JPS6050744B2 - High strength calcium phosphate sintered body - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high-strength and high-density calcium phosphate sintered body useful as a biomaterial (bioceramics) that can replace bones and teeth, or as a highly dense ceramic base material for IC package substrates, etc. .

Calcium phosphate has an affinity for living organisms, and its sintered body has been proposed to be used as a biomaterial that can replace bones and teeth.

In addition, it is useful as a highly expandable ceramic material in addition to being used as an IC package substrate by utilizing its highly dense properties. Conventional methods for producing this calcium phosphate sintered body include a normal sintering method in which the material is sintered under normal pressure after pressing, a hot pressing method, and the like. When calcium phosphate powder is sintered under normal pressure (normal sintering), the compressive strength is 900 kgI.
cd (Ceramics 10 [7] 1975, p. 474), the density is low, and spalling is likely to occur during the cooling process after firing, that is, it is weak in spalling resistance. On the other hand, in the hot breath method, the compressive strength is 1
000~2000kgkT1 (Medical Equipment Research Report [RepO
rtsOftheInstitutefOrMedlc
al&Dental Engineering] Volume 7 11
3-118 (1973)), the strength is considerably high, but the manufacturing method is complicated, the equipment cost is high, and mass production is difficult. The present applicant has already applied for a Japanese patent (1983) for a sintered body that solves these problems.
-127851) Smell. The company has applied for a method for producing a sintered body made of calcium phosphate and calcium/phosphorus frit.

According to this type of sintered body, the maximum bending strength is about 1400k9
A value of 1d is obtained, which is approximately the strength of human bone (approximately 1500
k91cI! ') (compared to about 800 kgId for conventionally known sintered bodies). Furthermore, according to the applicant's Japanese Patent Application No. 53-153035 (unpublished), conventionally known calcium phosphate sintering aids such as Ae2O3, ZrSlO4, ZrO2, SiO2 can be used for the above-mentioned sintered bodies.
It is clear that none of the above methods have the strength improvement effect above 7, and it is disclosed that the strength of the calcium phosphate sintered body can be further increased by containing Y2O3 (the highest resistance Orientation power 1560
k91c! l).

The present invention aims to eliminate the drawbacks of the conventionally known techniques described above and to provide a novel calcium phosphate sintered body with even higher strength. That is, the present invention provides powder mainly composed of calcium phosphate with a calcium phosphorus atomic ratio of 1.4 to 1.75, and an alkali metal of 0.5 to 15% by weight based on the fired calcium phosphate sintered body. Provided is a calcium phosphate sintered body containing a zinc and/or alkaline earth metal oxide-phosphate frit and sintered therein. Furthermore, the present invention provides powder mainly composed of calcium phosphate with a calcium/phosphorus atomic ratio of 1.4 to 1.75, and an alkali metal, zinc and/or Alkaline earth metal oxide monophosphate frit and Y2O3 3-23% by weight
The present invention also provides a calcium phosphate sintered body characterized by containing and sintering the calcium phosphate sintered body.

The present invention will be explained in detail below. The starting material used in the present invention for producing a calcium phosphate sintered body has a calcium/phosphate atomic ratio (Ca/p ratio) of 1.4 to 1.7.
A powder mainly composed of calcium phosphate as described in No. 5 is used.

As this raw material powder, hydroxyapatite 112 (Ca(
0H)23Ca3(PO4)2) (Ca/p ratio 5 no 3)
, apatite represented by the general formula Ca5(0H,F,Cf)(PO4)3 (F,Cf apatite), tricalcium phosphate (Ca/p ratio 312), or a mixture thereof.

Such a starting raw material powder is prepared by adding a calcium salt such as calcium carbonate to other calcium phosphate raw materials such as calcium pyrophosphate and monobasic calcium phosphate to obtain a composition similar to that of hydroxyapatite or tribasic calcium phosphate. It can be obtained by heat treatment (calcination) at 1400°C. Regarding this, Monma, Kanazawa, Abstract of the 54th Academic Conference of the Gypsum and Lime Society, page 10 (1977)
and Monma, Kanazawa, 7th Summit of the 16th Ceramics Basics Forum (197
P-) and Kanazawa, Umegaki, Ceramics 10 [7] P46
3 (1975). To this raw material powder, 0.5 to 15% by weight of an alkali metal, zinc and/or alkaline earth metal oxide-phosphate frit is added and mixed with respect to the calcium phosphate component after firing, and the mixture is sintered. There is no significant effect when the amount of frit added is 0.5% or less;
If it exceeds 5%, the desired high strength cannot be obtained, and the amount added is preferably about 3 to 10%. The composition of this frit is P2O54O~75 mol%, BaO, CaO, M
It contains 20 to 55 mol% of an oxide of one or more alkali metals, zinc and/or alkaline earth metals selected from the group consisting of gO, ZnO, Na2O and K2O, and the total amount of these is 90% of the total frit. It shall be at least mol%.

The remaining components of the frit are B2O3, Fe2O3, TjO2
, Al2O3, SiO2, etc. are usually mixed in from frit melting, the raw materials themselves, and other preparation processes, but as long as these impurities are within about 10 mol% of the total frit, even if they are contained in the frit, sintering will not be possible. No particular decrease in the transverse rupture strength of the body was observed. Furthermore, the alkali metal in the frit,
Zinc and/or alkaline earth metal oxides include BaOO~55, Ca00~55, and MgO,
ZnO, Na2O and K2O shall each be contained in an amount of 0 to 20 mol%, and one or more components of these oxides shall be contained in the frit in an amount of 20 to 55 mol%, preferably 25 to 54 mol%. .

Any frit with a composition outside this range tends to reduce the strength of the sintered body. Note that the alkali metal,
The oxide of zinc and/or alkaline earth metal preferably contains 20 mol% or more of the oxide of alkaline earth metal, and all composition examples within the range shown in Examples (Table 1) A predetermined effect is achieved. Note that the alkali metal oxide is preferably about 10 mol% or less, and alumina,
Silica may be contained up to about 10 mole percent. Regarding the P2O5 content in the frit, P2(1) is less than 40 mol%, and when it exceeds 55 mol% of alkali metal, zinc and/or alkaline earth metal oxides, the frit is difficult to melt and cannot be used as a frit. Difficult to demonstrate effectiveness.

Also, less than about 20 mol% of alkaline earth metal oxides, about 20 mol% or more of alkali metal oxides alone, or P2O5
It has been found that when the content exceeds 75 mol%, the frit becomes unstable and significantly lacks water resistance, and when used as a water-cooled frit, it hydrates rapidly.

CaO, MgO, and ZnO reduce the lactic acid solubility of the sintered body, while BaO, Na2O, and K2O have the opposite effect. The frit of the present invention has extremely high strength (particularly transverse rupture strength) when the calcium phosphate sintered body is fired using the above composition and addition amount. The transverse rupture strength ranges approximately from 1300 to 1770 k91 cIt. In the present invention, the strength can be further increased by further containing 3 to 2 weight percent of Y2O3 as a reinforcing agent in the sintered body.

The content of Y2O3 is generally 3-2% by weight, particularly preferably 5-2% by weight. This is because the effect of adding Y2O3 appears at about 3%, and when it exceeds 24%, the strength of the sintered body decreases significantly. As Y2O3, in addition to pure oxides, substances containing Y2O3 as a main component, such as yttrium compounds which decompose during heating to form oxides such as yttrium chloride YC'3-HaO, can be used. The effect of adding Y2O3 worked synergistically with the effect of the frit of the present invention, and the strength of the sintered body was further increased by one level, achieving a transverse rupture strength of 2000k91cd or more.

In other words, Y2O3 has the effect of further increasing the toughness of the sintered body, and in addition, calcium also has the effect of widening the optimum firing temperature range to achieve maximum strength compared to a product without Y2O3.・Performs in the same way as for phosphoric acid frit. As a result, in actual industrial production, it is possible to easily produce a high-strength calcium phosphate sintered body. The sintered body of the present invention, especially Y2O
3 and sintered using a frit containing a predetermined amount of ZnO and/or alkaline earth metal oxides has low solubility in lactic acid and is not suitable for biomaterials such as bones and teeth, especially dental materials. It is extremely useful when used.

In addition, the sintered body of the present invention has various excellent properties. That is, the sintered body is dense and can be used for ceramic substrates such as ICs, and has a thermal expansion coefficient α=120.
~140x10-70C-1, which is large enough to approximate a certain type of metal, so it can be used as a material in combination with metals. It can also be used as a stopper material for a ceramic head (made of ferrite) such as a VTR tape deck, and furthermore, based on its high expansion property, it can also be used as a high expansion sealing material or a material for enamel. Examples of the present invention will be described below. Step 1 H3PO4, BaCO3, C
aCO3, MgCO3, ZnO, Na2cO3, K2c
O3, Ae2O3, and SiO2 were weighed and mixed, the mixture was melted in an alumina crucible at 1300 to 1400°C, and the melt was rapidly cooled with water to obtain a frit No.8.

The characteristic values of the obtained frit samples are also shown in Table 1. Step 2 Calcium phosphate powder (hydroxyapatite, tribasic calcium phosphate, and mixtures thereof) prepared with the above frit in advance
and wet-mixed in the composition ratio shown in Table 2, 3% camphor as a binder was mixed with an appropriate amount of tether, and a molded body of width 12 x length 40 x thickness 4Tf0n was pressurized with a press pressure of 800 k91 cIt. The molded body is heated at a temperature increase rate of 300°C/Hr and a firing temperature of 1000-150°C.
A sintered body was obtained after holding each temperature at 0'C for 1 hour.

Table 2 shows the bending strength (K9lC7lf) and other properties of the sintered body fired at each of these temperatures as the optimum example for each composition ratio of the one with the highest strength.
Step 3 By the same operation as Step 2, Y as a reinforcing agent is added.
A sample was obtained by adding a predetermined amount of 2O3 powder.

The results are also shown in Table 2 (Sample No. 13).

Claims (1)

[Scope of Claims] 1 Calcium/phosphorus atomic ratio 1.4 to 1.75 and hydroxyapatite or general formula Ca_5 (OH, F, C
l) Powder mainly composed of calcium phosphate consisting of one or more of apatite and tricalcium phosphate represented by (PO_4), and 0.5 to 15% by weight of an alkali metal and zinc based on the calcium phosphate component after firing. and/or a calcium phosphate sintered body comprising an oxide-phosphoric acid frit of an alkaline earth metal. 2 The alkali metal, zinc and/or alkaline earth metal oxide-phosphoric acid frit has P_2 to the frit.
O_540-75 mol%, and BaO, CaO, MgO
, ZnO, Na_2O and K_2O, containing 20 to 55 mol% of an oxide of one or more alkali metals, zinc and/or alkaline earth metals selected from the group consisting of % or more, the calcium phosphate sintered body according to claim 1. 3 The alkali metal, zinc and/or alkaline earth metal oxide in the frit has a BaO0 to
55, CaO0-55, MgO0-20, ZnO0-2
The calcium phosphate sintered body according to claim 2, characterized in that the calcium phosphate sintered body contains 0 to 20 mol% of Na_2O, and 0 to 20 mol% of K_2O. 4. The calcium phosphate sintered body according to claim 1, wherein the powder mainly composed of calcium phosphate is hydroxyapatite and/or tertiary calcium phosphate. 5 Calcium/phosphorus atomic ratio 1.4 to 1.75 and hydroxyapatite or general formula Ca_5 (OH, F, C
l) A powder mainly composed of calcium phosphate consisting of one or more of apatite and tricalcium phosphate represented by (PO_4), and 0.5 to 15% by weight of an alkali metal, zinc and /or alkaline earth metal oxide-phosphoric acid frit and Y_2
A calcium phosphate sintered body comprising 33 to 23% by weight of O. 6 The calcium metal, zinc and/or alkaline earth metal oxide phosphate frit has P_2 to the frit.
O_540-75 mol%, and BaO, CaO, MgO
, ZnO, Na_2O and K_2O, containing 20 to 55 mol% of an oxide of one or more alkali metals, zinc and/or alkaline earth metals selected from the group consisting of % or more, the calcium phosphate sintered body according to claim 5. 7 The alkali metal, zinc and/or alkaline earth metal oxide in the frit has a BaO0 to
55, CaO0-55, MgO0-20, ZnO0-2
The calcium phosphate sintered body according to claim 6, characterized in that the calcium phosphate sintered body contains 0 to 20 mol% of Na_2O, and 0 to 20 mol% of K_2O. 8. The calcium phosphate sintered body according to claim 5, wherein the powder mainly composed of calcium phosphate is hydroxyapatite and/or tertiary calcium phosphate.