JP3422964B2 - Method for producing ceramics for medical and dental use, molding composition and kneading agent - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing medical or dental ceramics. Further, the present invention relates to a ceramics molding composition used in producing a medical or dental ceramics. It also relates to a kneading agent used when preparing such a composition.

[0002]

2. Description of the Related Art From the viewpoint of aesthetics, durability and the like, ceramics are used as prostheses and other therapeutic tools for dental applications such as artificial teeth and artificial joints and medical applications. These dental or medical ceramics are formed into various shapes by molding various ceramic materials (including porcelain and other inorganic materials such as dental or medical glass materials and cement materials. The same applies hereinafter). It is produced by firing the molded product under suitable firing conditions depending on the properties of the ceramic material. A specific example of manufacturing dental ceramics will be described below.

For example, when the upper part of one tooth (crown portion) becomes caries or when one or more teeth are missing, the dentistry is molded into a prosthesis called crown or bridge, respectively. Ceramics are used. Such dental ceramics are typically manufactured as follows. That is, using a working model (positive type) obtained based on an impression (negative type) corresponding to the shape of the affected part (namely, the site where the dental ceramics is attached), a core frame made of a metal or ceramic sintered body is preliminarily used. Create. Then, the core frame is left attached to the working model, and then a kneaded product obtained by kneading a powdery ceramic material such as porcelain with various kneading liquids (such as water) is typically used. While being attached to the core frame using a brush or the like, the core frame is formed into a desired shape (crown, etc.) (this is called “building up” in the dental field). Next, in order to prevent bubbles and the like from entering, a water absorption treatment called condensation is performed, and a dense packing treatment is performed on the ceramic materials forming the molded product. Then, after coagulating such molded products by an appropriate method, the core frame together with the molded products is removed from the working model and transferred into a firing furnace. Then, the target dental ceramics (crown, bridge, etc.) is manufactured by firing under an appropriate temperature condition according to the material of the ceramic material used.

By the way, such dental ceramics or medical ceramics (hereinafter, medical or dental ceramics are generically referred to as "medical / dental ceramics").
When molding / manufacturing into a desired shape,
There were the following problems. That is, according to a kneaded product (that is, a molding composition before firing) obtained by kneading a conventional kneading liquid such as water and a powdery ceramic material, the composition is The mutual adhesiveness (mutual adhesive ability) or cohesiveness (cohesive ability) of the constituent ceramic particles was weak, and as a result, the physical strength of the molded product (buildup) was weak. For this reason, a worker such as a dental technician can remove the molded product from the work model (typically, remove the core frame) or carry the molded product into the firing furnace (typically, the core frame). In order to carry it, he was forced to handle the molded product with great caution and concentration. This is because if a molded article having such a low physical strength is inadvertently subjected to vibration or impact, a part of the molded article may easily fall off or be damaged.

Therefore, as a means for preventing a part of the composition from being collapsed or damaged after the molding and agglomeration, a kneading solution containing a photopolymerizable monomer and a photopolymerization initiator has hitherto been used for the manufacture of medical and dental ceramics. It is used in the field (see, for example, Japanese Patent Laid-Open No. 5-25015). That is, a kneaded product (composition) obtained by kneading the kneading liquid and the ceramic powder material is irradiated with light such as ultraviolet rays to polymerize and cure the photopolymerizable monomer contained in the composition. By doing so, it becomes possible to increase the physical strength of the composition after molding.

[0006]

However, when the kneading liquid containing the photopolymerizable monomer is used, a step of irradiation with light such as ultraviolet rays is added. Such a step is not preferable because it complicates the ceramic manufacturing process. In addition, depending on the size (thickness) or shape of the molded product, it may be difficult to sufficiently irradiate the entire molded product with light in a short time, and there is a risk of insufficient photopolymerization and curing. Therefore, the present invention is to solve the above-mentioned problems in producing dental ceramics or medical ceramics, and an object thereof is to perform simple curing without performing complicated and uncertain light irradiation treatment. It is an object of the present invention to provide a medical / dental ceramics molding composition capable of improving the physical (mechanical) strength of the above-mentioned molded product before firing, and a kneading agent used for preparing the composition. It is also to provide a method for producing a medical / dental ceramics using the composition and the kneading agent.

[0007]

Means for Solving the Problems The kneading agent of the present invention provided to solve the above problems is a kneading agent which is preferably used for ceramics molding for medical and dental purposes, and is one kind or two or more kinds. Is a kneading agent containing the water-soluble or water-dispersible acrylic polymer and / or acrylic copolymer in water or a hydrophilic solvent.

The kneading agent of the present invention is a powdery or other crushed ceramic material (typically silica-based, alumina-based, for molding and manufacturing ceramics for medical use or dental ceramics, By kneading with a zirconia-based, magnesia-based, spinel-based, or other ceramic-based material), the following effects can be obtained. That is, as a result of kneading the water-soluble or water-dispersible acrylic polymer and / or acrylic copolymer with the ceramic material in the presence of water or a hydrophilic solvent, the composition of the kneaded product It is possible to improve the adhesive strength or cohesive force between the substances (that is, the individual ceramic particles and the acrylic polymer or acrylic copolymer). Further, according to the kneading agent of the present invention, when the kneaded product (composition) is dried, a cured product that achieves high physical strength according to the adhesive strength or cohesive force is obtained.

The preferred kneading agent of the present invention has a viscosity (viscosity at room temperature of 25 ° C. or around 25 ° C .; the same applies hereinafter) in the range of 1 to 50,000 cP (centipoise). It is a kneading agent. According to the kneading agent having such a viscosity range, a good kneading state of the kneading agent and the ceramic material (that is, the kneading agent and the ceramic material are uniformly mixed and stirred throughout) can be quickly and It can be easily realized.

Particularly preferred as the kneading agent of the present invention is that the acrylic polymer and / or acrylic copolymer as the main component of the kneading agent is polyacrylic acid,
One selected from the group consisting of a polymer containing polymethacrylic acid, polyvinyl alcohol, polyacrylamide, acrylic acid or methacrylic acid or a hydrophilic derivative thereof as a monomer component or a copolymer containing the component, and salts thereof, or It is a kneading agent characterized by being two or more. A kneading agent containing these specific polymers or copolymers as a main component is a kneading material composed of a glass (silica) -based material (porcelain, etc.) or a hydroxyapatite-based material, which are often used as ceramic materials for medical and dental fields. The strength of the dried (molded) cured product can be particularly improved.

The present invention also provides a medical / dental ceramics molding composition obtained by using the kneading agent of the present invention. That is, the medical / dental ceramics molding composition of the present invention is obtained by firing a cured or coagulated molded product.
For molding medical and dental ceramics manufactured by
Used and adhered on a pre-prepared model to a predetermined shape
A composition for molding the molded article of above onto the model,
One or more water-soluble or water-dispersible acrylic polymers and / or acrylic copolymers are contained in water or a hydrophilic solvent and have a viscosity of 1 to 50,000 cP.
And there kneading agent (typically powdery material) ceramic material Ri formed by Toganeri sum, the weight of the ceramic material
The ratio of the total amount of the ceramic material and the kneading agent is
The composition is in the range of 70% to 90% . In the composition for molding ceramics for medical and dental use of the present invention (hereinafter simply referred to as “composition of the present invention”), the kneading agent of the present invention is kneaded so that the composition during molding and drying / curing The adhesive strength or cohesive force between the constituents of the composition can be improved, and when dried, a cured product that maintains high physical strength is formed. For this reason, it is possible to prevent a part of the molded product (cured product) from being collapsed or damaged due to an inadvertent impact after being molded into a predetermined shape.

Further, in the composition of the present invention, the weight ratio of the ceramic material to be kneaded is within the range of 70% to 90% of the total amount of the ceramic material and the kneading agent. It is a thing. The composition of the present invention obtained in such a weight ratio has a good kneading balance between the kneading agent and the ceramic material, and can have a dense structure with a high filling degree. For this reason,
It is possible to further improve the adhesive strength or cohesive force between the constituent substances of the composition. Further, the composition of the present invention more preferably has a viscosity of 100 to 10
It is within the range of 2,000 cP. A composition having such a viscosity range can further improve the adhesive strength or cohesive force between the constituent substances of the composition during molding and during drying and curing.

More preferably, the acrylic polymer and / or acrylic copolymer is polyacrylic acid, polymethacrylic acid, polyvinyl alcohol, polyacrylamide, acrylic acid or methacrylic acid. Alternatively, one or more compositions selected from the group consisting of a polymer containing a hydrophilic derivative thereof as a monomer component or a copolymer containing the component, and a salt thereof are provided. Further, in this case, it is more preferable that the ceramic material is porcelain or other silica-based material, hydroxyapatite-based material, alumina-based material, zirconia-based material, magnesia-based material, or spinel-based material.

The present invention also provides a method for producing a medical / dental ceramics in connection with the use of the above-mentioned kneading agent of the present invention. That is, the method for producing a ceramic for medical and dental use of the present invention comprises (a) one or more water-soluble or water-dispersible acrylic polymers and / or acrylic copolymers contained in water or a hydrophilic solvent. The viscosity is 1
The weight ratio of the ceramic-based material is obtained by kneading the kneading agent of 50,000 cP and the ceramic-based material.
Is 70% of the total amount of the ceramic material and the kneading agent
A step of obtaining a composition within a range of 90% to 90% , (b) a composition prepared in advance of the composition obtained by the kneading.
A step of adhering onto a mold and molding into a predetermined shape, (c) a step of curing the molded composition, and (d)
Baking the cured composition. According to the medical / dental ceramics manufacturing method of the present invention (hereinafter, simply referred to as “the manufacturing method of the present invention”), the above (a) is used.
Due to the physical strength of the ceramic molding composition of the present invention obtained in the process, the above-mentioned excessive caution and attention should be paid to the build-up and other molding operations in dental ceramic production and the subsequent handling of the composition. It can be done without compulsion.

The preferred production method of the present invention is
The step (c) is a method performed by drying the molded composition at room temperature (typically 15 ° C to 35 ° C). According to this method, a cured product (molded product) having desired physical strength can be obtained without performing a complicated process such as the above-mentioned light irradiation process.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the kneading agent of the present invention, the composition of the present invention and the production method of the present invention will be described below.

The water-soluble or water-dispersible (typically present as an oil-in-water emulsion) acrylic polymer or acrylic copolymer used in the liquid kneading agent of the present invention is a ceramic particle. Mutual adhesiveness or cohesiveness, that is, physical strength after drying and curing (condensation) of the ceramic molding composition (kneaded product) can be improved. Further, silica-based materials and other ceramics for medical and dental use are fired at a relatively low temperature and / or a low amount of heat, and it is preferable that carbon is not significantly left in the fired body obtained under such firing conditions. This is because the remarkable carbon residue adversely affects the color tone and odor of the obtained ceramics, and is not preferable in the production of dental ceramics such as dentures or medical ceramics which require aesthetics. That is, materials for ceramics for medical and dental use represented by porcelain and other silica-based materials typically have a firing temperature of 1350 ° C. or less in a firing furnace and a melting start temperature of about 400.
C to 900C. In addition, the temperature rising condition during firing is approximately 2
0 ° C to 90 ° C / min. Therefore, it is preferable that carbon is not left in the obtained fired body or can be reduced to a negligible level even when fired for a relatively short time under a low calorific condition. In the conventional kneading agent having a photopolymerizable monomer, carbon may be remarkably left when it is baked under the condition of a low heat quantity in such a relatively short time. Therefore, when producing general medical and dental ceramics (typically ceramics made of porcelain and other silica-based materials), there is a case where it is unavoidable to perform firing under the condition of giving a higher heat amount than usual. Obtained.
Further, it is particularly preferable that the burning substance does not adhere to the firing furnace and contaminate the firing furnace during firing under the above conditions. Further, it is preferable that the drying and curing before firing proceed relatively gently, and the temperature after kneading (for example, 15 ° C to
Those that cure in a drying environment at 35 ° C., for example, in 3 to 10 minutes are particularly preferable. If the drying and curing are too quick, the molding process may be difficult to perform, and there is a possibility that there will be no time to make fine adjustments to the roughly molded shape. On the other hand, if the drying and curing are too slow, the entire manufacturing process is delayed, which is not preferable from the viewpoint of efficiency.

From the above viewpoint, the water-soluble or water-dispersible acrylic polymer or acrylic copolymer preferably used in the liquid kneading agent of the present invention has a hydrophilic functional group. Acryloyl group, vinyl group, methacryloyl group, 1-propenyl group, isopropenyl group, allyl group, 1-butenyl group, a polymer or copolymer of monomers or oligomers having a polymerizable unsaturated group such as 2-butenyl group It is a polymer. Polymers of monomers having an acryloyl group, vinyl group or methacryloyl group or copolymers containing them are particularly suitable.

Preferred hydrophilic functional groups are acidic groups such as carboxyl groups and hydroxyl groups, and basic groups such as amino groups. For example, when the particle surface of the ceramic material is positively charged, from the viewpoint of adsorption ability to the particle surface, an anionic acrylic polymer or acrylic copolymer rich in acidic groups such as carboxyl group and hydroxyl group is used. A polymer is suitable as the main component of the kneading agent of the present invention. Further, when enumerating particularly preferable ones as the water-soluble or water-dispersible acrylic polymer or acrylic copolymer, (1) .polyacrylic acid, (2) .polymethacrylic acid, (3) .polyvinyl alcohol, (4). Polyacrylamide, (5). A polymer containing acrylic acid or methacrylic acid as a monomer component or a copolymer containing the component,
(6). A polymer containing a hydrophilic derivative of acrylic acid or methacrylic acid as a monomer component or a copolymer containing the component, (7). These listed acrylic polymers or acrylic copolymers (hereinafter referred to as There is a salt of "acrylic polymer compound" collectively. According to the kneading agent using these acrylic polymer compounds, a drying / curing (condensing) time suitable for preparing medical / dental ceramics (typically, after kneading, the mixture is allowed to stand at room temperature (room temperature) and Min ~
10 minutes) can be realized.

Preferred examples of the hydrophilic derivative include maleic acid, itaconic acid, vinyl alcohol, acrylamide, and acrylic acid esters and methacrylic acid esters having various hydrophilic groups. By the way, the molecular weight (number average molecular weight or weight average molecular weight) of the acrylic polymer compound used is not particularly limited, but it has an effect on the viscosity after preparation of the kneading agent (that is, ease of kneading, etc.). Considering the adsorptivity and cohesiveness exhibited when kneaded with a ceramic material or a ceramic material, it may be appropriately changed depending on the difference in properties such as viscosity of the acrylic polymer compound to be used. If it is an acrylate or the like, the weight average molecular weight is preferably in the range of 200,000 to 20,000,000, more preferably in the range of 500,000 to 10,000,000.

From the viewpoint of improving the water solubility, the salt of the above-mentioned acrylic polymer compound can also be used in the practice of the present invention. Examples of such suitable salts include alkali metal salts such as sodium salts and potassium salts, ammonium salts, amine salts and the like. It should be noted that, although not particularly limited, a kneaded product (ceramic molding composition)
From the viewpoint of improving the physical strength (cohesive strength, etc.) of the acrylic polymer compound, the proportion of the acrylic polymer compound contained in the kneading agent of the present invention as a salt (ie, the neutralization ratio) is 70% or less of the whole molecular compound is more preferable, and 40% or less is further preferable.

Suitable solvents for dissolving or dispersing (typically suspending as an emulsion) these water-soluble or water-dispersible acrylic polymer compounds include, but are not limited to, water. Various hydrophilic solvents can be used. Examples of the hydrophilic solvent include methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, ethylene glycol or a polymer thereof,
Ethylene glycol monoethyl ether, ethylene glycol monomethyl ether, ethylene glycol mono n
-Butyl ether, propylene glycol or a polymer thereof, 1,3-butanediol, glycerin and the like can be mentioned. In the practice of the present invention, these hydrophilic solvents can be used alone or as a mixed solvent of two or more kinds or as a mixed solvent of these and water, and as the hydrophilic solvent in the present invention, these mixed solvents or A mixed solvent of these and water is also included.

The kneading agent of the present invention includes a water-soluble or water-dispersible acrylic polymer as the main component, as long as it does not affect the kneading property with a ceramic material and the non-residual property of carbon during firing. In addition to the compounds, various substances can be added. Such additives are typically surfactants for various uses (emulsifiers, dispersants, solubilizers, defoamers, wetting and penetrating agents, etc.), preservatives, pH adjusters, inorganic or organic pigments, etc. Can be used as needed. Further, in order to efficiently dissolve or disperse an acrylic polymer compound having an excessive acidic group (carboxyl group etc.) in water or other hydrophilic solvent (medium), the acidic group of the acrylic polymer compound should be At least a portion can be neutralized with a basic substance. The basic substances added for this purpose include monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, diethylenetriamine, triethylenetetramine, monoethanolamine, diethanolamine, triethanol. Amine, monoisopropanolamine, diisopropanolamine, dimethylethanolamine, diethylethanolamine, methylpropanolamine, morpholine, methylmorpholine, amines such as piperazine, ammonia, or inorganic compounds such as sodium hydroxide, potassium hydroxide, lithium hydroxide Is mentioned. Inorganic compounds such as sodium hydroxide and potassium hydroxide are particularly suitable.

The kneading agent of the present invention is not particularly limited, but typically, in a water or hydrophilic solvent placed in a predetermined container,
It can be obtained by adding one or more of the above acrylic polymer compounds, preferably in small portions, and appropriately stirring and mixing. Further, the acrylic polymer compound may vary depending on its solubility, but typically, it is in the form of a powder or is previously dissolved in a small amount of a suitable organic solvent, or as an emulsion water or a hydrophilic solvent. It may be added inside. Further, each of the above-mentioned additive substances may be added simultaneously with or separately from the acrylic polymer compound.

The appropriate concentration of the acrylic polymer compound used in the kneading agent of the present invention may vary depending on the properties such as the average molecular weight and the viscosity of the acrylic polymer compound used. From the viewpoint of ease of handling and easiness of kneading (that is, easiness of completely mixing and stirring the ceramic material and the kneading agent), regardless of the type of acrylic polymer compound used. Instead, it is preferable to adjust the concentration so that the viscosity of the kneading agent itself is 1 to 50,000 cP (centipoise) at room temperature around 25 ° C. According to a kneading agent having such a viscosity range, a ceramic material crushed into a powder (or fine particles) or a ceramic material prepared in advance into a paste with the same solvent used for the above kneading agent is used. Is easy to mix,
A good kneading state of the kneading agent and the ceramic material (that is, the kneading agent and the ceramic material are mixed and stirred more uniformly over the whole) can be quickly and easily realized. Therefore, the adhesiveness or cohesiveness between the ceramic particles can be more surely improved. It is more preferable to add a wet penetrant and other substances that can contribute to the improvement of the kneading efficiency.

On the other hand, the ceramic material used in the practice of the present invention is a ceramic that can be generally used for producing dental ceramics or dental ceramics used as a prosthesis or filling material for dentistry or medicine. Any type of material can be used without particular limitation. As a preferable example of such a ceramic material, for example, a dental silica material called porcelain (typical composition ratio (weight ratio) is 40 to 70% of SiO _{2 and} 1 of Al ₂ O _3).
0~20%, K ₂ O is 5~14%, Na ₂ O is from 1 to 11%
In addition to these, as minor components, BaO, CaO, M
gO, B ₂ O _3, may contain TiO ₂ and the like. ). Further, a calcium phosphate-based crystallized glass material, a mica-based crystallized glass material, and other castable glass-ceramics-based materials that are frequently used for medical or dental purposes can be cited. In addition to these, hydroxyapatite-based materials, crystalline ceramic materials such as silica, alumina, and zirconia, or composite materials thereof (including those having a spinel structure) can be preferably used. From the viewpoint of kneading efficiency with the kneading agent of the present invention, powdery (or fine granular) particles having an average particle diameter of 100 µm or less are preferable, and particles having an average particle diameter of 5 µm to 35 µm are particularly preferable.

Next, a preferred embodiment for producing medical / dental ceramics from the kneading liquid of the present invention and a ceramic material will be described. Since the kneading agent of the present invention is liquid at room temperature, it can be used in a smaller amount than that of the ceramic material. Although not particularly limited, the weight ratio of the ceramic material (typically powder) used is generally 60% to 95% of the total amount of the ceramic material and the kneading agent. Preferably 70% to 90%
Is more preferably within the range. Such a weight ratio is particularly suitable when the viscosity of the kneading agent used is in the above-mentioned suitable range. In a mortar or other suitable container, the ceramic material having the above weight ratio is typically kneaded with the kneading agent of the present invention in a room temperature state or a state of being heated to a desired temperature. At this time, the ceramic material is preferably used by crushing it into a dry powder form (fine particle form), but it is preferably wet with a small amount of water or other solvent similar to that used for the above kneading agent in advance. Alternatively, it may be in a paste state. Next, the kneaded product obtained by the kneading, that is, the composition of the present invention (typically kneaded into a paste) is molded into a predetermined shape. Such molding process is typically a crown or the like as a ceramic for dental as in the case of producing a denture, wet state before kneaded mixture (dry previously prepared metal frame or ceramic frame other on the model Object) and form (build up) into a predetermined shape.
The contents of the molding process performed by an operator such as a dental technician may be the same as those in the conventional method, and there is no limitation in carrying out the present invention.

Next, if necessary, general condensation or other water absorption, deaeration and / or filling / densification treatment is performed on the molded composition, and then the molding composition is cured. The hardening process can be performed by various methods used in conventional ceramics manufacturing.
In carrying out the present invention, it is preferable that the molded product after the molding step is naturally dried at room temperature (room temperature: typically 15 ° C to 35 ° C) to cure the molded product. For example, in the case of manufacturing a dental prosthesis such as a crown as dental ceramics, such curing can be achieved by placing the molded product in a suitable drying chamber at room temperature after performing condensation if necessary. it can. In the case of a molded product containing the above-mentioned suitable acrylic polymer compound, typically, 3 minutes to
Such drying and curing can be achieved in 10 minutes. In addition, although not particularly limited, if necessary, dry air is blown into the drying chamber and applied to the surface of the molded product, or the temperature is slightly higher than room temperature (for example, the boiling point of water is 35 ° C. or higher and the boiling point of water is The following temperatures: preferably 35 ° C to 80 ° C)
By placing the molded product underneath, it is possible to dry and cure the molded product more quickly.

Next, the cured or coagulated molded product is fired to produce the desired medical ceramic or dental ceramic. The conditions for firing the ceramic molding composition obtained by the present invention are not particularly limited, and various conventional methods can be used. In general,
The firing temperature and / or the temperature raising conditions are appropriately determined according to the material of the ceramic material used. For example, when using a silica-based material such as porcelain, the cured molded product is first heated to 400 ° C to 900 ° C, preferably 500 ° C to 70 ° C.
It is placed in the furnace opening of the firing furnace kept at 0 ° C. for 3 to 10 minutes to remove organic substances. Then, firing is performed in a firing furnace for 3 to 50 minutes under a temperature rising condition of about 20 to 65 ° C per minute. The firing temperature at this time is preferably 1350 ° C. or lower, and although not particularly limited, when a silica-based material such as porcelain is used, a relatively low firing temperature of about 900 ° C. to 1050 ° C. is applied. Can be done. Also, the firing should be about 101.3 kPa or less (ie 1 atm (7
It can be performed under a reduced pressure condition of 60 mmHg) or less).

[0030]

The present invention will be described in more detail by the following examples. The invention is not limited to these examples.

<Example 1> An emulsion type acrylic acid ester copolymer (A-104 (trademark or trade name) manufactured by Toagosei Co., Ltd.) was suspended in purified water (deionized water) to obtain a solid content. : About 40%, viscosity: 100-2000 cP
A kneading agent of / 25 ° C was obtained.

Example 2 A kneading agent obtained by diluting the kneading agent obtained in Example 1 by two times with purified water was obtained.

<Example 3> Emulsion type acrylic acid ester type copolymer in purified water (manufactured by Toagosei Co., Ltd .: H
T-303 (trademark or trade name) was suspended to obtain a kneading agent having a solid content of about 25% and a viscosity of 100 to 1000 cP / 25 ° C.

<Example 4> An emulsion type acrylic ester copolymer (ES-52 (trademark or trade name) manufactured by Chuo Rika Kogyo Co., Ltd.) was suspended in purified water to give a solid content of about 40%. Viscosity: 100-1000 cP / 25 ° C
To obtain a kneading agent.

<Example 5> A water-soluble acrylic ester copolymer in purified water (manufactured by Toagosei Co., Ltd .: HD-5
(Trademark or trade name)), solid content: about 25
%, Viscosity: 100-2000 cP / 25 ° C. A kneading agent was obtained.

<Example 6> The kneading agent obtained in Example 5 was diluted two-fold with purified water to obtain a kneading agent.

<Example 7> The kneading agent obtained in Example 5 was diluted 10 times with purified water to obtain a kneading agent.

Example 8 97.5 parts by weight of purified water, 2.0 parts by weight of sodium hydroxide and 0.5 part by weight of water-soluble carboxyvinyl polymer (Carbopol (trademark or trade name) manufactured by BFGoodrich). Mixing, viscosity: 100 ~
A kneading agent of 2000 cP / 25 ° C. was obtained.

Example 9 A kneading agent obtained by doubling the kneading agent obtained in Example 8 with purified water was obtained.

<Comparative Example 1> A one-component visible light curable acrylic resin (Acrylic One # 1320 (trademark or trade name, manufactured by Maruto) was appropriately suspended in purified water to prepare a kneading agent. .

Comparative Example 2 96 parts by weight of an aqueous solution of ditrimethylolpropane tetraacrylate (monomer) (manufactured by San Nopco: Nopcomer 4410 (trademark or trade name)) and a polymerization initiator (manufactured by San Nopco: Dolka Gure 18)
4 (trademark or trade name) 4 parts by weight were mixed under shading to prepare a kneading agent.

Comparative Example 3 96 parts by weight of an aqueous solution of dipentaerythritol pentaacrylate (monomer) (manufactured by San Nopco: Nopcomer 4510 (trademark or trade name)) and a polymerization initiator (manufactured by San Nopco: Ilkagua 18)
4 (trademark or trade name) 4 parts by weight were mixed under shading to prepare a kneading agent.

Comparative Example 4 Aqueous solution of epoxy acrylate (oligomer) (manufactured by San Nopco: Photomer 30)
16 (trademark or trade name)) and 4 parts by weight of polymerization initiator (manufactured by San Nopco: Ilkagua 184 (trademark or trade name)) were mixed under shading to prepare a kneading agent.

Comparative Example 5 96 parts by weight of an aqueous solution of a polyurethane acrylate (oligomer) (manufactured by San Nopco: Photomer 6008 (trademark or trade name)) and a polymerization initiator (manufactured by San Nopco: Ilkagua 184 (trademark or trade name)) ) 4 parts by weight were mixed under shading to prepare a kneading agent.

Comparative Example 6 An aqueous solution of an ultraviolet (UV) curable acrylic resin (SN-5X8639 manufactured by San Nopco Ltd.).
96 parts by weight (trademark or trade name) and 4 parts by weight of a polymerization initiator (Ilkagua 184 (trademark or trade name) manufactured by San Nopco Ltd.) were mixed under light shielding to prepare a kneading agent.

Comparative Example 7 An aqueous solution of an ultraviolet (UV) curable acrylic resin (SN-5X8640 manufactured by San Nopco Ltd.).
96 parts by weight (trademark or trade name) and 4 parts by weight of a polymerization initiator (Ilkagua 184 (trademark or trade name) manufactured by San Nopco Ltd.) were mixed under light shielding to prepare a kneading agent.

Comparative Example 8 A suspension of a water-dispersible polyester (Vylonal MD-1200 (trademark or trade name) manufactured by Toyobo Co., Ltd.) was appropriately suspended in purified water to prepare a kneading agent. .

<Comparative Example 9> A suspension of a water-dispersible polyester (manufactured by Toyobo Co., Ltd .: Bayronal MD-1500 (trademark or trade name)) was appropriately suspended in purified water to prepare a kneading agent. .

<Comparative Example 10> A suspension of linear saturated polyester (manufactured by Toyobo Co., Ltd .: Byron 20SS (trademark or trade name)) was appropriately suspended in purified water to prepare a kneading agent.

<Comparative Example 11> A polyester urethane suspension (Vylon UR1400 (trademark or trade name) manufactured by Toyobo Co., Ltd.) was appropriately suspended in purified water to prepare a kneading agent.

Comparative Example 12 A suspension of a water-dispersible polyester (manufactured by Toyobo Co., Ltd .: TAD-1000 (trademark or trade name)) was appropriately suspended in purified water to prepare a kneading agent.

Comparative Example 13 A kneading agent was prepared by mixing 5 parts by weight of ethyl cellulose (Etocel STD-45 (trademark or trade name) manufactured by Dow Chemical Co.) and 95 parts by weight of ethanol.

<Example 10> -Preparation of ceramics molding composition and evaluation of filling degree of the composition-In the kneading agent according to the present invention obtained in Examples 1 to 9 and Comparative Examples 1 to 13 A ceramic molding composition was prepared using each of the prepared kneading agents, and the filling degree of each composition after molding was examined. That is, the kneading agent obtained above and porcelain powder (super porcelain AAA (trademark or trade name) manufactured by Noritake Co., Ltd.) commercially available for producing dental ceramics are mixed and kneaded at a weight ratio of 1: 3. Then, a ceramics molding composition corresponding to each of the above kneading agents was prepared. Then, each composition was built up in the form of a crown on the left central incisor of the metal frame upper jaw, which was previously baked with opaque porcelain. Then, the ordinary condensation treatment was performed on each of the built-up products (molded products). The filling degree of each composition was evaluated using the ease of performing the condensation treatment at this time as an index. The reason why condensation is easy is that excess water and air bubbles can easily escape from the inside of the molded product, and as a result, the filling degree (denseness) of the porcelain powder is improved. The filling degree reflects whether or not the moldability (the property relating to the ease of obtaining a fired body without cracks or partial peeling) is good or bad. The results are shown in Table 1 for each kneading agent (Examples 1 to 9 and Comparative Examples 1 to 13). In addition, Comparative Example 14 in Table 1 is a result regarding a composition obtained by using pure water in the same weight ratio instead of the above kneading agent (the same applies to the following Examples). The double circle mark (⊚) in the column of filling degree in Table 1 shows that the condensation was performed very well and that a relatively high filling degree was recognized.
The single circle mark (∘) indicates that the condensation was performed almost completely and that the filling degree was recognized to the extent that there was no problem in moldability. On the other hand, a cross mark (x) indicates that a defective condensation such as leaving a sticky feeling after the treatment was observed and that the filling degree was insufficient.

[0054]

[Table 1]

As is clear from Table 1, all the compositions obtained by using the kneading agent according to the present invention obtained a good filling degree, but the kneading agents prepared in the respective comparative examples were used. Some of the used ones were found to have insufficient condensation and an insufficient filling degree.

<Example 11> -Curing treatment of molded product and evaluation of adhesion strength of cured molded product- Each molded product prepared in Example 10 was cured on the metal frame, and at the same time, the cured product was treated as described above. The adhesion strength to the frame was evaluated. That is, at room temperature (here, 2
5 ° C.) by leaving it in a drying chamber for drying or using a kneading agent containing a photopolymerizable monomer or oligomer, an ultraviolet irradiator (manufactured by Morita: α-Light (trademark) Each molded product was completely cured on the metal frame by irradiating it with ultraviolet rays. Then, the cured molded article was gently scratched using a spatula, and the cured molded article was examined for peeling. The results are shown in Table 1 above. The circle mark (○) in the column of adhesive strength in Table 1 is
The one in which the cured molded product is entirely attached to the frame side is shown. The cross mark (x) indicates that the cured molded product is peeled from the frame by the scratching treatment. As is clear from Table 1, the compositions using any of the kneading agents except for purified water (Comparative Example 14) showed good adhesive strength.

<Example 12> -Curing treatment of molded article for a predetermined time and evaluation of physical strength after the curing treatment- Each composition prepared in the above Example 10 was filled in a predetermined mold for 5 minutes. After the curing treatment, the physical strength of each composition (molded product) after the treatment was examined. That is, each composition prepared in Example 10 was surface-treated with a surface treatment agent (Noritake Stone Hardener (trademark or trade name) manufactured by Noritake Co., Ltd.), and then a V-shaped gypsum model (previously coated with a separating agent). Depth 1.5 mm x Width 3.5 mm x Length 2
6 mm) was pressed and supplied and filled in the mold. Next, the model is placed in a drying cabinet under room temperature (here, 25 ° C) conditions.
By leaving it for a minute to dry or using a kneading agent containing a photopolymerizable monomer or oligomer, an ultraviolet irradiator (manufactured by Morita: α-Lig
The curing process was carried out by irradiating with UV light for 5 minutes using ht (trademark or trade name). Then, each composition cured using a spatula was taken out of the model. Then, an attempt was made to cut each of the groove-shaped molded products with fingers. The results are shown in Table 1 above. Double circle mark (◎) in the column of cutting strength in Table 1
Shows that it can be cut cleanly by applying a certain amount of strength. The single circle mark (∘) indicates a mark that can be cut when a certain amount of strength is applied but may be slightly deformed. The cross mark (x) indicates that it is crushed before being cut. As is clear from Table 1, the composition using any of the kneading agents except for purified water showed good or sufficient strength.

At the same time, the dryness of each composition (molded product released from the mold) after the curing treatment for 5 minutes was examined by touching the surface with fingers. The results are shown in Table 1 above. Table 1
A circle mark (○) in the column of dryness indicates that a wet feeling is not recognized when touched with fingers. The cross mark (x) indicates that a wet feeling is recognized when touched with fingers. As is clear from Table 1, all the compositions using the kneading agent according to the present invention were able to achieve a good dry state (that is, a cured state) during the above-mentioned treatment for 5 minutes. Some of the ones using the kneading agents prepared in the examples were found to be insufficiently dried.

<Example 13> -Baking treatment of molded article and evaluation of carbon residue after firing- After molding each composition prepared in Example 10 into a predetermined shape, firing treatment was carried out under the following conditions. . Each of the obtained fired bodies was examined for the presence or absence of carbon residue. That is, each of the compositions prepared in Example 10 was molded into a button shape using an acrylic resin mold (diameter 10 mm × thickness 1.0 mm). Then, after carrying out the same curing treatment as that carried out in Example 11 above, it was placed at the furnace opening of a porcelain furnace (manufactured by JELENKO: COMMODORE75 (trademark or trade name)) kept at 700 ° C. for 7 minutes. Organic matter removal treatment was performed. Then, a firing process was performed in the furnace under a reduced pressure of 96 kPa while increasing the temperature from 700 ° C. to 930 ° C. at 55 ° C. per minute. Then, the color tone was compared with that before firing by visually observing the obtained fired body, and the presence or absence of carbon residue was examined using the difference in the color tone as an index. The results are shown in Table 1 above. The double circle mark (⊚) in the column of carbon residue in Table 1 indicates that no difference in color tone was observed before and after firing. The single circle mark (∘) indicates that there was only a slight difference in color tone before and after firing. The cross mark (x) indicates that the difference in color tone before and after firing was remarkable. As is clear from Table 1, all of the molded and fired compositions using the kneading agent according to the present invention showed good carbon non-residuality. On the other hand, remarkable carbon residue was observed in the molded and fired compositions using the kneading agents prepared in Comparative Examples 1 to 13 above.

[0060]

EFFECTS OF THE INVENTION According to the present invention, it is possible to provide a medical or dental ceramic molding composition which can be a cured product excellent in physical strength (curing strength) by a simple treatment such as natural drying. According to such a composition of the present invention, a dental technician and other workers involved in the production of medical or dental ceramics can be treated with a great deal of caution and concentration without pre-baking steps comprising the composition of the present invention. It is possible to handle molded articles of. Thus, the composition of the present invention having such an effect can be obtained by using the kneading agent of the present invention. Further, according to the present invention, it can be produced by firing medical ceramics or dental ceramics having no significant carbon residue that affects aesthetics or the like in a medical or dental prosthesis under normal firing conditions.

Front page continued (72) Inventor Hideki Nonokawa, No. 1 36, Noritake Shinmachi, Nishi-ku, Nagoya, Aichi Prefecture, No. 36, Noritake Company Limited (72) Inventor, Keizo Shibata, No. 3, Noritake Shincho, Nishi-ku, Nagoya, Aichi Prefecture 36-36 Noritake Co., Ltd. (72) Inventor Midori Takahashi 3-36 Noritake Shinmachi, Nishi-ku, Nagoya-shi, Aichi Prefecture Noritake Dental Supply Co., Ltd. (72) Inventor Kiyoko Saka Sanori Noritake, Nishi-ku, Nagoya-shi, Aichi Prefecture No. 1-36 Noritake Dental Supply Co., Ltd. (72) Inventor Hajime Sakakibara No. 1-336 Noritake Shinmachi, Nishi-ku, Nagoya City, Aichi Prefecture Noritake Dental Supply Co., Ltd. (56) Reference JP 62- 167250 (JP, A) JP 2-160708 (JP, A) JP 4-329961 (JP, A) JP 7-39577 (JP, A) JP 5-285214 (JP, A) (58) investigated the field (Int.Cl. ^7, DB ) A61L 27/00 A61K 6/00 A61K 6/083 500 C04B 35/632

Claims (12)

(57) [Claims] 1.It is made by firing a cured or solidified molded product.
It is used to mold the manufactured medical and dental ceramics.
It is attached to a pre-prepared model and molded into a predetermined shape.
A composition for molding an article on the model, comprising: One or more water-soluble or water-dispersible acrylics
Water-based polymer and / or acrylic copolymer
Contained in hydrophilic solventThe viscosity is 1 to 50,000 cP
is thereThe kneading agent and the ceramic material are kneaded and formed., The weight ratio of the ceramic material is the ceramic material.
Within the range of 70% to 90% of the total amount of the ingredients and the kneading agent
is there Medical and dental ceramics molding composition. 2. The medical / dental ceramics is a dental prosthesis.
The composition according to claim 1, which is a substance. 3. The viscosity of the kneading agent is 100 to 2000 c.
The composition of claim 1 or 2, which is P. 4. The composition according to claim 1, having a viscosity in the range of 100 to 100,000 cP. 5. The acrylic polymer and / or acrylic copolymer contains polyacrylic acid, polymethacrylic acid, polyvinyl alcohol, polyacrylamide, acrylic acid or methacrylic acid or a hydrophilic derivative thereof as a monomer component. The composition according to any one of claims 1 to 4 , which is one or more selected from the group consisting of a polymer or a copolymer containing the component, and salts thereof. 6. The ceramic material is porcelain.
The composition according to any one of claims 1 to 5. 7. A method for producing a ceramic for medical and dental use, comprising: (a) adding one or more water-soluble or water-dispersible acrylic polymers and / or acrylic copolymers to water or hydrophilic. Included in the solvent , the viscosity is 1 to 50,000
and kneading agent is cP, this for kneading a ceramic material
And the weight ratio of the ceramic material is
70% to 90% of the total amount of the slag-based material and the kneading agent.
A step of obtaining a composition to be an enclosure, (b) preparing the composition obtained by the kneading in advance
Medical and dental treatment including a step of adhering onto a manufactured model and molding into a predetermined shape, (c) a step of curing the molded composition, and (d) a step of baking the cured composition Ceramics manufacturing method. 8. The medical / dental ceramics is a dental prosthesis.
The manufacturing method according to claim 7, which is a product. 9. The prosthesis is in the form of a crown.
The manufacturing method described in. 10. The model is a metal frame or ceramic
10. The frame according to claim 7, which is a back frame.
Production method. 11. The method according to claim 11, wherein the step (c) is performed by drying the molded composition at room temperature.
7. The method according to any one of 7 to 10 . 12. A further composition for the molded composition.
The density treatment is performed, according to any one of claims 7 to 11.
Manufacturing method.