JPH06134030A - Method for producing α-type tricalcium phosphate - Google Patents

Abstract

(57) [Summary] [Structure] When α-type tribasic calcium phosphate is produced from γ-type calcium pyrophosphate and calcium carbonate, the contents of magnesium and aluminum contained in the α-type tribasic calcium phosphate are each 0. 1% by weight
The following is a method for producing α-type tricalcium phosphate. [Effect] By specifying the content of each of magnesium and aluminum in the α-type tribasic calcium phosphate to be 0.1% by weight or less, a highly pure and stable product can be obtained.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing α-type tricalcium phosphate. More specifically, the present invention relates to a method for producing α-type tribasic calcium phosphate as a hydration-hardening cement raw material using γ-type calcium pyrophosphate and calcium carbonate as raw materials.

[0002]

2. Description of the Related Art α-type tribasic calcium phosphate reacts with water and self-hardens to form hydroxyapatite. The hydroxyapatite is similar to the main components of teeth and bones in a living body, and has recently attracted attention as a medical cement for teeth, bone filling agents and the like.

Wet methods and dry methods are known as methods for producing α-type tribasic calcium phosphate. In the wet method, calcium ions and phosphate ions are reacted in an aqueous solution to precipitate amorphous calcium phosphate, which is dried and then heat-treated at a high temperature for production. On the other hand, the dry method uses dicalcium phosphate at about 5
It is manufactured by mixing γ-type calcium pyrophosphate obtained by heating at 50 ° C. for about 2 hours with calcium carbonate and firing at about 1200 ° C.

Since α-type tribasic calcium phosphate prepared by the wet method has low strength of hydroxyapatite produced by self-hardening, the dry method is mainly adopted for producing α-type tribasic calcium phosphate for self-hardening.

However, in the dry method, if γ-type calcium pyrophosphate and calcium carbonate are not uniformly mixed, impurities such as calcium oxide will be produced in addition to α-type tricalcium phosphate after firing. In addition, when magnesium oxide is included, β-type tribasic calcium phosphate is produced, so that it is difficult to obtain a pure phase of α-type tribasic calcium phosphate. Therefore, in order to obtain a pure phase of α-type tribasic calcium phosphate, it is necessary to sufficiently mix the γ-type calcium pyrophosphate and calcium carbonate while preventing the mixing of magnesium and perform the firing.

[0006] Conventionally, in order to prevent the coloring and the mixing of magnesium due to the contamination of the metal components, the mixing of these has been carried out by using a ball mill or a mortar made of mullite (silica alumina) or alumina. However, the prevention of by-product of β-type tribasic calcium phosphate may not be prevented only by preventing the mixture of magnesium, and the purity of the α-type tribasic calcium phosphate produced is not constant. In addition to the problem that β-type tribasic calcium phosphate is contained in this α-type tribasic calcium phosphate, the quality (strength, hardening time) of the α-type tribasic calcium phosphate single phase obtained by X-ray diffraction when it is made into cement. ) Is not constant.

Further, in order to prevent the mixture of β-type tribasic calcium phosphate, if it is baked at a temperature higher than the normal baking temperature of 1200 ° C., the mixing can be prevented, but since the baking temperature rises, the power cost and the cost increase. Besides that,
The α-type tribasic calcium phosphate that is produced progresses in sintering, and the fired product becomes a hard mass, so it is not easily pulverized, and the crushing cost is high. Therefore, not only the problem that the particle size and particle size distribution of the powder are not constant occurs but also the problem that the quality is not constant when cement is used cannot be solved. Therefore, it is strongly desired to develop a method for producing α-type tricalcium phosphate having stable quality when it is used as cement.

[0008]

SUMMARY OF THE INVENTION In view of the above situation, the present inventors have decided to use β-type calcium triphosphate in the dry process when producing γ-type calcium pyrophosphate and α-type calcium triphosphate using calcium carbonate as a raw material. As a result of extensive studies on a method for producing high-purity α-type tribasic calcium phosphate with stable quality when not using cement, not only magnesium but also aluminum containing not only in the raw material or in the container used during mixing, etc. If the amount is limited to a specific range or less and the content of β-type tricalcium phosphate is low, it is found that α-type tricalcium phosphate having stable quality can be obtained when used as cement, and the present invention is completed. It has come.

That is, according to the present invention, when producing α-type tribasic calcium phosphate from γ-type calcium pyrophosphate and calcium carbonate, the contents of magnesium and aluminum contained in the α-type tribasic calcium phosphate are 0.1 and 0.1%, respectively. It relates to a method for producing α-type tricalcium phosphate, which is characterized in that it is not more than wt%.

The present invention will be described in more detail below. The γ-type calcium pyrophosphate and calcium carbonate used in the present invention are not particularly limited as long as the contents of magnesium and aluminum contained as impurities are 0.1% by weight or less (hereinafter,% by weight is represented by% unless otherwise specified).

When the γ-type calcium pyrophosphate and calcium carbonate are uniformly mixed (crushed), in order to prevent the mixing of magnesium and aluminum, a ceramic material containing no magnesium or aluminum (zirconia, silicon nitride,
A silicon carbide) ball mill or mortar is preferably used. However, made of metal, mullite (silica alumina)
Even a manufactured product can be used if the mixing method and mixing time are appropriately selected and the aluminum content is less than 0.1%. Alumina mixers are not preferred because aluminum is inherently prone to contamination.

When uniformly mixing (pulverizing) as described above, magnesium and aluminum mixed depending on the mixing method, mixing time, etc. are less than 0.1% of each of magnesium and aluminum contained as impurities in α-type tertiary calcium phosphate. Is preferred. Further, even during firing, when the alumina and magnesium which are easily mixed with aluminum or magnesium are used for firing, β-type tertiary calcium phosphate is by-produced and the quality becomes unstable when used as cement. Has confirmed.

The β-type tribasic calcium phosphate was measured by a powder X-ray diffractometer, and the β-type tribasic calcium phosphate was measured from the main peak of the characteristic diffraction line, 31.0 °.
The α-type tribasic calcium phosphate produced by the method of the present invention does not contain β-type tribasic calcium phosphate, and when used as a cement, high-quality α-type tribasic calcium phosphate having extremely stable quality can be easily obtained.

[0014]

The present invention will be described in more detail with reference to the following examples. Example 1 Aluminum and magnesium as impurities 31 and 31 respectively
50.8 g of γ-type calcium pyrophosphate containing 0 ppm and 230 ppm and 20 g of calcium carbonate containing 290 ppm and 380 ppm of aluminum and magnesium as impurities, respectively, were charged into a mortar made of silicon carbide, and the mixture was mixed for 2 hours using a pestle made of silicon carbide, and the firing temperature was set. Is 1200
It was performed at 3 ° C. for 3 hours. A powder agent made of 0.975 g of α-type tribasic calcium phosphate and 0.025 g of calcium fluoride and 0.425 ml of a 1 mol citric acid solution (however, adjusted to pH 3.0 with ammonia water) were kneaded. When the setting time and setting time of the kneaded product were measured,
It was 7 minutes and 8 minutes, respectively. After curing, the hardness of the cured body after being immersed in distilled water at 37 ° C for 24 hours is the Knoop hardness (kg
/ Mm ² ) 16.

The setting time was based on JIS-T-6604, and the curing time was the time required until the Vicker needle could not be traced. The produced α-type tribasic calcium phosphate contains aluminum and magnesium at 300 pp each.
m, 270 ppm. Further, as a result of measuring the produced α-type tribasic calcium phosphate by a powder X-ray diffractometer, β-type tribasic calcium phosphate was not detected as shown in FIG.

Example 2 The same conditions as in Example 1 except that the mixing time was changed to 6 hours.
I went with the matter. The setting time and hardness were the same as in Example 1.
Time and Knoop hardness (kg / mm ²) Is 6 minutes each,
It was 7 minutes and 15 minutes. Produced α-type tricalcium phosphate
Aluminum and magnesium are 310 pp each
m, 280 ppm. Also, the manufactured α type third
The result of measuring calcium phosphate with a powder X-ray diffractometer
As a result, β-type tricalcium phosphate was not detected.

Example 3 A mullite mortar and mulley were used as a silicon carbide container at the time of mixing.
The same conditions as in Example 1 except that the pestle was changed to
It was The setting time, curing time and curing time were the same as in Example 1.
Knoop hardness (kg / mm ²) Is 8 minutes, 10 minutes,
It was 13. The manufactured α-tribasic calcium phosphate
720pp each of aluminum and magnesium
m, 270 ppm. Also, the manufactured α type third
The result of measuring calcium phosphate with a powder X-ray diffractometer
As a result, β-type tricalcium phosphate was not detected.

Comparative Example 1 Aluminum and magnesium as impurities 12 and 12 respectively
50.8 g of γ-type calcium pyrophosphate containing 00 ppm and 1100 ppm and 20 g of calcium carbonate containing 1400 ppm and 1300 ppm of aluminum and magnesium as impurities, respectively, were charged into a mortar made of silicon carbide, and mixed for 2 hours using a pestle made of silicon carbide, and the firing temperature was 14
It was carried out at 00 ° C for 3 hours. The setting time and curing time under the same conditions as in Example 1 were increased to 28 minutes and 47 minutes, respectively, and the Knoop hardness (kg / mm ² ) was also decreased to 7. The produced α-type tribasic calcium phosphate contained aluminum and magnesium at 1300 ppm and 1200 ppm, respectively. Further, as a result of measuring the produced α-type tribasic calcium phosphate with a powder X-ray diffractometer, β-type tribasic calcium phosphate was not detected.

Comparative Example 2 Aluminum and magnesium as impurities 27
50.8 g of γ-type calcium pyrophosphate containing 00 ppm and 820 ppm and 20 g of calcium carbonate containing 2400 ppm and 630 ppm of aluminum and magnesium as impurities, respectively, were charged in a mortar made of silicon carbide and mixed for 2 hours using a pestle made of silicon carbide, and the firing temperature was 1200
It was performed at 3 ° C. for 3 hours. The setting time and curing time carried out under the same conditions as in Example 1 were as long as 31 minutes and 50 minutes, respectively, and the Knoop hardness (kg / mm ² ) was also reduced to 6 or less. still,
The produced α-type tribasic calcium phosphate contained 2600 ppm and 770 ppm of aluminum and magnesium, respectively. Further, as a result of measuring the produced α-type tribasic calcium phosphate with a powder X-ray diffractometer, β-type tribasic calcium phosphate was detected as shown in FIG.

Comparative Example 3 Aluminum and magnesium were used as impurities, respectively.
50.8 g of γ-type calcium pyrophosphate containing 0 ppm and 2800 ppm and 20 g of calcium carbonate containing 950 ppm and 2400 ppm of aluminum and magnesium respectively as impurities were charged into a silicon carbide mortar and mixed for 2 hours using a silicon carbide pestle. 1200
It was performed at 3 ° C. for 3 hours. The setting time and curing time under the same conditions as in Example 1 were increased to 33 minutes and 52 minutes, respectively, and the Knoop hardness (kg / mm ² ) was also decreased to 6 or less. still,
The produced α-type tribasic calcium phosphate contained 820 ppm and 2700 ppm of aluminum and magnesium, respectively. In addition, as a result of measuring the produced α-type tribasic calcium phosphate with a powder X-ray diffractometer, β-type tribasic calcium phosphate was detected.

COMPARATIVE EXAMPLE 4 Manufactured under the same conditions as in Example 3 except that the mixing time was changed to 6 hours. Setting time carried out under the same conditions as in Example 1,
The curing time was increased to 20 minutes and 35 minutes, respectively, and the Knoop hardness (kg / mm ² ) was also decreased to 8. The manufactured α
The type 3 calcium phosphate contained 1600 ppm and 280 ppm of aluminum and magnesium, respectively.
In addition, as a result of measuring the produced α-type tribasic calcium phosphate with a powder X-ray diffractometer, β-type tribasic calcium phosphate was detected.

[0022]

Industrial Applicability According to the present invention, it has become possible to produce high-purity α-type tribasic calcium phosphate at a low temperature, which has not been achieved by the prior art, and a stable quality product can be obtained. That is, the comparative examples outside the scope of the present invention,
It was difficult to produce high-purity α-type tribasic calcium phosphate and the quality (strength, setting time) was not constant when it was used as cement. On the other hand, the examples within the scope of the present invention enable firing at low temperature without generation of β-type tribasic calcium phosphate, and when used as cement, high-quality α-type tribasic calcium phosphate with extremely stable quality. I was able to get

[0023]

[Brief description of drawings]

FIG. 1 is a measurement result by a powder X-ray diffractometer in Example 1.

2 is a measurement result by a powder X-ray diffractometer in Comparative Example 2. FIG.

[Explanation of symbols]

 1 β-type tricalcium phosphate

Claims (1)

[Claims] 1. When producing α-type tribasic calcium phosphate from γ-type calcium pyrophosphate and calcium carbonate, the content of magnesium and aluminum contained in the α-type tribasic calcium phosphate is each 0.1 wt% or less. And a method for producing α-type tricalcium phosphate.