| 摘要 |
PROBLEM TO BE SOLVED: To provide a polyester type heat-shrinkable film having good heat-shrinking properties and excellent heat resistance, giving a good shrinking finish and combining excellent breaking resistance and good flexibility. SOLUTION: The film shows an elongation (A) after fracture of≥400% for all specimens when two or more specimens are subjected to a tensile test in directions orthogonal to the principal shrinking direction of the specimens under specified conditions. When cooled after immersion in warm water, the film shows a shrinkage rate in the principal shrinking direction of 30-70%. The sum of the tensile elastic modulus in the principal shrinking direction and that in a direction orthogonal to the principal shrinking direction is 6,500 MPa or smaller. After two-week storage in an atmosphere of 35°C and a relative humidity of 50%, at least 80% of all the stored specimens show an elongation (B) after fracture of at least 90% of the average of the elongations (A) after fracture, where the elongations (B) after fracture are measured by subjecting two or more specimens to a tensile test under the same conditions. COPYRIGHT: (C)2005,JPO&NCIPI |
