Process for producing chitin derivatives and/or chitosan derivatives having a crosslinked structure

Abstract

A process for producing a chitin derivative and/or a chitosan derivative that have a crosslinked structure, which comprises irradiating a paste of a mixture consisting of 100 parts by weight of a chitin derivative and/or a chitosan derivative and 3˜1,000 parts by weight of purified water.

What is claimed is:  
     
         1 . A process for producing a chitin derivative and/or a chitosan derivative that have a crosslinked structure, which comprises irradiating a paste of a mixture consisting of 100 parts by weight of a chitin derivative and/or a chitosan derivative and 3˜1,000 parts by weight of purified water.  
     
     
         2 . The process according to  claim 1 , wherein the chitin derivative and/or chitosan derivative as the starting material is carboxyalkyl-chitin, carboxyalkyl-chitosan, hydroxyalkyl-chitin, hydroxyalkyl-chitosan, alkyl-chitin, alkyl-chitosan or a mixture that have at least one hydroxy or carboxyl group per gulcose unit.  
     
     
         3 . The process according to  claim 1 , wherein a total of at least 20 hydroxyl groups and carboxyl groups in the chitin derivative and/or chitosan derivative as the starting material form an alkali metal salt, an ammonium salt or an amine salt.  
     
     
         4 . The process according to  claim 1 , wherein the chitin derivative and/or chitosan derivative have an average degree of substitution of at least 0.01.  
     
     
         5 . The process according to  claim 1 , wherein the viscosity of the paste of mixture increases to a value above 1.0 upon irradiation, with 1.0 being assumed as the value before irradiation.  
     
     
         6 . The process according to  claim 1 , wherein the irradiation is by exposure to an ionizing radiation to a dose of at least 0.5 kGy.  
     
     
         7 . The process according to  claim 1 , wherein the chitin derivative and/or chitosan derivative having a crosslinked structure has absorbed purified water in a volume at least 5 times as much as its own weight.  
     
     
         8 . The process according to  claim 1 , wherein a hydrogel and a dried film of the chitosan derivative having a crosslinked structure has antimicrobial activity.