JP2768424B2 - Apatite compacts and equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing an apatite compact and an apparatus therefor, and particularly to the production of an apatite compact applied to medical fields such as artificial bones and artificial teeth. The present invention relates to a method and an apparatus preferably used therefor.

[Conventional technology]

Hydroxyapatite [Ca ₁₀ (PO ₄ ) ₆ (OH) ₂ ] is a main component of bone and teeth, and attention is paid to utilizing bacteria and synthetic hydroxyapatite in the medical field.

The main methods for the conventional synthesis of hydroxyapatite include a dry method in which a calcium salt and a phosphate are subjected to a solid reaction at 1000 ° C or higher in an air or steam atmosphere, and a method in which calcium and iron phosphate are dissolved in an alkaline solution. Sedimentation wet method, CaHP
Wet method for hydrolyzing undissolved calcium phosphate such as O ₄ · 2H ₂ O and α-Ca ₃ (PO ₄ ) ₂
There are a method of hydrolyzing O ₄ , a method of precipitating calcium and phosphate in an alkaline solution, and a heat treatment of the precipitate.

[Problems to be solved by the invention]

However, as in the above wet method, etc., hydroxyapatite artificially created in a solution that approximates normal conditions is unstable, and 1000
If it exceeds ℃, it may be easily decomposed. Therefore, conventional apatite compacts have problems such as insufficient strength and instability when used in place of bones and teeth.

An object of the present invention is to provide a method and apparatus for producing a hydroxyapatite compact having sufficient strength to be used in place of bones and teeth.

[Means for solving the problem]

The present invention provides a method for producing an apatite consolidated body, wherein a raw material mixture obtained by adding water to apatite powder and silica-based glass powder is subjected to hydrothermal hot pressing in a state where both gas and water phases coexist. A pressure vessel having means, provided with a pair of opposed caste rods connected to a pressure rod via a packing, and a cylinder unit for loading a raw material between the caste rods, wherein the reaction apparatus, A hydrothermal hot press apparatus characterized in that an open space for water reprocessing is formed between the caste rod and the inner wall of the pressure-resistant container, in which the compressed raw material is stored. It is.

[Action]

The apatite compact of the present invention is obtained by subjecting a hydroxyapatite (apatite) material as a raw material to a solidification treatment with silica glass by a hydrothermal hot pressing method. The hydrothermal hot pressing method is to mechanically pressurize the inorganic compound powder under hydrothermal conditions as shown in the Examples below, thereby squeezing out water existing in the particle gaps to densify it, This is a method for producing a molded article having high mechanical strength by connecting particles to each other by an action, which is basically different from hydrothermal synthesis in the presence of high-temperature, high-pressure water by an autoclave. According to this method, water is added to the raw material powder and molded under hydrothermal conditions. At the same time, the particles are strongly connected, and pores are formed by removing the water remaining between the particles, thereby forming a porous body. Can be obtained.

In this hydrothermal hot pressing, a small amount of water is mixed into the raw material powder (mixed powder of apatite and silica-based glass), the temperature is 200 to 350 ° C., and the mechanically applied pressure is 250 to 500 kg.
/ cm ² for hydrothermal reaction.

The solidification by hydrothermal reaction of the hydrothermal hot pressing method is extremely short compared to the natural sedimentary rock forming action, for example, when silica powder containing caustic soda solution is solidified by hydrothermal reaction, it is extremely short in minutes. In time, it becomes a high-strength solidified material like a chart (shale).

Further, silica-based glass used in the present invention plays a good adhesion function for coagulation of apatite from the chemical properties, for example, while applying a mechanical pressure in 250~500kg / cm ²
Just maintaining at 325 ° C. for a few minutes acts to produce a stable apatite compact.

Therefore, according to the production method and apparatus of the present invention, it is possible to obtain an apatite consolidated body having high strength and suitable as an artificial aggregate or an artificial tooth in an extremely short time.

〔Example〕

FIG. 1 is an explanatory view showing an example of a hydrothermal hot pressing device used when producing an apatite compact according to the present invention.

In FIG. 1, a cylinder portion 2 whose outer periphery is wound by an induction heating coil (not shown) is disposed in a pressure-resistant container 1, and a pressure rod 3, a packing 4, and a caste rod 5 are inserted into the cylinder portion 2. The caste rod 5 is provided with an open space 7 for water reprocessing. These insertion members 3, 4,
5 (7) is provided with a pair of upper and lower portions, respectively, as is apparent from FIG.

The raw material 6 is placed in the space between the upper and lower cast rods.
Is charged and maintained at a predetermined temperature, time and pressure,
The apatite compact of the present invention is formed by solidification.

The procedure and conditions at that time will be described with reference to FIGS.

First, a mixed powder of apatite and borosilicate glass is mixed with a small amount of water. This water-containing powder is charged into the cylinder 2 as a raw material 6, is pressurized by the pressing rod 3, and is heated by an induction heating coil (not shown). At this time, an appropriate ratio of apatite to borosilicate glass can be obtained from FIG. FIG. 2 shows the relationship between compressive strength and density, using the borosilicate glass component as a coefficient.
The heating temperature was 300 ° C., the pressure was 480 kg / cm ² , and the reaction time was 10 minutes. As is clear from FIG. 2, when the borosilicate glass occupies 50 to 60% of the total mass, it has the maximum compressive strength and density.

As is evident from the results, the glass and apatite are linked to each other, and the consolidated body of the present invention is stronger than the single component, and the glass and apatite reinforce each other. You can see that it is.

Thus, the following examples are all examples in which the ratio of borosilicate glass to apatite is 1: 1.

FIG. 3 shows the relationship between the compressive strength and the density when reacting at a heating temperature of 300 ° C. for 10 minutes with the amount of water added as a coefficient for indicating an appropriate amount of water. .

As is clear from FIG. 3, it is suitable that the amount of water to be added is about 25% of the whole (the total amount of glass and apatite). That is, the compressive strength of the consolidated body obtained when the amount of water added is about 25% becomes maximum, and the compressive strength decreases as the amount of water further increases.

This means that if the amount of added water is too large,
The excess space (open space 7 for water reprocessing) is filled with an aqueous solution during the reaction, and the raw material 6 (solidified body) does not progress to a dense state. Means that the reaction hardly proceeds.

Therefore, optimally, it is desirable that the raw material 6 be immersed in water and the open space 7 for water reprocessing be filled with both air and water phases (that is, the degree that both air and water phases coexist). The amount to produce is around 25% of the total mass.

FIG. 4 shows the relationship between the compressive force and the density of the raw material 6 (solidified body) with the addition amount of water being 25%, the reaction time being 10 minutes, and the reaction temperature being a coefficient.

As apparent from FIG. 4, the compressive strength rapidly increases with the temperature rise at 325 ° C. or lower, but decreases with the temperature rise at 325 ° C. or higher. This means that at 325 ° C. or higher, the water activity decreases.

The pressure applied to the pressure rod 3 is 100 kg / cm ²
Although it hardens even to the extent, in the above examples, it was performed at 480 kg / cm ² which is close to the optimum value.

As for the pressure and strength, the pressure is 100 to 500 kg / cm ²
The intensity gradually rises in the range.

Under these conditions, the apatite compact obtained at a temperature of 325 ° C., a pressure of 480 kg / cm ² , a mass of apatite to glass of 1: 1 and a water content of 25% by mass has a compressive strength of 2100 kg / cm ² showed that.

The density of this apatite compact is 1.91 g / cm ³ ,
It has a large number of micropores, and since the micropores absorb stress, they also have toughness. This means that it is difficult to prevent the generation of micropores, which is a feature of the hydrothermal reaction itself, which means that the present invention brings about an effect suitable for use of the apatite compact.

Furthermore, the porosity can be adjusted in this case by increasing or decreasing the amount of apatite. Although a quantitative correlation is not required, it is qualitatively sufficient.

In addition, when the apatite solid body of the present invention is used as an artificial bone, there is a case where it is desired to use the apatite with reduced strength depending on a part to be used. This is because if there is too much strength at a specific location, the bone around the location becomes weak, and it is necessary to adjust the strength of the usage location in consideration of the strength around the usage location.

In this case, the strength adjustment reduces the amount of glass,
The strength can be easily adjusted to an arbitrary strength of 2100 kg / cm ² or less by lowering the compression pressure applied to.

〔The invention's effect〕

As described above in detail, according to the production method of the present invention, since the silica-based glass has a function as an adhesive, apatite is solidified firmly by the silica-based glass, and a stable apatite compact is formed. Can be manufactured.

Further, the hydrothermal hot pressing device of the present invention is a device suitable for carrying out the method for producing the apatite compact.

The apatite compact obtained by the production method and apparatus of the present invention has a high compressive strength and is porous, so that it can easily absorb stress and is excellent in toughness. As an alternative material, etc., the function can be sufficiently exhibited.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing an example of a hydrothermal hot pressing apparatus used for producing an apatite compact of the present invention. FIGS. 2 to 4 are diagrams showing conditions and conditions for producing an apatite compact of the present invention. It is a figure which shows the relationship with the physical property of the apatite compact obtained by the conditions, FIG. 2 is a correlation diagram with the compressive strength and density which make a glass component into a coefficient, FIG. FIG. 4 is a correlation diagram between the compressive strength and the density with temperature as a coefficient.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) A61L 27/00 C01B 25/32 C04B 28/34

Claims (3)

(57) [Claims] 1. A method for producing an apatite consolidated body, wherein a raw material mixture obtained by adding water to apatite powder and silica-based glass powder is subjected to hydrothermal hot pressing in the presence of both gas and water phases. 2. The proportion of the silica glass powder in the total amount of the apatite powder and the silica glass powder is 50 to 60% by mass, and the conditions of the hydrothermal hot pressing are as follows: temperature: 200 to 350 ° C., pressure: :twenty five
Method of manufacturing apatite solid sintered body according to claim 1, characterized in that the 0~500kg / cm ^2. 3. A reaction in which a pair of caste rods opposed to each other and connected to a pressure rod via a packing is provided in a pressure vessel having a heating means, and a cylinder portion for loading a raw material is formed between the caste rods. The apparatus is characterized in that the caste rod is configured to have an open space for water reprocessing for storing water squeezed from compressed raw materials between the caste rod and the inner wall of the pressure-resistant container. Hydrothermal hot press equipment.