JP3125016B2 - Curable material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a curable material having self-curing properties, and more particularly, to a self-curing biomaterial which is converted into apatite after curing, and is useful as a biomaterial for, for example, bioreplacement and filling.

[0002]

2. Description of the Related Art The theoretical formula of calcium-phosphorus apatite (hereinafter, calcium-phosphorus apatite is simply referred to as apatite), which is a kind of calcium phosphate, is expressed as Ca ₁₀ (PO
₄ ) ₆ X ₂ (X represents an anion such as OH ⁻ , C 1 ⁻ , F ⁻ ). Here, the gram-atom ratio of Ca / P is theoretically 10/6 = 1.67, but in practice, it is possible to obtain an apatite structure in the range of 1.3 to 2.0 as the Ca / P ratio. Have been. Accordingly, various general formulas have been proposed, such as, for example, Ca _10-X (HPO ₄ ) _X (PO ₄ ) _6-X X _2-X .

[0003] This apatite is a main component of the inorganic components of teeth and bones and has excellent affinity in vivo and is easily assimilated with living tissue. Therefore, it is actively used as a filler for artificial roots and bone defects. Has been studied. However, apatite is extremely rarely used for biomaterials such as dental materials and medical materials for the following reasons despite its excellent biocompatibility.

Conventionally, apatite is used as a biomaterial by a method in which hydroxyapatite powder is molded by a method such as die press molding or casting, and then sintered to obtain a desired molded body. Have been. However, it is difficult to mold a material having a complicated shape by such a molding method, and it is virtually impossible to cope with a case where molded articles having different shapes and dimensions are required for individual treatments. Was.

On the other hand, among the conventionally used biomaterials, there are dental cement, dental composite resin, bone cement and the like. When these biomaterials are used, they are in the form of a paste or putty, and are used in a method of filling them into the oral cavity or a necessary place in the living body and then curing them. Therefore, it is possible to mold a biomaterial having an optimum shape for each treatment from these biomaterials.

However, the above-mentioned conventional dental cements, composite resins, bone cements and the like are composed of substances different from those of living hard tissue, for example, inorganic and organic substances such as zinc white, silica powder, polyacrylate and eugenol. There is a drawback that operation is difficult in terms of spinnability or viscousness. In addition, it is merely fixed by physical or chemical adhesion with the living body,
Assimilation with living tissue does not occur at all.

Therefore, when used, a putty- or paste-like apatite precursor substance is filled in a required portion in a living body or an oral cavity, and this filling material cures at a living body temperature in a relatively short time to form a cured product. It is considered ideal if the cured product becomes apatite over time and can be assimilated with living tissue. (Hereinafter, a cured product that becomes apatite over time is referred to as an apatite cured product.)

From such a viewpoint, a method of using a paste-like kneaded material mainly composed of calcium phosphate which can be converted into apatite for the above purpose has been studied (JP-A-59-88351 and JP-A-59-88351). No. 59-182263, gypsum and coal No. 188, 11, 1984). According to the technology disclosed in the above-mentioned publications and literatures, by adding an organic, inorganic acid or easily water-soluble halide to tribasic calcium phosphate, apatite hardening can be performed within a relatively short period of time around a biological temperature. It is possible to generate a body.

[0009]

However, according to our studies, in order to actually use a cured apatite obtained by the techniques disclosed in the above-mentioned publications and literatures as a biomaterial, the following is required. It turns out that there are still problems to be solved.

That is, the obtained cured product has a low hardness and a Knob hardness of at most 6
Only about kg / mm ² can be obtained. The cured product has extremely low stability in water and easily disintegrates in water. The cured product from which a large amount of shrinkage during curing is obtained lacks dimensional accuracy, and it is difficult to adapt it to the affected part. The strength of the obtained cured product is low, and the crushing resistance is at most 1
Only about 50 kg / cm ² was obtained.

In Japanese Patent Application Laid-Open No. 62-182146, calcium / phosphorus atomic ratio of Ca / P = 1.3.
A hydrated self-hardening calcium phosphate containing at a ratio of ~ 2.0, a hardly soluble fluoride in water, and a hardened body formed using a hardenable material composed of an acid and water are disclosed and conventionally obtained. Although the hardness is higher than that of the product, the stability in water is high, and the product with high dimensional accuracy is obtained, the inventors of the present invention have further examined this, and the crushing which shows the strength of the cured body obtained from it The drag value cannot be said to have reached a sufficient value, for example, compared to the strength of human compact bone, etc., and the powder and the liquid are kneaded to cure the curable material. Nature (the kneadability will be described in detail later)
Was also inadequate.

[0012]

Means for Solving the Problems The present inventors have conducted intensive studies to develop a new self-curing biomaterial which overcomes such disadvantages of the conventional product. The above problem is encountered in a cured product formed using a curable material containing a specific range of a fluoride, a neutralizing agent, an acid, and water that are soluble in water with respect to a system comprising a hardly soluble fluoride. The inventors have found that the points can be solved, and have completed the present invention based on this finding.

That is, the present invention provides a hydrated self-hardening calcium phosphate containing calcium and phosphorus at an atomic ratio of Ca / P = 1.3 to 2.0, a fluoride which is hardly soluble in water, At least one water-soluble fluoride selected from sodium, sodium acid fluoride, potassium fluoride and potassium acid fluoride; an acid; and at least one neutralizer selected from sodium hydroxide and potassium hydroxide And water, and the ratio of each atom of sodium and potassium and fluorine of at least one fluoride soluble in water and the neutralizing agent is (Na + K) / F = 0.
The present invention provides a curable material having a ratio of 2 to 40.

The hydrated self-hardening calcium phosphate used in the present invention is one which exhibits curability by hydration when kneaded with water or water to which a hardening accelerator such as an acid is added. Hydrated self-hardening calcium phosphate such as tricalcium phosphate and tetracalcium phosphate or α-
Hydration self-curing with a mixture of tricalcium phosphate and tetracalcium phosphate or a mixture of these with non-hydrated self-hardening calcium phosphate such as hydroxyapatite, octacalcium phosphate, β-tricalcium phosphate, calcium hydrogen phosphate , With the atomic ratio of calcium to phosphorus
a / P = 1.3 to 2.0.

The atomic ratio of calcium to phosphorus is Ca / P =
It is preferably in the range of 1.3 to 2.0, and more preferably the atomic ratio of calcium to phosphorus is in the range of Ca / P = 1.4 to 1.8. If the composition of the Ca / P ratio is out of this range, the difference from the theoretical apatite composition ratio of 1.67 is too large. It is difficult to obtain a cured product.

The method of producing these calcium phosphates is not particularly limited, but as is well known, calcium sources such as CaCO ₃ , CaO, Ca (O
H) ₂ , P ₂ O ₅ , H ₃ PO ₄ , NH ₄ as phosphoric acid sources
H ₂ PO ₄ and CaHPO ₄ containing both calcium and phosphate, Ca (H ₂ PO _4), using such Ca ₂ P ₂ O _7, are prepared in a conventional manner, the manufacturing method is particularly limited Not something. Further, as a method for producing a mixture, a method of mixing a plurality of types of calcium phosphate produced by a conventional method so as to have a predetermined Ca / P ratio, and a method of heating hydroxyapatite or the like produced by a conventional method under reduced pressure Etc., but any method may be used.

Next, in the present invention, a fluoride which is hardly soluble in water is added under the above-mentioned conditions to promote the hydration and hardening of calcium phosphate and to improve the strength of the hardened material. The water-insoluble fluoride is used in combination with a water-soluble fluoride described below, and is used in a method of adding it to the powder portion in a solid state.
The effect is exhibited. Specific examples include calcium fluoride, magnesium fluoride, strontium fluoride, alkaline earth metal fluorides of barium fluoride, lithium fluoride, chromium fluoride, lead fluoride, nickel fluoride, iron fluoride, and fluorine fluoride. Examples thereof include metal fluorides such as aluminum fluoride, sodium silicofluoride, potassium silicofluoride, calcium silicofluoride, and barium silicofluoride. In addition to the above examples, fluorides having a solubility of 1 g or less in 100 ml of water at 25 ° C. If present, it is preferably used. These hardly soluble fluorides may be used alone or as a mixture of a plurality of them. The amount of the hardly soluble fluoride added is such that the amount of fluorine in the hardly soluble fluoride is Ca / F = 4.5 to 1 in atomic ratio with respect to the calcium amount of calcium phosphate.
It is preferably 50, and if it is outside this range, the desired effect may not be obtained.

Next, in the present invention, calcium phosphate under the above conditions is mixed with an alkali metal fluoride selected from sodium fluoride, sodium acid fluoride, potassium fluoride and potassium acid fluoride as a water-soluble fluoride, and a neutralizing agent. And an alkali metal hydroxide selected from sodium hydroxide and potassium hydroxide as the addition amount, the ratio of each atom of sodium, potassium and fluorine in these is (Na +
K) /F=0.2 to 40. By adding a soluble fluoride and a neutralizing agent to this water, the kneadability of the self-curable biomaterial when it is hydrated and hardened can be significantly improved, and in addition, the strength of the hardened body can be improved. ,
Dimensional accuracy is also improved. In addition to the above four kinds of fluorides soluble in water or an acid aqueous solution, generally, for example, cobalt silicofluoride, iron silicofluoride, iron borofluoride,
Potassium borofluoride, sodium borofluoride, ammonium borofluoride, neoborn, copper fluoride, stannous fluoride, zinc fluoride, magnesium silicate fluoride, ammonium silicate fluoride, manganese silicate fluoride, zinc silicate fluoride,
Potassium titanium fluoride, manganese fluoride, ammonium zirconium fluoride, potassium zirconium fluoride, sodium hexafluorophosphate, potassium hexafluorophosphate, etc. can also be used, provided that this is less than half of the total water-soluble fluoride. It may be used in combination with an alkali metal fluoride selected from sodium fluoride, sodium fluoride, sodium fluoride, potassium fluoride and potassium fluoride.

The method of adding the soluble fluoride is generally in the form of a salt. In addition, for example, a method of adding a hydrofluoric acid and an alkali metal hydroxide to neutralize to form a soluble fluoride, or a method of decomposing A method such as adding a precursor in the form of a soluble fluoride by reaction or the like may be used.

This water-soluble alkali metal fluoride selected from sodium fluoride, sodium acid fluoride, potassium fluoride and potassium acid fluoride, and sodium hydroxide and potassium hydroxide as neutralizing agents The addition amount of the alkali metal hydroxide selected from the above is such that the ratio of each atom of sodium, potassium and fluorine in these is (Na +
K) / F needs to be 0.2 to 40, and if it is outside this range, the desired effect cannot be obtained.

The amount of the soluble alkali metal fluoride to be added is preferably in an atomic ratio of Ca / F = 4.5-600, more preferably 4.5-300, with respect to calcium of calcium phosphate. In some cases, the desired effect may not be obtained even if the deviation is too small.

When a predetermined amount of the soluble alkali metal fluoride and the neutralizing agent are added, the effect of improving the kneadability is remarkable. It is difficult to describe the kneadability quantitatively, and there is no general measurement method. However, when the curable material according to the present invention is actually used, powders and liquids are mixed, kneaded into a paste or putty, and inserted, filled or poured into the application site, set and cured, Immediately upon kneading, it becomes moderately viscous immediately, and it is very significant that it can be smoothly inserted, filled or poured into the application site. If kneaded, if it is in a state close to powder, it will be difficult to operate even if it is inserted, filled or poured into the application site, and the adhesion to the application site will be poor, and a good effect as a biomaterial will be obtained. I can't show it. However, if only the fluidity of the kneaded material is simply improved, for example, by increasing the liquid-powder ratio (by increasing the ratio of the liquid agent), it can be easily improved. Since the amount of water required is at most a few percent of the weight of the dust, the addition of excess water only reduces the strength. Therefore, it is very significant to find an additive that can maintain good kneading properties even when the amount of water added is reduced. The present inventors have conducted intensive studies on such additives, and as a result, surprisingly, water-soluble alkali metals selected from sodium fluoride, sodium acid fluoride, potassium fluoride, and potassium acid fluoride are surprisingly soluble in water. The fluoride and the alkali metal hydroxide selected from sodium hydroxide and potassium hydroxide as the neutralizing agent are mixed with each other at a ratio of each atom of sodium, potassium and fluorine of (Na + K) /F=0.2 to 4
It has been found that, if added so as to fall within the range of 0, extremely good kneadability can be maintained and strength can be increased even if the liquid-powder ratio is lowered.

The curable material of the present invention contains an acid such as an organic acid and an inorganic acid in addition to the above fluoride as a curing accelerator. Organic acids used in the practice of the present invention include lower monobasic fatty acids such as formic acid, acetic acid, and propionic acid; hydroxycarboxylic acids such as malic acid, glycolic acid, lactic acid, citric acid, sugar acid, and ascorbic acid;
Acidic amino acids such as glutamic acid and aspartic acid; dibasic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, and adipic acid; keto acids such as pyruvic acid, acetoacetic acid, and levulinic acid; salicylic acid, benzoic acid, and cinnamic acid And the organic acid derivatives which easily form a carboxylic acid group by hydrolysis, such as acid anhydrides and acid chlorides. Further, examples of the inorganic acids include phosphoric acid, hydrochloric acid, nitric acid, sulfuric acid and the like. Among these, organic acids are particularly preferred.

The curable material of the present invention contains water for promoting a curing reaction. The amount of water is P (P
(1 mol as O ₄ ), and at least 1 /
3 moles are required. However, an appropriate amount of water can be used more in consideration of kneadability, workability and the like, but the H ₂ O / PO ₄ molar ratio is usually about 1/3 to 50.

The curable material of the present invention refers to a material before or after the curing treatment comprising a combination of the above components, and in an embodiment, each component is separately prepared, kneaded and cured upon use. May be used as the desired cured product,
In consideration of practical handling convenience, for example, a powder component and a liquid component as shown below, that is, separately prepared as a powder portion and a liquid portion, kneaded and cured at the time of use, and cured as desired. It is preferably a body.

For example, when (1) the powder component is composed of calcium phosphate and a fluoride which is hardly soluble in water, a fluoride which is soluble in water, an acid and a neutralizing agent, while (2) when the liquid component is water When the powder component is composed of calcium phosphate and a fluoride that is hardly soluble in water and a fluoride that is soluble in water, while the liquid component is water, an acid and a neutralizing agent, (3) the powder component is composed of calcium phosphate and water. Made of hardly soluble fluoride,
On the other hand, the liquid component may be water, a water-soluble fluoride, an acid, and a neutralizing agent, but is not limited thereto.

There are two types of fluorides, ones that are hardly soluble in water and those that are soluble in water, and the amount of each is defined. Therefore, the powder component of (3) is composed of calcium phosphate and a water-insoluble fluoride, while the liquid component is water, a water-soluble fluoride, an acid, and a neutralizing agent. Fluoride and soluble fluoride are separated, so the amount of each can be confirmed by measuring the amount of fluorine and the like. (1) Fluoride which is hardly soluble in calcium phosphate and water, and soluble in water Consisting of fluoride, acid and neutralizing agent, while the liquid component is water,
(2) The powder component is composed of calcium phosphate and a fluoride which is hardly soluble in water, and a fluoride which is soluble in water. On the other hand, when the liquid component is water, an acid and a neutralizer, the powder component is hardly soluble in water. If the fluoride and the soluble fluoride are in the same powder component, for example, the soluble fluoride is extracted with water to separate the hardly soluble fluoride from the soluble fluoride. The amount of each fluorine may be confirmed by, for example, analyzing by an ion electrode method or the like, and the amount of sodium and potassium may be confirmed by analyzing by an atomic absorption method or the like.

The liquid component and the powder component are mixed and used at a ratio of 0.1 to 0.5, which is represented by the ratio of the liquid volume (ml) to the powder weight (g) (powder-liquid ratio ml / g). Is preferred. If the liquid component is less than this, the kneaded product obtained by mixing the powder component and the liquid component is insufficient in flowability to form a desired shape, and if it is more than this, the kneaded material becomes excessively fluid. It is difficult to maintain a specific shape, and neither is preferable.

The amount of the acid relative to calcium phosphate is about 2
It is preferably in the range of × 10 ⁻⁵ mol / g to 1.2 × 10 ⁻³ mol / g. If the amount is less than the lower limit, a long time is required for curing, and if the amount exceeds the upper limit, the curing speed is too high and the operability is poor. In the case where the powder component is calcium phosphate and fluoride and the liquid component is an aqueous solution of acids, 0.1 mol / liter to 2.5 m
It is preferable to add an aqueous solution of an acid of o liter / liter to the powder component and knead the mixture.

[0030]

As described above in detail, each component of the curable material of the present invention, ie, hydrated self-hardening calcium phosphate having a gram atom ratio of Ca / P in the range of 1.3 to 2.0, A hardly soluble fluoride in water, a fluoride soluble in water, a neutralizing agent, an acid and water are mixed at a prescribed ratio to obtain a curable material of the present invention, which is kneaded and left to stand. Upon hydration self-curing, a cured product having excellent hardness can be obtained.
This cured product is converted into apatite having excellent biocompatibility with the passage of time.

In addition, if the time required for self-curing of the cured product is too long or too short for use as a biomaterial, for example, clinical operation becomes difficult. Therefore, it is preferable that the time required for curing can be easily and largely controlled according to the purpose of use. According to the curable material of the present invention, it is possible to change the curing time in the range of about 5 minutes to several hours at a relatively low temperature near the body temperature by adjusting the amount of the acid added, the amount of the neutralizing agent, and the like. .

Further, since the cured product of the curable material of the present invention hardly shrinks in the process of curing, it does not form a gap at the interface between the living body and the filler when used in filling a living body. Therefore, it is a remarkable advantage for the fusion with the living body.

Biomaterials are required to have two basic functions. One of them is the functional strength as a material,
Another is biocompatibility. As mechanical strength,
Hardness, compressive strength, flexural strength, etc. are required, but in order to keep them at a certain level, it is essential that the cured product is sufficiently cured. Although it is difficult to reproduce the environment in which a biomaterial is used in a test tube (in vitro), when the cured product obtained in the present invention is applied to a living body, the cured product has a basic function as a cured product. When the cured product according to the present invention was stored in water to observe whether or not the cured product collapsed, the cured product did not collapse and kept its shape. When the strength expressing the physical properties of the cured product was measured, all the cured products had a crushing resistance of about 800 kg / cm ² . Furthermore, remarkably, when the cured product was stored in water, the strength increased with time, and a crushing resistance as high as 1500 kg / cm ² was observed. Therefore, it is shown that the cured product obtained from the curable material of the present invention has improved physical properties in terms of mechanical strength, and can be said to be an excellent biomaterial. Further, in order to check the biocompatibility of the cured product based on the present invention, an artificial defect was created in the mandible of a male male of SD rats and the kneaded material was pressed and filled. Inflammatory cells disappeared with the passage of time without tissue intervention, and formation of bone tissue was observed, suggesting that it was extremely excellent as a biomaterial.

It should be noted that in the hardened cement which is conventionally used and comprises a liquid component containing an inorganic powder and a water-soluble polymer, in many cases, the viscosity derived from the water-soluble polymer is reduced by a kneading operation or a treatment. Had created difficulties. However, in the cured product of the curable material of the present invention, since no polymer is used as a component, there is no problem such as the above-mentioned viscous or spinnable properties, and it is easy to operate. It is the feature.

[0035]

Next, the present invention will be described in more detail with reference to examples, but it is needless to say that the present invention is not limited only to the examples.

Example 1 γ-Ca ₂ P ₂ O ₇ and calcium carbonate were mixed, and 125
After heating at 0 ° C. for 4 hours, the mixture was rapidly cooled to obtain a hydrated self-curing α-tricalcium phosphate. The Ca / P ratio in this hydrated self-curing α-tricalcium phosphate was 1.5. 1.951 g of this α-tricalcium phosphate and 0.049 g of calcium fluoride as a poorly soluble fluoride were mixed and pulverized to obtain a powder.
The ratio of the amount of fluorine in the poorly soluble fluoride to the amount of calcium in the calcium phosphate, Ca / F, in this powder was 15. Aside from this powder, citric acid 0.75,
Potassium hydroxide 1.0, Sodium acid fluoride 0.63
Of each molar concentration was prepared. Water-soluble fluoride and neutralizing agents sodium, potassium,
The ratio of each fluorine atom (Na + K) / F is 1.3.

2 g of this powder and 0.5 ml of the liquid were kneaded in a glass mortar. At this liquid-powder ratio, the amount of calcium in the calcium phosphate in the kneaded product is 30 in atomic ratio with respect to the amount of fluorine in the fluoride soluble in water. The consistency during kneading was good and the fluidity was sufficient. The kneaded product was poured into a mold in which an acrylic resin ring having an inner diameter of 10 mm and a height of 5 mm and a glass plate at the bottom thereof were combined.
The setting time of this kneaded product was measured according to JIS T6604. The time until the traces of the bigger needles no longer adhere was defined as the curing time. As a result, the setting time is 6 minutes,
Curing time was 24 minutes. For crushing resistance,
The measurement was carried out according to IS T6602, and the crushing resistance value after 24 hours from the curing was 1000 kg / cm ² . Further, the cured product was stored in pure water kept at 37 ° C., and the change in crushing resistance was examined.
It was improved to 0 kg / cm ² . The results are summarized in Tables 1 and 2.

The kneadability becomes soft and viscous as soon as it is kneaded with the liquid, and when it is easy to pour into a mold, it becomes ◎. In this case, it was marked with x. In ordinary use, ◎ to ○ are appropriate consistency.

Examples 2 to 10 As shown in Tables 1 and 2, a predetermined amount of hydrated self-curing α-
Using tricalcium phosphate, a sparingly soluble fluoride, a water-soluble fluoride, a neutralizing agent, and an acid, employing a predetermined amount of a liquid powder ratio, a kneaded product is prepared by the same operation as in Example 1, The curing time, kneadability and strength were measured. The results are also shown in Tables 1 and 2.

Example 11 γ-Ca ₂ P ₂ O ₇ and calcium carbonate were mixed,
After heating at 0 ° C. for 4 hours, the mixture was rapidly cooled to obtain tetracalcium phosphate.
The α-tricalcium phosphate obtained in Example 1 and this tetracalcium phosphate were mixed at a molar ratio of 2: 1 and Ca was added.
A hydrated self-hardening calcium phosphate having a / P ratio of 1.67 was obtained. Next, as shown in Tables 1 and 2, the hydrated self-hardening calcium phosphate and the hardly soluble fluoride, the water-soluble fluoride, the acid,
Example 1 A neutralizing agent and water were used, and a predetermined amount of liquid powder ratio was employed.
A kneaded material is prepared by the same operation as described above, and the setting, setting time,
The kneadability and strength were measured. The results are also shown in Tables 1 and 2.

Example 12 One part of hydroxyapatite obtained by a conventional method was added to 10 parts of the α-tricalcium phosphate obtained in Example 1 and mixed, and the hydration self-hardening was performed at a Ca / P ratio of 1.51. Calcium phosphate was obtained. Using this calcium phosphate, a sparingly soluble fluoride, a water-soluble fluoride, and an acid solution, a predetermined amount of a liquid-powder ratio was used to prepare a kneaded product in the same manner as in Example 1, and the setting, setting time, and kneading were performed. The properties and strength were measured. The results are also shown in Tables 1 and 2.

Example 13 A solution was prepared by adding citric acid 0.75, sodium hydroxide 0.63,
A kneaded product was prepared in the same manner as in Example 1 except that the aqueous solutions were changed to potassium hydroxide 0.28 and potassium fluoride 1.26 at each molar concentration, and the setting, curing time, kneadability and strength were measured. did. The results are also shown in Tables 1 and 2.

Example 14 The same procedure as in Example 1 was carried out except that the solution was changed to an aqueous solution having each molar concentration of citric acid 0.75, potassium hydroxide 0.91, sodium fluoride 0.63 and potassium fluoride 0.63. To prepare a kneaded product, and the setting, curing time, kneadability and strength were measured. The results are also shown in Tables 1 and 2.

Example 15 A solution was prepared by adding citric acid 0.50, potassium hydroxide 0.01, potassium acid fluoride 0.63, stannous fluoride 0.35,
A kneaded product was prepared in the same manner as in Example 1 except that the aqueous solution was changed to each molar concentration, and the setting, curing time, kneadability and strength were measured. The results are also shown in Tables 1 and 2.

Example 16 The hydrated self-curing α-having a Ca / P ratio of 1.5 obtained in Example 1
1.951 g of tricalcium phosphate, 0.049 g of calcium fluoride, and 0.026 g of sodium fluoride were mixed and pulverized to obtain a powder. The ratio of the amount of fluorine in the poorly soluble fluoride to the amount of calcium in calcium phosphate in this powder,
Ca / F is 15. The ratio of the amount of fluorine in the water-soluble fluoride to the amount of calcium in the calcium phosphate, Ca / F, of this powder was 30. Separately from the powder, an aqueous solution of citric acid 0.75 and potassium hydroxide 1.5 at each molar concentration was prepared. 2g of this powder and 0.5m of liquid
was mixed in a glass mortar. In this liquid-powder ratio, the water-soluble fluoride and the neutralizing agent sodium in the kneaded product,
The ratio of each atom of potassium and fluorine (Na + K) / F is 2.1
9 This kneaded product was also measured for setting, curing time, kneadability, and strength. The results are also shown in Tables 1 and 2.

In this case, since the powder contains both a fluoride which is hardly soluble in water and a fluoride which is soluble in water, in order to confirm the amount of each fluorine, the powder is mixed with water four times or more by weight. It was dispersed and a water-soluble fluorinated product was extracted. The amount of fluorine in the extract was analyzed by the ion electrode method, and the amount of sodium was analyzed by the atomic absorption method. As a result, fluorine and sodium were detected in an amount substantially equivalent to the added sodium fluoride.

Examples 17 and 18 As shown in Tables 1 and 2, a predetermined amount of hydrated self-curing α-
Using tricalcium phosphate, a sparingly soluble fluoride, a water-soluble fluoride, a neutralizing agent, and an acid, employing a predetermined amount of a liquid powder ratio, a kneaded product is prepared by the same operation as in Example 1, The curing time, kneadability and strength were measured. The results are also shown in Tables 1 and 2.

Comparative Example 1 The α-tricalcium phosphate having a Ca / P ratio of 1.5 obtained in Example 1 was pulverized into a powder. Citric acid 0.7
5, potassium hydroxide 1.0, sodium acid fluoride 0.
63 aqueous solutions of each molarity were prepared and used as liquid preparations. The ratio (Na + K) / F of each of the sodium, potassium and fluorine atoms of the fluoride soluble in water and the neutralizing agent in this solution is 1.3.

2 g of the powder and 0.5 ml of the liquid were thoroughly kneaded in a glass mortar, and the setting and hardening time were measured in the same manner as in Example 1 to test the kneadability. The setting time was 4 minutes and the setting time was 46 minutes. The crushing effect 24 hours after curing is 3
It was 00 kg / cm ² . Further, this cured product was stored in pure water kept at 37 ° C., and the change in crushing resistance was examined. As a result, the crushing resistance value after one week was 480 kg / cm ² . The results are shown in Tables 1 and 2.

Comparative Examples 2 and 3 As shown in Tables 1 and 2, a predetermined amount of calcium phosphate, a sparingly soluble fluoride, a water-soluble fluoride, a neutralizing agent, an acid, and water were used, and a predetermined And a kneaded product was prepared in the same manner as in Comparative Example 1, and the setting, curing time and strength were measured. The results are also shown in Tables 1 and 2.

COMPARATIVE EXAMPLE 4 A solution was prepared by adding citric acid 0.50, potassium hydroxide 0.01, potassium acid fluoride 0.1, magnesium silicofluoride 0.1.
A kneaded material was prepared in the same manner as in Example 1 except that the aqueous solution was changed to each of the molar concentrations of 1, and the coagulation, curing time, kneadability and strength were measured. The results are also shown in Tables 1 and 2.

As can be seen from the above examples, the self-curing material of the present invention has high strength (crush resistance) and extremely excellent kneadability which is an important property in practical use. is there. In contrast, those that do not meet the requirements of the present invention,
For example, in the case where the hardly soluble fluoride is not added (Comparative Example 1), since the water-soluble fluoride is added, the kneadability is aside and the strength is completely insufficient. In the case where the water-soluble fluoride was not added (Comparative Example 2), although the strength was slightly increased, the kneadability was quite poor and it was not practical. Further, the ratio of each atom of sodium, potassium and fluorine in the fluoride soluble in water and the neutralizing agent is (Na + K) /F=0.2 to 4
Even those out of the range of 0 (Comparative Examples 3 and 4) have very poor kneading properties and low crushing drag.

[0053]

[Table 1]

[0054]

[Table 2]

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI // (C04B 28/34 22:06 22:08 22:12) (56) References JP-A-62-182146 (JP, A JP-A-63-123854 (JP, A) JP-A-63-95148 (JP, A) JP-A-59-88351 (JP, A) JP-A-1-100048 (JP, A) 182263 (JP, A) JP-A-62-83348 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C04B 28/34

Claims (5)

(57) [Claims] 1. The method according to claim 1, wherein the atomic ratio of calcium and phosphorus is Ca /
Selected from hydrated self-hardening calcium phosphate containing P at a ratio of 1.3 to 2.0, a fluoride insoluble in water, and sodium fluoride, sodium acid fluoride, potassium fluoride and potassium acid fluoride. And at least one water-soluble fluoride, an acid, at least one neutralizing agent selected from sodium hydroxide and potassium hydroxide, and water. A curable material characterized in that the ratio of each kind of fluoride, sodium and potassium of the neutralizing agent and each atom of fluorine is (Na + K) /F=0.2 to 40. 2. The atomic ratio of calcium in calcium phosphate to fluorine in sparingly soluble fluoride is Ca / F =
The curable material according to claim 1, wherein the number is from 4.5 to 150. 3. An atomic ratio of calcium in calcium phosphate to fluorine in water-soluble fluoride selected from sodium fluoride, sodium acid fluoride, potassium fluoride, and potassium acid fluoride in an atomic ratio of Ca / F = 4. .5-
The curable material according to claim 1, wherein the number is 600. 4. The curable material according to claim 1, wherein the hardly soluble fluoride is an alkaline earth metal salt. 5. The curable material according to claim 1, comprising a powder part and a liquid part.