Study on Characteristics of Paper Laminated with Biodegradable Plastics, 1.Burial Test in Soil 

Paperboards laminated with biodegradable, plastics were buried in soil for six months to evaluate the biodegradability. The degradation rate of biodegradable plastics was slower than that of our expectations. These results are partly similar to those previously obtained. It is considered that a longer period than one year is required for the observation of significant change such as a disappearance of materials when a temperature and humidity are not controlled. The concerted effect of composite consisting of paper and biodegradable plastic was not found on the biodegradation in the present work. Their degradation might independently take place. The rate of biodegradation decreased in the following order; simple paperboard＞paper coated with biodegradable plastic＞ paperboard laminated with biodegradable plastic＞ simple biodegradable plastic＞plastic made from fossil fuel. It was suggested that the biodegradation might be promoted by the design of complexity