| 摘要 |
PROBLEM TO BE SOLVED: To produce a hardened product, excellent in chemical durability and stability and capable of assuming a strong hardened state for a long period by adding an aqueous solution of silicic acid at a specific pH to a calcium phosphate or the calcium phosphate and an aggregate, kneading the resultant mixture and hardening the kneaded mixture. SOLUTION: An aqueous solution of silicic acid at pH <=5.5 and preferably 10-70 wt.% silicic acid concentration in an amount of preferably 10-70 pts.wt. based on 100 pts.wt. calcium phosphate which is preferably hydroxyapatite and/or its solid solution or tricalcium phosphate and/or its solid solution and an aggregate (e.g. silica sand) in an amount of preferably <=200 pts.wt. based on 100 pts.wt. calcium phosphate is added to the calcium phosphate and the resultant mixture is then kneaded and hardened. The resultant hardened product is chemically nearly neutral, hardly causes elution of alkalis and is capable of maintaining a stable hardened state and a relatively high strength for a long period. |
