| 摘要 |
<p>PURPOSE:To decompose a biodegradable resin together with a base of a card and make this card excellent in strength and durability in ordinary use by a method wherein the biodegradable resin layer shown by a specific formula of a specific numberaverage molecular weight is laminated on one or both surfaces of the base constituted of naturally degradable materials. CONSTITUTION:A card 1 is formed by a method wherein a biodegradable resin layer 3 shown by a formula of a number-average molecular weight of 10000 to 100000 is laminated on one or both surfaces, on both surfaces in this case, of a paper base 2 constituted of naturally degradable materials such as paper. In this formula, (m) denotes a degree of polymerization required for the number- average molecular weight of the formula to be 10000 to 100000, M a number of 0 or 1 or above, R1 and R2 an alkylene group, a cyclo cyclic group or a cycloalkylene group of 2-10C and R3 a residual group of dior poly-isocyanate. By making the naturally degradable materials having degradability, paper in particular, be the paper base 2 of the card and by using the bio-degradable resin layer 3 as an outer layer in this way, the durability of the whole at the card is improved and the card is degraded naturally even when it is left as it is after disposal as waste.</p> |
