Polylactic acid film or sheet, and pressure-sensitive adhesive tape or sheet

A polylactic acid film or sheet comprising polylactic acid (A) and a reforming agent (E),

• wherein the polylactic acid film or sheet comprises polyglycerol fatty acid ester and/or polyglycerol condensed hydroxy fatty acid ester (a) as the reforming agent (E) such that the weight ratio of the polylactic acid (A) to the polyglycerol fatty acid ester and/or polyglycerol condensed hydroxy fatty acid ester (a), (A):total amount of (a), is 99:1 to 80:20,
• wherein a melt flow rate of the polylactic acid (A) at 190° C. and a load of 21.2 N is 0.1 to 50 g/10 min,
• wherein a tear strength, according to JIS K7128-3:
• Plastics—Film and Sheeting—Determination of Tear Resistance, Part 3:
• Right angled tear method, is not less than 136 N/mm when the film or sheet is torn in a flow direction (machine direction:
• MD),
• the film or sheet stored under an atmosphere at 100° C. for 1 minute has a rate of dimensional change due to heating of not more than ±3% in the flow direction (MD) and a transverse direction (TD), the rate of dimensional change due to heating being determined by Expression (1):
• rate of dimensional change due to heating (%) =(L2−L1)/L1×100 (1)
• where L1 represents a gauge length before a first test, and L2 represents a gauge length after the first test, and
• the film or sheet stored under an atmosphere at 100° C. for 1 minute while a load of 300 g/mm2 is applied in the flow direction (MD) has a rate of dimensional change due to loaded heating of not more than ±3% in the flow direction (MD), the rate of dimensional change due to loaded heating being determined by Expression (2):
• rate of dimensional change due to loaded heating (%) =(L4−L3)/L3×100 (2)
• where L3 represents a gauge length before a second test, and L4 represents a gauge length after the second test.