JPS61122150A - Manufacture of porous calcium phosphate compound ceramics - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a method for producing porous calcium phosphate compound ceramics.

This type of porous ceramic is useful as a material for prosthetic implants in the body, such as artificial bones and artificial tooth roots, and is also expected to be used as a chemical functional agent such as a catalyst or adsorbent. be.

In this specification, the term "calcium phosphate compound" refers to a compound produced as a result of the reaction of CaHPO4.0-2H2O and CaCO3 in the required ratio, and a representative example thereof is Caa(PO4)2, i.e., tricalcium phosphate. Fate (hereinafter abbreviated as TCP) and Ca + o (OH) 2 (PO4)s, that is, calcium hydroxyapatite (hereinafter simply abbreviated as apatite).

In addition, all percentages in this specification are calculated based on weight.

Conventional technology and its problems Conventionally, in order to produce porous ceramics such as apatite or TCP, non-porous apatite or TCP was first synthesized, the powder of this synthesized product was slurried with water, and the slurry was foamed. The conventional method was to add hydrogen peroxide or naphthalene as a foaming agent, gradually dry the slurry containing the foaming agent, and then sinter it.

However, as mentioned above, this method requires a foaming agent in addition to the raw materials, which increases the cost of the product.

The present invention was made in view of the above-mentioned circumstances, and an object of the present invention is to provide a new method for producing porous ceramics that allows products to be obtained without using a foaming agent.

Means for Solving the Problems In order to achieve the above object, the method for producing porous ceramics according to the present invention uses CaHPO4.0~2H2O and Ca
It is characterized in that CO3 is wet-pulverized and kneaded in the presence of water to react, the resulting slurry of amorphous calcium phosphate compound is dried to make it porous, and the porous body is fired.

The ratio of CaHPO4.0 to 2H2O and CaCO3 is set to be 1.4 to 1.75 in terms of atomic ratio (Ca/P). However, the above atomic ratio (Ca/P) range is not limited.

When the atomic ratio (Ca/P) is 1.67, apatite is obtained as a reaction product, and when the atomic ratio (Ca/P) is 1.5, TCP is obtained. Then, water is added to the mixture of CaHPO4.0-2H2O and CaCO3 in a bot mill or a ball mill, and the mixture is wet-pulverized and kneaded. Through this wet grinding and kneading, powdered CaHPO4.0~2H2O and C
a CO3 reacts mechanochemically and CaCO3 gradually.

Upon decomposition, many bubbles of CO2 gas are generated in the slurry, and an amorphous calcium phosphate compound is generated. Then, the reaction progresses and CaCO3 completely disappears (X
(confirmed by line diffraction and Raman spectrum), the kneading is finished. The kneading time is usually about 24 hours.

If necessary, a required amount of water is added to the slurry of the amorphous calcium phosphate compound.

The amount of water added determines the cell diameter of the porous ceramic obtained as a product. That is, the smaller the amount of water added, the larger the bubble diameter, and the larger the amount of water added, the smaller the bubble diameter. For example, when the slurry concentration is adjusted to 25% by adding water, the cell diameter of the obtained porous ceramics is approximately 800 mm, and when the slurry concentration is adjusted to 10%, the cell diameter is approximately 80 mm.
III (however, in these cases, the drying temperature is 80
℃, and the firing temperature is 12O0℃).

Drying of the slurry is preferably carried out at 40-200°C. This drying hardens the surface of the slurry, and the slurry as a whole expands uniformly and becomes porous.

The obtained porous body is fired at a temperature of 600 to 1350°C. If the temperature is 600° C. or lower, the firing will not be performed sufficiently, and if the temperature is 1350° C. or higher, the fired product will melt, so the firing temperature is limited to the above range. and temperature about 75
Amorphous material crystallizes at temperatures above 0°C, and temperatures of 1000 to 115°C
At 0°C, significant shrinkage occurs and firing progresses rapidly. As a result of firing the porous body, ceramics are obtained with significantly increased strength.

Ca HP O4・0~2 in a bot mill or ball mill
When water is added to a mixture of H2O and CaCO3 and these are wet-pulverized and kneaded, CaHPO4.0~2H2O and C
aCO3 reacts mechanochemically, CaCO3 gradually decomposes, many bubbles of CO2 gas overlap in the slurry, and an amorphous calcium phosphate compound is produced.

Next, if necessary, the required amount of water is added to the slurry of the amorphous calcium phosphate compound to adjust the slurry concentration to the required value, and then the slurry is dried.The surface of the slurry hardens and the entire slurry is It expands uniformly and becomes porous.

When the obtained porous body is then fired, the strength of the porous body is increased and a ceramic is obtained.

In accordance with the effects of the invention, the method for producing porous ceramics according to the present invention involves wet-pulverizing and kneading CaHPO4.0-2H2O and CaCO3 in the presence of water, reacting them, and producing the resulting amorphous calcium phosphate compound. Since the slurry is dried to make it porous and then the porous body is fired, Ca
By the mechanochemical reaction between HPO4.0~2H2O and CaCO3, CaCO3 can be gradually decomposed and many bubbles of CO2 gas can be generated in the slurry. Therefore, a porous ceramic product can be obtained without using a foaming agent, and the cost of the product can be reduced.

Furthermore, according to the manufacturing method of the present invention, there is no need to synthesize non-porous apatite or TCP in advance as in the prior art described at the beginning, so the manufacturing process is simplified.
In this respect as well, the cost of the product can be reduced.

Example Next, examples will be shown to demonstrate the effects of this invention.

Example 1 In a bot mill, CaHPO4.2H2O powder and ca
Coa powder was blended so that the atomic ratio (Ca/P) was 1°67, and a small amount of water was added to the blend to make these powders at 24°C.
Pulverized and kneaded over time.

Then, a required amount of water was added to the obtained slurry to adjust the slurry concentration to 20%. Next, the slurry was placed in a dryer kept at 80°C and dried, and then the obtained porous body was placed in an electric furnace and the temperature was raised at a rate of 30°C/hour to 12O0. It was kept at ℃ for 1 hour. The porous ceramic thus obtained had an average pore diameter of about 510 square meters and an apatite crystal phase.

Example 2 The same procedure as Example 1 was repeated, except that the slurry concentration was adjusted to 15% by addition of water. The resulting porous apatite ceramic had a pore diameter of 230 tun.

Example 3 The atomic ratio of CaHPO4.2H2O and CaCO3 (Ca/
The procedure of Example 1 was repeated, except that the P) was formulated to be 1.5. The obtained porous ceramic had a pore diameter of about 5,004 mm and had a TCP crystal phase.

Patent applicant: Director of the Agency of Industrial Science and Technology Designated agent: Tatsu Todoroki
Toshiharu Nagase, Director, Nagoya Industrial Technology Testing Institute, Agency of Industrial Science and Technology

Claims (4)

[Claims] (1) CaHPO_4・0~2H_2O and CaCO_3
Porous calcium phosphate compound ceramics, characterized in that the slurry of the amorphous calcium phosphate compound obtained by wet-pulverizing and kneading in the presence of water is reacted, the slurry of the obtained amorphous calcium phosphate compound is dried to make it porous, and the porous body is fired. manufacturing method. (2) CaHPO_4・0~2H_2O and CaCO_3
The method according to claim 1, wherein the ratio of Ca/P is 1.4 to 1.75 in terms of atomic ratio (Ca/P). (3) The method according to claim 1 or 2, wherein the firing temperature is 600 to 1350°C. (4) Adding the required amount of water to the slurry as necessary;
A method according to any one of claims 1 to 3.