KR940003461B1 - Method for glass ceramic withused living body material - Google Patents

Abstract

The crystalized glass for biomaterials is prepd. by milling the glass powder comprising SiO2 50-58 wt.%, P2O5 4-10 wt.%, and CaO 34-45 wt.% (and opt. MgO 1-5 wt.%), which generates spontaneously phase-separation, to lower than 200 mesh of the particle size; molding the powder; heat-treating at 950-1050 deg.C for 2-10 hrs, then preciptating the crystal. The phase separation is generated to both of silica. Segment and calcium phosphate segment. In the heat-treatment step, the main crystal component comprises CaSiO3 (Wollastonite) and SiO2 (quartz) and the sub-crystal component comprises Ca10(PO4)6O (Apatite).

Description

Crystallized glass for high strength biomaterials and its manufacturing method

1 is a microstructure showing the phase separation of the mother glass according to the present invention,

2 is a microstructure that appeared after heat-treating the glass powder subjected to phase separation at 1050 ℃ for 4 hours.

* Explanation of symbols for main parts of the drawings

1: calcium phosphate (CaO · P ₂ O ₅ ) large area 2: silica (SiO ₃ ) large area

3: apatite [Ca ₁₀ (PO ₄ ) ₆ O] crystal 4: Wallastonite (CaSiO ₃ ) crystal

5: quartz (SiO ₂ ) crystal

The present invention relates to a crystallized glass for high-strength biomaterials using a phase separation property and a method of manufacturing the same.

Conventional bioactive ceramics capable of bonding to bones include sintered apatite ceramics with a strength value of about 120 MPa and Na ₂ OK ₂ O-MgO-CaO-P ₂ O ₅ -SiO ₂ -based crystallized glass, Na ₂ OK ₂ O-MgO-CsO-P ₂ O ₅ -Al ₂ O ₃ -SiO ₂ -F system crystallized glass, and the like. Such crystallized glass has biocompatibility, surface activity, and good workability, but has a strength value of about 150 MPa, which is not satisfactory for use in artificial teeth or bones subjected to high loads.

Japanese Patent Application Laid-Open No. 57-191252 discloses a crystallized glass containing SiO ₂ , CaO, P ₂ O ₅ , MgO as the main component, and containing wollastonite crystals and apatite crystals. In Japanese Patent No. 61-197446, SiO ₂ , CaO, P ₂ O ₅ , MgO, Al ₂ O ₃ , ZrO _2, etc. are the main components, and a small amount of additives are used as _secondary components, and apatite, beta-tricalcium phosphate and diopide ( Diopside) Crystallized glass for biomaterials containing crystals is presented. Japanese Patent No. 61-255663 and U.S. Patent No. 4722534 make SiO ₂ , CaO, P ₂ O ₅ as main components, and small amounts of additives as subcomponents, and crystallized glass for biomaterials containing wollastonite and apatite crystals. Presenting. Japanese Patent No. 62-72540 and US Pat. No. 4,834,29 have SiO ₂ , CaO, P ₂ O ₅ , MgO, etc. as main components, small amounts of additives as minor components, and contain wollastonite, apatite and diopside crystals. Crystallized glass is presented. Japanese Patent No. 63-242944 discloses SiO ₂ , CaO, P ₂ O ₅ , Na ₂ , Al ₂ O ₃ as a main component, and a small amount of additives as a minor component, and includes apatite, wollastonite, and whittite (Whitlockite). ) Crystallized glass containing crystals. Japanese Patent No. Hei 1-218460 discloses a crystallized glass for a biomaterial having CaO, P ₂ O ₅ and Al ₂ O ₃ as main components, ZrO ₂ as a main component, and SiO ₂ and apatite as main crystal phases.

Such crystallized glass has a biocompatibility and surface activity as well as a high bending strength of about 170 to 200 MPa, but Japanese Patent Nos. 61-197446, 61-255663, 62-72540, So-63-242944 and Japanese Patent No. 1-218460 report that when SiO ₂ is about 50% or more, devitrification or phase separation is likely to occur in the glass, making it difficult to manufacture crystallized glass. In general, when phase separation occurs, it is known that the sinterability is poor during heat treatment by powder sintering. In the present invention, by using the characteristics of the phase separation with respect to the composition of the phase separation region having excellent powder sintering properties to induce uniform dispersion of the crystal phase generated in each phase separation glass composition to enable the production of high-strength biomaterial crystallized glass.

The present invention comprises 50 to 58% by weight of SiO ₂ , 4 to 10% by weight of P ₂ O ₅ and 34 to 45 of CaO, and spontaneous phase separation occurs in a large amount of silica and a large amount of calcium phosphate in crystallization and glass manufacturing. When the glass powder is heat-treated by powder sintering, wollastonite (CaSiO ₃ ) and quartz (Quartz; SiO ₂ ) are the main crystalline phase and apatite (Ca ₁₀ (PO ₄ ) ₆ O) is dispersed in the subcrystalline phase. It relates to a crystallized glass for a biomaterial, characterized in that. In addition, the present invention contains MgO up to 5% by weight as a minor additive in the above composition, spontaneous phase separation occurs during glass manufacturing, when the glass powder is heat-treated by powder sintering method, wollastonite and quartz or Crystalline glass for biomaterials characterized in that cristobalite (SiO ₂ ) is the main crystalline phase and diopside (CaMgSi ₂ O ₆ ) and akermanite (Ca ₂ MgSi ₂ O ₇ ) are dispersed in the subcrystalline phase. Include. In the crystallized glass of the present invention, SiO ₂ , P ₂ O ₅ , CaO is an essential component for the biomaterial according to the present invention to exhibit surface activity in vivo.

When the content of SiO _{2 in} the crystallized glass composition is less than 50% by weight, the sintering property of the glass powder and the precipitation amount of quartz crystals are reduced. When the content of SiO ₂ is more than 58%, devitrification easily occurs and the sinterability of the glass powder is reduced. If the content of P ₂ O ₅ is less than 4%, the sinterability of the glass powder and the precipitation amount of the apatite are lowered, and if it exceeds 10%, the sinterability of the glass powder is lowered. If the CaO content is less than 34%, the devitrification tends to be large or difficult to vitrify. If the CaO content is more than 45%, phase separation does not occur. If the MgO content is more than 5%, devitrification tends to occur or phase separation does not occur.

The present invention also relates to a method for producing crystallized glass for biomaterials. The present invention is a glass powder containing 50 to 58% by weight of SiO ₂ , 4 to 10% by weight of P ₂ O ₅ , 34 to 45% by weight of CaO and 0 to 5% by weight of MaO as a minor additive to the above composition. In the manufacturing method of the crystallized glass for biomaterials characterized in that the pulverized glass powder containing a weight% to a particle size of 200 mesh or less, and then molded into a predetermined shape and sintered and crystallized at 950 to 1150 ℃ for 2 to 10 hours It is about. If the heat treatment temperature is lower than 950 ℃, the sintering degree and crystallinity of the crystallized glass is low, the strength is lowered, and when heat treatment at a temperature higher than 1150 ℃ beta- wollastonite begins to transition to high-temperature alpha- wollastonite The strength is lowered.

In addition, when MgO is contained in an amount of about 2.5% by weight or more and the glass powder is heat-treated at 1150 ° C., precipitation of calcium-containing diopsides and akermanite crystals increases, thereby increasing the strength of the material but making it difficult to have surface activity. Therefore, when MgO is contained in an amount of about 2.5 wt% or more and 5 wt% or less, the heat treatment temperature is preferably 1050 ° C. or less.

If the molten glass is directly formed and heat-treated, the wollastonite crystals precipitate only on the surface, so that cracks are formed inside the crystallized glass, and mechanical strength is significantly reduced. In addition, when the particle diameter of the glass powder is 75 µm or more, there is a high possibility that pores remain in the interior, so that high strength crystallized glass cannot be obtained. That is, in order to obtain high-strength crystallized glass, crystals must be uniformly deposited and the average particle diameter of the glass powder must be at least 75 μm or less.

In general, the sintering temperature range for the glass powder is determined by measuring the heat shrinkage rate after heat-treating the molded body at a constant heating rate. This ranges from the temperature at which heat shrinkage begins to the temperature at which shrinkage ends. The crystallization temperature can be determined by differential thermal expansion analysis (DTA) of the glass powder. That is, the crystallization temperature ranges from the temperature at which the exotherm starts to the temperature at which the exotherm ends.

The crystallized glass for biomaterials of the present invention prepared as described above has a complex effect due to the formation of different crystals from two different glass phases formed by phase separation as shown in FIGS. 1 and 2, and is uniformly dispersed Precipitating the quartz crystal from the silica large region leads to the strengthening effect between the wollastonite and the apatite crystals, thereby enhancing the strength. In addition, even after crystallization, the phase separation region is separated into a large amount of silica and a large amount of calcium phosphate, and the large amount of calcium phosphate is moved to a composition region capable of exhibiting surface activity. It is characterized by having a surface activity unlike that. In addition, MgO added as a trace component stabilizes beta wollastonite precipitation by inhibiting the precipitation of pseudo wollastonite, which negatively affects the strength of the material in the crystallized glass, and stabilizes the diopside and aconateite crystals. Precipitation has the effect of enhancing the strength of the material. On the other hand, the precipitation of diopside crystals does not affect the surface activity, but when the akermanite crystals are precipitated, the time for the formation of hydroxide apatite is delayed.

In addition, the production method thereof according to the present invention has a merit in that a manufacturing process is simple and a complicated shape can be easily manufactured as a method for producing crystallized glass by powder sintering.

Hereinafter, the present invention will be described in more detail with reference to specific examples of the present invention. However, the present invention is not limited thereto.

Example 1

A glass badge having a composition of 57.0% SiO ₂ , 37.0% CaO and 6.0% P ₂ O ₅ by weight is prepared by using an oxide, carbide or phosphoric acid and melted in a platinum crucible at a temperature of 1500 to 1600 ° C. for 2 to 5 hours. After melting, the melt was quenched, dried, and then ground in a mortar grinder. The pulverized powder is sieved to 200 mesh to shape the passed particles at a molding pressure of about 450kg / cm ² , and then placed in a sintering furnace and heated to a temperature of 1050 ℃ at a temperature increase rate of 1 to 10 ℃ / min. At this time, for effective sintering and crystallization it is maintained for 2 to 10 hours and then cooled to room temperature to obtain a crystallized glass. X-ray diffraction analysis of this crystallized glass revealed that the precipitated crystal phases were wollastonite, quartz and apatite. According to the KS L 1591 standard, a 3 × 4 × 40mm cuboid was made and finally polished with 1㎛ CeO ₂ to measure the three-point bending strength, which showed a high value of 185MPa.

In the case of phase separation in the mother glass, the uniformity of quartz crystals dispersed in two different glass phases in the production of crystallized glass and the quartz crystals uniformly dispersed in the quartz crystals act as a composite reinforcing material, thereby increasing strength. As a result of an in vitro test in a simulated body fluid for the crystallized glass, the composition of the remaining glass phase shifted to a region showing surface activity due to the difference in crystal phase formation in phase separation. Hydroxyapatite required for bonding with was formed on the surface within about 50 hours, and when reacted for one month, a surface reaction layer of about 25㎛ was formed.

Example 2

Crystallized glass was prepared in the same manner as in Example 1, except that the composition of the glass badge was the same as that in Example 1, and the heat treatment temperature was 950 ° C. The results obtained, such as precipitated crystal phase, bending strength, and apatite hydroxide formation time, were shown in the table. 1 is shown.

[Examples 3 to 5]

Crystallized glass was prepared in the same manner as in Example 1, except that the composition of the glass badge was contained as shown in Table 1. The precipitated crystal phases were crystal phases of wollastonite, quartz and apatite, and the obtained results such as X-ray diffraction analysis, bending strength and hydroxide apatite formation time are shown in Table 1 below.

TABLE 1

＊ W: Wallastonite (CaSiO ₃ )

Q: Quartz (SiO ₂ )

A: apatite (Ca ₁₀ (PO ₄ ) ₆ O)

# HAp formation time: The time when Hydroxyapatite (Ca ₁₀ (po ₄ ) ₆ (oh) ₂ : Apatite Hydroxide) is formed on the surface in SBF (Simulated Body Fluid)

Example 6

By weight, a glass badge having a composition of 55.3% SiO ₂ , 37.3% CaO, 6.0% P ₂ O ₅ , 1.3% MgO was prepared as an oxide, carbide, phosphoric acid, etc., in a platinum crucible at a temperature of 1500 to 1600 ° C. After melting for 5 hours, the melt is quenched in water, dried and then ground in a mortar grinder. The pulverized powder is sieved with 200 mesh, and the particles passed through are formed at a molding pressure of about 450 kg / cm ² , and then placed in a sintering furnace to be heated to a temperature of 1150 ° C. at a temperature rising rate of 1 to 10 ° C./min. At this time it is maintained for 2 to 10 hours for effective sintering and crystallization and then cooled to room temperature. X-ray diffraction analysis of the crystallized glass revealed that the precipitated crystal phases were wollastonite, quartz, akermanite, and trace diopsides. According to the KS L 1591 standard, the three-point bending strength value of 3 × 4 × 40 mm cuboids and final polishing with 1 μm CeO ₂ showed a value of 175 MPa.

As a result of the in vitro reaction in the similar biological solution on the crystallized glass, the composition of the remaining glass phase moved to the region showing the surface activity due to the difference in the crystal phase formation due to the phase separation. It formed on the surface within hours. The above result is shown in Table 2.

[Examples 7 to 8]

The crystallized glass was manufactured in the same manner as in Example 6, wherein the composition of the glass badge was 5% by weight SiO ₂ 55.6%, CaO 35.7%, P ₂ O ₅ 6.1%, and MgO 2.7%. The precipitated crystal phases were wollastonite, quartz, diopside and akermanite. The bending strength of this crystallized glass was 182 MPa, and even after 240 hours in the similar biological solution, hydroxide apatite was not formed on the surface.

When the glass powder molded product having the same composition was heat-treated at 1050 ° C. for 4 hours, the precipitated crystal phases were wollastonite, quartz, diopside and trace apatite, and the bending strength of the crystallized glass was 171 MPa, which was similar within 50 hours. Hydroxyapatite was formed on the surface in the biological solution.

[Examples 9 to 10]

Crystallized glass was prepared in the same manner as in Example 6, wherein the composition of the glass badge was 5% by weight SiO ₂ 55.9%, CaO 34.0%, P ₂ O ₅ 6.1%, and MgO 4.1%. The precipitated crystal phases were wollastonite, quartz, diopside, cristobalite and akermanite. The bending strength of this crystallized glass was 200 MPa, and even after 240 hours in the similar biological solution, hydroxide apatite was not formed on the surface.

When the glass powder compact having the same composition was heat-treated at 1050 ° C. for 4 hours, the precipitated crystal phases were wollastonite, quartz, diopside and trace apatite, and within 50 hours, hydroxide apatite was formed on the surface in the analogous biological solution. It became.

[Examples 11 to 12]

Crystallized glass was prepared in the same manner as in Example 6, wherein the composition of the glass badge was 5 wt% SiO ₂ , 37.1% CaO, 5.7% P ₂ O ₅ , and 4.8% MgO. The precipitated crystal phases were wollastonite, quartz, diopside, cristobalite and akermanite. The bending strength of this crystallized glass was 191 MPa, and even after 240 hours in the similar biological solution, hydroxide apatite was not formed on the surface.

When the crystallized glass was manufactured in the same manner as in Example 8, the glass powder molded article having the same composition as above was precipitated crystal phases were wollastonite, quartz, diopside and a trace of apatite, and were hydrated in a similar biological solution within 50 hours. Apatite was formed on the surface.

Example 13

Crystallized glass was prepared in the same manner as in Example 6, wherein the composition of the glass badge was 5% by weight SiO ₂ 57.3%, CaO 35.3%, P ₂ O ₅ 6.0%, MgO 1.%. Precipitated crystal phases were wollastonite, cristobalite and akermanite, and the bending strength of the crystallized glass was 198 MPa, and within 240 hours, hydroxide apatite was formed in the analogous biological solution.

Example 14

Crystallized glass was manufactured in the same manner as in Example 9, wherein the composition of the glass badge was 5% by weight SiO ₂ 53.3%, CaO 39.4%, P ₂ O ₅ 6.0%, and MgO 1.3%. Precipitated crystal phases were wollastonite, quartz, and akermanite. The bending strength of the crystallized glass was 188 MPa, and within 120 hours, hydroxide apatite was formed in the analogous biological solution.

Example 15

Crystallized glass was prepared in the same manner as in Example 6, wherein the composition of the glass badge was 5% by weight SiO ₂ 51.3%, CaO 39.4%, P ₂ O ₅ 8.0%, and MgO 1.3%. Precipitated crystal phases were wollastonite, quartz and cristobalite, and traces of akermanite. The bending strength of this crystallized glass was 195 MPa, and within 240 hours, hydroxide apatite was formed in the analogous biological solution.

TABLE 2

＊ W: Wallastonite (CaSiO ₃ )

Q: Quartz (SiO ₂ )

C: cristobalite (SiO ₂ ) Anti D: diopside (CaMgSi ₂ O ₆ )

K: Akermanite (Ca ₂ MgSiO ₂ O ₇ )

A: apatite (Ca ₁₀ (PO ₄ ) ₆ O)

Claims (4)

50 to 58% by weight of SiO ₂ , 4 to 10% by weight of P ₂ O ₅ and 34 to 45% by weight of CaO, the spontaneous phase separation phenomenon occurs in the large amount of silica and calcium phosphate in the crystallized glass production, Sea crystal crystalline glass for biomaterials, characterized in that the wollastonite (CaSiO ₃ ) and quartz (SiO ₂ ) is the main crystalline phase and the apatite (Ca ₁₀ (PO ₄ ) ₆ O) is dispersed in the subcrystalline phase. 50 to 58% by weight of SiO ₂ , 4 to 10% by weight of P ₂ O _5, and 34 to 45% by weight of CaO, and ground the glass powder having spontaneous phase separation to a particle size of 200 mesh or less, and then Forming into a shape, and heat treatment at 950 to 1050 ℃ for 2 to 10 hours to produce a crystallized glass for a biological material, characterized in that to precipitate the crystals. 50 to 58% by weight of SiO ₂ , 4 to 10% by weight of P ₂ O ₅ , 34 to 45% by weight of CaO, and 1 to 5% by weight of MgO, and the glass powder having spontaneous phase separation is less than 200 mesh. And then pulverized into a predetermined shape, and heat-treated at 1050 to 1150 ° C. for 2 to 10 hours to precipitate crystals. It contains 50 to 58% by weight of SiO ₂ , 4 to 10% by weight of P ₂ O ₅ , 34 to 45% by weight of CaO and 1 to 5% by weight of MgO. In the preparation of crystallized glass, a large amount of silica and calcium phosphate are used. In spontaneous phase separation, wollastonite (CaSiO ₃ ) and quartz (SiO ₂ ) form the main crystalline phase during heat treatment, diopside (CaMgSi ₂ O ₆ ), akermanite (Ca ₂ MgSiO ₂ O ₇ ), Cristobalite (SiO ₂ ) and apatite (Ca ₁₀ (PO ₄ ) ₆ O) is a crystallized glass for biomaterials, characterized in that the dispersed in the amorphous phase.