JP5072333B2 - Processing method of organic-inorganic composite powder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic-inorganic composite powder reduced in the shrinkage in polymerization and easy to have a preferable fluid flow characteristic. <P>SOLUTION: The organic-inorganic composite powder which is obtained by mixing, hardening and crushing a polymerizable monomer composition imparting a crosslinked polymer by curing and the inorganic particles, is subjected to the treating process by charging into a treating space of the powder treating system provided with a first member carrying out a repeated movement and a second member carrying out a movement different from the first member or not moving, wherein the composite powder is subjected to the treatment with the first member set so as to move with &ge;20 m/second of a linear velocity and &ge;10 times/second of repeating frequency. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention relates to a method for treating an organic / inorganic composite powder, and more particularly, to a mechanical treatment method for an organic / inorganic composite powder suitable for producing a dental composite material having small polymerization shrinkage and excellent operability.

  Organic-inorganic composite powders are used in cosmetics, external preparations for skin, medical materials, dental materials and the like as functional fillers that provide properties that are difficult to achieve with organic powders or inorganic powders alone.

  As an example of an organic-inorganic composite powder used for a dental material, application to a composite resin that is a restoration material for a tooth defect is generally known (see, for example, Patent Documents 1 to 4). By using such an organic-inorganic composite powder as a filler, the polymerization shrinkage is reduced to some extent while realizing the excellent surface smoothness and anti-abrasion characteristics that are characteristic when using a fine inorganic filler. It is possible to obtain good operability.

  Such an organic-inorganic composite powder usually includes an inorganic powder composed of oxide particles such as silica, silica zirconia, and silica titania, and a polymerizable monomer having at least one polymerizable functional group. Manufactured by mixing with a crosslinkable polymerizable monomer composition, polymerizing and curing the bulk material, and then pulverizing it until the average particle size is about several μm to 200 μm Is done. The organic-inorganic composite powder thus produced is often treated with a silane coupling agent in order to further improve dispersibility in the matrix monomer.

  However, in recent years, resin materials including dental composite resins have been required to further reduce polymerization shrinkage. In order to reduce polymerization shrinkage, a larger amount of filler may be added. However, if the filler content is increased, the fluidity of the resulting composite paste will decrease, so if it is added too much, there will be a problem in operability and the like, so there is a limit to simply increasing the content. . Although the flow characteristics are improved by the silane coupling agent treatment, there is still room for improvement.

  Among the dental composite resins, the flowable type composite resin, which has been increasing in importance in recent years, needs to add more matrix monomer (less filler content) than ordinary composite resins in order to obtain good flow characteristics. Yes, polymerization shrinkage is a bigger problem.

JP 54-107187 A JP-A-61-241303 Japanese Patent Application Laid-Open No. 10-114616 JP 2002-255722 A

  Accordingly, the present invention provides an organic-inorganic composite that can provide a dental composite material having good flow characteristics with little polymerization shrinkage and excellent operability when used as a filler (filler) for a dental composite material. The purpose is to provide powder.

  The inventors of the present invention have made extensive studies to solve the above problems. As a result, it has been found that an organic-inorganic composite powder having a small polymerization shrinkage and good flow characteristics can be produced through a specific mechanical treatment, and the present invention has been completed.

That is, the present invention includes (1) a step of obtaining a bulk body of an organic-inorganic composite by curing a polymerizable monomer composition that gives a crosslinkable polymer when cured and inorganic particles, and then curing the mixture. 2) A step of pulverizing a bulk body of an organic-inorganic composite to obtain an organic-inorganic composite powder. (3) A first member that repeatedly moves the organic-inorganic composite powder, and is it possible to move differently from the first member? Alternatively, a step of introducing the surface modification device having a treatment space having a second member that does not move into the treatment space; (4) the first member provided in the treatment space of the surface modification device is moved at the highest speed. The organic-inorganic composite powder introduced into the treatment space is moved by moving the portion so that the movement speed of the portion to be moved is a linear velocity of 20 m / second or more relative to the second member and the repetition frequency is 10 times or more per second. Each process of processing Comprising a, the surface modifying apparatus, (2) with form a round and Donma the acute angle portion of the organic-inorganic composite powder produced by pulverizing step, the composite nailed to large particles more particle size of fine particles It is the manufacturing method of the organic inorganic composite powder characterized by the above-mentioned.

Further, in the present invention, the first member is an outer wall that forms a processing space of the surface modification device , and the outer wall has a circular cross-sectional shape on the inner surface, and is further rotatable about the center of the circle. The method for producing an organic-inorganic composite powder according to claim 1, wherein the repetitive motion is a rotational motion of the outer wall.

In the present invention, the second member is an outer wall forming a processing space of the surface reforming apparatus , the outer wall has a circular cross-sectional shape on the inner surface, and the first member is a central axis of the processing space cross-sectional circle 2. A method for producing an organic-inorganic composite powder according to claim 1, wherein the rotating body is disposed in the processing space so as to rotate on a concentric axis, and the repetitive motion is the rotational motion of the rotating body.

  Furthermore, the present invention also provides a method for producing a dental composite material in which an organic-inorganic composite powder is produced by the method according to claims 1 to 3 and the obtained organic-inorganic composite powder is mixed with a polymerizable monomer.

  The organic-inorganic composite powder produced by the production method of the present invention has a lower proportion of reducing the fluidity of the composite material paste than the organic-inorganic composite powder produced by other production methods. Therefore, when the dental composite material using the organic-inorganic composite powder produced by the production method of the present invention is blended so as to have the same polymerization shrinkage compared to the organic-inorganic composite powder produced by other production methods, Good flow characteristics can be obtained. On the other hand, if the flow characteristics are made comparable, a dental composite material with smaller polymerization shrinkage can be obtained.

The manufacturing method of the organic-inorganic composite powder of the present invention includes the following steps (1) to (4).
(1) A step of obtaining a bulk body of an organic-inorganic composite by mixing a polymerizable monomer composition that gives a crosslinkable polymer when cured and inorganic particles and then curing the mixture (hereinafter referred to as (1) step)
(2) A step of pulverizing a bulk body of an organic-inorganic composite to obtain an organic-inorganic composite powder (hereinafter referred to as (2) step)
(3) In the treatment space of the surface modification apparatus having a treatment space comprising a first member that repeatedly moves the organic-inorganic composite powder and a second member that can move or does not move differently from the first member. Process (hereinafter referred to as (3) process)
(4) The first member provided in the processing space of the surface modification apparatus has a motion speed of a portion that moves at the highest speed relative to the second member, and a linear speed of 20 m / second or more, and a repetition frequency of 10 times per second. A step of treating the organic-inorganic composite powder charged into the treatment space by exercising as described above (hereinafter, (4) step).

  Step (1) in the present invention is a step of producing a bulk body of an organic-inorganic composite. The steps (1) and (2) are described in detail in the above-mentioned Patent Documents 1 to 4 and the like, and the methods described in these known documents may be adopted as appropriate. Specifically, the steps are as follows. is there.

  A known polymerizable monomer can be used as the polymerizable monomer composition (hereinafter simply referred to as a polymerizable monomer composition) that gives a cross-linked polymer when cured, although there is no particular limitation. The polymerizable monomers to be blended in the polymerizable monomer composition are preferably all polymerizable monomers having two or more polymerizable functional groups. In this case, the durability against heat and solvent is enhanced by the construction of a three-dimensional network structure. When a polymerizable monomer composition that does not give a crosslinkable polymer, for example, a polymerizable monomer having only one polymerizable functional group, is softened against energy such as impact and compression, Since it is possible to obtain an organic-inorganic composite powder having the property of being easily deformed, it is advantageous from the viewpoint of surface modification of the organic-inorganic composite powder, but it leads to a decrease in mechanical strength and durability of the obtained composite material. It is not preferable.

  Examples of the polymerizable monomer having two or more polymerizable functional groups to be blended in the polymerizable monomer composition include the monomers shown below.

  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; 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 3-chloro Methacrylates such as 2-hydroxypropyl methacrylate or vinyl monomers having -OH groups such as acrylates corresponding to these methacrylates, and diisocyanates Diadducts obtained from addition with diisocyanate compounds having aromatic groups such as tilbenzene and 4,4′-diphenylmethane diisocyanate, 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; 2-hydroxyethyl methacrylate; Meta such as 2-hydroxypropyl methacrylate and 3-chloro-2-hydroxypropyl methacrylate Vinyl monomers having an —OH group such as acrylate corresponding to acrylate or these methacrylates, and diisocyanate compounds such as hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, diisocyanate methylcyclohexane, isophorone diisocyanate, and methylenebis (4-cyclohexyl isocyanate) Diaducts obtained from the addition of acrylonitrile, acrylic anhydride, methacrylic anhydride, 1,2-bis (3-methacryloyloxy-2-hydroxypropoxy) ethyl, di (2-methacryloyloxypropyl) phosphate, etc., trimethylolpropane tri Methacrylate, trimethylolethane trimethacrylate, pentaerythritol trimethacrylate, trimethylol methanetri Methacrylates such as tacrylate and acrylates corresponding to these methacrylates, such as pentaerythritol tetramethacrylate, pentaerythritol tetraacrylate and diisocyanate methylbenzene, diisocyanate methylcyclohexane, isophorone diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, methylene bis (4-cyclohexyl) Isocyanate), diadducts obtained from the addition of diisocyanate compounds such as 4,4-diphenylmethane diisocyanate, tolylene-2,4-diisocyanate and glycidol dimethacrylate, and the like.

  These polymerizable monomers may be used singly or as a mixture of different types to form a polymerizable monomer composition.

  The inorganic particles to be mixed with the polymerizable monomer composition are not particularly limited, and are known inorganic particles such as amorphous silica, silica zirconia, silica titania, silica titania barium oxide, quartz, alumina, aluminosilicate glass, barium. Powders of inorganic compounds such as glass can be used. As these inorganic compounds, composite oxides to which a small amount of Group I metal oxides are added can be used for the purpose of easily obtaining a dense material when fired at a high temperature. As the material of the inorganic particles, a composite oxide having silica and zirconia as main constituent components is particularly preferably used since a cured product having X-ray contrast properties and more excellent wear resistance can be obtained.

  The average particle size of the inorganic particles is preferably 0.001 to 1 μm. More preferably, it is 0.01-0.7 micrometer, especially 0.05-0.5 micrometer. When the average particle size of the inorganic particles is less than 0.001 μm, the viscosity becomes high and handling becomes difficult. When the average particle size of the inorganic particles exceeds 1 μm, it is difficult to obtain lubricity after polymerization and curing. The average particle diameter of the inorganic particles is a value obtained from the average volume diameter by taking a photograph of the powder with a scanning electron microscope, determining the number of particles observed within the unit field of view of the photograph and the particle diameter. Say.

  The shape of the inorganic particles used in the production of the organic-inorganic composite powder of the present invention is preferably spherical or substantially spherical from the viewpoint of the surface smoothness and wear resistance of the resulting cured product. Note that the term “substantially spherical” as used herein refers to a particle diameter in a direction perpendicular to the maximum diameter of a particle observed in the unit field of view by taking a photograph of the filler with a scanning electron microscope (SEM). Means the average uniformity divided by the maximum diameter is 0.6 or more. These inorganic particles may be used by mixing a plurality of types having different particle size distributions and materials.

  The method for producing these inorganic particles is not particularly limited, and is selected from, for example, a solution containing a hydrolyzable organosilicon compound, or a group consisting of metals of Groups I, II, III, and IV of the periodic table. A mixed solution containing a hydrolyzable organic compound containing at least one metal is added to an alkaline solvent in which these raw materials are dissolved but the reaction product is not substantially dissolved, and the reaction product is obtained by hydrolysis. A so-called sol-gel method for precipitating slag is preferably employed.

  The inorganic particles produced by such a method are preferably fired at a temperature of 500 to 1000 ° C. after drying in order to maintain the surface stability. Further, since the particles are aggregated during firing, it is preferable to use the particles after the aggregated particles are unwound using a jet mill, a vibration ball mill or the like to adjust the particle size. Even if such an operation is performed, it is difficult to completely bring the aggregated particles into a state before aggregation. When the above heat treatment is performed, inorganic particles having an average particle diameter of 0.001 to 1 μm and In some cases, fillers mixed with agglomerates may be obtained, but unlike the case of adding independent particles with a large particle size, even if some agglomerates are included, lubricity and wear resistance after polymerization and curing are improved. If there is no adverse effect, it does not matter.

  The inorganic particles have a surface treated for the purpose of improving dispersibility in the polymerizable monomer composition or imparting a binding property to the polymerizable monomer composition. Is preferred. Such a surface treatment method is not particularly limited, and may be treated by any known method. Specific examples of the surface treatment method include inorganic particles such as silica and silane coupling agents as surface treatment agents, such as organosilicon compounds such as γ-methacryloyloxyalkyltrimethoxysilane and hexamethyldisilazane. A method of dispersing and mixing in a suitable solvent using a ball mill, etc., drying with an evaporator or spray drying, heating to 50 to 150 ° C., heating the inorganic particles and the surface treatment agent in a solvent such as alcohol for several hours The method of returning is listed. Although there is no restriction | limiting in particular in the quantity of the said surface treating agent used at this time, If a suitable range is illustrated, it will be the range of the said surface treating agent 1-10 mass parts with respect to 100 mass parts of inorganic particles.

  (1) The amount ratio of the polymerizable monomer composition and the inorganic particles in the bulk of the organic-inorganic composite powder in the present invention produced in the step is not particularly limited, but the strength of the obtained organic-inorganic composite powder, etc. The amount of inorganic particles is usually 150 to 600 parts by weight with respect to 100 parts by weight of the polymerizable monomer.

  There is no restriction | limiting in particular as a method of mixing a polymerizable monomer composition and inorganic particle | grains, A well-known mixer, a stirrer, and a disperser can be used.

  There is no limitation on the method for curing the mixture of the polymerizable monomer composition and the inorganic particles, and a known method can be used, but generally a polymerization initiator is used to obtain a cured product in a short time. To do. The polymerization method includes a reaction by light energy such as ultraviolet light and visible light (hereinafter referred to as photopolymerization), a chemical reaction between a peroxide and an accelerator, a heating method, etc., depending on the polymerization method employed. Various polymerization initiators shown below may be appropriately selected and blended into the polymerizable monomer composition.

  For example, as a photopolymerization initiator, benzoin alkyl ethers such as benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzyl ketals such as benzyl dimethyl ketal and benzyl diethyl ketal, benzophenone, 4,4′-dimethylbenzophenone, Benzophenones such as 4-methacryloxybenzophenone, diacetyl, 2,3-pentadionebenzyl, camphorquinone, 9,10-phenanthraquinone, α-diketones such as 9,10-anthraquinone, 2,4-diethoxy Thioxane compounds such as thioxanthone, 2-chlorothioxanthone, methylthioxanthone, bis- (2,6-dichlorobenzoyl) phenylphosphine oxide, bis- (2,6-dichlorobenzoy ) -2,5-dimethylphenylphosphine oxide, bis- (2,6-dichlorobenzoyl) -4-propylphenylphosphine oxide, bis- (2,6-dichlorobenzoyl) -1-naphthylphosphine oxide, bis (2 , 4,6-trimethylbenzoyl) -phenylphosphine oxide, etc. can be used.

  Incidentally, a reducing agent is often added to the photopolymerization initiator. Examples thereof include tertiary amines such as 2- (dimethylamino) ethyl methacrylate, ethyl 4-dimethylaminobenzoate, and N-methyldiethanolamine. Aldehydes such as lauryl aldehyde, dimethylaminobenzaldehyde and terephthalaldehyde, and sulfur-containing compounds such as 2-mercaptobenzoxazole, 1-decanethiol, thiosalicylic acid and thiobenzoic acid.

  Examples of the thermal polymerization initiator include benzoyl peroxide, p-chlorobenzoyl peroxide, tert-butyl peroxy-2-ethylhexanoate, tert-butyl peroxydicarbonate, and diisopropyl peroxydicarbonate. Peroxides, azo compounds such as azobisisobutyronitrile, tributylborane, tributylborane partial oxide, sodium tetraphenylborate, sodium tetrakis (p-fluorophenyl) borate, triethanolamine tetraphenylborate And boron compounds such as 5-butyl barbituric acid, 1-benzyl-5-phenyl barbituric acid and the like, and sulfinates such as sodium benzenesulfinate and sodium p-toluenesulfinate. .

  These polymerization initiators may be used alone or in combination of two or more. The addition amount of the polymerization initiator is appropriately selected according to the ratio of the polymerizable monomer / inorganic particles, but is usually 0.01 to 30 parts by weight with respect to 100 parts by weight of the polymerizable monomer. Yes, more preferably 0.1 to 5 parts by weight.

  In addition, known additives such as pigments and ultraviolet absorbers can be blended before polymerization within a range that does not impair the effects of the present invention.

  In the present invention, the bulk of the organic-inorganic composite obtained by the above method is pulverized in the step (2) to obtain an organic-inorganic composite powder. Although there is no restriction | limiting in particular as a grinding | pulverization method, For example, a ball mill, bead mill, a roll mill, a hammer mill, a jet mill etc. can be used.

  Further, if necessary, an organic-inorganic composite powder having a desired particle size distribution can be obtained by performing a classification process using a sieve, an air classifier, or a hydration classifier.

  The average particle size of the organic-inorganic composite powder is not particularly limited. However, since it is easy to obtain a curable paste with less stickiness and crispness and good filling operability, the average particle size is 1 to 100 μm, more preferably 5 to 5 μm. 50 μm, most preferably 6 to 15 μm. When the average particle size is too small, when used as a composite material, the filler filling rate decreases, and thus the polymerization shrinkage may increase. In addition, when the average particle size is too large, there is a possibility that sufficient surface modification treatment may not be performed due to the dominant pulverization when the treatment of the present invention is performed.

The organic-inorganic composite powder production method of the present invention includes a first member that repeatedly moves the organic-inorganic composite powder obtained in step (2) as step (3), and a motion different from that of the first member. A step of introducing into the treatment space of a surface modification device having a treatment space comprising a second member that is capable or non-moving.

  The repetitive motion performed by the first member is not particularly limited and may take any form such as a rotational motion, a reciprocating motion, a waveform motion, a pendulum motion, etc., but a rotational motion capable of obtaining a uniform linear velocity is preferable.

  Although there is no restriction | limiting in particular as a raw material of a 1st member, In order to transmit mechanical energy efficiently, it is preferable that it is a material which has a high elasticity modulus. Specifically, iron, steel, stainless steel, titanium, and ceramics such as metal oxide, silicon carbide, silicon nitride, barium titanate, and boron nitride are preferably used. In particular, it is preferable to use ceramic parts or to coat with ceramics because there is little influence of contamination caused by wear of the apparatus with the organic / inorganic composite powder. As such a ceramic material, alumina, zirconia, and partially stabilized zirconia are preferable from the viewpoint of wear resistance and color tone.

  Further, the second member may be movable or fixed, but it is preferable that the second member is fixed from the viewpoint of not complicating the apparatus and controlling the relative speed between the first member and the second member. When moving, it may take any form such as rotational motion, reciprocating motion, waveform motion, pendulum motion, etc., but at least one of the conditions such as rotational direction, period and speed is different from the first member. As the movement, when the first member is moved as will be described later, the relative speed with respect to the first member is set to a linear velocity of 20 m / second or more. The material for the second member can be selected from the same materials as the first member without any particular limitation.

(4) step of the production method of the present invention, by movement of the first member of the above such surface modification apparatus, the impact to the organic-inorganic composite powder having been put into the processing space of the surface modification apparatus, shearing, This is a process of applying mechanical energy such as compression and friction. At this time, the first member provided in the processing space of the surface modification device has a movement speed of the part that moves at the highest speed (hereinafter, unless otherwise specified, the movement speed of this part is simply referred to as “movement speed”). It is necessary to move the linear member so that the linear velocity is 20 m / sec or more relative to the second member and the repetition frequency is 10 times or more per second.

  When the motion speed of the first member is slow and the relative speed with respect to the second member is less than 20 m / sec, a mechanical action sufficient for surface modification cannot be imparted to the powder. A more preferable range is a linear velocity of 30 to 1000 m / second, and a further preferable range is 35 to 300 m / second.

  Although the mechanism of action by which the effect of the present invention can be obtained is not clear, the first member is moved at a high speed as described above in a state where the organic-inorganic composite powder obtained in the step (2) is put into the processing space. Thus, the organic-inorganic composite powder is brought into contact with the first member and / or the second member, and a strong mechanical action such as impact, shear, compression, friction is applied to the organic-inorganic composite powder, and the step (2) The sharp corners of the organic-inorganic composite powder produced by grinding are rounded and rounded, and the fine particles are struck into a larger particle size to form a composite, so when blended with a polymerizable monomer It is presumed that the effect of increasing the viscosity can be reduced, and therefore the filler filling rate can be improved, or the operability such as fluidity and familiarity can be improved.

  In the present invention, in order to obtain the action as described above, the amount of the organic-inorganic composite powder to be introduced into the processing space in the step (3) is the state in which the first member is moved in the step (4). The amount should be such that at least a portion of the powder contacts both the first member and the second member. In a state where only one of the first member and the second member is in contact, the effect of the present invention cannot be obtained.

  In the present invention, the movement of the first member is a repetitive movement. If it is not a repetitive motion, the size of the member for obtaining the necessary processing effect is not realistic.

  Further, it is necessary to move the first member so that the repetition frequency is 10 times or more per second. A more preferable range is 20 to 400 repetitions per second. When the repetition frequency is less than 10 times, the frequency with which each particle constituting the organic-inorganic composite powder to be treated comes into contact with the first member and / or the second member is reduced, and the surface modification is performed in an industrially practical time. Therefore, the effect of the present invention is insufficient because a sufficient mechanical action cannot be imparted to the powder.

  The treatment time in the step (4) varies depending on the movement speed, repetition frequency, etc. of the first member, but in order to give sufficient mechanical action to the whole particles constituting the organic-inorganic composite powder, A treatment time of 5 minutes or more, more preferably 5 minutes or more is preferable, and from the viewpoint of suppressing particle breakage and deterioration, the treatment is preferably performed for 60 minutes or less, more preferably 20 minutes or less. As the repetition frequency is increased, the effect can be obtained in a shorter processing time.

The surface reforming apparatus having the above members may be a batch type or a continuous type, but is preferably a batch type because it is easy to increase the repetition frequency, and the effect of the present invention is more effective. The first member is an outer wall that forms a treatment space of the surface reforming apparatus because it is high, and the structure is simple and easy to handle, and the outer wall has a circular cross-sectional shape on its inner surface, and further the center of the circle A surface modification device (hereinafter referred to as a compression-shear type device) that can rotate around the shaft, and the second member is an outer wall that forms a processing space of the surface modification device , and the outer wall is a cross-sectional shape of its inner surface Is a circle, and the first member is a surface reforming device (hereinafter referred to as a high-speed rotating device) that is a rotating body arranged in the processing space so as to rotate on a concentric axis with the central axis of the processing space sectional circle. It is preferable to use it.

  The compression shearing apparatus will be described more specifically with reference to FIG. 1. The processing space in which the presence / absence machine composite powder is processed is constituted by an outer wall whose inner surface shape is circular. The outer wall can be rotated at high speed around the center of the circle. In the form of FIG. 1, an indenter is disposed in the processing space as the second member.

  When the organic-inorganic composite powder obtained in step (2) is put into the treatment space and the outer wall is rotated at a high speed, the organic-inorganic composite powder is pressed against the outer wall by centrifugal force. By appropriately setting the distance between the tip of the indenter and the inner surface of the outer wall and the amount of the organic-inorganic composite powder to be introduced, compression and shear force are applied to the powder between the indenter and the outer wall. In this case, the movement speed of the first member is a relative speed between the inner surface of the first member and the portion where the second member (indenter) contacts the organic-inorganic composite powder, that is, the tip portion.

  The second member is not limited to the illustrated member, and the shape, position, and number of the second member can be appropriately set as long as the member has the above-described action.

  The distance between the tip of the indenter and the inner surface of the outer wall is preferably selected from 1 to 20 mm, more preferably from 5 to 12 mm, from the viewpoints of processing effect, processing time and processing amount.

  In such a compression shear type apparatus, the indenter as the second member may be movable or in a fixed state, but is preferably fixed in view of simplifying the structure of the apparatus. When the second member is fixed (not moved), the second member is rotated so that the linear velocity of the inner surface of the outer wall is 20 m / second or more. On the other hand, when the second member is moved, for example, when the second member is rotated, the rotation speed of the outer wall may be adjusted by rotating in the same direction as the outer wall or rotating in the opposite direction.

  In order to improve the processing efficiency, it is also preferable to use an apparatus having a mechanism for scraping off the powder pressed against the inner surface of the outer wall in the processing space.

  The above compression shear type devices are commercially available such as Mechano-Fusion System (Hosokawa Micron), Nobilta (Hosokawa Micron), Nanocura (Hosokawa Micron), Theta Composer (Tokuju Kosakusho), Miraro (Nara Machinery Works), etc. A surface modification device or a mechanical particle composite device can be used.

  Next, the high-speed rotary device will be described with reference to FIG. Even in a high-speed rotary apparatus, the processing space is constituted by an outer wall whose inner shape of the cross section is circular, but the first member that repeatedly moves is a rotating body (rotor) arranged in the processing space. is there. In order to reduce the dead space in the processing space and increase the processing efficiency, the rotating body is arranged so as to rotate about the central axis of the processing space cross-sectional circle.

  By rotating the rotating body at a high speed, the rotating body collides with the organic-inorganic composite powder put into the processing space, and gives a mechanical action to the powder. The outer wall may be rotated, but is usually fixed to simplify the device structure.

  The rotator may be a simple cylindrical rotator, but from the viewpoint of processing efficiency, a rotor with a board, blade, hammer, pin, etc. as shown in FIG. 2 is preferable.

  When the outer wall is not moved, the moving speed of the first member is the speed of the tip of the board, blade, hammer, pin, or the like. When rotating the outer wall, the rotational speed of the rotating body may be adjusted according to the rotational speed.

  As such a high-speed rotating apparatus, commercially available surface modification apparatuses such as hybridization systems (Nara Machinery Co., Ltd.), kryptron (Kawasaki Heavy Industries), and mechanical particle composite apparatuses can be used. .

In the case of using the batch type surface reforming apparatus as illustrated above, in order to effectively bring the powder into contact with the first member, the processed powder is once taken out from the processing space and processed again by the circulation mechanism. You may take the method of introducing in space.

The state of the organic-inorganic composite powder to be introduced into the surface reforming apparatus used in the present invention may be either a dry type in which the organic-inorganic composite powder is introduced as it is, or a wet type in which a dispersion or slurry dispersed in water or an appropriate organic solvent is introduced. Although it is good, the dry method is preferable because the effect of the present invention is easily obtained and the separation step of the dispersion medium and the powder is not necessary.

  A dental composite material can be produced by mixing the organic-inorganic composite powder produced by the production method of the present invention with a polymerizable monomer. The said dental composite material can also be manufactured by a well-known method as described in the said patent documents 1-4.

  Although the organic-inorganic composite powder can be used as it is produced by the above production method, it improves the strength of the dental restorative material composition after curing by improving the familiarity with the polymerizable monomer as a matrix, It is desirable to treat with a silane coupling agent. As the surface treatment method, any of the methods described for treating the inorganic particles with the silane coupling agent may be adopted.

  The content of the organic-inorganic composite powder to be blended in the dental composite material is not particularly limited, but from the viewpoint of the operability of the paste before curing and the strength of the cured body, 50 to 600 weight with respect to 100 parts by weight of the polymerizable monomer. Parts, particularly 80 to 300 parts by weight are preferred.

  In addition, inorganic particles may be added to the dental composite material of the present invention. As the inorganic particles, those described above can be used. Here, inorganic particles that have been surface-treated with a silane coupling agent can be used. The kind of the silane coupling agent and the surface treatment conditions may be the same as or different from those described above.

  In any case, the average particle size of the inorganic particles used here is preferably 0.1 to 1 μm. When it is less than 0.1 μm, the viscosity of the paste tends to be high. If it exceeds 1 μm, surface lubricity and wear resistance tend to be lowered. Furthermore, for the purpose of improving the strength of the cured product, inorganic particles having an average particle size larger than 1 μm and / or inorganic particles having an average particle size smaller than 0.1 μm within a range in which the surface smoothness and wear resistance are not lowered. May be added. The inorganic particles may be used by mixing a plurality of types having different particle size distributions and materials.

  Also, the above-mentioned polymerizable monomers can be used as appropriate, and even if the same type and the same composition as the polymerizable monomer used in the production of the organic-inorganic composite powder are used, different types and different compositions are used. May be used.

  The content of the filler containing the organic-inorganic composite powder in the dental composite material of the present invention is not particularly limited, but from the viewpoint of filling operability and cured body strength, with respect to 100 parts by weight of the polymerizable monomer composition, It is preferably 65 to 800 parts by weight, particularly 100 to 400 parts by weight.

  Usually, a polymerization initiator is blended in the dental composite material in order to polymerize and cure the polymerizable monomer. Photopolymerization is preferably used because of the ease of operation at the time of use, and the above-mentioned photopolymerization initiator can be used. Particularly preferred are camphorquinone, bis (2,4,6-trimethylbenzoyl). ) -Phenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylphenylphosphine oxide, and the like. These polymerization initiators may be used alone or in combination of two or more. The addition amount of the polymerization initiator may be appropriately selected according to the purpose, but is usually 0.01 to 30 parts by weight, more preferably 0.1 to 5 parts by weight with respect to 100 parts by weight of the polymerizable monomer. It is.

  To the dental composite material, known additives such as pigments and ultraviolet absorbers can be further blended within a range not impairing the effects of the present invention. The curable composition of the present invention can be obtained by sufficiently uniformly kneading each essential component and, if necessary, each optional component into a paste, and further defoaming under reduced pressure.

  The use of the dental composite material thus produced is not particularly limited, and specific examples include a dental filling composite resin. In general, the dental cavity to be repaired is treated with an appropriate pretreatment agent or adhesive, and then directly filled with a composite resin for dental filling. And a method of polymerizing and curing.

EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not restrict | limited to these Examples. The polymerizable monomers and polymerization initiators used in the examples and comparative examples are as follows.
Polymerizable monomer:
GMA: 2,2-bis (4- (3-methacryloyloxy) -2-hydroxypropoxyphenyl) propane TEGDMA: triethylene glycol dimethacrylate polymerization initiator AIBN: azobisisobutyronitrile CQ: camphorquinone DMBE: dimethylbenzoic acid Acid ethyl ester The test method is as follows.
(1) Preparation of organic-inorganic composite powder {(1) step and (2) step}
As a polymerizable monomer, 0.5 wt% of a polymerization initiator AIBN was dissolved in 30 parts by weight of GMA and 70 parts by weight of TEGDMA to obtain a polymerizable monomer composition. To 100 parts by weight of this polymerizable monomer composition, 300 parts by weight of a spherical silica zirconia (average particle size 0.2 μm) surface-treated product of γ-methacryloyloxypropyltrimethoxysilane is mixed and kneaded well in a mortar. And pasty. The paste was polymerized and cured by heating at 95 ° C. under nitrogen pressure for 1 hour, and the cured product was pulverized with a vibration ball mill to obtain an organic-inorganic composite powder C-1 having an average particle size of 9 μm.
(2) Preparation of photocurable composite resin To 60 parts by weight of GMA and 40 parts by weight of TEGDMA, 0.5% by weight of CQ and 0.5% by weight of DMBE are added and mixed to obtain a uniform polymerizable monomer. A body composition was prepared and used as a matrix.

90 parts by weight of the organic / inorganic composite powder treated by the respective methods described in Examples and Comparative Examples, and 60% by weight of γ-methacryloyloxypropyltrimethoxysilane surface treated product of spherical silica zirconia (average particle size 0.2 μm). And 100 parts by weight of the polymerizable monomer composition were gradually added thereto and sufficiently kneaded in a dark place to obtain a uniform curable paste. Furthermore, this paste was degassed under reduced pressure to prepare a curable composite resin.
(3) Polymerization shrinkage rate Measured by Archimedes method.
(4) Fluidity of paste When 0.03 g of a photocurable composite resin is placed on a glass plate so that the diameter is within 5 mm, and after naturally developing for 5 seconds, the glass plane is placed vertically and left standing. The distance that the position of the lowermost end of the photocurable composite resin developed on the glass plane moved in 3 minutes immediately after the glass plane was made vertical was measured as the plastic flow distance.

Example 1
50 g of the organic / inorganic composite powder C-1 was processed using a hybridization system (ceramic specification) at a linear velocity of 100 m / sec and a processing time of 5 minutes to obtain a processed organic / inorganic composite powder T-1. The repetition frequency at this time was estimated to be 270 times per second from the number of rotations of the rotor. The average particle size of the obtained powder was 10 μm, and the surface property was smoother than that before the treatment as observed by SEM.

  A photocurable composite resin was prepared by the above-described method using this processed organic / inorganic powder T-1, and the polymerization shrinkage and fluidity were measured. The results are shown in Table 1. The fluidity was good.

Example 2
500 g of the organic / inorganic composite powder C-1 was processed using a mechanofusion system (ceramic specification) at a linear velocity of 39 m / sec and a processing time of 30 minutes to obtain a processed organic / inorganic composite powder T-2. The repetition frequency at this time was estimated to be 38 times per second from the number of rotations of the outer wall. The average particle diameter of the obtained powder was 9 μm, and the surface property was smoother than that before treatment as observed by SEM.

  A photocurable composite resin was prepared by the above-described method using this processed organic / inorganic powder T-2, and the polymerization shrinkage and fluidity were measured. The results are shown in Table 1. The fluidity was good.

Comparative Example 1
Using the organic-inorganic composite powder C-1 as a filler, a photocurable composite resin was prepared by the method described above, and the polymerization shrinkage and fluidity were measured. The results are shown in Table 1. The fluidity was low.

Comparative Example 2
50 g of organic-inorganic composite powder C-1 and 300 g of a zirconia ball having a diameter of 5 mm as a medium were placed in a zirconia pot having a capacity of 400 ml, and rotated for 30 minutes at a rotational speed of 100 rpm on a rotating platform. At this time, the linear velocity of the inner wall of the pot corresponded to 1.5 m / sec. As a result, a processed organic-inorganic composite powder T-3 was obtained. The average particle size of the obtained powder was 8 μm, and the surface property did not change significantly as compared with that before treatment as observed by SEM.

  Using this organic-inorganic powder-treated product T-3, a photocurable composite resin was prepared by the method described above, and the polymerization shrinkage rate and fluidity were measured. The results are shown in Table 1. The fluidity was almost the same as that of Comparative Example 1.

Comparative Example 3
50 g of organic / inorganic composite powder C-1 and 300 g of zirconia balls having a diameter of 5 mm as a medium are placed in a 400 ml zirconia pot and treated for 60 minutes at a vibration frequency of 20 Hz using a small vibration mill manufactured by Chuo Kakoki. Product T-4 was obtained. The linear velocity at this time was estimated to be 0.2 mm / sec from the amplitude and frequency. The average particle diameter of the obtained powder was 5 μm. In observation by SEM, large particles were reduced as compared with those before treatment, and a large amount of fine powder was generated.

  Using this processed organic / inorganic powder T-4, a photocurable composite resin was prepared by the method described above, and the polymerization shrinkage and fluidity were measured. The results are shown in Table 1. The paste was hard and not fluid at all.

Comparative Example 4
15 parts by weight of a matrix was added to 250 parts by weight of the photocurable composite resin prepared in Comparative Example 1 and kneaded to prepare a photocurable composite resin. Polymerization shrinkage and fluidity were measured. The results are shown in Table 1. Although the fluidity was improved, the polymerization shrinkage was increased.

It is a schematic diagram which shows a compression shearing apparatus . It is a schematic diagram which shows a high-speed rotary apparatus . more than

Claims (4)

(1) to (4) below
(1) Step of obtaining a bulk body of an organic-inorganic composite by mixing a polymerizable monomer composition that gives a cross-linkable polymer when cured and inorganic particles and then curing the mixture (2) of the organic-inorganic composite Step of pulverizing bulk body to obtain organic-inorganic composite powder (3) A first member that repeatedly moves the organic-inorganic composite powder, and a second member that can or does not move differently from the first member (4) The first member provided in the treatment space of the surface modification apparatus is moved into the treatment space of the surface modification apparatus having the treatment space provided. Each of the steps of processing the organic-inorganic composite powder charged into the processing space by exercising such that the linear velocity is 20 m / sec or more at a relative speed and the repetition frequency is 10 times or more per second,
The surface reformer is a device that dulls the sharp corners of the organic-inorganic composite powder produced by the pulverization in the step (2) to round it, and strikes and combines the fine particles with larger particles. A method for producing an organic-inorganic composite powder, wherein   The first member is an outer wall that forms a processing space of the surface modification device, and the outer wall has a circular cross-sectional shape on its inner surface, and is rotatable about the center of the circle, and is repeatedly moved The method for producing an organic-inorganic composite powder according to claim 1, wherein the rotational movement of the outer wall.   The second member is an outer wall that forms a processing space of the surface reforming apparatus, and the outer wall has a circular cross-sectional shape on its inner surface, and the first member rotates on a concentric axis with the central axis of the processing space cross-sectional circle The method for producing an organic-inorganic composite powder according to claim 1, wherein the rotating body is disposed in the processing space, and the repetitive motion is the rotational motion of the rotating body. The manufacturing method of the dental composite material which manufactures organic-inorganic composite powder by the method as described in any one of Claims 1 thru | or 3 , and mixes the obtained organic-inorganic composite powder with a polymerizable monomer.

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