| 摘要 |
PROBLEM TO BE SOLVED: To obtain the subject foamed material free from unpleasant acetic acid-odor and having stable quality by using cellulose acetate as raw material, and combining specific properties of foamed material and specific conditions for the treatment of the foamed material. SOLUTION: This foamed material, which is obtained by using cellulose acetate as biodegradable raw material, has foamed material properties of 0.001-0.8 mm in foamed cell diameter and 0.01-0.12 g/cm<3> in apparent density regardless of the shape of foamed material, and has been treated with a weak alkaline solution (preferably, pH of 7.5-8.5), has a degree of oxidation of 45-60% and no acetic acid-odor. Further, the judgment of acetic acid-odor is performed according to the method in which 10 g of a sample of the foamed material is sealed in a 500 cc-closed container, it is left to stand for 24 at 20 deg.C, 40 deg.C or 60 deg.C under a relative humidity of 65%, and it is judged odorless if the acetic acid content in the air in the container after the standing is less than 3 ppm. Further, the weak alkaline-solution treatment is preferably carried out using 20-100 pts.wt. of the weak alkaline solution to the foamed material. |
