JP2000129314A - Composite body of hydroxyapatite and titanium and production of hydroxyapatite and titanium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a composite body of hydroxyapatite and titanium excellent in bioaffinity and moreover provided with sufficient mechanical strength and to provide a producing method capable of producing this composite body by a simple method. SOLUTION: In a composite body 10a of hydroxyapatite and titanium having a mixed layer 103 contg. hydroxyapatite and titanium or a titanium alloy and a titanium layer 105 composed of titanium or a titanium alloy, at least a part of the composite body 10a is provided with a double structure in which the mixed layer 103 positions at the inside of the titanium layer 105. It is preferable that the titanium layer 105 and the mixed layer 103 are arranged on a concentric circle. Moreover, the composite body 10a is formed preferably by a discharge plasma sintering method.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite of hydroxyapatite and titanium, and more particularly to a composite of hydroxyapatite and titanium used as bioceramics and a method for producing the same.

[0002]

BACKGROUND ART Among ceramics, hydroxyapatite, which is a kind of calcium phosphate ceramics, has excellent biocompatibility because it resembles the structure of the inorganic component of bone, and has artificial roots, bone fillers, dental cements. It is applied as a biomaterial such as.

However, hydroxyapatite has insufficient mechanical strength, toughness and the like, and there is a limit to the use of hydroxyapatite alone.

In order to obtain bioceramics having sufficient mechanical strength and toughness, for example, the surface of a tough and excellent moldable metal material is coated with a bioceramic material or mixed with a photopolymerizable resin. For example, a method of compounding with a different material has been proposed.

However, the production process is complicated and time-consuming, and there is no method for producing a biomaterial having sufficient strength and toughness easily and in a short time.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a composite of hydroxyapatite and titanium having excellent biocompatibility and sufficient mechanical strength, and to produce such a composite by a simple method. An object of the present invention is to provide a method for producing a composite of hydroxyapatite and titanium.

[0007]

This and other objects are achieved by the present invention which is defined below as (1) to (11).

(1) In a composite of hydroxyapatite and titanium having a mixed layer containing hydroxyapatite and titanium or a titanium-based alloy, and a titanium layer made of titanium or a titanium-based alloy, at least a part of the composite A composite of hydroxyapatite and titanium, wherein the composite layer has a double structure in which the mixed layer is located inside the titanium layer.

(2) The composite of hydroxyapatite and titanium according to (1), wherein the composite is formed by a spark plasma sintering method.

(3) The composite of hydroxyapatite and titanium according to (1) or (2), wherein the content of the hydroxyapatite in the mixed layer is 5 to 50% by weight.

(4) The method according to any one of (1) to (3), wherein the titanium or titanium-based alloy contained in the mixed layer and the titanium or titanium-based alloy contained in the titanium layer have the same composition. Of hydroxyapatite and titanium.

(5) The composite of hydroxyapatite and titanium according to any one of (1) to (4), wherein the mixed layer and the titanium layer are arranged concentrically or concentrically.

(6) A mixed layer containing hydroxyapatite and titanium or a titanium-based alloy, and a titanium layer made of titanium or a titanium-based alloy, wherein at least a part or all of the mixed layer is provided inside the titanium layer. A method for producing a composite of hydroxyapatite and titanium, characterized by comprising sintering the composite by spark plasma sintering to form the composite.

(7) The method for producing a composite of hydroxyapatite and titanium according to (6), wherein the sintering is performed at a sintering temperature of 600 ° C. or lower.

(8) The method for producing a composite of hydroxyapatite and titanium according to (7), wherein the hydroxyapatite is preliminarily sintered at 700 to 1300 ° C.

(9) The hydroxyapatite according to any one of (6) to (8), wherein the sintering is performed by heating at least a part of the mixed layer and the titanium layer via a heat insulating material. A method for producing a composite with titanium.

(10) The method for producing a composite of hydroxyapatite and titanium according to any one of the above (6) to (9), wherein the pressurized state is released after the sintering and the mixture is allowed to cool.

(11) The composite according to any one of (6) to (10), wherein the composite layer and the titanium layer are concentrically or concentrically arranged. How to make the body.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the composite of hydroxyapatite and titanium according to the present invention will be described in detail.

The composite of hydroxyapatite and titanium (hereinafter referred to as “composite”) according to the present invention comprises a mixed layer containing hydroxyapatite and titanium or a titanium-based alloy, and a titanium layer made of titanium or a titanium-based alloy. Wherein the composite has a double structure in which the mixed layer is located inside a titanium layer in at least a part of the composite.

By adopting such a double structure, the inside of the composite can be made excellent in biocompatibility, and the mechanical strength of the composite surface and the whole can be improved.
For example, the mixed layer located inside the composite has excellent stability in body fluids because it contains hydroxyapatite,
It is possible to improve the bonding property with the bone. On the other hand, by providing a titanium layer made of tough titanium or a titanium-based alloy on the surface of the composite to improve the strength of the entire composite, and when a fixing member or the like is attached to the surface of the composite,
The fixing member can be firmly supported.

The mixed layer contains hydroxyapatite and titanium or a titanium-based alloy. Titanium or titanium-based alloys have extremely low harm to living organisms, and metal ions hardly elute in body fluids.Therefore, by combining with hydroxyapatite, the biocompatibility of hydroxyapatite is maintained while maintaining mechanical strength. Can be improved.

The content of hydroxyapatite in the mixed layer is not particularly limited, but is preferably about 5 to 50% by weight, more preferably 10 to 50% by weight. If the content of hydroxyapatite is less than 5% by weight, the properties of hydroxyapatite are lost, and the biocompatibility may be reduced. On the other hand, if it exceeds 50 wt%, the mechanical strength may be insufficient depending on the application.

The above-mentioned hydroxyapatite may be formed by any method, and for example, those which have been temporarily sintered to improve the strength of the hydroxyapatite particles and the like can be used. in this case,
The sintering is preferably performed at a temperature of about 700 to 1300 ° C. When such hydroxyapatite is used, a composite of hydroxyapatite and titanium is used for 60%.
It can be manufactured by low-temperature sintering of 0 ° C or less,
Thermal decomposition of hydroxyapatite generated in the sintering process can be effectively suppressed.

The metal element other than titanium constituting the titanium-based alloy contained in the mixed layer is not particularly limited, but is preferably one having excellent corrosion resistance and being safe for living bodies.
r, Fe, Co, Cu, Mo, Ag, Au, Ni, P
d, Pt, Al, Nd, Sn, Zr, etc., and these can be used alone or in combination of two or more. In the titanium-based alloy, the content of these metal elements is 5
About 20% by weight is preferable.

The titanium or titanium-based alloy contained in the mixed layer and the titanium or titanium-based alloy constituting the titanium layer may be of the same composition or different compositions. Is preferred. Thereby, the bondability between the mixed layer and the titanium layer is further improved, the internal stress of the composite can be reduced, and delamination between the mixed layer and the titanium layer can be prevented.

The form of the titanium or titanium-based alloy contained in the mixed layer and the form of the titanium or titanium-based alloy constituting the titanium layer may be the same or different. When they are used, their particle shapes, average particle diameters and the like may be the same or different.

In the composite of the present invention, the mixed layer and the titanium layer are preferably arranged concentrically or concentrically. Thereby, the unevenness of the strength of the composite can be reduced, and the durability can be improved.

Next, a method for producing a composite of hydroxyapatite and titanium according to the present invention will be described in detail based on a preferred embodiment shown in the accompanying drawings.

FIG. 1 is a longitudinal sectional view showing an example of a molding die and a material filling jig used in the method for producing a composite according to the present invention, and FIGS. It is a longitudinal section showing an embodiment.

A molding die 1 shown in FIG. 1 has a cylindrical outer die 2 having a hollow portion 21 capable of accommodating a material constituting a composite, a pressing element 3a for pressing a sintered material, and a second And a pair of pressing elements composed of the pressing elements 3b.

First, a titanium layer material 5a made of titanium or a titanium-based alloy powder is filled in the molding die 1. Filling is performed using a material filling jig 8 as shown in FIG.
As a result, the titanium layer material 5a is annularly filled around the protrusion 82.

The material filling jig 8 includes a fitting portion 81 that can be fitted into the hollow portion 21 of the outer mold 2 and a projection 82 that can be inserted into the hollow portion 21. Fitting portion 81 and protrusion 82
Both have a circular cross section and are provided concentrically. The constituent material of the material filling jig 8 is not particularly limited, and examples thereof include metal.

A hollow portion 21 is formed concentrically on the outer die 2, and a conductive carbon sheet 7 is formed on the inner peripheral surface.
Is provided. As a result, a metal material such as titanium contained in the titanium layer material 5a is interposed as a cushion material between the titanium layer material 5a and the inner peripheral surface of the hollow portion 21 and the outer mold 2 is formed.
Can be prevented from reacting with the carbon constituting and fixing to the inner peripheral surface. Further, it is possible to prevent each pressing element from digging into the inner peripheral surface of the outer mold 2 at the time of sintering, and to smoothly slide.

The constituent material of the outer mold 2 is preferably a conductive material suitable for spark plasma sintering, for example, a cemented metal, a cemented carbide, a carbon-based material, etc. Materials are more preferred.

As shown in FIG. 2, the material filling jig 8 is fitted by fitting the fitting portion 81 to the hollow portion 21. The surface of the projection 82 is covered with a Teflon sheet 88 in order to keep good releasability from the green compact.

Next, as shown in FIG.
Is filled with the titanium layer material 5a. The titanium layer material 5a may be in any form such as a powder or a block such as a block, but a powder is more preferable because of easy adjustment of the filling amount. When the titanium layer material 5a is a powder, a titanium or titanium-based alloy powder having an average particle size of about 10 to 400 μm is preferably used. If the particle size is too small, secondary agglomeration may occur, and the handleability may be poor.If the particle size is too large, particularly when producing a complex having a precise shape, poor bonding at the interface with the mixed layer or There is a case where the workability is deteriorated such as the occurrence of chipping.

Next, as shown in FIGS. 4 and 5, the titanium layer material 5a filled in an annular shape is pressed into an annular pressing member 91 for compression.
Compact 51a made of titanium layer material 5a
To form By forming the green compact 51a in advance,
The strength and bonding strength after sintering can be further improved, and the porosity, the pore diameter, and the like can be controlled more accurately.

Further, if a green compact is formed for each layer, the density, strength, etc. after sintering can be adjusted for each layer, and a double structure in which the layers are stacked in a direction perpendicular to the pressing direction can be obtained. Different materials can be easily filled as configured.

The pressing force at the time of forming the green compact 51a is appropriately selected according to the composition and form of the titanium layer material 5a.
It is preferably in the range of 00 to 500 kgf / cm ² . The compression pressing element 91 is an annular body that is slidably fitted to the hollow portion 21 of the outer die 2, and has a hollow portion 910 formed concentrically with the center axis thereof. The hollow portion 910 is formed so as to slidably fit the projection 82 of the material filling jig 8. Thereby, the titanium layer material 5a can be compressed, and the annular green compact 51a can be formed. Compression presser 9
As the constituent material of 1, for example, a metal material is used.

The method for forming the compression body 51a is not particularly limited, and may be, for example, a cold isostatic pressing method (CIP) or a hot isostatic pressing method (CIP), in addition to the uniaxial forming method using a pressing element as shown in the figure. HIP) and the like, but a uniaxial molding method is more preferable. The uniaxial molding method has a simple manufacturing method and is most excellent in mass productivity. When the titanium layer material 5a is a block, the step of forming a green compact can be omitted.

After the green compact 51a is formed, the material filling jig 8 is replaced with a cylindrical first pressing element 3a as shown in FIG. This makes it possible to fill the hollow portion of the green compact 51a with a new material.

The first pressing member 3a is provided with the hollow portion 21 of the outer mold 2.
Is configured to be fittable. As a constituent material of the first pressing element 3a, the same material as that of the outer mold 2 can be used, and for example, a carbon-based material is preferably used.

It is preferable that the carbon sheet 7 is interposed between the green compact 51a and the first pressing element 3a. Thereby, interaction such as welding between the green compact 51a and the first pressing element 3a can be prevented, and after sintering, the composite can be easily taken out.

Next, as shown in FIG.
Is filled with a mixed layer material 5b composed of hydroxyapatite and titanium or a titanium-based alloy.

The form of the mixed layer material 5b may be any form such as a powdery substance or a block such as a block, but a powdery substance is more preferable because of easy adjustment of the filling amount. In the case of a powdery substance, hydroxyapatite has an average particle size of 1 to 500 μm.
m, and titanium or titanium-based alloy powder having an average particle size of about 10 to 400 μm is preferably used.

Then, as shown in FIGS. 7 and 8, the mixed layer material 5b is compressed by a columnar compression pressing element 92 to produce a green compact 51b as shown in FIG. Compression presser 92
Is a cylindrical shape that can be fitted and slid into the hollow portion 910 of the compression pressing element 91, and is made of, for example, a metal material.

The pressing force at the time of forming the green compact 51b is appropriately selected according to the composition and form of the mixed layer material 5b.
It is preferably in the range of 0 to 500 kgf / cm ² .

At this time, if the green compact 51b is formed at a compression ratio different from that at the time of forming the green compact 51a, the density after sintering,
A composite in which the strength and the like are changed for each layer can be obtained. Therefore, for example, when the thermal expansion coefficients of the mixed layer and the titanium layer are significantly different, the compression ratio of the material of the layer having the large thermal expansion coefficient is made small, and the compression ratio of the material having the small thermal expansion coefficient is made large. It is possible to improve the bonding strength between the layers and prevent the occurrence of cracks and the like. In addition, the shape of the composite after sintering can be accurately controlled.

When a green compact is formed by compressing the titanium layer material 5a and the mixed layer material 5b at different compression ratios, the compression ratio may be controlled by, for example, as shown in FIG. 7 and FIG. 91 and 92 have different lengths (projection amounts),
The compression ratio can be adjusted by changing the pushing amount for each compression pressing element. In the present invention, spark plasma sintering may be performed after forming a green compact with the same compression ratio of the titanium layer material 5a and the mixed layer material 5b.

As a method for forming the compression body 51b, the same method as that for forming the compression body 51a can be mentioned.
Uniaxial molding is preferred. When the mixed layer material 5b is a block, the step of forming a green compact can be omitted.

As described above, the outer mold 2 is placed so that the mixed layer material 5b is located concentrically inside the titanium layer material 5a.
Is filled in. In this way, the titanium layer material 5a and the mixed layer material 5b are arranged concentrically or concentrically,
By sintering, the temperature and pressure distribution in a direction (radial direction) orthogonal to the pressing direction can be made uniform, and a composite having more excellent strength can be manufactured.

Next, as shown in FIG.
1 and 92 are exchanged for the second pressing element 3b. The second pressing element 3b has a cylindrical shape and is formed so as to slidably fit in the hollow portion 21 of the outer mold 2.

The compression pressing members 91 and 92 are connected to the second pressing member 3.
After the replacement with b, the molding die 1 is set in a discharge plasma sintering apparatus 70 as shown in FIG. 14, and then sintered by a discharge plasma sintering method to produce a composite.

The discharge plasma sintering apparatus 70 includes a vacuum chamber 76, a pair of upper and lower pressurizing rams 74, 75, a sintering power supply 72 for generating a pulse voltage, and pressurizing rams 74, 7.
5 has a hydraulic pressurizing drive mechanism 73 that drives up and down the actuator 5 and a control unit 71 that controls these mechanisms.

The molding die 1 into which the above-mentioned compacts 51a and 51b are loaded is provided with a pressurizing ram 74 in a vacuum chamber 76,
Set between 75. The inside of the vacuum chamber 76 is preferably degassed by a vacuum pump 77, and sintering is preferably performed in a vacuum state (in a reduced pressure state) or in an inert gas atmosphere in the vacuum chamber 76. This allows the vacuum chamber 76
Oxygen, nitrogen, water, and the like therein can react with highly reactive components and the like contained in the sintering object such as the green compacts 51a and 51b, thereby avoiding undesirable effects on the sintered body.

The control unit 71 controls the output of the sintering power supply 72 so that the material temperature detected by a temperature sensor (thermocouple) (not shown) installed on the molding die 1 matches a preset temperature rising curve. Control. Further, the control unit 71 controls the driving of the pressure driving mechanism 73 and the vacuum pump 77.

A pair of upper and lower first pressing members 3a and second pressing members 3b are fixed to pressing rams 74 and 75, respectively, and feed terminals (not shown) provided in the pressing rams 74 and 75 are provided. ) Is electrically connected to the power source 72 for sintering. By the operation of the pressure drive mechanism 73, the pressure rams 74, 7
5 are moved in a direction approaching each other, and the first pressing member 3a and the second pressing member 3b fixed to them move the green compact 51a,
Compress 51b.

At this time, between the green compacts 51a and 51b and the first pressing element 3a and the second pressing element 3b,
It is preferable to interpose the heat insulating material 4 in each case. Accordingly, when the current is concentrated on the first pressing member 3a or the second pressing member 3b, the diffusion of heat from the overheated first pressing member 3a or the second pressing member 3b to the green compact 51a or the like is prevented. Is shut off, preventing local heating and high temperature. Therefore, the temperature during sintering of the green compact 51a and the like is made uniform, and a homogeneous and high-quality sintered body can be obtained.

As the heat insulating material 4, for example, alumina powder which is a non-conductive substance and is hardly sintered is preferably used.

Further, the heat insulating material 4 and the green compacts 51a, 51
It is preferable that a carbon sheet 7 is interposed between each of the first pressing member 3a and the first pressing member 3a and the second pressing member 3b.

The discharge plasma sintering is performed by the first pressing member 3a,
A pulse voltage is applied through the second pressing element 3b and the outer mold 2 to heat the compression energizing system. When the temperature of the sintering system reaches a predetermined temperature, the sintering system is maintained at the temperature for a certain period of time, and the composite 10
a is formed.

The sintering temperature is not particularly limited.
00 ° C or lower is preferred. If the sintering temperature is too high, hydroxyapatite will be over-sintered and decompose,
Cracks and the like may occur in the composite and the strength may be significantly reduced.

The sintering time is preferably about 5 to 20 minutes. Pressure is preferably in the 100~600kgf / cm ² approximately about 200 to 500 kgf / cm ² is more preferable.

In the discharge plasma sintering method, pulsed electric energy is directly applied to the gap between the compact particles, and the high energy of the high-temperature plasma instantaneously generated by spark discharge is effectively applied to thermal diffusion, electric field diffusion, and the like. By doing so, sintering or sintering can be performed in a short time of several minutes to tens of minutes, including a temperature rise and a holding time, as compared with a hot press method or the like. In addition, a uniform high-quality composite having excellent bonding strength can be easily and efficiently produced by uniform heating by dispersion of discharge points.

According to the spark plasma sintering method, the steps of filling the material, compacting as necessary, and sintering can be performed in one outer mold 2. It is also possible to reduce costs.

After maintaining at the above-mentioned sintering temperature for a predetermined time, it is left to cool, and the composite 10 a is taken out from the molding die 1.

At the time of cooling, it is preferable to release the pressurized state of the composite 10a and allow it to cool. Usually, after sintering, the sintered body is water-cooled through a forming punch or the like in a pressurized state. However, in the present invention, the sintered body is a composite of relatively small-strength hydroxyapatite and a metal such as titanium. Since there is a large difference between the thermal expansion coefficient and the strength, there is a possibility that cracks or chips may occur due to thermal stress. For this reason, it is preferable to release the pressurized state and allow it to cool.

According to the above-described method, a composite 10a of hydroxyapatite and titanium having a double structure in which the titanium layer 105 and the mixed layer 103 are provided concentrically as shown in FIGS. 12 and 13 is obtained. .

FIG. 11 is a longitudinal sectional view showing a second embodiment of the method for producing a composite of hydroxyapatite and titanium according to the present invention.

The composite 10b manufactured according to the present embodiment
Is different from the first embodiment in that titanium layers 106 are provided above and below a double structure portion composed of a mixed layer 103 and a titanium layer 105. In the composite 10b having such a structure, since the titanium layer 105 constitutes the entire surface, the mechanical strength, abrasion resistance, maintenance of the external shape, and the like of the composite 10b can be further improved.

The method for producing the composite 10b is not particularly limited. For example, a green compact made of the material of the titanium layer 106 separately prepared in advance and a green compact 51a molded by the same method as in the first embodiment are used. The composite 10b can be manufactured by superposing 51b with the outer mold and simultaneously sintering them. In this case, as shown in the figure, the titanium layer 106, the first pressing member 3a and the second pressing member 3b
It is preferable to interpose the heat insulating material 4 between the two.

The titanium layer 105 and the titanium layer 10
The composition, form and the like of 6 may be the same or different.

The composite of hydroxyapatite and titanium according to the present invention and the method for producing the same have been described with reference to the illustrated embodiments. However, the present invention is not limited to these embodiments. The composite may be provided with a third layer in addition to the mixed layer and the titanium layer.

[0075]

Next, specific examples of the present invention will be described. 1. Production of Composite of Hydroxyapatite and Titanium (Example 1) A composite 10a was produced using a material filling jig and a molding die shown in FIG.

As a titanium layer material, Ti powder (average particle size:
On the other hand, as a mixed layer material, 0.48 g of spherical hydroxyapatite powder (average particle size: 10 μm) temporarily sintered at 950 ° C. in an air furnace, and T
A mixed powder with 1.12 g of i powder (average particle size: 25 μm) was used.

First, a material filling jig 8 is placed at one end of a hollow portion 21 of a carbon outer mold 2 having an outer diameter of 40 mm and an inner diameter of 10.4 mm.
(FIG. 2). The material filling jig 8 used had an outer diameter of the fitting portion 81 of 10 mm and an outer diameter of the projection 82 of 5 mm.

The titanium layer material 5a is charged from the hollow portion 21 (FIG. 3), and the titanium layer material 5a is compressed using a metal compression presser 91 (outer diameter 10 mm, inner diameter 5 mm) (FIG. 4). A green compact 51a was formed (FIG. 5). The compression force at the time of forming the green compact 51a was 200 kgf / cm ² .

Next, the material filling jig 8 was replaced with a first pressing member 3a (outer diameter 10 mm) made of carbon (FIG. 5). From the hollow portion 910 of the compression pressing element 91, the mixed layer material 5b
(FIG. 6), and the metal compression presser 92
(Outer diameter 5 mm) to form a green compact 51b (FIG. 7).
To FIG. 9).

Thereafter, the compression pressers 91 and 92 were replaced with carbon second pressers 3b (outer diameter 10 mm) (FIG. 10).

At this time, between the green compacts 51a and 51b and the first presser 3a and the second presser 3b, alumina powder (average particle size 0.15 μm) 2.5
g each. Further, the heat insulating material 4 and the green compact 51
a and 51b, and the carbon sheet 7 was interposed between the heat insulating material 4 and the first and second pressers 3a and 3b, respectively.

This was set in a discharge plasma sintering apparatus (SPS-510L manufactured by Sumitomo Coal Mining Co., Ltd.), and the sintering system was evacuated.

Next, the compacts 51a and 51b were pressed from above and below with a pressing force of 350 kgf / cm ² , and a pulse voltage (pulse condition = 12: 2) was applied to heat the compression energizing system to perform sintering. . The sintering conditions were as follows: sintering temperature: 550 ° C., sintering time (holding time): 10 minutes.

After sintering, the pressurized state was released and the mixture was allowed to cool at room temperature, and the composite 1 shown in FIGS.
0a was taken out.

The composite 10a had a concentric outer layer composed of the titanium layer 105 and an inner layer composed of the mixed layer 103.

Tables 1 and 2 show the compositions and sintering conditions of the mixed layer and the titanium layer.

[0087]

[Table 1]

[0088]

[Table 2]

Example 2 A composite was produced in the same manner as in Example 1 except that the sintering temperature and average particle size of hydroxyapatite, the composition of the mixed layer, and the sintering temperature were changed.

Example 3 A composite was prepared in the same manner as in Example 1 except that the sintering temperature and average particle size of hydroxyapatite, the average particle size of titanium powder, and the sintering conditions (temperature and pressure) were changed. Was prepared.

Example 4 A composite was produced in the same manner as in Example 1, except that the sintering temperature and average particle size of hydroxyapatite and the average particle size of titanium powder were changed.

Example 5 A composite was prepared in the same manner as in Example 1 except that the sintering temperature and average particle size of hydroxyapatite, the composition of the mixed layer, and the sintering conditions (temperature, pressure, time) were changed. Was prepared.

Comparative Example 1 A composite was produced in the same manner as in Example 1 except that the inner layer and the outer layer were made of the same mixed layer material, and the sintering temperature was changed.

Comparative Example 2 A composite was produced in the same manner as in Comparative Example 1 except that the sintering temperature was changed.

2. Quality evaluation of composite Underwater immersion test Composite 10 produced in Examples 1 to 5 and Comparative Examples 1 and 2
After removing a from the molding die, the alumina powder and the carbon sheet used as the heat insulating material were removed, and the contact surface of the composite 10a surface with the carbon sheet was scraped off with a grinder.

This complex is immersed in a 20-fold amount of pure water,
After leaving at room temperature for 3 days, the pH value of the immersion liquid was measured with a pH meter. Furthermore, after the immersion, the presence or absence of the collapse phenomenon of the composite was visually confirmed.

Bending strength test The three-point bending strength of each composite prepared in Examples 1 to 5 and Comparative Examples 1 and 2 was measured. The bending strength was determined by performing a three-point bending test with a span of 1.7 cm and calculating the following formula (I) from the measured value.

Strength (σ _f ) [kgf / cm ² ] = (8 × P × L) / (π × d ³ ) (I) P: Breaking load [kgf] L: Span [ cm] d ... diameter of specimen (composite) [cm] The results are shown in Table 2.

From these results, in each of the composites produced in the examples, the mixed layer was composed of hydroxyapatite and titanium homogeneously, and the mixed layer and the titanium layer were satisfactorily joined. When the composite was immersed in pure water for 3 days, no increase in the pH value of the immersion liquid or the collapse of the composite was observed.

On the other hand, in the composite produced in Comparative Example 1, hydroxyapatite was decomposed because the sintering temperature was too high. Therefore, if the composite is immersed in pure water for 3 days,
Decomposition products of hydroxyapatite such as calcium oxide and phosphine eluted, and the pH value of the immersion liquid increased.
In addition, the mechanical strength decreased due to the decomposition of hydroxyapatite, and a collapse phenomenon of the composite in the immersion liquid was observed.

Although the composite prepared in Comparative Example 2 hardly changed the pH value of the immersion liquid, the outer layer and the inner layer were composed of the same material, so that the composite had a higher bending strength than the composites of Examples. It was significantly inferior.

[0102]

As described above, according to the method for producing a composite of hydroxyapatite and titanium according to the present invention,
A composite having a double structure consisting of an inner layer and an outer layer can be produced by a simple method. Furthermore, since hydroxyapatite is not decomposed by sintering, no harmful decomposition products are leached out or collapsed from the composite in water, and the stability and safety in water are excellent.

The composite produced by the method of the present invention has an inner layer composed of a mixed layer of hydroxyapatite and titanium or a titanium-based alloy, and an outer layer composed of a titanium layer composed of titanium or a titanium-based alloy. The inside has excellent biocompatibility and the surface has excellent strength and toughness. By utilizing such characteristics, it can be widely applied as a bone replacement material, an artificial tooth root, an artificial joint, or the like used when a disc is resected in, for example, a cervical vertebra or a lumbar vertebra.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an example of a molding die and a material filling jig used in a method for producing a composite of the present invention.

FIG. 2 is a longitudinal sectional view showing a first embodiment of a method for producing a composite according to the present invention.

FIG. 3 is a longitudinal sectional view showing a first embodiment of the method for producing a composite according to the present invention.

FIG. 4 is a longitudinal sectional view showing a first embodiment of the method for producing a composite according to the present invention.

FIG. 5 is a longitudinal sectional view showing a first embodiment of the method for producing a composite according to the present invention.

FIG. 6 is a longitudinal sectional view showing a first embodiment of the method for producing a composite according to the present invention.

FIG. 7 is a longitudinal sectional view showing the first embodiment of the method for producing a composite according to the present invention.

FIG. 8 is a longitudinal sectional view showing the first embodiment of the method for producing a composite according to the present invention.

FIG. 9 is a longitudinal sectional view showing the first embodiment of the method for producing a composite according to the present invention.

FIG. 10 is a longitudinal sectional view showing a first embodiment of the method for producing a composite according to the present invention.

FIG. 11 is a longitudinal sectional view showing a second embodiment of the method for producing a composite according to the present invention.

FIG. 12 is a cross-sectional view of a composite manufactured by the method for manufacturing a composite of the present invention.

FIG. 13 is a longitudinal sectional view of the composite shown in FIG.

FIG. 14 is a schematic diagram showing a configuration example of a spark plasma sintering apparatus.

[Explanation of symbols]

Reference Signs List 1 Molding die 2 Outer die 21 Hollow part 3a First presser 3b Second presser 4 Heat insulating material 5a Titanium layer material 5b Mixed layer material 51a, 51b Compact 7 Carbon sheet 70 Discharge plasma sintering device 71 Control Part 72 Power supply for sintering 73 Pressure drive mechanism 74, 75 Pressure ram 76 Vacuum chamber 77 Vacuum pump 8 Material filling jig 8a, 8b Material filling jig 81 Fitting part 82, 82b Projection part 88 Teflon sheet 91 Compression Presser 910 Hollow part 92 Presser for compression 93 Presser for compression 10a, 10b Composite of hydroxyapatite and titanium 103 Mixed layer 105, 106 Titanium layer

Continuation of the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) C22C 14/00 C04B 35/64 E (72) Inventor Shotaro Miya 2-36-9 Maenocho, Itabashi-ku, Tokyo Manabu Asahi Kogaku Industrial Co., Ltd. F term (reference) 4C089 AA06 BA03 BA16 BB01 BB07 CA04 CA06 4K018 AA06 AB10 DA24 KA70

Claims (11)

[Claims] 1. A composite of hydroxyapatite and titanium having a mixed layer containing hydroxyapatite and titanium or a titanium-based alloy, and a titanium layer made of titanium or a titanium-based alloy, wherein at least a part of the composite A composite of hydroxyapatite and titanium, wherein the composite has a double structure in which the mixed layer is located inside the titanium layer. 2. The composite of hydroxyapatite and titanium according to claim 1, wherein said composite is formed by a spark plasma sintering method. 3. The composite of hydroxyapatite and titanium according to claim 1, wherein the content of the hydroxyapatite in the mixed layer is 5 to 50 wt%. 4. The hydroxyapatite according to claim 1, wherein the titanium or titanium-based alloy contained in the mixed layer and the titanium or titanium-based alloy contained in the titanium layer have the same composition. Complex with titanium. 5. The composite of hydroxyapatite and titanium according to claim 1, wherein said mixed layer and said titanium layer are arranged concentrically or concentrically. 6. A mixed layer containing hydroxyapatite and titanium or a titanium-based alloy, and a titanium layer made of titanium or a titanium-based alloy, wherein at least a part or all of the mixed layer is inside the titanium layer. A method for producing a composite of hydroxyapatite and titanium, the method comprising sintering the composite by spark plasma sintering to form the composite. 7. The method for producing a composite of hydroxyapatite and titanium according to claim 6, wherein the sintering is performed at a sintering temperature of 600 ° C. or lower. 8. The method according to claim 1, wherein the hydroxyapatite is previously 70
The method for producing a composite of hydroxyapatite and titanium according to claim 7, wherein the composite is pre-sintered at 0 to 1300 ° C. 9. The composite of hydroxyapatite and titanium according to claim 6, wherein the sintering is performed by heating at least a part of the mixed layer and the titanium layer via a heat insulating material. How to make the body. 10. The method for producing a composite of hydroxyapatite and titanium according to claim 6, wherein the pressurized state is released after the sintering and the mixture is allowed to cool. 11. The composite according to claim 6, wherein the mixed layer and the titanium layer are arranged concentrically or concentrically.
11. The method for producing a composite of hydroxyapatite and titanium according to any one of claims 10 to 10.