2 μm filter to prepare a sample. The sample was analyzed by high performance liquid chromatography, and the amount of unpolymerized material in the organic-inorganic composite filler was measured from a calibration curve prepared in advance. In the examples and comparative examples, the total amount of the cured polymer layer obtained in the above (5) and the total amount of the polymerizable monomers used when coating the inorganic particles were in good agreement. .

(7) Measuring method of bending strength In Examples 7-12 and Comparative Examples 5-8, the organic-inorganic composite filler produced in each Example / Comparative Example, a polymerizable monomer having the following blending ratio, and light A polymerizable monomer composition containing a polymerization initiator and an inorganic filler is prepared, and uniformly stirred and defoamed using a mortar under red light to obtain a paste-like dental curable composition. Prepared.

  Polymerizable monomer UDMA 80 parts by mass, 3G 20 parts by mass, polymerization initiator CQ 0.20 part by mass, DMBE 0.5 part by mass, organic / inorganic composite filler produced in Examples / Comparative Examples 300 parts by mass, inorganic filling Material F-1 A polymerizable monomer composition containing 200 parts by mass was prepared, and a paste-like dental curable composition was prepared by the method described above.

  Next, the paste of the dental curable composition was filled into a stainless steel mold using a filling device. A polypropylene sheet was pressed against the paste surface, and light was irradiated through the polypropylene sheet. Irradiation was performed using a visible light irradiator power light (manufactured by Tokuyama Corporation). The irradiation window of the visible light irradiator was brought into close contact with the polypropylene sheet, and irradiation was performed three times for 20 seconds each from one side while changing the place so that the entire cured body was exposed to light. Next, light was irradiated from the opposite surface three times for 20 seconds in the same manner to obtain a cured product.

  Using a # 800 water-resistant abrasive paper, the cured body was adjusted to a 2 × 2 × 25 mm prismatic shape. This sample piece was mounted on a testing machine (manufactured by Shimadzu Corp., Autograph AG5000D), and the three-point bending fracture strength was measured under the test conditions of a distance between fulcrums of 20 mm and a crosshead speed of 1 mm / min. Five test pieces were evaluated, and the average value was defined as the bending strength.

(8) Evaluation of transparency The paste having the same dental curable composition as the paste prepared by the method of (7) was filled in a mold having 7 mmφ × 1 mm holes. A polyester film was pressed against the paste surface at both ends of the hole. Through the polyester film, both surfaces of the paste were irradiated with light for 30 seconds with a visible light irradiator (manufactured by Tokuyama, Powerlight). After the paste hardened, it was removed from the mold. Using a color difference meter (manufactured by Tokyo Denshoku Co., Ltd., TC-1800MKII), Y values (background color black and white) of tristimulus values of the cured paste were measured. The following formula,
Contrast ratio = Y value in the case of black background color / contrast ratio was calculated based on the Y value in the case of white background and used as an index of transparency.

Example 1
<Preparation of aggregated particles>
100 g of the inorganic particles F-1 were added to 200 g of water, and a dispersion liquid in which the inorganic particles were dispersed was obtained using a circulating pulverizer SC mill (manufactured by Mitsui Mining Co., Ltd.).

  Next, 4 g (0.016 mol) of γ-methacryloyloxypropyltrimethoxysilane and 0.003 g of acetic acid were added to 80 g of water and stirred for 1 hour and 30 minutes to obtain a uniform solution having a pH of 4. This solution was added to the inorganic particle dispersion and mixed uniformly. Thereafter, while the dispersion was lightly mixed, it was supplied onto a disk rotating at high speed and dried by a spray drying method.

The spray dryer used was a spray dryer (spray dryer “TSR-2W”, manufactured by Sakamoto Giken Co., Ltd.) that has a rotating disk and is atomized by centrifugal force. The disk rotation speed was 10,000 rpm, and the temperature of the dry atmosphere air was 200 ° C. Thereafter, the spray-dried inorganic powder was vacuum-dried at 60 ° C. for 18 hours to obtain 71 g of inorganic agglomerated particles. The pore volume of the aggregation gaps of the inorganic aggregated particles was 0.28 cm ³ / g, and the average pore diameter was 50 nm. The average particle size of the inorganic aggregated particles was 40.0 μm.

<Manufacture of organic-inorganic composite filler>
Next, 1.78 g of UDMA as a polymerizable monomer, 0.005 g of AIBN as a polymerization initiator, and 5.0 g of ethanol as an organic solvent handle were mixed (based on 100 parts by mass of the organic solvent). 9.4 g of the above-mentioned inorganic aggregated particles were immersed in 35.6 parts by mass of the polymerizable monomer. The mixture was sufficiently stirred and allowed to stand for 1 hour after confirming that the mixture became a slurry.

  The above-mentioned mixture was dried for 1 hour using a vacuum dryer under conditions of a degree of vacuum of 10 hectopascal heating conditions of 40 ° C. to remove the organic solvent. When the organic solvent was removed, a powder having high agglomeration and no fluidity was obtained.

  The powder is heated for 20 minutes under the conditions of a vacuum degree of 10 hectopascals and 140 ° C., the polymerizable monomer in the powder is polymerized and cured, and the obtained powder is pulverized using a vibration ball mill. As a result, 8.0 g of an organic-inorganic composite filler was obtained.

The average particle diameter of the organic-inorganic composite filler was 1.2 μm, and pores could not be confirmed according to measurement with a mercury porosimeter. Furthermore, when the quantity of the total polymerization hardening material layer in an organic inorganic composite filler was measured, the quantity of the total polymerization hardening material layer was 18.9 mass parts with respect to 100 mass parts of inorganic particle F-1. Moreover, the quantity of the unpolymerized material contained in the all-polymerization cured | curing material layer in an organic inorganic composite filler was 0.2 mass%.
The production conditions are summarized in Table 1, and the properties of the obtained organic-inorganic composite filler are summarized in Table 2.

Example 2
An organic-inorganic composite filler was obtained in the same manner as in Example 1 except that the temperature at which the polymerizable monomer was polymerized and cured was changed to 130 ° C. in <Method for producing organic-inorganic composite filler> in Example 1. . About this organic inorganic composite filler, it carried out similarly to Example 1, and measured each physical property.
The production conditions are summarized in Table 1, and the properties of the obtained organic-inorganic composite filler are summarized in Table 2.

Example 3
An organic-inorganic composite filler was obtained in the same manner as in Example 1 except that the temperature at the time of polymerizing and curing the polymerizable monomer was changed to 120 ° C. in <Method for producing organic-inorganic composite filler> in Example 1. . About this organic inorganic composite filler, it carried out similarly to Example 1, and measured each physical property.
The production conditions are summarized in Table 1, and the properties of the obtained organic-inorganic composite filler are summarized in Table 2.

Example 4
9.4 g of aggregated particles F-1 obtained in <Preparation of aggregated particles> in Example 1, 1.78 g of UDMA as a polymerizable monomer, 0.005 g of a polymerization initiator, and 5.0 g of ethanol in a mortar To make a paste. The obtained paste was defoamed and heated for 20 minutes under the conditions of a vacuum degree of 10 hectopascals and 140 ° C. to obtain a cured paste. The cured body was pulverized using a vibration ball mill to obtain an organic-inorganic composite filler. About this organic inorganic composite filler, it carried out similarly to Example 1, and measured each physical property.
The production conditions are summarized in Table 1, and the properties of the obtained organic-inorganic composite filler are summarized in Table 2.

Example 5
<Preparation of agglomerated particles (F-2)>
In <Preparation of Aggregated Particles> in Example 1, 100 g of inorganic particles F-1 were added to 200 g of water, and inorganic particles were dispersed using a circulation type pulverizer SC mill (Mitsui Mine Co., Ltd.). A dispersion was obtained.

  Next, 4 g (0.016 mol) of γ-methacryloyloxypropyltrimethoxysilane and 0.003 g of acetic acid were added to 80 g of water and stirred for 1 hour and 30 minutes to obtain a uniform solution having a pH of 4. This solution was added to the inorganic particle dispersion and mixed uniformly. Then, it dried by the spray-drying method, mixing a dispersion liquid lightly.

The spray dryer used was a spray dryer (spray dryer “RL-8”, manufactured by Okawara Chemical Co., Ltd.). The spray pressure was 0.1 MPa, and the temperature of the dry atmosphere air was 200 ° C. Thereafter, the spray-dried inorganic powder was vacuum-dried at 60 ° C. for 18 hours to obtain 71 g of inorganic agglomerated particles (F-2). The pore volume of the aggregation gap of the inorganic aggregated particles was 0.28 cm ³ / g, and the average pore diameter was 200 nm. The average particle size of the inorganic aggregated particles was 16.0 μm.

<Method for producing organic-inorganic composite filler>
Next, in <Method for producing organic-inorganic composite filler> in Example 1, 1.78 g of UDMA as a polymerizable monomer, 0.005 g of AIBN as a polymerization initiator, and 5.0 g of ethanol as an organic solvent were mixed. 8. Inorganic agglomerated particles (F-2) prepared in <Preparation of agglomerated particles> in a polymerizable monomer solution (containing 35.6 parts by mass of a polymerizable monomer with respect to 100 parts by mass of an organic solvent) 4 g was immersed. The mixture was sufficiently stirred and allowed to stand for 1 hour after confirming that the mixture became a slurry. The above-mentioned mixture was dried for 1 hour using a vacuum dryer under conditions of a degree of vacuum of 10 hectopascal heating conditions of 40 ° C. to remove the organic solvent. When the organic solvent was removed, a powder having high agglomeration and no fluidity was obtained.

The above powder was heated for 20 minutes under the conditions of a vacuum degree of 10 hectopascals and 140 ° C., and the polymerizable monomer in the powder was polymerized and cured to obtain 9.0 g of an organic-inorganic composite filler. The average particle diameter of the organic-inorganic composite filler was 21.0 μm, the pore volume of the aggregation gap was 0.06 cm ³ / g, and the average pore diameter was 150 nm. Furthermore, when the quantity of the total polymerization hardening material layer in an organic inorganic composite filler was measured, the quantity of the total polymerization hardening material layer was 18.9 mass parts with respect to 100 mass parts of inorganic particle F-2. Moreover, the unpolymerized material contained in the total polymerizable cured product layer in the organic-inorganic composite filler was 0.2% by mass. The production conditions are summarized in Table 1, and the properties of the obtained organic-inorganic composite filler are summarized in Table 2.

Example 6
An organic-inorganic composite filler was obtained in the same manner as in Example 5 except that the temperature at which the polymerizable monomer was polymerized and cured was changed to 130 ° C. in <Method for producing organic-inorganic composite filler> in Example 5. . About this organic inorganic composite filler, it carried out similarly to Example 1, and measured each physical property. The production conditions are summarized in Table 1, and the properties of the obtained organic-inorganic composite filler are summarized in Table 2.

Example 7
An organic-inorganic composite filler was obtained in the same manner as in Example 5 except that the temperature at which the polymerizable monomer was polymerized and cured was changed to 120 ° C. in <Method for producing organic-inorganic composite filler> in Example 5. . About this organic inorganic composite filler, it carried out similarly to Example 1, and measured each physical property. The production conditions are summarized in Table 1, and the properties of the obtained organic-inorganic composite filler are summarized in Table 2.

Example 8
An organic-inorganic composite filler was obtained in the same manner as in Example 5 except that the amount of the polymerizable monomer UDMA used in <Method for producing organic-inorganic composite filler> in Example 5 was changed to 1.50 g. About this organic inorganic composite filler, it carried out similarly to Example 1, and measured each physical property. The production conditions are summarized in Table 1, and the properties of the obtained organic-inorganic composite filler are summarized in Table 2.

Example 9
An organic-inorganic composite filler was obtained in the same manner as in Example 5 except that the amount of the polymerizable monomer UDMA used in <Method for producing organic-inorganic composite filler> in Example 5 was changed to 2.06 g. About this organic inorganic composite filler, it carried out similarly to Example 1, and measured each physical property. The production conditions are summarized in Table 1, and the properties of the obtained organic-inorganic composite filler are summarized in Table 2.

Example 10
An organic-inorganic composite filler was obtained in the same manner as in Example 5 except that the polymerizable monomer used in <Method for producing organic-inorganic composite filler> in Example 5 was changed to NBM80. About this organic inorganic composite filler, it carried out similarly to Example 1, and measured each physical property. The production conditions are summarized in Table 1, and the properties of the obtained organic-inorganic composite filler are summarized in Table 2.

Example 11
An organic-inorganic composite filler was obtained in the same manner as in Example 5 except that the polymerizable monomer used in <Method for producing organic-inorganic composite filler> in Example 5 was changed to BisGMA. About this organic inorganic composite filler, it carried out similarly to Example 1, and measured each physical property. The production conditions are summarized in Table 1, and the properties of the obtained organic-inorganic composite filler are summarized in Table 2.

Example 12
An organic-inorganic composite filler was obtained in the same manner as in Example 5 except that the polymerizable monomer used in <Method for producing organic-inorganic composite filler> in Example 5 was changed to 3G. About this organic inorganic composite filler, it carried out similarly to Example 1, and measured each physical property. The production conditions are summarized in Table 1, and the properties of the obtained organic-inorganic composite filler are summarized in Table 2.

Comparative Example 1
An organic-inorganic composite filler was obtained in the same manner as in Example 1 except that the temperature when polymerizing and curing the polymerizable monomer was changed to 180 ° C. in <Method for producing organic-inorganic composite filler> in Example 1 . About this organic inorganic composite filler, it carried out similarly to Example 1, and measured each physical property. The production conditions are summarized in Table 3, and the properties of the obtained organic-inorganic composite filler are summarized in Table 4.

Comparative Example 2
An organic-inorganic composite filler was obtained in the same manner as in Example 1 except that the temperature at which the polymerizable monomer was polymerized and cured was changed to 90 ° C. in <Method for producing organic-inorganic composite filler> in Example 1. . About this organic inorganic composite filler, it carried out similarly to Example 1, and measured each physical property.
The production conditions are summarized in Table 3, and the properties of the obtained organic-inorganic composite filler are summarized in Table 4.

Comparative Example 3
An organic-inorganic composite filler was obtained in the same manner as in Example 4 except that the paste curing temperature in Example 4 was changed to 170 ° C. or the curing time was changed to 60 minutes. About this organic inorganic composite filler, it carried out similarly to Example 1, and measured each physical property. The production conditions are summarized in Table 3, and the properties of the obtained organic-inorganic composite filler are summarized in Table 4.

Comparative Example 4
An organic-inorganic composite filler was obtained in the same manner as in Example 5 except that the temperature at the time of polymerizing and curing the polymerizable monomer was changed to 180 ° C. in <Method for producing organic-inorganic composite filler> in Example 5. . About this organic inorganic composite filler, it carried out similarly to Example 5, and measured each physical property. The production conditions are summarized in Table 3, and the properties of the obtained organic-inorganic composite filler are summarized in Table 4.

Comparative Example 5
An organic-inorganic composite filler was obtained in the same manner as in Example 4 except that the temperature at the time of polymerizing and curing the polymerizable monomer was changed to 90 ° C. in <Method for producing organic-inorganic composite filler> in Example 5. . About this organic inorganic composite filler, it carried out similarly to Example 4, and measured each physical property. The production conditions are summarized in Table 3, and the properties of the obtained organic-inorganic composite filler are summarized in Table 4.

Comparative Example 6
In Example 5 <Method for producing organic-inorganic composite filler>, the same procedure as in Example 5 was repeated, except that the temperature when polymerizing and curing the polymerizable monotone was changed to 100 ° C. and the polymerization time was changed to 60 minutes. An inorganic composite filler was obtained. About this organic inorganic composite filler, it carried out similarly to Example 5, and measured each physical property. The production conditions are summarized in Table 3, and the properties of the obtained organic-inorganic composite filler are summarized in Table 4.

Comparative Example 7
In Example 5 <Method for producing organic-inorganic composite filler>, the amount of polymerizable monomer UDMA used was changed to 1.50 g, and the temperature at which the polymerizable monomer was polymerized and cured was changed to 180 ° C. In the same manner as in Example 5, an organic-inorganic composite filler was obtained. About this organic inorganic composite filler, it carried out similarly to Example 5, and measured each physical property. The production conditions are summarized in Table 3, and the properties of the obtained organic-inorganic composite filler are summarized in Table 4.

Comparative Example 8
In Example 5 <Method for producing organic-inorganic composite filler>, the amount of polymerizable monomer UDMA used was changed to 2.06 g, and the temperature at which the polymerizable monomer was polymerized and cured was changed to 180 ° C. In the same manner as in Example 5, an organic-inorganic composite filler was obtained. About this organic inorganic composite filler, it carried out similarly to Example 5, and measured each physical property. The production conditions are summarized in Table 3, and the properties of the obtained organic-inorganic composite filler are summarized in Table 4.

Comparative Example 9
In Example 5 <Method for producing organic-inorganic composite filler>, Example 5 and Example 5 were changed except that the polymerizable monomer to be used was changed to NBM80 and the temperature at which the polymerizable monomer was polymerized and cured was changed to 180 ° C. Similarly, an organic-inorganic composite filler was obtained. About this organic inorganic composite filler, it carried out similarly to Example 1, and measured each physical property. The production conditions are summarized in Table 3, and the properties of the obtained organic-inorganic composite filler are summarized in Table 4.

Comparative Example 10
In Example 5 <Method for producing organic-inorganic composite filler>, Example 5 is the same as Example 5 except that the polymerizable monomer used is BisGMA and the temperature at which the polymerizable monomer is polymerized and cured is 180 ° C. Similarly, an organic-inorganic composite filler was obtained. About this organic inorganic composite filler, it carried out similarly to Example 1, and measured each physical property. The production conditions are summarized in Table 3, and the properties of the obtained organic-inorganic composite filler are summarized in Table 4.

Comparative Example 11
In Example 5 <Method for producing organic-inorganic composite filler>, Example 3 is the same as Example 5 except that the polymerizable monomer used is changed to 3G and the temperature at which the polymerizable monomer is polymerized and cured is changed to 180 ° C. Similarly, an organic-inorganic composite filler was obtained. About this organic inorganic composite filler, it carried out similarly to Example 1, and measured each physical property. The production conditions are summarized in Table 3, and the properties of the obtained organic-inorganic composite filler are summarized in Table 4.

Examples 13-24, Comparative Examples 12-22
Using each organic-inorganic composite filler shown in Tables 5 and 6, the bending strength of (7) and the transparency of (8) were measured. The results are also shown in Tables 5 and 6.

Claims (7)

An organic-inorganic composite filler in which the surface of inorganic particles is covered with a polymerized cured product layer formed by polymerizing a polymerizable monomer,
The organic-inorganic composite filler, wherein the polymerized cured product layer contains 0.1% by mass or more and 5.0% by mass or less of an unpolymerized product of the polymerizable monomer. The inorganic particles are aggregated particles obtained by agglomerating inorganic primary particles having an average particle diameter of 10 to 1000 nm,
The polymerized cured product layer is a layer that covers at least a part of the surface of each inorganic primary particle and is a layer that binds each inorganic primary particle to each other;
A pore volume formed by the mercury intrusion method formed between the polymerized cured product layers covering at least a part of the surface of each inorganic primary particle (wherein the pore is a pore diameter in the range of 1 to 500 nm) 2. The organic-inorganic composite filler according to claim 1, wherein the organic-inorganic composite filler has a coagulation gap of 0.01 to ³⁰ cm ³ / g.   The organic-inorganic composite filler according to claim 1 or 2, wherein the content of the polymerized cured product layer is 1 to 40 parts by mass with respect to 100 parts by mass of the inorganic particles. The inorganic particles are agglomerated particles having a pore volume measured by a mercury intrusion method (where the pores are pores having a pore diameter in the range of 1 to 500 nm) of 0.015 to 0.35 cm ³ / g. The organic-inorganic composite filler according to any one of claims 1 to 3. A method for producing the organic-inorganic composite filler according to any one of claims 1 to 4,
The organic solvent is removed while contacting the polymerizable monomer solution obtained by diluting the polymerizable monomer with the organic solvent and the inorganic particles, and a predetermined amount of the polymerizable monomer is attached to the surface of the inorganic particles. A polymerizable monomer adhering step; and the polymerizable monomer adhering to the surface of the inorganic particles in the polymerizable monomer adhering step is polymerized to polymerize the surface of the inorganic particles. Including a polymerization step of coating with a polymerized cured product layer,
Based on at least one relationship shown in the following (1), (2), (3) and (4) separately confirmed in advance, the unpolymerized polymerization contained in the polymerization cured product layer obtained in the polymerization step The amount of the polymerizable monomer is represented by the unpolymerized monomer combined content defined by the concentration (% by mass) of the unpolymerized polymerizable monomer based on the mass of the entire polymerization cured product layer, The method according to claim 1, wherein a condition that is in a range of 0.1% by mass or more and 5.0% by mass or less is determined, and the polymerizable monomer attaching step and / or the polymerization step is performed under the determined condition.
(1) When the polymerization inhibitor is blended in the polymerizable monomer solution, the polymerization inhibitor is contained in the polymer to be adhered to the surface of the inorganic particles, and polymerization is performed under predetermined conditions, Relationship between polymerization inhibitor concentration in polymerizable monomer preparation and unpolymerized monomer total content (2) In the polymerization step, only the polymerization time is set as a predetermined condition other than the polymerization time. (3) In the polymerization step, only the polymerization temperature is changed as a predetermined condition other than the polymerization temperature in the polymerization step. Relationship between polymerization temperature and unpolymerized monomer content when polymerization is performed (4) In the polymerization step, the oxygen concentration is set as a predetermined condition other than the oxygen concentration in the atmosphere in which the polymerization is performed. Only change the polymerization Wherein said oxygen concentration in the case of Tsu relationship between unpolymerized monomer if content   A curable composition further comprising the organic-inorganic composite filler according to claim 1 and a polymerizable monomer.   A dental curable composition comprising the curable composition according to claim 6.

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