FILM MAKING METHOD OF CHITOSAN-CELLULOSE-BASED FILM

摘要

PURPOSE:To continuously make high strength biodegradable chitosan-cellulose- based film by a method wherein the temperature of a flow casting face and the water content of film at peeling off are prescribed at the film making performed by flow casting with cellulose dispersed in the acid solution of chitosan. CONSTITUTION:The preferable degree of deacetylation of the chitosan used is 60-95mol.% from the view point of solubility and biodegradability. The proper cellulose is powdered cellulose prepared by grinding pulp. The proper composition ratio is 10-50 pts.wt. of chitosan to 100 pts.wt. of cellulose. Further, the addition of starch polyhydric alcohol and various additives is allowed. The proper acid used is acetic acid. The face of a chromium-plated drum, the face of a stainless steel endless belt or the like is employed as the metal flow casting face due to acidic stock liquid. Continuous flow casting is performed under the condition that the temperature of the metal flow casting face is held at 75-100 deg.C. The strength of film becomes very high when its drying is performed at 75 deg.C or higher, especially at 85 deg.C or higher. Furthermore, when the water content at the peeling off of the film is 3-10wt.%, the peeling of the film off the metal face becomes extremely easy.