JPS63159207A - Production of hydroxyapatite - Google Patents

Abstract

PURPOSE:To obtain hydroxyapatite having fine particle size, high uniformity and purity with simple apparatus and operation under mild condition in a short time, by producing an aqueous slurry containing CaCO3 powder and CaHPO4(.2 H2O) powder at a specific ratio and reacting the slurry under grinding and mixing with a wet pulverizer. CONSTITUTION:CaCO3 powder and CaHPO4 are dispersed in water at a Ca/P atomic ratio of 1.5-1.67 to obtain an aqueous slurry having a concentration of 5-40wt%. The slurry is made to react at 20-50 deg.C for 30min-5hr under grinding and mixing with a wet pulverizer such as ball mill, colloid mill, etc., to obtain the objective hydroxyapatite useful as a material to be used in a living body, a filler for column of liquid chromatography, a humidity sensor, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an improved method for producing hydroxyapatite. More specifically, the present invention provides water-dispersible apatite, which is useful for biological materials such as artificial bone materials, artificial tooth root materials, and ear ossicular materials, as well as column packing materials for liquid chromatography, fertilizers, humidity sensors, etc. The present invention relates to an industrially advantageous manufacturing method in a short period of time under certain conditions.

Conventional technology In recent years, with the development of medical technology, treatment methods have been developed and widely used to restore lost parts and functions of the body by implanting artificial joints, artificial bones, artificial tooth roots, etc. ing.

The materials for these artificial aggregates are those that have a composition similar to that of biological inorganic materials such as bones and teeth, are non-toxic to living organisms, and have excellent bonding properties with bone and ability to replace new bone. Biocompatible calcium phosphates such as hydroxyapatite and β-tricalcium phosphate have attracted attention as preferred materials that meet these requirements, and it has been proposed to prepare artificial tooth roots using these materials. (See, for example, Japanese Patent Laid-Open No. 56-5481).

By the way, there are dry methods and wet methods for producing hydroxyapatite and β-tricalcium phosphate. For example, in the dry method for producing hydroxyapatite, calcium hydrogen phosphate and excess calcium oxide are mixed at A method is known in which hydroxyapatite is produced by reacting in a steam stream at a high temperature of 1300°C. However, this method has disadvantages in that the operation is complicated, the equipment cost is high, and manufacturing costs are inevitably increased.

It is also known that hydroxyapatite can be cleaved by a wet method in which 0.5 mol/l calcium is reacted with an aqueous phosphoric acid solution under conditions of a biological temperature of 37°C and a physiological pH of 7.1 to 7.4. It is being However, this wet method requires strict control of temperature and pH, and also requires a long time to produce hydroxyapatite, so it cannot be considered a practical method.

On the other hand, as a method for developing β-tricalcium phosphate, for example, calcium hydrogen phosphate is calcined at a temperature of 800 to 1000°C to produce β-calcium pyrophosphate (β-ca2p2
07), and this and calcium carbonate? Wet mix using a bot mill, ball mill, etc. at a molar ratio of about 1:l, and then mix this mixed powder at a temperature of 1000 to -100°C.
A dry method is known in which β-tricalcium phosphate is produced by firing at a temperature in the range of . However, in this method, calcination operation of calcium hydrogen phosphate and β-
It is necessary to calcinate the mixed powder of calcium pyrophosphate and calcium charcoal, and the process is complicated.
Equipment costs are high and manufacturing costs inevitably rise.

In addition, as a wet production method of β-tricalcium phosphate,
A method of neutralizing an aqueous slurry of calcium hydroxide and an aqueous phosphorus solution, a method of reacting an aqueous calcium nitrate solution and an aqueous ammonium hydrogen phosphate solution, and the like are known. However, in the former method, the heat of one reaction is large, making it difficult to control the temperature of the reaction system, and if the pH is not kept constant at 6 to 7, particles with various calcium/phosphorus atomic ratios are generated. In addition, even in the latter method, if the pH and temperature of the liquid are not kept constant, particles with various calcium/phosphorus atomic ratios will be generated and become non-uniform. In order to become
There are problems such as the need for sufficient care in its control.

Problems to be Solved by the Invention The present invention improves the drawbacks of the conventional method for promoting biocompatible calcium phosphate, and solves the problem without using complicated equipment and requiring strict control of pH and temperature. The purpose of this invention is to provide an industrially advantageous method for producing biocompatible calcium phosphate in a short time under mild conditions using simple operations that do not require any nuisance.

Means for Solving the Problems The present inventors have conducted extensive research in order to develop a method for industrially advantageous production of biocompatible calcium phosphate, and have found that calcium carbonate powder and calcium hydrogen phosphate or its dihydrate It has been shown that hydroxyapatite can be easily obtained by preparing an aqueous slurry using a specific proportion of powder and a specific proportion of hydroxyapatite, and then reacting this slurry while grinding it under specific mechanical conditions. Based on this finding, we have completed the present invention.

That is, the present invention uses calcium carbonate powder and calcium hydrogen phosphate or its dihydrate powder in a ratio such that the atomic ratio of calcium atoms to phosphorus atoms is in the range of 1.5 to 1.67. The present invention provides a farm road method for producing hydroxyl aba-Zite, which is characterized in that an aqueous slurry is prepared using a wet grinder, and then this slurry is subjected to a reaction while being ground and mixed in a wet grinder.

The present invention will be explained in detail below.

In the method of the present invention,! First, calcium carbonate powder and calcium hydrogen phosphate or its dihydrate powder are used as raw materials, and the atomic ratio of calcium atoms to phosphorus atoms is 1.5.
Aqueous slurries are prepared using proportions ranging from 1.67 to 1.67. When the atomic ratio is less than 1.5, the content of β-tricalcium phosphate and unreacted calcium hydrogen phosphate is high in the product, resulting in low purity of hydroxyapatite, and when it exceeds 1.67, If the product contains a large amount of unreacted calcium carbonate, the purity of the hydroxyapatite decreases.

Further, the slurry concentration is usually selected within the range of 5 to 40% by weight. If the concentration is less than 5% by weight, the concentration is too low to be practical, while if it exceeds 40% by weight, the reactivity will decrease, which is not preferred.

Next, the aqueous slurry thus prepared is reacted while being ground and mixed using a wet grinder, preferably at a temperature in the range of 20 to 50°C. As the grinding device used in this case, for example, a ball mill, a red devil mill (paint conditioner), a vibration mill, a colloid mill, etc. can be used. In the case of grinding and mixing without using a wet grinder, the reaction does not proceed smoothly and a homogeneous hydroxyapatite with high purity cannot be obtained.

By grinding under such conditions, calcium hydrogen phosphate and calcium carbonate are gradually dissolved, a more homogeneous reaction state is obtained, and fine, homogeneous particles of hydroxyapatite are produced. At this time, there is no need to perform pH adjustment, which is different from conventional wet methods. The Mayu reaction time depends on the reaction temperature and shear stress, but is generally 30
About 5 minutes to 5 hours is sufficient.

After 8 reactions in this manner, the reaction product is taken out by means such as filtration or centrifugation, and is preferably
By drying at a temperature in the range of 200° C., a fine, homogeneous and highly pure hydroxyapatite dry powder is obtained.

By firing this dry powder at a temperature in the range of 600 to 1200°C, a sintered hydroxyapatite body with good strength can be obtained.

Effects of the Invention The method of the present invention is a method for producing hydroxyapatite by a wet method using calcium carbonate powder and powder of calcium hydrogen phosphate or its dihydrate as raw materials. A device.

Fine, homogeneous, and highly pure hydroxyapatite can be obtained in a short time under mild conditions by an extremely simple operation without requiring strict control of pH and temperature.

The hydroxyapatite obtained by the method of the present invention can be used for biological materials such as artificial bone materials, artificial tooth root materials, ear ossicle materials, column packing for liquid chromatography, fertilizers, etc.
Suitable for use in humidity sensors, etc.

Example Next, the present invention will be explained in more detail with reference to Examples.

Example 1 An alumina ball zoor with a diameter of 5 fm was placed in a 250-capacity polyethylene container. Calcium hydrogen phosphate trihydrate powder 1
8F, add 7f of calcium carbonate powder and 1002ml of water,
The mixture was ground and mixed at 25° C. for 1 hour using a Redville mill.

Note that the calcium/phosphorus atomic ratio was 1.67.

The slurry is then filtered to remove the solid product,
After drying at 100°C, it was fired at 900°C for 60 minutes. This thing is X! It was confirmed by s diffraction that it was hydroxyapatite. This X-ray diffraction chart is shown in FIG.

Example 2 The same operation as in Example 1 was performed on the crab, except that the amount of water was changed to t-6Of and the firing temperature was changed to 800°C. The obtained product was confirmed to be hydroxyapatite by X-ray diffraction, and the X-ray diffraction chart is shown in Figure 2.

Example 3 In a 250-volume polyethylene container, 200 alumina balls with a diameter of 5 x m and 1 calcium hydrogen phosphate trihydrate powder were placed.
8.4f, calcium carbonate powder 6,62 and water 1009
The mixture was mixed by pulverization at 25° C. for 1 hour using a red pill mill. Note that the calcium/su/atomic ratio was 1.62.

Next, the slurry was filtered, the solid product was taken out, and 1
It was dried at 30°C. This material was confirmed to be hydroxyapatite based on the results of X-ray diffraction. This X-ray diffraction chart is shown in FIG.

Comparative Example In Example 3, the amount of calcium hydrogen phosphate trihydrate powder was 14. , M, the amount of calcium carbonate powder is 10.
The same operation as in Example 3 was performed except that the temperature was changed to 7f. The obtained product was confirmed to be a mixture of hydroxyapatite and unreacted calcium carbonate based on the results of X-ray diffraction. This X-ray chart is shown in FIG. Note that the calcium/phosphorus atomic ratio was 1.75.

[Brief explanation of the drawing]

Figures 1, 2 and 3 are the xi1 diffraction chart and the 4th diffraction chart of hydroxyapatite obtained in the example of the present invention, respectively.
The figure is an X@ diffraction chart of a mixture of hydroxyapatite and calcium carbonate obtained in a comparative example.

Claims (1)

[Claims] 1. Prepare an aqueous slurry by using calcium carbonate powder and calcium hydrogen phosphate or its dihydrate powder in a ratio such that the atomic ratio of calcium atoms to phosphorus atoms is in the range of 1.5 to 1.67. and then reacting this slurry while grinding and mixing using a wet grinder.