| abstract |
A thermo-shrinkable polystyrene film, conformed in an elongated shape with a constant width made from a polystyrene resin, with its main direction of retraction in the longitudinal direction, the following requirements 1) to 4) satisfying the thermo-shrinkable polystyrene film: 1 ) the heat shrinkage index in hot water in the longitudinal direction is 25% or higher and 80% or less, when the film is treated in hot water at 90 ° C for 10 seconds; 2) the heat shrinkage index in hot water in the transverse direction, which is orthogonal to the longitudinal direction, is -5% or higher and 10% or less, when the film is treated in hot water at 90 ° C for 10 seconds; 3) the tear resistance at right angles in the transverse direction per unit thickness, after the film retracts 10% in the longitudinal direction in hot water at 80 ° C is 50 N / mm or greater and 200 N / mm or less; and 4) each of the breaking energies in the longitudinal direction and in the transverse direction is 1,000 MPao% or 20 higher and 10,000 MPao% or lower, when the film is maintained at 30 ° C for 2 weeks or more, and then a tensile test is performed at 23 ° C. |