| 摘要 |
PROBLEM TO BE SOLVED: To obtain a mulching sheet having excellent light-shielding property an air-permeability and exhibiting biodegradability to enable easy disposal by forming a sheet composed of a specific polylactate-based mass-colored filament. SOLUTION: The objective biodegradable mass-colored filament mulching sheet has a single fiber fineness of <=15 de, an areal density of the sheet of 10-50 g/m2, a translucency of >=20%, an air-permeability of 100-800 cc/cm2/sec and a strength retention [(S1/S0)×100(%) (S1 is a tensile product of specimen irradiated for 300 hr; S0 is a tensile product of specimen before irradiation)] of >=50% determined by weather resistance test using a weather meter. The sheet can be produced from a poly(D-lactic acid), poly(L-lactic acid), a copolymer of D-lactic acid and L-lactic acid, a copolymer of D-lactic acid and a hydroxycarboxylic acid, a copolymer of L-lactic acid and a hydroxycarboxylic acid or their blended product by adding a crystal nucleation agent such as talc and a pigment such as carbon black to the polymer and forming a sheet by spun-bonding method.
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