JPH0651735B2 - Curable composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a novel curable composition containing an inorganic filler and a polymerizable monomer as main components. Specifically, a resin cured product obtained by polymerizing and curing this (also simply referred to as a cured product)
The present invention provides a curable composition having extremely high mechanical strength, especially flexural strength.

[Conventional technology and problems]

A curable composition containing an inorganic filler and a polymerizable monomer as main components is being used as a dental restorative material. That is, the curable composition is generally used by directly filling the cavity of a tooth and polymerizing and curing by a polymerization means such as light irradiation to restore the tooth. The repaired part obtained by the above method has relatively low mechanical strength, and such repair has been generally performed on a part where mechanical strength is not so required.

However, in recent years, in order to solve the problem of the color difference between the metal and the tooth in the metal restorative material that has been conventionally used for the restoration of molars or the like to which occlusal pressure is applied, in order to solve the above-mentioned curable composition instead of the metal restorative material. Attempts have been made to use. For example, a method has been used in which a curable composition is polymerized in a mold in which a cavity portion of a tooth is preliminarily taken for a sufficient polymerization time and then adhered to the cavity portion.

However, although the repaired part made of the cured resin obtained by the above method is satisfactory in compressive strength and tensile strength to some extent, the bending strength is remarkably low with respect to the metal, so that fracture occurs at the edge of the repaired part. Had a problem.

Against this problem, by using an inorganic powder having a different particle size as the inorganic filler constituting the curable composition at a specific ratio, a curable composition in which the packing density of the inorganic filler is simply increased Although it has been studied, the bending strength of the cured product obtained from this is at most 1800 kg / cm ² , and a curable composition capable of obtaining a cured product having a bending strength of 2000 kg / cm ² or more, which is comparable to a metal restoration material. There was nothing.

[Means for solving problems]

The present inventors have conducted extensive studies to develop a curable composition that gives a resin cured product having high mechanical strength, particularly bending strength. As a result, with respect to the polymerizable monomer, by blending the amorphous inorganic particles having a specific particle diameter and properties and the spherical inorganic particles having the specific particles at a specific ratio, respectively, to achieve such an object. The inventors have found that they can obtain it and completed the present invention.

The present invention relates to A. Polymerizable monomer B. At least a portion is amorphous and has an average particle size of 1 to
Irregular inorganic particles having a particle size of 9 μm and a particle size of 1 to 10 μm accounting for 95% by weight or more. Spherical inorganic particles having an average particle diameter of 0.08 to 1 μm, and D. A polymerization initiator, and B is added to 100 parts by weight of the polymerizable monomer A.
Amorphous inorganic particles (hereinafter, simply referred to as “inorganic inorganic particles”) and spherical inorganic particles of C (hereinafter simply referred to as “spherical inorganic particles”)
And) in a total amount of 300 to 900 parts by weight and a weight ratio (B / C) of the amorphous inorganic particles to the spherical inorganic particles of 1 to 4 is added. is there.

In the present invention, the polymerizable monomer is not particularly limited, and those polymerizable by heat, light, etc. are used without limitation. The specific examples of the polymerizable monomer are as follows. B) Monofunctional monomers Methyl methacrylate; Ethyl methacrylate; Isopropyl methacrylate; Hydroxyethyl methacrylate; Tetrahydrofurfuryl methacrylate; Glycidyl methacrylate; and their acrylates or acrylic acid, methacrylic acid, p-methacryloxybenzoic acid, N-2- Hydroxy-3-methacryloxypropyl-N-phenylglycine, 4-methacryloxyethyl trimellitic acid and its anhydride, 6-methacryloxyhexamethylenemalonic acid, 10-methacryloxydecamethylenemalonic acid, 2-methacryloxyethyldi Hydrogen phosphate, 10-methacryloxydecamethylene dihydrogen phosphate, 2-hydroxyethyl hydrogen phenyl phosphate. B) Bifunctional monomer (i) Aromatic compound type 2,2-bis (methacryloxyphenyl) propane; 2,2
-Bis [4- (3-methacryloxy) -2-hydroxypropoxyphenyl] propane (hereinafter abbreviated as Bis-GMA); 2,2-bis (4-methacryloxyethoxyphenyl) propane; 2,2-bis ( 4-methacryloxydiethoxyphenyl) propane; 2,2-bis (4-methacryloxytetraethoxyphenyl) propane; 2,2-bis (4-methacryloxypentaethoxyphenyl) propane; 2,2-bis (4- Methacryloxydipropoxyphenyl) propane; 2 (4-methacryloxyethoxyphenyl) -2 (4-methacryloxydiethoxyphenyl)
Propane; 2 (4-methacryloxydiethoxyphenyl) 2 (4-methacryloxytriethoxyphenyl) propane; 2 (4-methacryloxypropoxyphenyl)
2- (4-methacryloxytriethoxyphenyl) propane; 2,2-bis (4-methacryloxypropoxyphenyl) propane; 2,2-bis (4-methacryloxyisopropoxyphenyl) propane and their acrylates: 2 -Hydroxyethyl methacrylate, 2-
Hydroxypropyl methacrylate, 3-chloro-2
A diadduct obtained from the addition of a vinyl monomer having an -OH group such as hydroxypropylmethacrylate or these acrylates and a diisocyanate compound having an aromatic group such as diisocyanate methylbenzene, 4,4'-diphenylmethane diisocyanate (ii) ) Aliphatic compound type ethylene glycol dimethacrylate; diethylene glycol dimethacrylate; triethylene glycol dimethacrylate (hereinafter abbreviated as TEGDMA); butylene glycol dimethacrylate; neopentyl glycol dimethacrylate; propylene glycol dimethacrylate; 1,3- Butanediol dimethacrylate; 1,4-butanediol dimethacrylate; 1,6-hexanediol dimethacrylate and their acrylates; -
Hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 3-chloro-2-hydroxypropyl methacrylate or vinyl monomers having an -OH group such as acrylates and hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, diisocyanate methylcyclohexane, isophorone diisocyanate , Methylenebis (4
-Cyclohexyl isocyanate) and diadducts obtained by addition with a diisocyanate compound; acrylic anhydride, methacrylic anhydride, 1,2-bis (3-methacryloxy-2-hydroxypropoxy) ethyl, di (2
-Methacryloxyethyl) phosphate, di (3-methacryloxypropyl) phosphate c) trifunctional monomer trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, pentaerythritol trimethacrylate, trimethylolmethane trimethacrylate and these Acrylic di) tetrafunctional monomers pentaerythritol tetramethacrylate, pentaerythritol tetraacrylate and diisocyanate methylbenzene, diisocyanate methylcyclohexane, isophorone diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, methylenebis (4-cyclohexyl isocyanate), 4 , 4-diphenylmethane diisocyanate, tolylene-2, Diadduct obtained by addition of diisocyanate compound such as 4-diisocyanate and glycidol dimethacrylate In addition to the above vinyl monomers, those generally known for industrial use can be used. Typical examples of typical ones that are generally suitably used include vinyl acetates such as vinyl acetate and vinyl propionate; vinyl ethers such as methyl vinyl ether, ethyl vinyl ether and isobutyl vinyl ether; styrene, vinyltoluene, α-methylstyrene, Alkenylbenzenes such as chloromethylstyrene and stilbenzene are preferably used.

When using multiple kinds of polymerizable monomers, it is preferable to use in combination with a low-viscosity polymerizable monomer when the polymerizable monomer has a very high viscosity at room temperature or is a solid. preferable. This combination is not limited to two types and may be three types or more.

When a monofunctional monomer is used among the above polymerizable monomers, it is preferable to use it together with a polyfunctional monomer in order to obtain a cured product having high bending strength. The preferred combination of the polymerizable monomer is a mode in which the aromatic compound of the bifunctional polymerizable monomer is the main component, and the aliphatic compound of the bifunctional polymerizable monomer is combined with the aromatic compound, the trifunctional polymerization. Of combining a polymerizable monomer and a tetrafunctional polymerizable monomer, a trifunctional polymerizable monomer and / or a tetrafunctional compound in the aromatic compound and the same aliphatic compound of the bifunctional polymerizable monomer And a combination of monofunctional polymerizable monomers, and the like.

Next, the composition ratio in the combination of the above-mentioned polymerizable monomers may be determined as necessary, but the composition ratio generally adopted is shown below.

(1) The aromatic compound of the bifunctional polymerizable monomer is 30 to 8
70% to 20% by weight of the same aliphatic compound at 0% by weight (2) 30 to 100% by weight of trifunctional polymerizable monomer and 0 to 70% by weight of tetrafunctional polymerizable monomer (3) difunctional The aromatic compound of the polymerizable monomer is 30 to 6
The composition ratio is preferably 0% by weight, the aliphatic compound is 5 to 30% by weight, the trifunctional polymerizable monomer is 10 to 80% by weight, and the tetrafunctional polymerizable monomer is 0 to 50% by weight. .

The polymerizable monomer may be used alone or in combination of two or more, in particular, a resin cured product having a bending strength of 1000 kg / cm ² or more when a reinforcing material such as a filler is not added can be obtained. It is preferable since the bending strength of the cured product of the curable composition can be sufficiently improved. Specific examples of suitable combinations of such polymerizable monomers include Bis-GM
Examples include a combination of A and TEGDMA, a combination of Bis-GMA, TEGDMA and pentaerythritol trimethacrylate, and a combination of pentaerythritol trimethacrylate and pentaerythritol tetramethacrylate.

The polymerization initiator used in the present invention is not particularly limited, and known ones can be used without particular limitation. Further, the addition amount may be a known addition range without particular limitation.

Generally, the polymerization initiator varies depending on the means of polymerizing the polymerizable monomer. This polymerization means includes one by light energy such as ultraviolet rays and visible light, one by reaction between a peroxide and an accelerator, one by heating and the like, and the polymerization means can be selected as necessary. For example, in the case of a reaction by light energy (hereinafter referred to as photopolymerization), as a polymerization initiator, camphorquinone, benzyl, α-naphthyl, acetobutenequinone, P, P′-dimethoxybenzyl, 4-
Nitrobenzyl, hexadione, cyclohexadione,
Α-diketone compounds such as P, P′-dichlorobenzyl, biacetyl, pentanedione, 1,2-phenanthrenequinone, 3,4-phenanthrenequinone, 9,8-phenanthrenequinone β-naphthoquinone, the α-diketone compound and the A combination of a tertiary amine, the α-diketone compound and a tertiary amine, a carboxylic acid having an oxy group at the α-position, the α-diketone compound and an α-diketone such as a phophyte compound, and a known reducing agent is preferable. is there. In this case, the weight ratio of α-diketone / reducing agent is preferably 10-60 / 90-40. The blending amount of the above-mentioned polymerization initiator is selected without any particular limitation. Generally, 0.
It is used in a proportion of 01 to 5% by weight.

In the case of thermal polymerization, as a polymerization initiator, for example,
Organic peroxides such as benzoyl peroxide, di-P-chlorobenzoyl peroxide, and dilauroyl peroxide, 2,2'-azobisisobutyronitrile, 4,
Known polymerization initiators such as azo compounds such as 4'-azobis (4-cyanovaleric acid) and 2,2'-azobis (2,4-dimethylvaleronitrile) can be used. The compounding amount of the above-mentioned polymerization initiator is selected without any particular limitation, which is usually adopted. Generally 0.01 to the polymerizable monomer
Used in a proportion of 5% by weight.

In the present invention, an important requirement is to use the amorphous inorganic particles and the spherical inorganic particles as the inorganic filler in the above-mentioned specific ratios. In the curable composition, it is known that the mechanical strength of the obtained cured product is improved by combining the metal oxides having different particle diameters and increasing the packing density thereof. It was discovered for the first time by the present invention that the bending strength of a cured product can be dramatically improved as compared with a conventional curable composition by specifying its shape and properties together with the conventional curable composition.

In the present invention, the irregular-shaped inorganic particles are at least partially amorphous and have 95 particles having an average particle diameter of 1 to 9 μm, preferably 1.5 to 5 μm and a particle diameter of 1 to 10 μm.
Amorphous inorganic particles that make up more than weight% are used. That is, in the case of the amorphous inorganic particle of the present invention, even if any one of the above requirements is lacking, it becomes difficult to obtain a cured product having high bending strength. The amorphous inorganic particles can be used without particular limitation as long as they satisfy the above requirements, but amorphous particles having a proportion of 50% by weight or more are particularly preferably used.

As a material for the amorphous inorganic particles, an inorganic material that is insoluble in water and at least a part of which is amorphous is used without particular limitation. For example, inorganic oxides such as silica, zirconia, titania and alumina, and composite inorganic oxides are suitable.

As the above-mentioned complex inorganic oxide, 0.01 to 5 mol% of Group I metal oxide of the periodic table and IV of the periodic table are used with respect to SiO ₂ .
A composite inorganic oxide composed of 1 to 25 mol% of a group metal oxide (excluding SiO ₂ ) is suitable particularly when the curable composition of the present invention is used as a dental restorative material. That is, the Group IV metal oxide of the periodic table is effective in improving the transparency of the obtained cured product and matching the color tone with the tooth substance. Further, the Group I metal oxide of the periodic table is necessary to prevent discoloration / coloring of the obtained cured product by adjusting the acidity of the composite oxide. Na ₂ O, K ₂ O and the like are preferably used as the group I metal oxide of the periodic table, and ZrO ₂ , TiO _{2 and the} like are preferably used as the group IV metal oxide of the periodic table.

The method for producing the composite inorganic oxide is not particularly limited, and a known method is adopted. To illustrate a typical method, an alkoxysilane compound is dissolved in an organic solvent,
After partial hydrolysis by adding water to this, alkoxide of another metal and an alkali metal compound to be further complexed are added and hydrolyzed to form a gel, and then the gel is dried, A method of pulverizing and firing as needed may be mentioned. Examples of the alkoxysilane compound include ethyl silicate, methyl silicate, and butyl silicate, and examples of organic solvents include alcohols such as methanol, ethanol, butanol, and isopropanol, benzene,
Hydrocarbon compounds such as toluene and chlorinated hydrocarbon compounds such as methylene chloride and carbon tetrachloride are preferably used.
Further, as the alkoxide of the other metal, an alkoxide of Group IV metal of the periodic table such as tetrabutyl titanate and tetrabutyl zirconate, and as the alkali metal compound, sodium methyl oxide, potassium methyl oxide, sodium salt, Examples thereof include potassium salt. Further, the gel-like material is dried at 60 to 200 ° C.
Then, the firing is preferably performed at 700 to 1500 ° C. for 1 to 20 hours.

The amorphous inorganic particles used in the present invention can be generally obtained in the form of a pulverized product obtained by pulverizing the above-mentioned metal oxide. The pulverization is not particularly limited, and known pulverizing means can be adopted without particular limitation. For example, ball mill, vibrating ball mill,
Crushing using a crusher such as a crusher or a jet mill is generally used, and the amorphous inorganic particles obtained by the crushing are used after being dispensed if necessary.

In the present invention, the spherical inorganic particles have an average particle diameter of 0.08.
Spherical inorganic particles of ˜1 μm are used. That is, when the average particle size of the spherical inorganic particles is smaller than the above range, it becomes difficult to increase the filling amount to the target range, and when the particle size is larger than the above range, the obtained cured product is obtained. There is little improvement effect on the bending strength of the above, and in any case, a cured product having a high bending strength cannot be obtained. It is sufficient for the spherical inorganic particles to satisfy the above-mentioned conditions regarding the particle diameter, but in particular, the particle diameter is 0.06 μm.
It is preferable to adjust the particle size distribution so that the following particles are 5% by weight or less. Further, when the shape of the above-mentioned inorganic particles is not spherical, it becomes difficult to increase the filling amount to a target range, and a cured product having high bending strength cannot be obtained. The spherical inorganic particles do not have to be perfectly spherical. Generally, if the average degree of uniformity is 0.6 or more, it can be sufficiently used.

As the material of the spherical inorganic particles, an inorganic substance insoluble in water is used without particular limitation. For example, inorganic oxides, composite non-oxides, quartz, aluminum nitride, silicon nitride and the like shown as the material of the amorphous inorganic particles are preferably used.

The method for producing the spherical inorganic particles used in the present invention is not particularly limited. As a typical production method, there is a method in which the particles of the inorganic material are melted in a dispersed state, spheroidized by the surface tension thereof, and cooled to be solidified. More specifically, such a method is preferable, for example, a method in which inorganic particles are brought into contact with a flame having a temperature higher than the melting point of the particles and then cooled. Further, as disclosed in Japanese Patent Application No. 56-206862 (Japanese Patent Laid-Open No. 58-110414), a reaction product which is precipitated by carrying out hydrolysis in the production of the composite inorganic oxide in an alkaline solvent. A method of drying and firing the particles of can also be used.

In the curable composition of the present invention, it is preferable that the amorphous inorganic particles and the spherical inorganic particles have their surfaces made hydrophobic for the purpose of improving dispersibility in the polymerizable monomer. The hydrophobizing treatment is not particularly limited, and known methods can be adopted without any limitation. Typical hydrophobizing methods are, for example, a method using a silane coupling agent and a titanate coupling agent as a hydrophobizing agent, and a method of graft-polymerizing the polymerizable monomer on the particle surface.

Among them, the method using a silane coupling agent is general. Specifically, inorganic particles are dispersed in an organic solvent, added to an alkoxysilane compound having a hydrophobic group, the solvent is removed, and heating and vacuum drying are performed to obtain a hydrophobized product. As the organic solvent, a hydrophobic solvent such as a hydrocarbon compound such as hexane, toluene and benzene, and a chlorine-based hydrocarbon compound such as carbon tetrachloride, chloroform and methylene chloride is preferably used. As the alkoxy compound having a hydrophobic group, for example, in addition to methyltrimethoxysilane, vinyltrimethoxysilane, preferably alkoxysilane having a polymerizing group such as γ-methacryloxypropyltrimethoxysilane, vinyltrimethoxysilane, etc. are used. It Removal of the solvent is generally carried out by an evaporator, and heating and drying under reduced pressure may be carried out at 80 to 200 ° C. for 1 to 20 hours.

In the curable composition of the present invention, the amorphous inorganic particles and the spherical inorganic particles are 300 parts by weight based on 100 parts by weight of the polymerizable monomer.
To 900 parts by weight, preferably 400 to 700 parts by weight, and the ratio (B / C) of the amorphous inorganic particles (B) to the spherical inorganic particles (C) is 1 to 4, preferably 1.2 to 2 It is important to use it at a ratio of 0.5. That is, when the total amount of the amorphous inorganic particles and the spherical inorganic particles is less than the above range, it is difficult to obtain a cured product having high bending strength because the filling rate is insufficient. When the total amount is more than the above range, the inorganic particles cannot be uniformly dispersed in the polymerizable monomer, and not only the bending strength of the obtained cured product but also other mechanical strength is low. Become. Further, when the above ratio (B / C) is less than 1 or more than 4, the dispersibility of each inorganic particle in the polymerizable monomer is deteriorated even if the total amount satisfies the above range. However, it becomes difficult to obtain a cured product having high bending strength.

The curable composition of the present invention can contain known additives within a range that does not significantly impair the effect. Examples of such additives include polymerization inhibitors, pigments, ultraviolet absorbers and the like.

As the method for curing the curable composition of the present invention, an optimal method may be selected according to the type of the polymerization initiator. For example, when a polymerization initiator for photopolymerization is used, it is generally preferable to irradiate light for 10 seconds or longer, preferably 30 seconds to 1 hour,
Furthermore, heating at a temperature of 80 to 120 ° C. for 10 minutes to 20 hours is more preferable in order to obtain a cured product having high bending strength.

When it is used as a polymerization initiator for thermal polymerization,
~ 200 ° C, especially 80 ~ 120 ° C, 10 min ~ 2
A method of heating for 0 hour, particularly 20 minutes to 1 hour is preferable.
In this case, the polymerization is preferably carried out in an atmosphere of an inert gas such as nitrogen or helium, or steam.

〔effect〕

As can be understood from the above description, the curable composition of the present invention can obtain a resin cured product having extremely high bending strength. Further, such a curable composition can effectively improve not only the bending strength of the obtained cured product but also the compression strength.

Therefore, in the use of a dental restorative material such as an inlay which requires high bending strength, it is possible to form a restorative portion having no color difference with the tooth by using the metallic restorative material which has been conventionally used in place of the restorative material. it can.

Further, the curable composition of the present invention can be used without particular limitation in applications other than the above dental restorative material.

〔Example〕

Hereinafter, the contents of the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples. Incidentally, various physical properties of the inorganic particles shown in the following Production Examples, Examples and Comparative Examples (average particle diameter, variation coefficient of particle size distribution), production of a curable composition, polymerization and curing method and compression,
The tensile and bending strengths were measured by the methods described below.

(1) Average particle size and particle size distribution The number of particles (n) and particle size (diameter X _i ) observed per unit field of view of a scanning or transmission electron micrograph of the powder is taken. Was calculated and calculated by the following formula.

(2) Average uniformity of particles A scanning or transmission electron microscope photograph of the powder is taken, and the maximum width of the particles observed in the unit field of view of the photograph is defined by the major axis (L
_i ), the maximum width in the direction orthogonal to this major axis is the minor axis (B _i ).
And n, L _i , and B _i were calculated as follows.

(3) Compressive strength A paste-like cured composition is filled in a split mold having holes with a diameter of 4 mm and a depth of 10 mm, and each is irradiated with a visible light irradiator White Light (trade name, manufactured by Takara Belmont Co., Ltd.) from the top to the bottom. It was irradiated for 2 seconds and the cured product was taken out from the split mold. next,
The cured product was further polymerized at 95 ° C. under a pressure of 5 kg / cm ^{2 of} nitrogen for 1 hour.

Then, the cured product was immersed in water at 37 ° C. for 24 hours to obtain a test piece. This test piece was mounted on a testing machine (Toyo Boardwin, UTM-5T) and crosshead speed 1
The compressive strength was measured at 0 mm / min. Compressive strength is test piece 5
The average value of the books is shown.

(4) Tensile strength A paste-like cured composition was filled in a split mold having a hole having a diameter of 6 mm and a depth of 3 mm, and a visible light irradiator White Light (trade name, manufactured by Takara Belmont Co., Ltd.) was used for each 30 from the top and bottom.
It was irradiated for 2 seconds and the cured product was taken out from the split mold. Next, the cured product was further polymerized at 95 ° C. under a pressure of 5 kg / cm ^{2 of} nitrogen for 1 hour.

Then, the cured product was immersed in water at 37 ° C. for 24 hours to obtain a test piece. This test piece was mounted on a testing machine (Toyo Boardwin, UTM-5T) and crosshead speed 1
The tensile strength was measured at 0 mm / min. Test piece 5 for tensile strength
The average value of the books is shown.

(5) Bending strength A paste type curable composition was filled in a split mold having holes of 2 × 2 × 25 mm, and the visible light irradiator White Light (trade name, manufactured by Takara Belmont Co., Ltd.) was used to make three places on the upper surface. Each 30 seconds, and the cured product was taken out from the split mold. next,
The cured product was further polymerized at 95 ° C. under a pressure of 5 kg / cm ^{2 of} nitrogen for 1 hour.

Then, the cured product was immersed in water at 37 ° C. for 24 hours to obtain a test piece. This test piece was mounted on a tester (UTM-5T, manufactured by Toyo Boardwin), and the tensile strength was measured at a crosshead speed of 0.5 mm / min. The tensile strength was shown as the average value of 5 test pieces.

The abbreviations of the compounds are shown below.

Example 1 Method for producing irregular-shaped inorganic particles At room temperature, 1600 g of tetraethyl silicate (manufactured by Nippon Corcoat) was dissolved in 2.01 of isobutanol, 54 g of 0.05% hydrochloric acid was added, and the mixture was stirred for 5 hours. Tetrabutyl zirconate 67 after partial hydrolysis
0 g, 77 g of sodium methylate were added. After continuing stirring for 1 hour, 0.31 of water was added with stirring and further hydrolyzed to obtain a gel. Then remove the gel, 10
The solvent was removed by heating and drying at 0 ° C to obtain a dry gel.
The dried gel was ground with a ball mill. 900 this crushed product
Baking was performed at 0 ° C. for 2 hours to obtain a white powder.

The white powder is zirconium or silicon containing a part of tetragonal zirconia crystals from X-ray diffraction and fluorescent X-ray analysis.
The particles were amorphous inorganic particles composed of a sodium complex oxide.

Use 4 types of this white powder with elutriation (B-1, B-2, B-
3, B-4) an amorphous filler was produced. The average particle size and particle size range of each filler are summarized in Table 1.

Method for producing spherical inorganic particles 40 g of 0.05% sulfuric acid aqueous solution and 150 g of tetraethyl silicate were dissolved in 600 ml of isobutanol, and this solution was hydrolyzed while stirring at 35 ° C. for about 5 hours. Thereafter, 65 g of tetrabutyl zirconate and 1.5 g of sodium methylate were added to this solution to prepare a solution (A) containing a hydrolyzate of tetraethyl silicate, tetrabutyl zirconate and sodium methylate.

Next, in a glass reactor with an internal volume of 31 equipped with a stirrer, 600 ml of methanol, 900 ml of isobutanol and 25%
375 ml of ammonia water was added. While maintaining this solution at 35 ° C., 3 g of tetraethyl silicate was added to 2 parts of methanol.
A solution dissolved in 2 ml was added, and 10 minutes after the completion of the addition, the reaction solution became slightly milky white, and then the above solution (A) was further added over about 5 hours. After the completion, 38 g of tetraethyl silicate was added to methanol 450 The solution dissolved in ml was added over about 2 hours to precipitate a white reaction product.

After completion of the reaction, stirring was continued for another 30 minutes, then the solvent was removed from the reaction solution by an evaporator, and further dried under reduced pressure to obtain a milky white powder.

Next, this milky white powder was fired at 900 ° C. for 2 hours to obtain a white powder. This white powder is titanium containing a part of the titania anatase crystal from X-ray diffraction and fluorescent X-ray analysis,
Table 1 shows the average particle size and the particle size range of the spherical inorganic particles (C-1) which were spherical inorganic particles (C-1) composed of a composite oxide of silicon and sodium.

Hydrophobically processable amorphous inorganic particles (B-1) 100 g was added to methylene chloride 1
The mixture was placed in a flask and dispersed with a stirrer to prepare a suspension. To this suspension, 1.8 g of n-propylamine was added, and after 20 minutes, 2.0 g of γ-methacryloxypropyltrimethoxysilane was added, followed by addition of 0.2 g of methyltrimethoxysilane, Stirring was continued for 30 minutes.

Then, the solvent was removed from the suspension using an evaporator to obtain a powder. This powder was dried under reduced pressure at 90 ° C. for 12 hours to obtain a hydrophobized product.

The amorphous inorganic particles (B-2), (B-3) and (B-4) were also hydrophobized in the same manner as above.

The spherical inorganic particles (C-1) were also hydrophobized in the same manner as above.

In the case of producing a curable composition, a hydrophobized product was used for both the amorphous inorganic particles and the spherical inorganic particles.

Manufacturing method of curable composition The curable composition shown below was prepared.

Curable composition Irregular inorganic particles (B-1) 50.4 g Spherical inorganic particles (C-1) 33.6 g Bis-GMA 9.6 g TEGDMA 6.4 g Camphorquinone 0.08 g DMPT 0.08 g Malic acid 0.08 g BHT 0.001 g The above curable composition The total amount of each inorganic particle was 525 parts by weight with respect to 100 parts by weight of the polymerizable monomer, and the product (B-1) and (C
It is a paste having a ratio of -1) of 1.5.

Using the above curable composition, test pieces for compression, tensile and bending strength tests were prepared and each test was conducted. As a result, compressive strength 4800 kg / cm ² , tensile strength 740 kg / cm ² , bending strength 23
A high mechanical strength of 00 kg / cm ² was obtained.

Example 2-9 Method for producing spherical inorganic particles (1) 3.2 g of a 0.1% hydrochloric acid aqueous solution and 113 g of tetraethyl silicate were dissolved in 280 ml of methanol, and this solution was hydrolyzed while stirring at 30 ° C. for about 1 hour. did. Thereafter, 41 g of tetrabutyl titanate and 2.6 g of sodium methylate were added to this solution to prepare a solution (B) containing a hydrolyzate of tetraethyl silicate, tetrabutyl titanate and sodium methylate.

Then add 1050 ml of methanol, 120 ml of isopropanol and 28% to a glass reactor with a stirrer and an internal volume of 31.
270 ml of ammonia water was added. While maintaining this solution at 30 ° C., the above solution (A) was added over about 5 hours,
After the completion, 130 g of tetraethyl silicate was added to methanol 4
The solution dissolved in 50 ml was added over about 2 hours to precipitate a white reaction product.

After completion of the reaction, stirring was continued for another 30 minutes, then the solvent was removed from the reaction solution by an evaporator, and further dried under reduced pressure to obtain a milky white powder.

Next, this milky white powder was baked at 900 ° C. for 2 hours to obtain spherical inorganic particles (C-2). This spherical inorganic particle (C-
The average particle size of 2) and the particle size range are shown in Table 1.

(2) 600 g of tetraethyl silicate was added to methanol 6
The solution dissolved in 00 ml is designated as solution C. Next, add 1400 m of methanol to a glass reactor with an internal volume of 31 equipped with a stirrer.
1 and 600 ml of 28% ammonia water were added, and this solution was designated as D. The above solution C was added to this solution D over about 5 hours to precipitate a white reaction product.

After completion of the reaction, stirring was continued for another 30 minutes, then the solvent was removed from the reaction solution by an evaporator, and further dried under reduced pressure to obtain a milky white powder.

Next, this milky white powder was baked at 900 ° C. for 5 hours to obtain spherical inorganic particles (C-3) made of silica. The average particle size and particle size range of the spherical inorganic particles (C-3) are shown in Table 1. The spherical inorganic particles (C-4) were ultrafine particulate anhydrous silica 0X50 (trade name, manufactured by Nippon Aerosil Co., Ltd.), and the average particle diameter, particle size range, average uniformity and coefficient of variation are shown in Table 1.

The amorphous inorganic particles, spherical particles, and inorganic particles were all subjected to a hydrophobizing treatment in the same manner as in Example 1 and used for producing a curable composition.

Method for producing curable composition By the same method as in Example I, the type and the blending ratio of inorganic particles were changed as shown in Table 2 to prepare a curable composition, and each strength test was performed.

As a result, all of the examples showed high bending strength of 2000 kg / cm ² or more.

Comparative Examples 1 to 9 A curable composition was produced in the same manner as in Example 1 except that the amorphous inorganic particles and the spherical inorganic particles shown in Table 3 were used.

In Table 3, the amorphous inorganic particles (B-5) are crystallite VXS (trade name, crushed quartz powder manufactured by Tatsumori Co., Ltd. average particle size 3.4 μm, particle size range 1 μm to 24 μm) divided by elutriation. , Surface-treated, average particle size 2.4μ
m, a particle diameter range of 1 to 8 μm, an average degree of uniformity of 0.60, and a coefficient of variation of 1.40.

Further, in Comparative Example 9, the amorphous inorganic particles (B-1) were used by spraying in a flame to melt and spheroidizing the inorganic particles (average particle size 1.8 μm, particle size range 1 μm to 10 μm, average uniformity ratio). 0.90, coefficient of variation 1.40).

Example 10 Method for producing amorphous inorganic particles In the method for producing amorphous inorganic particles of Example 1, tetrabutyl titanate 4 was used instead of tetrabutyl zirconate.
Amorphous inorganic particles made of a composite oxide of titanium, silicon and sodium were produced in the same manner as in Example 1 except that 15 g was used, and classified by elutriation. The classified inorganic particles (B-6) had an average particle size of 3.2 μm and a particle size range of 2 to
It was 10 μm, the average degree of uniformity was 0.50, the coefficient of variation was 1.32, and it was an amorphous silica-titania containing a slight amount of anatase crystals by X-ray diffraction and fluorescent X-ray analysis.

Next, the inorganic particles (B-6) were subjected to a hydrophobizing treatment in the same manner as in Example 1.

Manufacturing method of curable composition In Example 1, amorphous inorganic particles (B-6) 50.4
g, PE-TRA 8.0 g as a polymerizable monomer, PE-TEA 8.
A curable composition was prepared in the same manner except that 0 g and CQ 0.04 g and ALBN 0.04 g were used as polymerization initiators.

Next, test pieces for compression, tensile and bending strength tests were prepared using the curable composition, and each test was conducted. As a result, compressive strength 4,600 kg / cm ² , tensile strength 670 kg / c
High mechanical strength of m ² and bending strength of 2,270 kg / cm ² was obtained.

Example 11 Method for Producing Amorphous Inorganic Particles Tetraethyl silicate (1600 g) was added to isobutanol 2.0.
A gel was prepared by dissolving it in water, adding 300 ml of 0.05% hydrochloric acid, and hydrolyzing it. Next, the gel was taken out and dried by heating at 100 ° C. to remove the solvent to obtain a dried gel. Dried gel is crushed with a ball mill and 2 at 1000 ℃
It was fired for a time to obtain a white powder.

This white powder was amorphous silica as determined by X-ray diffraction and fluorescent X-ray analysis.

This white powder classified elutriation. The classified white powder is
Amorphous inorganic particles (B-
It was 7). Hydrophobization treatment was performed in the same manner as in Example 1.

Manufacturing method of curable composition In Example 1, amorphous inorganic particles (B-7) 50.4
g, Bis-GMA 5.6 g, TEGDMA as the polymerizable monomer
5.6 g, PE-TRA 4.8 g; BPO as a polymerization initiator
A curable composition was prepared in the same manner except that 0.06 g was used.

Next, compression, tensile and bending strength tests were performed using the curable composition. In the preparation of the test piece, the polymerization and curing were directly carried out at 95 ° C. under a nitrogen pressure of 5 kg / cm ² for 1 hour without passing through the photopolymerization and curing step.

As a result, compressive strength 4,500 kg / cm ² , tensile strength 680 kg
High mechanical strength of 2/100 kg / cm ² and bending strength of 2,100 kg / cm ² was obtained.

Claims (1)

[Claims] 1. A. Polymerizable monomer B. At least a portion is amorphous and has an average particle size of 1 to
Irregular inorganic particles having a particle size of 9 μm and a particle size of 1 to 10 μm accounting for 95% by weight or more. Spherical inorganic particles having an average particle diameter of 0.08 to 1 μm, and D. A polymerization initiator, and B is added to 100 parts by weight of the polymerizable monomer A.
The amorphous inorganic particles and spherical inorganic particles of C have a total amount of 3
A curable composition comprising 100 to 900 parts by weight and a weight ratio (B / C) of the amorphous inorganic particles to the spherical inorganic particles of 1 to 4.