TRANSPARENT STRETCHED FILMS OF BIODEGRADABLE RESINS IMPROVED IN GAS BARRIER PROPERTIES AND RESIN ARTICLES

摘要

A biodegradable resin stretched film made of a composition (C) comprising a polylactic acid resin (A) which comprises at least 50 wt% of lactic acid units and an aliphatic polyester (B) which comprises units derived from an aliphatic dicarboxylic acid having 2 to 6 carbon atoms and units derived from an aliphatic glycol having 2 or 3 carbon atoms in a sum total of 50 wt% or above and has a melting point (Tm) of 200˚C or below (as determined according to JIS-K7121), characterized by satisfying all of the following relationships: (1) OH = [(100 x OA x OB) / (OA x XB + OB x XA)] (2) OC < OH (wherein XA and XB are respectively the proportions (wt %) of the components (A) and (B) as calculated by taking the total weight of the components (A) and (B) as 100; OA, OB, and OC are the oxygen permeabilities (found) of the components (A) and (B) and the composition (C) respectively; and OH is the calculated harmonic average of OA and OB (in terms of (cc x mum)/m<2>.day.atm) as determined according to ASTM D3985 in the atmosphere of 23˚C and relative humidity of 65%). The film is excellent in gas barrier properties and heat-sealing strength and favorable for biodegradable resin articles such as wrapping film, bags, gas transmission controlling material, ostomy bags, cushioning air bags, and so on.