Process for producing regenerated collagen fiber and process for setting the same

1. A process for producing regenerated collagen fiber which comprises treating regenerated collagen fiber with a monofunctional epoxy compound and a metal aluminum salt,

wherein treatment with said monofunctional epoxy compound is initiated by adding sodium hydroxide to become 0.001 to 0.8 N based on treatment solution and inorganic salt selected from the group consisting of sodium sulfate, sodium chloride, and ammonium sulfate in an amount which is

at least 13% by weight and up to an amount so that solution reaches the saturated concentration at 25° C. when the sodium hydroxide concentration of the reaction solution is at least 0.001 N and less than 0.05 N,

at least 15% by weight and up to an amount so that solution reaches the saturated concentration at 25° C. when the sodium hydroxide concentration is at least 0.05 N and less than 0.15 N,

at least 16% by weight and up to an amount so that solution reaches the saturated concentration at 25° C. when the sodium hydroxide concentration is at least 0.15 N and less than 0.35 N,

at least 19% by weight and up to an amount so that solution reaches the saturated concentration at 25° C. when the sodium hydroxide concentration is at least 0.35 N and at most 0.8 N.

2. The process of claim 1 , wherein a methionine residual group in collagen is a sulfoxidized methione residual group or a sulfonated methione residual group.

3. A process for setting regenerated collagen fiber produced by the process of claim 1 , which comprises thermally setting said regenerated collagen fiber by means of wet heat treatment at 50° to 160° C. and drying treatment at 20° to 220° C.

4. The process of claim 1 , wherein said inorganic salt is sodium sulfate.

5. A process for setting regenerated collagen fiber produced by the process of claim 4 , which comprises thermally setting said regenerated collagen fiber by means of wet heat treatment at 50° to 160° C. and drying treatment at 20° to 220° C.

6. The process of claim 1 , wherein said monofunctional epoxy compound is a compound represented by formula (I):

wherein R is a substituent group represented by R 1 —, R 2 —O—CH 2 —or R 2 —COO—CH 2 —, R 1 in said substituent group is a hydrocarbon group having at least 2 carbon atoms or CH 2 Cl and R 2 in said substituent group is a hydrocarbon group having at least 4 carbon atoms.

7. The process of claim 6 , wherein R 1 of said formula (I) is a hydrocarbon group having at least 2 to at most 6 carbon atoms or CH 2 Cl and R 2 of said formula (I) is a hydrocarbon group having at least 4 to at most 6 carbon atoms.

8. A process for setting regenerated collagen fiber produced by the process of claim 6 , which comprises thermally setting said regenerated collagen fiber by means of wet heat treatment at 50° to 160° C. and drying treatment at 20° to 220° C.

9. A process for setting regenerated collagen fiber produced by the process of claim 7 , which comprises thermally setting said regenerated collagen fiber by means of wet heat treatment at 50° to 160° C. and drying treatment at 20° to 220° C.

10. The process of claim 1 , wherein said regenerated collagen fiber is treated with said monofunctional epoxy compound and then treated with said metal aluminum salt.

11. The process of claim 10 , wherein content of metal aluminum salt in treatment with said metal aluminum salt is 0.3 to 40% by weight calculated as aluminum oxide.

12. The process of claim 10 , wherein said regenerated collagen fiber is treated with an oxidant for pre-treatment.

13. The process of claim 12 , wherein said oxidant is hydrogen peroxide.