Patent ID: 11919216
Assignee: TOYOBO CO., LTD.
Field: Other special machines (Mechanical engineering)
Classification: CPC B  C | IPC B  C

Claim 3:
4. The roll of the white heat-shrinkable polyester-based film according to claim 1, wherein
the heat shrinkage stress in the main shrinkage direction of the film is 9 MPa or less, wherein the heat shrinkage stress is measured according to a hot air treatment of a treatment temperature of 90° C.;
the difference between the maximum and minimum heat shrinkage stress in the main shrinkage direction among samples is 1 MPa or less, wherein the heat shrinkage stress is measured according to the hot air treatment of a treatment temperature of 90° C. and the samples are taken from each part of the film divided into five in the film width direction; and
the difference between the maximum and minimum heat shrinkage stress in the main shrinkage direction among samples is 1 MPa or less, wherein the heat shrinkage stress is measured according to the hot air treatment of a treatment temperature of 90° C. and the samples are taken from the film every 100 m in the film longitudinal direction from the place forming surface layer of the roll of the white heat-shrinkable polyester-based film to the starting place of winding the film.