JPH026537B2 - - Google Patents

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is useful for implant materials such as artificial bones, teeth, tooth roots, etc., and their bonding materials, and has a surface that is compatible with bone and tooth tissues. The present invention particularly relates to titanium or titanium alloy coated with an excellent calcium phosphate compound and a method for producing the same.

(Prior Art and its Problems) Metals have been used as biological implant materials for artificial bones, artificial tooth roots, and the like because of their physical strength and workability. In the past, precious metals were used because of their corrosion resistance and their impact on living organisms, but with the development of alloys that exhibit good corrosion resistance, alloy materials such as stainless steel have begun to replace them. In addition, metal materials for biological implants mainly made of cobalt have been developed and used.

Among these metal materials, noble metals are stable but expensive, and have the disadvantage of having a large specific gravity and weight. Although alloys such as stainless steel have good corrosion resistance, they may contain components that pose toxicity problems if they elute in vivo, so they are not necessarily all-purpose. It also has a specific gravity of around 8, which has the disadvantage of being too heavy.

Recently, titanium (d ²⁰ = 4.50) and titanium alloys have come into use because they are non-toxic, stable, have a relatively small specific gravity, are light, and are easy to handle.

All of these metal materials have sufficient mechanical strength and good workability, but they have a common drawback that they have no affinity with bone tissue in vivo if used as is.

On the other hand, research is being conducted on the use of ceramic materials that are more stable and lighter than metals, and α-alumina is known as a typical material. This material is not only chemically stable, but also non-toxic, lightweight, and has extremely high mechanical strength. The disadvantage is that there is no affinity for Stabilized zirconia is also beginning to be used due to its good toughness, but α
- Has the same drawbacks as alumina.

Glass materials whose surfaces are mainly porous are known as stable materials, but they have the drawbacks of insufficient mechanical strength, compatibility with living organisms, and processability.

Recently, apatite ceramics have been proposed that solve the common drawback of conventional materials, which is their lack of compatibility with living organisms. In other words, the main inorganic component of bones and teeth is a calcium phosphate compound (mainly composed of hydroxyapatite), and apatite ceramics containing this component have extremely good affinity with bones, and after implantation in a living body. Assimilation is extremely good.

However, even apatite ceramics, which seem to be ideal, have drawbacks such as low mechanical strength, poor moldability, and poor workability, and the areas where they can be used are limited.

In order to eliminate these drawbacks, it is desired to develop a biocompatible metal or ceramic material as a composite material by coating the surface of the metal or ceramic with apatite. For this purpose, metal-ceramic and ceramic-ceramic bonding techniques are required, but at present only plasma spraying is known.

Plasma spraying is useful for such joining, but it is difficult to coat the entire surface of materials with complex shapes, and due to its characteristics, it is difficult to coat the entire surface of porous materials. It is not possible and requires expensive equipment, the yield of expensive apatite particles is poor, and the bonding between the coating and the base material is not necessarily sufficient.

(Objective of the Invention) The object of the present invention is to create an artificial bone that is lightweight, has good workability, has sufficient mechanical strength, does not elute in the living body, and has increased compatibility in the living body such as bone tissue. The purpose of the present invention is to provide materials suitable for implant materials such as artificial tooth roots.

(Means for Solving the Problems) The present invention first provides a method for forming titanium or a titanium alloy base material by heating and baking a calcium phosphate compound and a hydrochloric acid or nitric acid aqueous solution of titanium and/or tin and/or those compounds. It is a titanium composite material that has a base layer made of a calcium phosphate compound and titanium oxide and/or tin oxide, and a coating layer of a calcium phosphate compound formed by heating and sintering on the base layer. The surface of the material is activated, a hydrochloric acid or nitric acid aqueous solution of a calcium phosphate compound and titanium and/or tin and/or those compounds is applied, and the calcium phosphate compound and titanium oxide and/or oxide are applied onto the base material by heating and baking. This method of manufacturing titanium composites involves forming a base layer made of tin, then applying a suspension of a calcium phosphate compound thereon, and heating and sintering it to form a coating layer of the calcium phosphate compound. The feature is that when coating a titanium or titanium alloy base material with a calcium phosphate compound, a base layer is formed by heating and sintering, and a coating layer is formed by heating and sintering, and the base layer can form a strong bond with the base material. The point is that it contains titanium oxide and/or tin oxide.

The present invention will be explained in more detail below.

The present invention is a titanium composite material suitable for implant materials such as artificial bones and artificial tooth roots, in which a calcium phosphate compound coating is formed on a titanium or titanium alloy base material, and a method for manufacturing the same.

In the present invention, the calcium phosphate compound is
Apatite-based calcium phosphates containing fluorine, chlorine, and hydroxyl groups, including tricalcium phosphate, calcium hydrogen phosphate, calcium dihydrogen phosphate, and hydroxyapatite (calcium hydroxyphosphate). It is a general term for compounds, and in the present invention, as the base layer and the coating layer, in addition to these compounds, materials containing some other compounds or impurities that are harmless to living organisms can be used as appropriate. In the present invention, by providing a coating of a calcium phosphate compound on the surface of titanium or a titanium alloy, it can be bonded to bones etc. with sufficiently high affinity in vivo.

The titanium or titanium alloy in the titanium or titanium alloy base material of the present invention refers to metallic titanium and e.g.
It is selected from titanium alloys to which Ta, Nb, platinum group metals, Al, V, etc. are added, and even if the base material is smooth and plate-shaped, rod-shaped, etc.
It may have a spongy porous surface. Titanium or titanium alloy is used as a base material because it is non-toxic and stable in vivo.
Moreover, compared to alloys such as eluted stainless steel, its specific gravity is approximately 60% lighter, and since it is a metal, it has sufficient mechanical strength and is easy to work with. The surface of the base material is cleaned in advance by water washing, pickling, ultrasonic cleaning, steam cleaning, etc. to remove impurities and improve the affinity of the calcium phosphate compound described below with titanium oxide and/or tin oxide. Furthermore, if necessary, the surface may be roughened by blasting and/or etching treatment to improve the affinity between the calcium phosphate compound described below and titanium oxide and/or tin oxide, and to perform activation. You can also do that. Note that etching may be performed not only by a chemical method but also by a physical method such as sputtering.

Next, an aqueous solution of the calcium phosphate compound and titanium and/or tin and/or their compounds in hydrochloric acid or nitric acid is applied to the surface of the base material, and heated and fired to form a strong bond with the titanium or titanium alloy of the base material. A base layer made of a calcium phosphate compound containing titanium and/or tin oxide is formed. In this case, it is desirable to use a highly soluble compound such as a calcium hydrogen phosphate compound or calcium dihydrogen phosphate as the calcium phosphate compound to form a uniform aqueous solution. In the present invention, a solution in which a calcium phosphate compound, etc. is dissolved is applied onto the substrate, and then the compound, etc. is precipitated from the solution. Therefore, no matter what shape the substrate is, for example, a material with a porous surface, the surface A uniform coating can be formed over the entire surface.

Titanium, tin, or a compound thereof to be dissolved in hydrochloric acid or nitric acid may be an elemental metal or a compound as long as titanium oxide or tin oxide is produced by dissolving it in hydrochloric acid or nitric acid and heating and baking it. Inorganic salts including halogen compounds such as titanium chloride, titanium chloride, stannous chloride, and stannic chloride, organic salts such as tin oxalate, and organometallic compounds such as n-butyl titanate and alkoxytin. titanium oxide and tin oxide themselves.

The use of hydrochloric acid or nitric acid aqueous solution to dissolve the calcium phosphate compounds, etc. not only facilitates the dissolution of the calcium phosphate compounds, etc.
This is because part of the titanium or titanium alloy of the base material melts during heating and firing, forms a chemical bond with the calcium phosphate compound, and forms a calcium phosphate coating with strong adhesion.

The temperature for heating and firing is 200 to 800°C, and if it is lower than 200°C, heating and firing will not be performed sufficiently, and adhesion to the base material will not be performed sufficiently. When the temperature is higher than 800°C, surface oxidation of the titanium or titanium alloy base material becomes dominant, and adhesion of the calcium phosphate compound to the base material deteriorates. When heated and fired, the titanium compound and/or tin compound in the hydrochloric acid or nitric acid aqueous solution becomes titanium oxide and/or tin oxide, and a base layer of a calcium phosphate compound containing titanium oxide and/or tin oxide is formed on the base material. .

The reason why the base layer of the calcium phosphate compound contains titanium oxide and/or tin oxide in the present invention is as follows.
This is because they form an extremely strong bond with the base material titanium or titanium alloy, making the bond between the base material and the underlying layer even stronger. Furthermore, titanium oxide and tin oxide are chemically extremely stable. Yes, because it does not undergo chemical changes in the living body, there is no chance of toxic substances leaching out or weakening of the underlying layer.

The amount of titanium oxide and/or tin oxide to be included in the underlayer can be selected as appropriate, but is preferably 80% or less by weight.

Next, a coating layer of a calcium phosphate compound is laminated on this surface to a required thickness, and the calcium phosphate compound in this coating layer may be the same as or different from the calcium phosphate compound in the base layer. This coating layer can be easily formed by a normal sintering method since the base material has a calcium phosphate compound coating that is strongly bonded to the base material.

That is, a suspension of the desired calcium phosphate compound is applied to a substrate coated with a thin underlayer of calcium phosphate compound. The suspension concentration can be freely selected depending on the required thickness of the coating layer. After drying, heating and sintering is performed at a temperature of 300°C.
A temperature between ℃ and 900℃ is good.

If it is below 300°C, heating sintering will not proceed, and if it is above 900°C, it may exceed the alpha-beta transition point of titanium, which may have an adverse effect on the base material, which is not desirable. Note that the sintering temperature and time are determined depending on the condition, thickness, etc. of the calcium phosphate compound. When the temperature is high, tricalcium phosphate becomes dominant, and when the temperature is relatively low, hydroxyapatite becomes dominant.

One of the reasons for using a suspension to form a coating layer is
The purpose is to provide unevenness to the surface of the coating layer to increase resistance to detachment and increase affinity.

Note that, if necessary, the above operation can be repeated for both the base layer and the coating layer to obtain a desired thickness.

In the present invention, the base layer of a calcium phosphate compound containing titanium oxide and/or tin oxide and the coating layer of a calcium phosphate compound are laminated on a titanium or titanium alloy base material. A heating sintering method in which a base layer mainly composed of a calcium phosphate compound that is uniform and has a high affinity is formed on the entire surface of titanium or titanium alloy, and a calcium phosphate compound having the same or similar physical properties as the base layer is deposited on the base layer. To provide a titanium composite material that has a strong affinity with the base material and has sufficiently high strength by coating it with a base layer to provide a strong bond between the base layer and the coating layer and to form a calcium phosphate compound with high strength. However, if only a single coating layer is formed on the base material by sintering, the strength of the coating layer is high, but the affinity with the base material is low and it becomes easy to peel off. Composite materials useful as implant materials etc. cannot be obtained.

(Examples) Examples of the present invention will be described below, but these Examples do not limit the present invention.

Example 1 The surface of a JIS grade 1 titanium material measuring 10 cm long x 10 cm wide x 3 mm thick was blasted using a #80 stainless steel cut wire, the surface was roughened and degreased with acetone, and then treated with a 20% aqueous hydrochloric acid solution at 60°C. A titanium base material was obtained by acid washing to remove surface deposits.

A coating solution was prepared by dissolving calcium hydrogen phosphate in an aqueous hydrochloric acid solution of titanium chloride containing 5 g/a of titanium so that the calcium content was 5 g/a. This coating solution was applied to the titanium base material and heated to 80°C.
Dry for 15 minutes at 500 °C and subsequently in flowing air.
It was heated and baked for 15 minutes. This operation was repeated four times to form a strong base layer coating of the titanium oxide-tricalcium phosphate mixture having a thickness of about 1 to 2 .mu.m.

On this titanium base material having a mixed coating of tricalcium phosphate and titanium oxide, tricalcium phosphate reagent (special grade) powder was crushed in an agate mortar for 10 hours and then 5%
A suspension of a calcium phosphate compound prepared by dispersing it in an aqueous hydrochloric acid solution was applied.

The titanium substrate coated with the suspension was dried at 80°C for 1 hour, and further heated at 900°C for 1 hour in argon gas. This operation was repeated twice to obtain a titanium base material having a strong and uniform coating layer of a calcium phosphate compound with a thickness of about 50 μm.

For comparison, the calcium phosphate compound suspension was applied directly onto a pretreated titanium plate without providing a base layer of tricalcium phosphate containing titanium;
When the heat treatment was repeated twice under the same conditions, it was possible to form a tricalcium phosphate coating with a thickness of about 50 μm, but the physical strength of the coating was insufficient and it cracked and peeled off just by tapping it with a hammer. A drop occurred.

Example 2 A titanium base material was prepared in the same manner as in Example 1.
Dissolve calcium hydrogen phosphate and tin oxalate in a 20% nitric acid aqueous solution, and add 5% calcium and tin each.
A coating solution containing g/g was prepared. This coating solution was applied onto the titanium base material, dried at 150°C for 10 minutes, and then baked at 520°C for 15 minutes in circulating air. This operation was repeated six times to obtain a strong base layer of a mixture of tin oxide and calcium phosphate compound having a thickness of about 1 to 2 μm.

A suspension of the calcium phosphate compound was further applied to the titanium base material having the base layer of the mixture of the calcium phosphate compound and tin oxide. The suspension was prepared by dissolving calcium hydroxide (Ca(OH) ₂ ) in a 10% nitric acid aqueous solution, and adding Ca ²⁺ ions and PO ^3- ions to this aqueous solution in a molar ratio of 3:2. It was prepared by adding calcium hydrogen phosphate (CaHPO ₄ ) and further adding tricalcium phosphate fine powder.

The titanium substrate coated with this suspension was dried at 80° C. for 1 hour, and then heated and sintered in air at 750° C. for 3 hours.
This operation was repeated twice to obtain a titanium base material having a strong and uniform coating layer of a calcium phosphate compound with a thickness of about 100 μm.

Example 3 A base layer made of a titanium oxide-tin oxide-calcium phosphate compound was formed on a titanium base material treated in the same manner as in Example 1.

The coating solution was prepared by dissolving stannous chloride in amyl alcohol and refluxing it to obtain alkoxytin, then adding a small amount of water, leaving it to stand, adding an aqueous hydrochloric acid solution of titanium chloride, and further dissolving calcium hydrogen phosphate. Created. The coating liquid contains 2 g of titanium and 3 g of tin.
and calcium 5g/.

This coating solution was applied to the titanium base material, dried at room temperature, further dried at 180°C for 20 minutes, and further heated and sintered at 480°C for 20 minutes. This operation was repeated six times to form a base layer coating of a titanium oxide-tin oxide-calcium phosphate compound having a thickness of 1 to 2 μm.

Applying the same suspension as in Example 1 onto this substrate,
After drying at 80℃ for 1 hour, drying at 850℃ in argon gas.
Sintered by heating for hours. This operation was repeated twice to obtain a titanium base material having a strong and uniform coating layer of a calcium phosphate compound with a thickness of about 50 μm.

For comparison, when the suspension was sintered at 950°C, above the transition point of titanium, a strong coating was obtained, but the grains of the titanium substrate became extremely large. Although this does not seem to be a problem during normal use, it is expected that problems will occur when used for a long period of time in areas where special force is applied.

Example 4 Ti-6%Al-4% treated in the same manner as Example 1
A base layer coating made of a titanium oxide-tin oxide-calcium phosphate compound was formed on a titanium base material made of a V alloy.

The coating liquid used in Example 1 and Example 2 was used. That is, first, a hydrochloric acid aqueous solution of titanium chloride-calcium hydrogen phosphate of Example 1 was applied under the same conditions, heated and baked to form a coating, and then tin oxalate-calcium hydrogen phosphate of Example 2 was applied. A nitric acid aqueous solution was applied and baked under the same conditions as in Example 1. This operation was repeated 8 times, 4 times each, to alternately form a titanium-calcium phosphate compound coating and a tin-calcium phosphate compound coating. This resulted in a strong base layer coating with a thickness of 2 to 3 μm, which was essentially a mixture of titanium oxide, tin oxide, and calcium phosphate compounds.

On top of this, apply hydroxyapatite suspension and
After drying at 800°C for 1 hour, the air was cut off and sintering was performed at 800°C for 2 hours. The suspension is prepared by dissolving calcium hydroxide (Ca(OH) ₂₎ in a 10% aqueous nitric acid solution.
Calcium hydrogen phosphate (CaHPO ₄ ) was added so that the molar ratio of Ca ²⁺ ions and PO ^3- ions was 5:3, and hydroxyapatite finely ground in an agate mortar for 10 hours was added. .

(Effects of the Invention) First, the present invention uses titanium or titanium alloy as the base material, so when the composite material of the present invention is used as an artificial bone or artificial tooth root, it is harmless to living organisms, stable, and does not elute. Moreover, it is lightweight, has sufficient mechanical strength, and is easy to work with.

Second, since the surface of titanium or titanium alloy is coated with a calcium phosphate compound, it has a sufficiently high affinity in vivo and can be bonded easily and with sufficient strength.

Thirdly, since it is a composite coating in which a base layer is first formed on the surface of the base material by heating and firing a calcium phosphate compound containing titanium oxide and/or tin oxide, and then a coating layer is formed by heating and sintering on top of that, the base layer is An extremely strong bond is formed between the titanium or titanium alloy and the titanium oxide and/or tin oxide of the underlayer, and its strength is increased compared to the case where titanium oxide and/or tin oxide is not included. The affinity between the base layer and the covering layer is also very large because both have a calcium phosphate compound as a main component, and since the surface layer is a layer formed by heating and sintering with high strength, the overall strength is high.

Fourth, since a solution such as a calcium phosphate compound is applied to the base material and the calcium phosphate compound is precipitated from the solution, a uniform coating can be formed over the entire surface of the base material of any shape. Furthermore, the yield of the calcium phosphate compound is good, and the state of the coating can be easily controlled to form a high-quality coating.

Claims (1)

[Claims] 1. A calcium phosphate compound, titanium oxide and/or titanium oxide, and/or a calcium phosphate compound formed on a titanium or titanium alloy base material from a hydrochloric acid or nitric acid aqueous solution of titanium and/or tin and/or those compounds by heating and firing. A titanium composite material comprising a base layer made of tin oxide and a coating layer of a calcium phosphate compound formed by heating and sintering thereon. 2. The titanium composite material according to claim 1, wherein the calcium phosphate compound of the base layer and/or the coating layer is mainly hydroxyapatite and/or tricalcium phosphate. 3 Activate the surface of the titanium or titanium alloy base material, apply a calcium phosphate compound and a hydrochloric acid or nitric acid aqueous solution of titanium and/or tin and/or those compounds, and heat and bake to form a calcium phosphate compound and a calcium phosphate compound on the base material. A titanium composite material characterized in that a base layer made of titanium oxide and/or tin oxide is formed, and then a suspension of a calcium phosphate compound is applied thereon and heated and sintered to form a coating layer of a calcium phosphate compound. Production method. 4. The manufacturing method according to claim 3, wherein the calcium phosphate compound formed as the base layer and/or the coating layer is mainly hydroxyapatite and/or tricalcium phosphate. 5. The manufacturing method according to claim 3, wherein titanium chloride is used as the titanium compound and tin chloride is used as the tin compound. 6 n-butyl titanate as a titanium compound,
The manufacturing method according to claim 3, in which alkoxytin is used as the tin compound. 7. The manufacturing method according to claim 3, wherein the surface of the titanium or titanium alloy base material is activated by blasting and/or etching. 8. The manufacturing method according to claim 3, wherein heating and firing for forming the base layer is performed at a temperature of 200 to 800°C. 9. The manufacturing method according to claim 3, wherein the heating sintering to form the coating layer is performed at a temperature of 300 to 900°C.