Heat contraction Characteristic poly lactic acid type film and its production manner

摘要

PROBLEM TO BE SOLVED: To produce a film which is decomposed in the natural environment and has excellent impact resistance and is thermally shrunk substantially in the uniaxial direction. ;SOLUTION: The heat-shrinkable polylactic acid-based film consists of a polylactic acid-based polymer and tensile elongation at break in both the longitudinal direction and the cross direction of the film is ≥30%. Furthermore, the heat shrinkage coefficient at 100°C is ≥30% in the either direction. The heat shrinkage coefficient in the direction orthogonal to the direction of shrinkage is ≤10%. The film is obtained by uniaxially stretching an unstretched sheet and thereafter preheating the unaxially stretched sheet at the temperature higher than the crystallization temperature thereof and successively performing the second stretching in the direction orthogonal to the above-memtioned uniaxial stretching direction.;COPYRIGHT: (C)1997,JPO