JPH10245257A - Hardened product and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide high resistance to hard water or an acidic atmosphere and maintain a stable hardened state and properties for a long period by preparing a hardened product of a structure in which the peripheries of calcium phosphate grains are surrounded with any one or more of a silicon oxide, silicic acid and a silicate. SOLUTION: This hardened product consists essentially of any one or more of a silicon oxide, silicic acid and a silicate and calcium phosphate. The calcium phosphate is in a wide sense and may be a compound consisting essentially of calcium phosphate or a calcium phosphate-based solid solution, e.g. apatite, hydroxyapatite or tricalcim phosphate is cited. The form of the calcium phosphate raw material is preferably powdery or granular and the grain diameter may be about <=3mm. One example of production methods is cited as follows: A silicon oxide, silicic acid or a silicate in a colloidal form in an amount of 2-100 pts.wt. expressed in terms of solid content is added to 100 pts.wt. calcium phosphate raw material and the resultant mixture is then kneaded at normal temperatures in the atmosphere. An acid is further added thereto to carry out kneading to afford a uniform hardened product. The weight ratio during the kneading (total liquid content/total solid content) is preferably 0.2-2.0.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cured product used for building materials or structural members requiring chemical durability and a method for producing the same.

[0002]

2. Description of the Related Art As a hardened material used for a building material or a structural member, concrete or mortar mainly using Portland cement as a hardened material is widely used. However, in Portland cement, structural water shows alkalinity, other hardened body components are corroded by the effect of alkali contained in its composition, the hardened body itself gradually deteriorates, and especially hard water and neutral or less In an environment exposed to an atmosphere, the corrosion rapidly progresses due to these and cracks and cracks are easily formed in the cured product, and it is not necessarily suitable for long-term stable use.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a cured product which has high resistance to the atmosphere and hard water, can maintain a stable cured state over a long period of time, and can maintain the properties, and a method for producing the same. And

[0004]

Means for Solving the Problems In order to achieve the above object, the present inventors have conducted intensive studies and, as a result, focused on calcium phosphate which can form a cured product by a hydration reaction, and studied the chemical resistance of the calcium phosphate. In order to improve the hardness, the calcium phosphate particles are surrounded by one or more of silicon oxide, silicic acid, and silicate to form a cured product, which has excellent resistance to atmosphere and hard water, It has been found that a stable cured state and properties can be maintained.

[0005] Moreover, the above-mentioned cured product is very easily prepared by adding a solution of a colloidal substance mainly composed of silicon and oxygen and an acid to calcium phosphate and kneading the mixture, and curing the kneaded product at a relatively low temperature. It was also found that it can be manufactured. From these findings, the inventors of the present invention have proposed the following inventions regarding the cured product described in (1) and (2) and the following (3) to (5).
The inventions on the method for producing a cured product described in (1) have been completed.

(1) A hardened body mainly composed of at least one of silicon oxide, silicic acid and silicate and calcium phosphate, wherein the periphery of the calcium phosphate particles is any of silicon oxide, silicic acid and silicate. Or a cured body having a structure surrounded by at least one kind.

(2) The calcium phosphate is hydroxyapatite,
The cured product according to the above (1), which is one or more of hydroxyapatite solid solution, tricalcium phosphate, and tricalcium phosphate solid solution.

(3) To a compound and / or solid solution mainly composed of phosphoric acid and calcium, a solution mainly composed of one or more of colloidal silicon oxide, silicic acid and silicate and an acid are added and kneaded, followed by curing. A method for producing a cured product.

(4) Addition and kneading are performed by adding a solution mainly containing at least one of a colloidal silicon oxide, silicic acid and silicate to a compound and / or solid solution mainly containing phosphoric acid and calcium, and kneading the mixture. Next, the method for producing a cured product according to the above (3), wherein an acid is added thereto and kneaded.

(5) The compound and / or solid solution mainly composed of phosphoric acid and calcium is mainly composed of one or more of hydroxyapatite, hydroxyapatite solid solution, tricalcium phosphate and tricalcium phosphate solid solution. The method for producing a cured product according to any one of (3) and (4), which is a compound, a solid solution, or a mixture.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The calcium phosphate constituting the cured product of the present invention is calcium phosphates in a broad sense, and includes not only a compound consisting of only phosphoric acid and calcium but also a compound mainly composed of calcium phosphate or a calcium phosphate-based compound. It may be a solid solution. That is, any compound may be used as long as it is a calcium phosphate compound, and examples thereof include apatite, hydroxyapatite, and tricalcium phosphate, and have a structure substantially similar to or close to the crystal structure of the original compound mainly composed of calcium phosphate. May be a solid solution in which another element or compound is dissolved in a compound mainly composed of calcium phosphate. Further, a solid solution in which an original or another kind of calcium phosphate-based solid solution or another kind of calcium phosphate-based solid solution is dissolved in such a calcium phosphate-based solid solution may be used. Or a mixture of two or more of the above.

Among such calcium phosphates, for example, a hydroxyapatite solid solution in which about 3 to 25% by weight of hydroxyapatite, alkaline earth metal, transition metal or the like is dissolved,
Any solid solution obtained by dissolving the hydroxyapatite solid solution in hydroxyapatite at an arbitrary ratio has low solubility in water, and has extremely low reactivity to hard water and alkali, and is stable. Further, for example, phosphoric acid 3 containing about 8 to 60% by weight of a solid solution of calcium phosphate, alkaline earth metal, transition metal, or the like.
Calcium solid solution, tricalcium phosphate
Any solid solution formed by solid solution in calcium at an arbitrary ratio is excellent in acid resistance because it hardens by generating hydroxyapatite under acidity.

The cured product of the present invention has a structure in which at least one of silicon oxide, silicic acid, and silicate surrounds the individual particles of calcium phosphate, and is firmly bonded to the calcium phosphate particles. It is. The silicon oxide, silicic acid, and silicate may be crystalline or amorphous. here,
The silicon oxide is an oxide mainly composed of silicon, and generally includes SiO _2, but may be a solid solution containing elements other than silicon and oxygen. Examples of the silicate include a silicate compound of an alkali metal such as sodium silicate and calcium silicate and a silicate compound of an alkaline earth metal, but a silicate compound of another metal, and a silicate containing a plurality of types of metals. Compounds and hydrated compounds containing structural water in the metal silicate compound may be used.

Hereinafter, a method for producing a cured product according to the present invention will be described. Compounds and / or solid solutions mainly composed of phosphoric acid and calcium used as raw materials are calcium phosphates in a broad sense. That is, the compound mainly composed of phosphoric acid and calcium,
For example, it may be a compound consisting of only phosphoric acid and calcium, such as tricalcium phosphate, a compound mainly composed of calcium phosphate such as hydroxyapatite, or a compound containing phosphoric acid and calcium as main components and other components. . Further, a solid solution mainly composed of phosphoric acid and calcium has a structure substantially similar to or close to the crystal structure of the original compound composed mainly of phosphoric acid and calcium, and is different from the original compound composed mainly of phosphoric acid and calcium by other elements and A solid solution formed by dissolving a compound in a solid solution, or a solid solution formed by dissolving an original or another compound mainly containing phosphoric acid and calcium or another calcium phosphate-based solid solution in the solid solution may be used. . Further, compounds or mixtures of two or more of these compounds and solid solutions may be used. More preferably, the compound and / or solid solution mainly composed of phosphoric acid and calcium is hydroxyapatite, hydroxyapatite solid solution, tricalcium phosphate, phosphoric acid 3
It is preferable to use one or more of the calcium solid solutions as main components. The form of the calcium phosphate raw material at the time of use is desirably in the form of powder or granules, and the particle size may be approximately 3 mm or less.

As one or more of silicon oxide, silicic acid and silicate constituting the cured product, a colloidal solution is used as a raw material in order to increase the reactivity with an acid and calcium phosphate. The silicon oxide may be an oxide mainly composed of silicon and a compound consisting of only silicon and oxygen, or may contain another element, structural water, or the like. Examples of the silicate include a silicate compound of an alkali metal such as sodium silicate and calcium silicate and a silicate compound of an alkaline earth metal, but a silicate compound of another metal, and a silicate containing a plurality of types of metals. It may be a compound, a hydrated compound of the metal silicate compound, a natural silicate mineral, or the like. When a colloidal solution of at least one of commercially available silicon oxide, silicic acid and silicate is not used as a raw material, a colloidal solution is prepared. The preparation of the colloidal solution is not particularly limited as long as it is a known method. The solid concentration of this colloidal solution is preferably about 10% by weight or more.

[0016] To 100 parts by weight of the calcium phosphate raw material,
Colloidal silicon oxide, silicic acid, at least one of silicates in an amount of about 2 to 100 parts by weight in terms of solids, and about 2 to 1 acid
The mixture is kneaded at room temperature at room temperature, and preferably kneaded with calcium phosphate to which at least one of colloidal silicon oxide, silicic acid and silicate is added. If an acid is added to the mixture and the mixture is further kneaded, a more uniform cured product can be obtained. However, in the kneaded material, the weight ratio of the total liquid component and the total solid component during kneading is (total liquid component / total solid component) =
It is desirable to be 0.2 to 2.0, and it is desirable to adjust the addition amount of each of the above-mentioned raw materials so as to make this weight ratio.
This is because the weight ratio (total liquid content / total solid content) of the kneaded material is 0.2.
If it is less than 30%, kneading becomes difficult due to insufficient fluidity, and if the weight ratio (total liquid content / total solid content) exceeds 2.0, cracks and the like are likely to occur during curing. The acid to be added may be any of an inorganic acid, an organic acid, and a mixture of both, and is not particularly limited. If the amount of the acid to be added is less than about 2 parts by weight, the dissolution / reprecipitation reaction of calcium phosphate does not sufficiently occur, and if it exceeds 100 parts by weight, the curing reaction after the dissolution of calcium phosphate does not sufficiently proceed, so neither is preferable. Furthermore, at the time of kneading, in addition to the above-mentioned raw material components, if necessary, known admixtures generally used for preparing an inorganic cured product such as a water reducing agent may be used.

The kneaded material produced by such kneading is:
In order to obtain a desired shaped product, it is poured into a mold, cured by being cured at normal temperature to about 100 ° C. in the air, and solidified.

[0018]

Function and effect The cured product forming mechanism and the cured product in the present invention show some differences depending on the kind of raw material, especially the kind of calcium phosphate used. For example, when hydroxyapatite and / or a solid solution thereof is used as calcium phosphate, a reaction between hydroxyapatite, an acid, and a colloidal silicate produces a silicic acid-containing apatite layer having an orthosilicate group,
A cured product is formed in which the silicate-containing apatite forms a strong bond with the silicate layer surrounding the hydroxyapatite.
When tricalcium phosphate and / or a solid solution thereof is used as calcium phosphate, an apatite phase is formed by a hydration hardening reaction between tricalcium phosphate and an acid, and at the same time, a silicate-containing apatite is reacted with a colloidal silicate solution. And a silicate layer containing calcium and orthophosphoric acid groups at the same time, and a hardened body having a stronger bond between them is formed. Regardless of the above example, in any case, the cured product of the present invention has a silicate layer that is stable against hard water or an acidic atmosphere, and each layer is firmly bonded to calcium phosphate particles, so that the cured product can be used for a long time. However, a stable cured state and properties can be maintained.

[0019]

Examples 1 to 4 and Comparative Examples 1 to 3 were prepared by using the raw materials shown in Table 1 and adding a colloidal solution of an acid and at least one of silicon oxide, silicic acid and silicate to calcium phosphate. It was added at the same time and kneaded for about 5 minutes. In Example 5, a mixture of calcium phosphate and a silicate solution was kneaded for about 5 minutes, then an acid was added, and the mixture was further kneaded for about 3 minutes. Each kneaded material was poured into a stainless steel cylindrical container having a bottom surface of 100 mm in diameter and a height of 200 mm, and was cured in the air at 100 ° C. for 7 days. After curing, the mold was released to obtain a cured product.

[0020]

[Table 1]

Each of the obtained cured products is visually checked for the occurrence of cracks, and then subjected to Japanese Industrial Standard JIS A-110.
Compressive strength was measured by the method according to No. 8, and a part of the fragments of each cured product after the compressive strength was subjected to qualitative analysis of the existing phase by powder X-ray diffraction. Further, a part of each hardened material fragment was immersed in hard water at 30 ° C. in which magnesium sulfate was added to pure water at normal temperature for 120 days. The cured body after immersion was examined for the occurrence of weight loss corresponding to 0.01% or more of the weight before immersion. These results are shown in Table 2.

[0022]

[Table 2]

The microstructure of a part of the fragments of each of the cured products of Examples 1 to 5 after the compressive strength was examined using an X-ray microanalyzer. As a result, it was confirmed that in all of the cured products of Examples 1 to 5, the layer containing a large amount of silicon surrounded the calcium phosphate particles.

Claims (5)

[Claims] 1. A cured product mainly composed of at least one of silicon oxide, silicic acid and silicate, and calcium phosphate,
A cured product having a structure in which at least one of silicon oxide, silicic acid and silicate surrounds calcium phosphate particles. 2. The cured product according to claim 1, wherein the calcium phosphate is any one or more of hydroxyapatite, hydroxyapatite solid solution, tricalcium phosphate, and tricalcium phosphate solid solution. 3. A compound mainly composed of at least one of a colloidal silicon oxide, silicic acid and silicate and an acid are added to a compound and / or solid solution mainly composed of phosphoric acid and calcium, kneaded and cured. A method for producing a cured product, comprising: 4. The method according to claim 1, wherein the kneading is performed by adding a compound mainly composed of phosphoric acid and calcium and / or a solid solution to a colloidal silicon oxide;
4. The method for producing a cured product according to claim 3, wherein a solution mainly containing at least one of silicic acid and silicate is added and kneaded, and then an acid is added and kneaded. 5. A compound mainly composed of one or more of hydroxyapatite, a hydroxyapatite solid solution, tricalcium phosphate, and a tricalcium phosphate solid solution, wherein the compound and / or solid solution mainly composed of phosphoric acid and calcium is used. 5. The method for producing a cured product according to claim 3, wherein the method is a solid solution or a mixture.