JP2007290952A - Calcium phosphate based sintered porous body, method of manufacturing the same and calcium phosphate based sintered porous body granule - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a calcium phosphate based sintered porous body provided with proper strength in a degree that the handling is not interrupted and workability in a degree that the working is easily carried out and useful as a base material as a living body supplement material and a granule obtained from the calcium phosphate based sintered porous body and a method of manufacturing the calcium phosphate based sintered porous body. <P>SOLUTION: In the calcium phosphate based sintered porous body, continuous pores mutually connected to have 0.1-50 μm average pore diameter and large pores mutually independent to have 100-600 μm average pore diameter are existed and total porosity is 50-95 vol.%. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a calcium phosphate-based sintered porous body useful as a material for bioprosthetic materials such as artificial bones, artificial teeth, and bone fillers in the medical / dental field, or as a material for purification filters, heat insulating materials, and the like. The present invention relates to a granular material obtained from a calcium phosphate-based sintered porous body and a method for producing a calcium phosphate-based sintered porous body.

  Calcium phosphate is a major component of human bones and teeth, and when it is implanted in a living body, it has good affinity with the living body and good chemical bonding with natural bone. It is used as a raw material for bioprosthetic materials such as bone fillers in the medical / dental field. In particular, a porous body of calcium phosphate is expected to be useful as a material for a bioprosthetic material because it has a large contact area with tissue in a living body and good workability. In addition, due to the porosity, calcium phosphate porous material is expected to be used as a material for purifying filters for gases and liquids, or as a material for building materials such as heat insulating materials due to its good heat insulation properties. Yes. Furthermore, when used as a bone filler in the medical / dental field, it is generally in the form of granules having a predetermined particle size.

  Various techniques related to such a calcium phosphate porous material have been proposed so far. For example, Patent Documents 1 and 2 propose a calcium phosphate porous body (calcium phosphate-based sintered porous body) having a three-dimensional continuous through hole having a pore diameter in the range of 0.1 to 10 μm or 10 to 100 μm. Yes. However, such small holes are disadvantageous for the formation of new bone. In other words, the formation of new bone requires pores that are large enough to allow cellular tissue and blood to enter the porous body. However, with such pores, cells and blood sufficiently enter the porous body. Such a calcium phosphate porous body has a limit in application as a bioprosthetic material because new bone cannot be sufficiently formed.

  As another technique related to a calcium phosphate porous material, for example, Patent Document 3 discloses a low-temperature-setting calcium phosphate porous material having artificial through holes having a size of 70 μm to 4 mm and a porosity (porosity) of about 20 to 80% by volume. Suggested about the body. In this technology, an artificial through-hole is formed by arranging a long column when reacting and curing a porous body, but bubbles other than the artificial through-hole become discontinuous bubbles (closed bubbles). Therefore, the penetration of cellular tissue and blood into the porous body is insufficient with the artificial through-hole alone.

  On the other hand, in Patent Document 4, a slurry containing a calcium phosphate material is formed, and a foaming agent is added thereto to generate bubbles in the slurry (hereinafter referred to as “foaming method”). A technique for producing a calcium phosphate porous body having relatively large bubbles having a diameter of 150 μm or more by being bonded has been proposed. However, in the calcium phosphate porous body formed by such a foaming method, the size of the bubbles is not uniform inside and outside due to manufacturing restrictions, and the size of the pores in the outside that directly contact the cellular tissue and blood. Becomes a small one (for example, 50 μm or less), and there is a limit in application as a biomaterial.

  In addition, in order to improve the applicability as a bone filler in the calcium phosphate porous material, it may be possible to form only relatively large pores (atmospheric pores). Will be low. The technique of Patent Document 4 basically aims to form large pores, but the calcium phosphate porous body formed by the foaming method has a problem in terms of strength regardless of the pore diameter. There is. That is, in the foaming method as described above, a surfactant is inevitably added to the raw material slurry preparation, but this surfactant inhibits the binding between calcium phosphate particles, and as a result, the calcium phosphate porous The strength of the body will be reduced.

  When the strength of the calcium phosphate porous body is reduced, it becomes difficult to handle the calcium phosphate porous body during a surgical operation, and there arises a problem that a predetermined shape cannot be maintained before entering the affected part as a bone filler. On the other hand, if the strength of the calcium phosphate porous body is too high, the workability deteriorates and fine adjustment according to the condition of the affected part becomes difficult during surgery, and it is necessary to perform cutting with a special device. As a result, the operation time becomes long, and a heavy burden is imposed on the patient.

Therefore, in order to apply the calcium phosphate porous material as a biomaterial, it has an appropriate strength that does not hinder the handling, and can be easily processed with a scalpel during surgery. It is necessary to have workability. Also, when the porous body is made into granules (granular materials), an appropriate strength is required as described above. That is, if the granular material is too soft, it will collapse upon filling into fine particles, and appropriate pores will disappear. On the other hand, if it is too hard, fine adjustment cannot be performed at the time of filling, so that many gaps exist. For these reasons, it is an important requirement to have an appropriate strength even in the case of a granular product.
JP, 2002-274968, A Claims etc. JP, 2004-284898, A Claims etc. JP, 2005-46530, A Claims etc. JP, 2000-10851, A Claims etc.

  The present invention has been made paying attention to the circumstances as described above, and the purpose thereof is to have a suitable strength that does not hinder handling and that can be easily processed. For producing a calcium phosphate-based sintered porous body that is suitable for use as a raw material for bio-complementary materials, granules obtained from such a calcium phosphate-based sintered porous body, and such a calcium phosphate-based sintered porous body It is to provide a method.

  The calcium phosphate-based sintered porous body of the present invention that has achieved the above-mentioned object is composed of continuous pores interconnected with an average pore size of 0.1 to 50 μm and independent pores with an average pore size of 100 to 600 μm. And the overall porosity is 50 to 95% by volume.

  In the calcium phosphate sintered porous body of the present invention, the continuous pores include one having fine pores having an average pore diameter of less than 0.1 to 10 μm and small pores having an average pore diameter of 10 to 50 μm. In such a form, three types of pores exist three-dimensionally.

  The calcium phosphate in the calcium phosphate sintered porous body of the present invention includes α-type tricalcium phosphate, β-type tricalcium phosphate, tetracalcium phosphate, hydroxyapatite, and the like, and one or more selected from the group consisting of these Thus, a calcium phosphate sintered porous body is formed.

  In producing the calcium phosphate sintered porous body as described above, a calcium phosphate raw material, a water-soluble polymer, spherical organic particles and water are mixed to prepare a slurry, and this slurry is subjected to a heat treatment including a firing step. Thus, a calcium phosphate sintered porous body can be obtained.

  In this manufacturing method, the heat treatment includes a drying / solidifying step performed in a temperature range of 35 to 500 ° C, a firing step performed in a temperature range of 500 to 1000 ° C, and a sintering step performed in a temperature range of 1000 to 1500 ° C. Those are preferred.

  The mixing ratio of calcium phosphate-based material, water-soluble polymer and spherical organic particles is as follows: calcium phosphate-based material: 5 to 85% by mass, water-soluble / swelling polymer: 2 to 80% by mass, spherical organic particles: 5 to 90% by mass It is preferable that

  Calcium phosphate materials used in the method of the present invention include dicalcium phosphate (dihydrate / anhydrous), α-type tricalcium phosphate, β-type tricalcium phosphate, tetracalcium phosphate, hydroxyapatite, octacalcium phosphate and non- The thing which consists of 1 or more types chosen from the group which consists of crystalline calcium phosphate is mentioned.

  Examples of the water-soluble polymer include starch, soluble starch, dextrin, α starch, sodium alginate, carboxymethylcellulose sodium salt, carboxymethylated starch sodium salt, hydroxyethylated starch, starch phosphate ester sodium salt, polyvinyl alcohol, polyacrylamide And at least one selected from the group consisting of polyacrylic acid sodium salt.

  Examples of the spherical organic particles include those composed of one or more selected from the group consisting of polystyrene resin, polymethacrylate resin, polyethylene resin, polypropylene resin, ABS resin, epoxy resin, and polyurethane resin.

  On the other hand, the calcium phosphate-based sintered porous granule that has achieved the above object is a granule obtained by pulverizing the calcium phosphate-based sintered porous body as described above, and the average particle size thereof is 0. It has a gist in that it is 1 to 5 mm.

  In the calcium phosphate sintered porous body of the present invention, continuous pores interconnected with an average pore size of 0.1 to 50 μm and air pores independent of each other with an average pore size of 100 to 600 μm are mixed. It has a moderate strength that does not hinder handling (for example, a compressive strength of 0.5 MPa or more, which will be described later), and has a good workability that can be easily processed. It is the best material for the material. In addition, since the calcium phosphate-based sintered porous body of the present invention has a large surface area as a basic characteristic as a porous body, it is not only useful as a material for a filter for purification, but also as a heat insulating material as a calcium phosphate-based sintered porous body. Taking advantage of its properties, it is also useful as a building material such as a heat insulating material. Furthermore, the granular material obtained by pulverizing such a calcium phosphate sintered porous body is extremely useful as a bone filler in the medical / dental field.

  The present inventors have studied from various angles in order to solve the above problems. As a result, continuous pores interconnected with an average pore diameter of 0.1 to 50 μm and atmospheric pores independent of each other with an average pore diameter of 100 to 600 μm are mixed, and the overall porosity is 50 to 95. In the calcium phosphate-based sintered porous body in which the volume% and the continuous pores include fine pores having an average pore diameter of less than 0.1 to 10 μm and small pores having an average pore diameter of 10 to 50 μm, The inventors have found that the object can be achieved brilliantly and have completed the present invention.

  In the calcium phosphate-based sintered porous body of the present invention, since the organic pores having an average pore diameter of 100 to 600 μm formed by burning off organic particles have mutually independent atmospheric pores, this portion has a region for capturing cellular tissue and blood. As a result, the function of the biomedical material is exhibited. In general, the porous body in which only the air holes having an average pore diameter of 100 μm or more are formed, the strength is lowered, and the handleability tends to be lowered. However, in the calcium phosphate sintered porous body of the present invention, By forming an air hole having an average pore diameter of 100 to 600 μm based on a calcium phosphate portion having continuous pores having an average pore diameter of 0.1 to 50 μm, a small base serving as a base between independent air holes. Appropriate strength can be ensured by causing the calcium phosphate portion having pores to bend and naturally forming a hard portion and a soft portion in the porous skeleton.

  In particular, continuous pores having an average pore size of 0.1 to 50 μm are obtained by sintering the raw material particles, and an average pore size between them is 0.1 to 10 μm. The average pore diameter formed by burning is small, and there are three types because small pores and fine pores exist in the atmospheric pores, and there are fine pores in the small pores. The pores communicate with each other, and appropriate strength can be ensured.

  Atmospheric pores are circular or elliptical, and continuous pores (or small and fine pores) are composed of voids formed from circular or elliptical to irregular shapes, and the skeletal shape is joined by sintering round particles. It becomes what was arranged and thickness becomes about 1-20 micrometers. When the thickness of the skeleton is larger than 20 μm, the number of small pores and fine pores decreases, and not only a sufficient porosity cannot be obtained, but also the workability becomes poor due to being too hard. On the other hand, if the thickness is less than 1 μm, the strength is low, and there is a risk of hindering handling. The atmospheric holes are independent of each other. However, in relation to the continuous pores, each atmospheric hole has continuous pores on its wall surface and communicates with each other. That is, the whole porous body is excellent in communication and exhibits the original performance of the porous body.

  The average pore diameter of the fine pores in the present invention is an average value obtained by photographing five places at a magnification of 2000 to 5000 times with a scanning electron microscope (SEM), and the average pore diameter of small pores is 250 to 250 with a scanning electron microscope. It is an average value when five places are photographed at a magnification of 1000 times, and the average pore diameter of the air holes is an average value when five places are photographed with a scanning electron microscope at a magnification of 30 to 100 times.

  In the calcium phosphate sintered porous body of the present invention, it is also an important requirement that the total porosity (total porosity of atmospheric pores and continuous pores) is 50 to 95% by volume. When the porosity is within such a range, the distribution ratio of atmospheric pores and continuous pores (or atmospheric pores, fine pores and small pores) is also in an appropriate state, and it has an appropriate strength that does not collapse even if it is held by hand. It is possible to maintain good workability that can be maintained and easily cut with a surgical knife. That is, when the porosity is lower than 50% by volume, the strength is increased, and when used as a bioprosthetic material, fine adjustment according to the condition of the affected area during surgery becomes difficult. On the other hand, when the porosity exceeds 95% by volume, it is difficult to handle the porous body at the time of operation because a suitable strength cannot be obtained, and it becomes difficult to hold the porous body in a predetermined shape before entering the affected area. In addition, the measurement of a porosity can be calculated | required by calculation based on the volume and mass of a porous body, the true specific gravity of calcium phosphate, etc.

  In the calcium phosphate sintered porous body of the present invention, the calcium phosphate used as the material includes α-type tricalcium phosphate, β-type tricalcium phosphate, tetracalcium phosphate, hydroxyapatite, and the like. A calcium phosphate-based sintered porous body is constituted by one or more selected. In addition, when the calcium phosphate-based sintered porous body of the present invention is used as a biomaterial, its solubility is also a necessary property, but this solubility varies depending on the type of calcium phosphate. Since the solubility of calcium phosphate is α-type tricalcium phosphate> tetracalcium phosphate> β-type tricalcium phosphate> hydroxyapatite, the ratio of calcium phosphate constituting the porous body should be adjusted. Thus, the solubility of the calcium phosphate sintered porous body can be controlled.

  Since the calcium phosphate sintered porous body of the present invention has the above-described characteristics, it is optimal as a raw material for a bioprosthetic material. In addition, as a basic characteristic as a porous body and a large surface area, as a material of an air purification filter for removing germs, pollen, dust, harmful gases (NOx and SOx) in the air, or Not only is it useful as a material for liquid purification filters for removing heavy metals, organic substances, bacteria, etc. in water, but it is also used as a building material such as heat insulating materials by taking advantage of the heat insulating properties of calcium phosphate sintered porous bodies. Is also useful.

  The calcium phosphate-based sintered porous body of the present invention can be used as it is as a biological filling material, but in order to further enhance the function as a biological filling material, various polysaccharides (for example, chitosan and cellulose), various proteins ( For example, the inner wall of the pores can be coated and filled with collagen or albumin). It can also be used in combination with various drugs (for example, various physiologically active substances, vitamins) and growth factors (for example, bone morphogenetic proteins).

  Moreover, even when used as a material for purification filters and building materials, it is coated with various polysaccharides (for example, chitosan and cellulose) and various polymers (for example, nylon, polyvinyl chloride, polyethylene, polypropylene, polyurethane, etc.). It is good as a thing.

  In manufacturing the calcium phosphate sintered porous body of the present invention, a calcium phosphate raw material, a water-soluble polymer, spherical organic particles and water are mixed to prepare a slurry, and this slurry is subjected to a heat treatment including a firing step. Thus, a calcium phosphate-based sintered porous body can be obtained.

  In this manufacturing method, the heat treatment includes a drying / solidifying step performed in a temperature range of 35 to 500 ° C, a firing step performed in a temperature range of 500 to 1000 ° C, and a sintering step performed in a temperature range of 1000 to 1500 ° C. It is preferable. In this heat treatment, the drying / solidification step (first heat treatment) performed in the temperature range of 35 to 500 ° C. is for drying and solidifying the slurry and for homogenizing the raw materials in the slurry. The heating temperature is preferably 35 ° C. or higher. However, when the temperature exceeds 500 ° C., degreasing occurs before solidification sufficiently proceeds, so that non-uniform pores are formed and internal defects are likely to occur. In the method of the present invention, the shape of the porous body can be set by injecting the slurry into a predetermined mold. However, at the stage of the first heat treatment, the slurry is in a dried and solidified state and is easily cut. Since it can be processed, it may be processed into a predetermined shape at this stage.

  In the firing step (second heat treatment) performed in the temperature range of 500 to 1000 ° C., the calcium phosphate-based raw material in the slurry is fired, and the water-soluble polymer and the spherical organic particles disappear, and these disappear. As a result, various pores (atmospheric pores and small pores) in the porous body are formed. In order to exert such an effect, the heating temperature needs to be at least 500 ° C., but if it exceeds 1000 ° C., sintering proceeds before solidification sufficiently proceeds, resulting in uneven pores and internal defects. Is likely to occur.

  Next, a sintering process (third heat treatment) is performed in a temperature range of 1000 to 1500 ° C. This sintering process is for stabilizing the crystalline structure and the amorphous structure of the calcium phosphate porous body. The heating temperature needs to be 1000 ° C. or higher, but if it exceeds 1500 ° C., the sintering proceeds vigorously, so that the workability becomes poor. In addition, the desired composition cannot be obtained homogeneously by thermal decomposition.

  Moreover, the said sintering process is also a process for determining a composition. That is, it is 1000-1400 ° C for hydroxyapatite, 1400-1500 ° C for tetracalcium phosphate, 1200-1500 ° C for α-type tricalcium phosphate, 1000-1200 ° C for β-type tricalcium phosphate, and other combinations and compositions. The temperature range in 1000-1500 degreeC is determined suitably. The composition can be defined by the molar ratio of Ca and P. If these molar ratios (Ca / P) are 1.5, α-type tricalcium phosphate and β-type tricalcium phosphate, and the molar ratio (Ca / P) is 1. 5 to 1.67 if α-type tricalcium phosphate, β-type tricalcium phosphate and hydroxyapatite, molar ratio (Ca / P) is 1.67, hydroxyapatite, molar ratio (Ca / P) is 1.67 to If 2.0, it is hydroxyapatite and tetracalcium phosphate, and if the molar ratio (Ca / P) is 2.0, it is tetracalcium phosphate, and the composition is determined by the combination of the raw material calcium phosphate.

  The time for the heat treatment is not particularly limited because it is affected by the type of raw material used and the heat treatment temperature, but usually about 1 to 30 hours is effective in each heat treatment step. That is, if the heat treatment time in the firing / sintering process is too long, thermal decomposition and particle size growth occur, so it is preferably 30 hours or less. Conversely, if it is too short, densification does not proceed sufficiently, so that it takes 1 hour or more. Good to do. Moreover, it is preferable that the temperature increase rate when making it raise to predetermined | prescribed temperature in a baking process is about 0.1-20 degreeC / min (more preferably 1-5 degreeC / min). When the rate of temperature increase is less than 0.1 ° C./min, the productivity is lowered, and when it exceeds 20 ° C./min, thermal decomposition of the water-soluble polymer and the spherical organic particles is abruptly caused and uneven pore distribution tends to occur. Become.

  The mixing ratio of the calcium phosphate-based material, the water-soluble polymer and the spherical organic particles when adjusting the slurry is as follows: calcium phosphate-based material: 5 to 85% by mass, water-soluble polymer: 2 to 80% by mass, spherical organic particles: 5 to 5% It is preferably 90% by mass. If the calcium phosphate-based material is less than 5% by mass, the water-soluble polymer ratio exceeds 80% by mass, or the spherical organic particle ratio exceeds 90% by mass, the porosity becomes too high (porosity 95). And the strength of the porous body decreases. Further, when the calcium phosphate raw material exceeds 85% by mass, the ratio of the water-soluble polymer is less than 2% by mass, or the ratio of the spherical organic particles is less than 5% by mass, the porosity becomes too low (porosity) The ratio is less than 50% by volume), and the strength of the porous body becomes too high and the workability is deteriorated. In addition, the surface area becomes small and the function as a porous body applied to various uses is hardly exhibited. The mixing ratio of the calcium phosphate-based material, the water-soluble polymer and the spherical organic particles is as follows: calcium phosphate-based material: 15 to 50% by mass, water-soluble polymer: 4 to 40% by mass, spherical organic particles: 20 to 80% by mass More preferably. Further, by adjusting the mixing ratio of the water-soluble polymer and the spherical organic particles within the above mixing ratio range, the distribution of the atmospheric pores and the continuous pores can be controlled.

  The raw materials (calcium phosphate raw material, water-soluble polymer and spherical organic particles) mixed at the above ratio are made into a slurry by mixing with water. The mixing ratio of the raw material and water at this time is not particularly limited, but is preferably about 0.1 to 2.0 in terms of water / raw material (mass ratio). When this ratio is less than 0.1, the fluidity of the slurry is deteriorated, and water and raw materials are not mixed. On the other hand, if this ratio exceeds 2.0, the raw material becomes difficult to disperse uniformly in water (or precipitates), and the pore distribution of the finally obtained porous body tends to be non-uniform.

  The calcium phosphate-based raw material used in the method of the present invention may be any calcium phosphate that forms a porous skeleton after sintering. Examples of such raw materials include α-tricalcium phosphate and β-type triphosphate described above. In addition to calcium, tetracalcium phosphate, and hydroxyapatite, dicalcium phosphate (dihydrate / anhydrous), octacalcium phosphate, amorphous calcium phosphate, and the like can be used, and one or more of these may be used. The usage form of the calcium phosphate-based raw material can be used in a powder or granule state, but among these, it is preferable to use it in a powder state. Moreover, in order to control the average pore diameter of the fine pores to 0.1 to 10 μm with the sintering of the raw material and the grain growth, it is preferable to use a powder having an average particle diameter of about 1 to 20 μm.

  The water-soluble polymer used as the raw material is a polymer that is dissolved or swollen in the slurry when it is made into a slurry, and this polymer disappears in the firing step, and continuous pores (particularly in that part) , Small pores) are formed. Therefore, the size of the water-soluble polymer is reflected in the size of the small pores.

Such water-soluble polymers include starch, soluble starch, dextrin, alpha starch, sodium alginate, carboxymethylcellulose sodium salt, carboxymethylated starch sodium salt, hydroxyethylated starch, starch phosphate ester sodium salt, polyvinyl alcohol, polyacrylamide And polyacrylic acid sodium salt. One or more of them can be selected and used.

  On the other hand, the spherical organic particles disappear in the firing step, and air holes are formed in the portions. Accordingly, since the size of the spherical organic particles reflects the size of the small pores, those having an average particle size of 100 to 600 μm are used.

  Examples of such spherical organic particles include those made of various resins such as polystyrene resin, polymethacrylate resin, polyethylene resin, polypropylene resin, ABS resin (acrylonitrile-butadiene-styrene resin), epoxy resin and polyurethane resin. One or more types can be selected and used.

  According to the method of the present invention, it is possible to obtain block bodies having various shapes (for example, a cylindrical shape, a disk shape, a prism shape, and a square shape) by injecting a slurry containing raw materials into a mold having a predetermined shape. Although it may be used for various purposes as it is, it can also be used as a granulated or powdered form of the obtained block. In addition, it is preferable that the average particle size of the granular material (calcium phosphate-based sintered porous granular material) is 0.1 to 5 mm, assuming that it is used as a bone prosthetic material in the medical / dental field. That is, if the average particle size of the granular material is less than 0.1 mm, the particle size is too small and is not stabilized in the filling portion, which prevents bone formation. The gap between them becomes large and the strength becomes low.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited by the following examples, but may be appropriately modified within a range that can meet the purpose described above and below. Of course, it is possible to implement them, and both are included in the technical scope of the present invention.

[Example 1]
α-type tricalcium phosphate powder (α-TCP) (average particle size: 4.7 μm, manufactured by Taihei Chemical Industrial Co., Ltd.), potato starch (average particle size 38 μm, manufactured by Sanwa Starch Co., Ltd.), polymethyl methacrylate ( PMMA) or polystyrene (PS) (average particle size: 233 μm, or 355 μm: manufactured by Sekisui Plastics Co., Ltd.) is mixed at a predetermined ratio, and the mixture is placed in a stainless steel beaker, and further distilled water (Wako Pure Chemical Industries, Ltd.). And water-soluble slurry was prepared by stirring for 60 minutes at a rotational speed of 100 rpm with a stirrer.

  The obtained various slurries were poured into an alumina crucible and subjected to a heat treatment (first heat treatment) at 100 ° C. for 3 hours to dry and solidify the slurry. Next, after cooling this crucible, it was transferred to an electric furnace, heated to 1000 ° C. at a temperature rising rate of 5 ° C./min, and held at that temperature for 3 hours (second heat treatment). Further, after cooling, it was transferred to a high temperature electric furnace, heated to 1400 ° C. at a heating rate of 5 ° C./min, and maintained at that temperature for 3 hours (third heat treatment) to obtain a sintered tricalcium phosphate porous body. .

About the obtained alpha type | mold tricalcium phosphate sintered porous body, while measuring compressive strength on the following conditions by the autograph (made by Shimadzu Corporation), workability was evaluated by cutting (cut) with a surgical knife. (Evaluation criteria ○: can be cut, Δ: softly collapses, x: cannot be cut hard). The porosity was determined from the volume, mass, and true specific gravity of the porous body. The results are shown in Table 1 below together with the raw material blending ratio of the slurry.
(Autograph condition)
Full scale: 980N
Test speed: 10 mm / min
Test piece: prismatic material (6.9 mm square x 20 mm height)

  From this result, it can be considered as follows. First, test no. Those of Nos. 1 to 7 were porous bodies satisfying the requirements defined in the present invention, the compressive strength also showed an appropriate value, and the workability was also good. In addition, regarding these materials, the morphology of the porous body was observed by SEM. As a result, fine pores having an average pore diameter of about 3 μm, small pores having an average pore diameter of about 24 μm, and air holes having an average pore diameter of 277 μm were mixed. It was confirmed that it was. Test No. 7 shows the crystal structure of the porous material obtained by 7 (electron micrograph of the drawing substitute) [FIG. 1 (a) is 50 times, FIG. 1 (b) is 100 times, FIG. 1 (c) is 600 times] .

  In contrast, test no. 8 to 10 are porous bodies that do not satisfy the requirements defined in the present invention, and either compression strength or workability is deteriorated. Specifically, test no. No. 8 does not contain starch (water-soluble polymer) as a raw material, and only air pores are formed by spherical organic particles, the compressive strength is low, and the processing is soft and easy to collapse. It was bad. Test No. No. 9 is not blended with polymethyl methacrylate (spherical organic particles) as a raw material, only small pores are formed, the compressive strength is very low, the processing is soft and easy to break, Met.

  Test No. No. 10 contains neither starch nor polymethyl methacrylate as a raw material, has almost no pores, has a very high compressive strength, and cannot be cut hard. there were. Test No. 9 shows the crystal structure of the porous material obtained by No. 9 (an electron micrograph of a drawing substitute) [FIG. 2 (a) is 50 times, FIG. 2 (b) is 100 times, FIG. 2 (c) is 600 times] .

[Example 2]
α-type tricalcium phosphate powder (α-TCP) (average particle size: 13.4 μm, manufactured by Taihei Chemical Industrial Co., Ltd.), β-type tricalcium phosphate powder (β-TCP) (average particle size: 1.8 μm, Taihei Chemical Industrial Co., Ltd.) or hydroxyapatite (HAP) powder (average particle size: 5.8 μm, Taihei Chemical Industrial Co., Ltd.), potato starch (average particle size: 38 μm, Sanwa Starch Co., Ltd.) and polystyrene (PS) (average particle size: 355 μm: manufactured by Sekisui Plastics Co., Ltd.) was mixed at a ratio of 2: 1: 1, and the mixture was placed in a stainless steel beaker and further distilled water (Wako Pure Chemical Industries, Ltd.). Product) was added so as to be 3 times the amount of starch, and stirred with a stirrer at a rotation speed of 100 rpm for 60 minutes to prepare a water-soluble slurry. At this time, about the mixed composition of HAP and (beta) -TCP, these were mixed in the ratio of the equivalent, and it prepared on the conditions similar to the above (test No. 15 of following Table 2).

  The obtained various slurries were poured into an alumina crucible and subjected to a heat treatment (first heat treatment) at 100 ° C. for 3 hours to dry and solidify the slurry. Next, after cooling this crucible, it was transferred to an electric furnace, heated to 800 ° C. at a heating rate of 5 ° C./min, and held at that temperature for 3 hours (second heat treatment). Further, after cooling, it is transferred to a high-temperature electric furnace, heated to a predetermined sintering temperature at a heating rate of 5 ° C./min, held at that temperature for 3 hours (third heat treatment), and various sintered porous bodies Got. At this time, a porous body in which water-soluble slurry was prepared using the β-type calcium phosphate powder (β-TCP) or hydroxyapatite (HAP) powder as a raw material, and bubbles were formed by a foaming agent (other conditions are the same as above) (Foaming method: Test Nos. 18 and 19 in Table 2 below).

  The obtained sintered porous body is cut to obtain a 1 cm square × 1 cm block body, and the porosity is obtained from the volume, mass, and true specific gravity of the porous body, and the workability is obtained by cutting with a surgical knife. (Evaluation criteria ○: can be cut, Δ: softly collapses, x: cannot be cut hard). Moreover, it grind | pulverized with the mortar and sieved and the granular material with an average particle diameter of 0.1-0.5 mm or 0.2-2 mm was obtained.

  About each obtained sample, the crystal phase was identified with the X-ray-diffraction apparatus (XRD apparatus: Rigaku Corporation make). Moreover, the size of the air pores, small pores and fine pores was confirmed by observing each sample (granular material) with SEM (manufactured by Hitachi, Ltd.). The results are shown in Table 2 below together with the raw material blending ratio of the slurry. In the evaluation of each granular pore, “◯” indicates that it is in each predetermined particle size range, and “x” indicates that it is out of the predetermined particle size range (or does not exist).

  From this result, it can be considered as follows. First, test no. Nos. 11 to 17 were granular materials satisfying the requirements defined in the present invention, and the processability of the porous body was also good. Further, when these granular materials were observed by SEM, it was confirmed that there were atmospheric pores having an average pore diameter of 252 μm, small pores having an average pore diameter of 18 μm, and fine pores having an average pore diameter of 3 μm. Test No. The crystal structure of the granular material obtained by No. 13 is shown in FIG. 3 (electron micrograph of drawing substitute) [FIG. 3 (a) is 60 times, FIG. 3 (b) is 500 times, FIG. 3 (c) is 3000 times] ].

  In contrast, test no. Nos. 18 and 19 are porous bodies that do not satisfy the requirements defined in the present invention (produced by the foaming method), and the workability is deteriorated. Test No. No. 18 was defective because it could not be cut hard because there were no fine pores. Test No. In No. 19, since there was no small pore, the processing was soft and easy to break, and it was defective. Test No. The crystal structure of the porous body obtained by No. 18 is shown in FIG. 4 (electron micrograph of drawing substitute) [FIG. 4 (a) is 60 times, FIG. 4 (b) is 500 times, FIG. 4 (c) is 3000 times] .

Test No. 7 is a drawing-substituting electron micrograph showing the crystal structure of the porous body obtained according to FIG. Test No. 9 is a drawing-substituting electron micrograph showing the crystal structure of the porous body obtained by No. 9. Test No. 13 is a drawing-substituting electron micrograph showing the crystal structure of the porous body obtained by No. 13. Test No. 18 is a drawing-substituting electron micrograph showing the crystal structure of the porous body obtained according to FIG.

Claims (10)

  A calcium phosphate-based sintered porous body having continuous pores interconnected with an average pore diameter of 0.1 to 50 μm and independent air pores with an average pore diameter of 100 to 600 μm, and the entire pores A calcium phosphate-based sintered porous body having a rate of 50 to 95% by volume.   The calcium phosphate sintered porous body according to claim 1, wherein the continuous pores include fine pores having an average pore diameter of less than 0.1 to 10 µm and small pores having an average pore diameter of 10 to 50 µm.   The calcium phosphate sintered porous body according to claim 1 or 2, wherein the calcium phosphate is at least one selected from the group consisting of α-type tricalcium phosphate, β-type tricalcium phosphate, tetracalcium phosphate, and hydroxyapatite. .   In producing the calcium phosphate sintered porous body according to any one of claims 1 to 3, a calcium phosphate raw material, a water-soluble polymer, spherical organic particles and water are mixed to prepare a slurry, A method for producing a calcium phosphate-based sintered porous body comprising obtaining a calcium phosphate-based sintered porous body by performing a heat treatment including a firing step.   5. The heat treatment includes a drying / solidifying step performed in a temperature range of 35 to 500 ° C., a firing step performed in a temperature range of 500 to 1000 ° C., and a sintering step performed in a temperature range of 1000 to 1500 ° C. 5. The manufacturing method as described.   The mixing ratio of the calcium phosphate-based material, the water-soluble polymer, and the spherical organic particles is calcium phosphate-based material: 5 to 85% by mass, the water-soluble polymer: 2 to 80% by mass, and the spherical organic particles: 5 to 90% by mass. The manufacturing method of Claim 4 or 5.   The calcium phosphate raw material is composed of dicalcium phosphate (dihydrate / anhydrous), α-type tricalcium phosphate, β-type tricalcium phosphate, tetracalcium phosphate, hydroxyapatite, octacalcium phosphate and amorphous calcium phosphate. The production method according to any one of claims 4 to 6, which comprises at least one selected from the group.   The water-soluble polymer is starch, soluble starch, dextrin, alpha starch, sodium alginate, carboxymethylcellulose sodium salt, carboxymethylated starch sodium salt, hydroxyethylated starch, starch phosphate sodium salt, polyvinyl alcohol, polyacrylamide, The production method according to any one of claims 4 to 7, which comprises at least one selected from the group consisting of polyacrylic acid sodium salts.   The spherical organic particles are made of at least one selected from the group consisting of polystyrene resin, polymethacrylic ester resin, polyethylene resin, polypropylene resin, ABS resin, epoxy resin and polyurethane resin. The manufacturing method of crab.   A granulated product obtained by pulverizing the calcium phosphate-based sintered porous body according to any one of claims 1 to 3, and having an average particle diameter of 0.1 to 5 mm. object.