SHOESTRING COMPOSED OF BIODEGRADABLE FIBER

摘要

PROBLEM TO BE SOLVED: To obtain a biodegradable shoestring by using a fiber in which the number of treatment days for a specified strength reduction rate is specified under the atmosphere of specified temperature and humidity. SOLUTION: This shoestring constituting fiber is composed of a biodegradable polymer and has the number of treatment days for 50% strength reduction under the atmosphere of 60 deg.C temperature and 80% humidity in the range 10 to 30 days. As polymers having this biodegradability, thermoplastic aliphatic polyesters are preferable from the viewpoints of fiber physical properties and biodegradability, e.g. a poly(α-hydroxy acid) such as polyglycolic acid and polylactic acid or a copolymer which has these as a main repeating unit element can be raised. The fiber form may be a sole aliphatic polyester or a composite fiber using two or more aliphatic polyester. This shoestring decomposes and does not contaminate soil in landfill for the biodegradability without air pollution nor environmental destruction in waste treatment by combustion or reclamation after shoe use.