Polar solvent solution and production method thereof

Abstract

A polar solvent solution of the present invention is a polar solvent solution in which a solute containing a polyamino acid is dissolved in a polar solvent. The solution has a moisture content of less than 5 mass % based on 100 mass % of the solution. A method for producing a polar solvent solution of the present invention includes changing a moisture content of the solution to adjust the viscosity of the solution. Further, another method for producing a polar solvent solution includes reducing a moisture content of the solution to increase the viscosity of the solution. Thus, the present invention provides a polar solvent solution that enables stable spinning and casting without lowering its viscosity when used as dopes for spinning, film, etc., and methods for producing the same.

1 . A polar solvent solution in which a solute containing a polyamino acid is dissolved in a polar solvent,
 wherein the solution has a moisture content of less than 5% by mass based on 100% by mass of the solution.   
     
     
         2 . The polar solvent solution according to  claim 1 , wherein the polyamino acid is a polypeptide. 
     
     
         3 . The polar solvent solution according to  claim 1 , wherein the polar solvent contains at least one selected from the group consisting of dimethylsulfoxide (DMSO), N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMA), and N-methyl-2-pyrrolidone (NMP). 
     
     
         4 . The polar solvent solution according to  claim 2 , wherein the polypeptide is a structural protein. 
     
     
         5 . The polar solvent solution according to  claim 4 , wherein the structural protein includes a crystal region. 
     
     
         6 . The polar solvent solution according to  claim 2 , wherein the polypeptide is a spider silk protein. 
     
     
         7 . A method for producing a polar solvent solution in which a solute containing a polyamino acid is dissolved in a polar solvent, comprising:
 changing a moisture content of the solution to adjust a viscosity of the solution.   
     
     
         8 . A method for producing a polar solvent solution in which a solute containing a polyamino acid is dissolved in a polar solvent, comprising:
 reducing a moisture content of the solution to increase a viscosity of the solution.   
     
     
         9 . The method for producing a polar solvent solution according to  claim 7 , wherein the polyamino acid is a polypeptide. 
     
     
         10 . The method for producing a polar solvent solution according to  claim 7 , wherein the solution has a moisture content of less than 5% by mass based on 100% by mass of the solution. 
     
     
         11 . The method for producing a polar solvent solution according to  claim 7 , wherein the polar solvent contains at least one selected from the group consisting of dimethylsulfoxide (DMSO), N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMA), and N-methyl-2-pyrrolidone (NMP). 
     
     
         12 - 14 . (canceled) 
     
     
         15 . The method for producing a polar solvent solution according to  claim 7 , wherein the moisture content of the solution is changed by drying the solute containing the polyamino acid and thereafter dissolving it in the polar solvent. 
     
     
         16 . The method for producing a polar solvent solution according to  claim 7 , wherein the moisture content of the solution is changed by adjusting a relative humidity of an atmosphere in the production and/or storage of the solution. 
     
     
         17 . The method for producing a polar solvent solution according to  claim 16 , wherein the relative humidity of the atmosphere in the production and/or storage of the solution is adjusted to 1.3% RH or less. 
     
     
         18 . The method for producing a polar solvent solution according to  claim 8 , wherein the polyamino acid is a polypeptide. 
     
     
         19 . The method for producing a polar solvent solution according to  claim 8 , wherein the solution has a moisture content of less than 5% by mass based on 100% by mass of the solution. 
     
     
         20 . The method for producing a polar solvent solution according to  claim 8 , wherein the polar solvent contains at least one selected from the group consisting of dimethylsulfoxide (DMSO), N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMA), and N-methyl-2-pyrrolidone (NMP). 
     
     
         21 . The method for producing a polar solvent solution according to  claim 8 , wherein the moisture content of the solution is changed by drying the solute containing the polyamino acid and thereafter dissolving it in the polar solvent. 
     
     
         22 . The method for producing a polar solvent solution according to  claim 8 , wherein the moisture content of the solution is changed by adjusting a relative humidity of an atmosphere in the production and/or storage of the solution. 
     
     
         23 . The method for producing a polar solvent solution according to  claim 22 , wherein the relative humidity of the atmosphere in the production and/or storage of the solution is adjusted to 1.3% RH or less.