JP3228955B2 - Method for producing apatite powder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a process for the preparation of superior apatite Powder dispersibility and free flow properties.

[0002]

2. Description of the Related Art Tribasic calcium phosphate is generally called hydroxyapatite and is useful for various industrial uses including a stabilizer for suspension polymerization. Recently, development as a column packing material for separation of artificial bones and biopolymer compounds has been active, but recently, hydroxyapatite carrying silver by the cation exchange action of hydroxyapatite has attracted attention as an inorganic antibacterial agent. I have.

[0003] In general, although hydroxyapatite has very small primary particles of submicron, apparent particles in powder form often exceed 10 µm and cannot be refined. Although such agglomeration of particles is a general phenomenon of fine powder particles, hydroxyapatite has a particularly strong phenomenon. This is because hydroxyapatite has a large specific surface area and a high surface activity, and in addition to aggregation and coagulation during drying,
In particular, it is considered that the pulverized particles are charged with static electricity and reagglomerate during the pulverization after drying.

[0004] As described above, hydroxyapatite powder is industrially very difficult to be made into a fine powder. Therefore, its excellent physical properties have not been fully utilized, and the effective use of the powder has been limited to agglomerates. It has been limited to only a few applications that do not interfere. For this reason, hydroxyapatite is often used in the form of a slurry, and even if it is a powder, it may be used after being subjected to ultrasonic dispersion treatment in an aqueous medium (Japanese Patent Publication No. 47-197).
38631).

[0005]

DISCLOSURE OF THE INVENTION In view of the above-mentioned drawbacks of hydroxyapatite powder, the present invention has been made as a result of intensive studies to solve the above-mentioned drawbacks, and has excellent dispersibility and free-flow properties. It is intended to provide a method of manufacturing apatite powder.

[0006]

In order to achieve the above object, a method for producing apatite powder according to the present invention comprises the steps of:
Aqueous slurry and higher fatty acid and / or its aqueous solution
And then drying after solid-liquid separation.
The above features.

[0007]

Hereinafter, the present invention will be described in detail. Usually, when referred to as apatite, typically, the general formula Ca (0.5 m
+ 1.5n) (OH) m · (PO 4) be one having a characteristic crystal structure represented by n, especially m = 2, 3 of n = 6
Tribasic calcium phosphate hydroxyapatite represented by Ca ₃ (PO ₄ ) ₂ .Ca (OH) ₂ , and the apatite in the present invention is represented by the general formula Me (0.5 m
+ 1.5n) (X) m · (PO ₄ ) n [where Me is Ca, Mg
Or Ba and X are OH, Cl or F, m and n are coefficients]
And a poorly soluble basic phosphate having a composition having a molar ratio Me / P of 1.4 to 1.8, and an exchanger with other ions or a modified product carrying other ions.

That is, the hydroxyapatite represented by the above-mentioned general formula is surface-active and therefore easily adsorbs and reacts with other cations or anions, and both Ca ⁺⁺ and OH ⁻ in the crystal structure are ion-exchanged. It is one of the representative inorganic ion exchangers having a function. In the present invention, such an ion exchanger or a modified product by carrying can be included.

Particularly preferred apatites in the present invention are hydroxyapatite of calcium and a modified product thereof.
g ⁺ , Cu ²⁺ , Zn ²⁺ , Pb ²⁺ , Ni ²⁺ , Se ²⁺ , Ce
An exchanger such as ²⁺ , Co ²⁺ , Mn ²⁺ , Sn ²⁺ or Zr ^4+, and an anion exchanger such as Cl ⁻ , F ⁻ ,
Examples include exchangers such as CO ₃ ^{2 −} and NO ₃ ⁻ .

Although there are various methods for producing hydroxyapatite, the production history and particle characteristics of the apatite according to the present invention are not particularly limited. For example, the primary particles of hydroxyapatite have various shapes such as granular oval shapes or needle-like shapes depending on the manufacturing method, and the average particle size is from submicron to several microns, but any shape may be used.

The apatite powder according to the present invention is obtained by subjecting the apatite to a surface treatment with a higher fatty acid or the like, and has powder characteristics with improved dispersibility and free flow property. Here, the higher fatty acid is a saturated or unsaturated fatty acid having 12 or more carbon atoms or a derivative thereof,
For example, higher fatty acids such as lauric acid, myristic acid, palmitic acid, stearic acid, alagic acid, behenic acid, erucic acid, linoleic acid, linoleic acid, oleic acid, succinic acid, ricinoleic acid, and derivatives thereof such as Ca, M
Metal salts, ammonium salts, or amides represented by g, Ba, Zn, Pb, or Al, and the like, and one or more kinds thereof are blended.

The amount of the higher fatty acid or the like varies depending on the physical properties of the apatite, the type of the higher fatty acid and the purpose of use of the apatite powder, but is at least 0.1% of the theoretical amount required for forming a monomolecular film of the higher fatty acid or the like on the surface of the apatite particles. It is desirable to set the amount to twice or more, preferably 0.8 to 2 times. If the amount is less than 0.1 times the theoretical amount, the surface modification of the apatite powder is insufficient. If the amount is more than 2 times, the effect is saturated and it is not economically practical.

In the present invention, the required theoretical amount (M) per 1 g of apatite powder such as a higher fatty acid is based on the value obtained by the following equation. M = A / m where m = R × S / n In the above formula, A is the specific surface area of the apatite powder (m ² / g), m
Is the area covered by 1 g molecule of higher fatty acid etc. (m ² / g), S is the area covered by 1 molecule of higher fatty acid etc. (angstrom square),
n represents the molecular weight of a higher fatty acid or the like, and R represents the avocado number.

The surface-treated apatite powder according to the present invention comprises:
It can be obtained by wet mixing of untreated apatite powder and higher fatty acids. The surface treatment by so-called dry mixing results in insufficient dispersibility of the apatite powder. That is, the apatite powder of the present invention is produced by mixing an aqueous apatite slurry with a higher fatty acid and / or a water-soluble salt thereof, followed by solid-liquid separation and drying.

In the preparation of the apatite aqueous slurry, it is most industrially most preferable to directly use the one obtained in the apatite production stage, but it may be a redispersion of a filter cake or a slurry of powder. . As described above, the apatite is typically calcium hydroxyapatite, but is a magnesium or barium type or a part of which is supported and modified by ion exchange or adsorption with another metal cation or anion. You may. The selection of such apatite should be set exclusively according to the purpose of use of the apatite powder.

The concentration of the apatite slurry is not particularly limited, but is set in the range of 3 to 50% by weight, preferably 5 to 30% by weight from the viewpoint of operation efficiency.

The mixing of the aqueous apatite slurry with the higher fatty acid or / and its water-soluble salt can be carried out by any suitable means such as stirring, high-speed stirring or mixing with shearing force. It is preferable to use a homogenizer, a colloid mill, or a dispersing mixer having a strong shearing force with an ultrasonic dispersing device or the like so that the mixture can be dispersed as much as possible. The mixing is preferably performed for 0.5 to 3 hours under heating, and a dispersant such as a surfactant, if necessary, before or after the mixing operation.
Auxiliary agents such as soluble metal salts and water-soluble agents that form metal soaps can be used as appropriate. After solid-liquid separation, it is washed with water, dried and pulverized according to a conventional method to finish.

The method of drying is not limited, but spray drying may be preferable for later use. In the pulverization, if necessary, the higher fatty acid or the like may be added to perform a dry surface treatment.

[0020]

According to the present invention, when the aqueous apatite slurry is subjected to mechanical dispersion as much as possible with a higher fatty acid or the like, the higher fatty acid or the like dissolved in the slurry is converted into surface-active apatite particles. React or adsorb,
For example, a calcium metal soap is formed to easily form a monolayer thereof. In this process, aggregation between the particles is suppressed, and a more effective dispersion state is obtained.

Therefore, the production of a metal soap does not require the addition of a soluble metal salt. However, it is necessary to produce another metal soap such as aluminum or to form a surface treatment layer more. A soluble metal salt may be added accordingly.

Apatite particles surface-treated with a higher fatty acid or the like, when dried and pulverized, impart remarkable dispersibility and free flow property, unlike untreated powder.

[0023]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples. In these examples, the following apatite slurry was used as a raw material. (1) Calcium hydroxyapatite slurry Calcium hydroxyapatite slurry (10 wt%) produced by nitrate lime slurry and phosphoric acid [trade name "Spatite" manufactured by Nippon Chemical Industry Co., Ltd.]. (2) Silver-modified calcium hydroxyapatite slurry 100 parts by weight of silver nitrate aqueous solution (5 wt%) was added to 1000 parts by weight of spatite to support Ag ⁺ , and then washed with water to remove the supernatant to 1000 parts by weight. (3) Copper-modified calcium hydroxyapatite slurry 100 parts by weight of a copper nitrate aqueous solution (10 wt%) was added to 1000 parts by weight of spatite to support Ca ⁺⁺ , and then washed with water, sedimented and concentrated, and the supernatant was removed to 1000 parts by weight. What you did. (4) Zinc-modified calcium hydroxyapatite slurry 100 parts by weight of zinc nitrate aqueous solution (10 wt%) was added to 1000 parts by weight of spatite to support Zn ⁺⁺ , washed with water, sedimented and concentrated, and the supernatant was removed to remove 1000 parts by weight. And what.

Examples 1 to 5 A small amount of a dispersant was added to 1000 parts by weight of each of the four types of modified or unmodified calcium hydroxyapatite slurries, and the mixture was dispersed through a colloid mill (manufactured by Kokusan Seiko Co., Ltd.). An aqueous solution of sodium oleate (11.5 wt%) shown in Table 1 was added at room temperature, and stirring was continued for 2 hours. Then, when the slurry was subjected to solid-liquid separation, almost no oleic acid was eluted in the mother liquor. After repeated washing and filtration, the filter cake was dried and ground at 100 ° C to produce a surface-treated apatite powder with oleate. did. Each of the obtained apatite powders was remarkably rich in dispersibility and free flow property as compared with the untreated apatite powder.

Next, the state of the particle size distribution of each apatite powder was measured using a laser scattering type particle size distribution measuring device (LPA-3000, manufactured by Otsuka Electronics Co., Ltd.), and the results are shown in Table 2.

Example 6 An apatite powder was produced in the same manner as in Example 1 except that the sodium oleate of Example 1 was replaced with a 10 wt% aqueous solution of sodium stearate in the amount shown in Table 1. Table 2 shows the results of measuring the particle size distribution of the obtained powder in the same manner as in Example 1.

Example 7 An apatite powder was produced in the same manner as in Example 2 except that the sodium oleate of Example 2 was replaced with a 10 wt% aqueous solution of sodium stearate in the amount shown in Table 1. Table 2 shows the results of measuring the particle size distribution of the obtained powder in the same manner as in Example 2.

Comparative Examples 1-2 The apatite powder was produced in the same manner as in Example 1 except that the amount of sodium oleate was changed to the amount shown in Table 1. Table 2 shows the results of measuring the particle size distribution of the obtained powder in the same manner as in Example 1.

[0029]

In each case, the theoretical coating value of sodium oleate is m = R × S / n = (6.02 × 10 ²³ × 20 ×
10 ⁻¹⁶ × 10 ⁴ ) / (304.4) = 396 m ² / [However, S = 20 (angstrom squared)], and the theoretical coating value of sodium stearin resistance is m = R × S / n = (6.02 × 10 ²³⁾ × 20 × 10
^-16 × 10 ⁴ ) / (306.47) = 393 m ² / g.

[0031] Table Note: Blank is hydroxyapatite slurry before drying (untreated product)

From the results shown in Table 2, all of the apatite powders according to the examples have a small particle diameter distribution, a single peak, and a uniform fine particle state with a narrow distribution width. It is recognized that the flowability is excellent.

Example 8 The calcium hydroxyapatite slurry to which the aqueous solution of sodium oleate of Example 2 was added was heated at an inlet temperature of 300 ° C.
Spray drying was performed using a hot air device under the conditions described above, and the outlet temperature was 105 ° C. to obtain a fine spherical apatite powder. This fine powder had a remarkable free flow property.

[0034]

As described above, according to the present invention, apatite particles having extremely high dispersibility and free flow property can be provided by subjecting apatite particles to a surface treatment with a higher fatty acid or the like. Therefore, it can be expected to be used for various resin additives and pigments for paints that could not be practically used in the past, and in particular, the modified apatite powder exhibits antibacterial properties, antifouling properties, anticorrosion properties, etc. according to the physical properties of the metal ions carried. Therefore, it is useful as a functional pigment.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Eiji Miyoshi, Inventor Research and Development Division, 9-15-1, Kameido, Koto-ku, Tokyo (56) References JP-A-64-60639 (JP, A) JP-A-3-83805 (JP, A) JP-A-5-17111 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C01B 25/32 CA (STN)

Claims (4)

(57) [Claims] 1. A process for producing apatite powder, comprising mixing an aqueous apatite slurry with a higher fatty acid and / or a water-soluble salt thereof, followed by solid-liquid separation and drying. 2. An aqueous apatite slurry mixed with a higher fatty acid and / or a water-soluble salt thereof, followed by adding and reacting an aqueous solution of a Group II metal salt of the periodic table, followed by solid-liquid separation and drying. Method for producing apatite powder. 3. A process for producing an apatite powder, comprising mixing an aqueous apatite slurry with a higher fatty acid and / or a water-soluble salt thereof, and then spray-drying the slurry. 4. The method of claim carried out under strong shearing force mixing of the apatite aqueous slurry and a higher fatty acid and / or its water-soluble salts 1, 2 or 3 manufacturing method of the apatite powder according.