SEALING SHEET

摘要

The present invention provides a sealing sheet mainly composed of an adhesive sheet composed of a core film having a water vapor transmission rate of less than 7.5 g/100 sq. in 24 hr as measured by a method according to JIS Z 0208, and a Relaxation rate of not less than 10% as measured by the following bending-stress relaxation rate measurement test, and an adhesive layer formed on both surfaces of the core film:
[bending-stress relaxation rate measurement test](1) a core film is cut into a tape (width 20 mm, length 100 mm), the tape is rolled to form a loop with one surface thereof being inside, one end (10 mm) of the rolled tape is laid on top of the other and fixed with an adhesive tape to give a loop sample,(2) the loop sample is put on a balance, and pressed with a flat plate surface of the jig such that the distance between the flat plate surface and the balance is 20 mm to deflect the loop sample, and(3) from the start of pressing, the weight of the loop sample is measured by the balance, a ratio of the weight of the loop sample at 60 seconds from the start of pressing to the weight of the loop sample at 0 second therefrom is calculated based on the following calculation formula, and the obtained rate is taken as the relaxation rate.;relaxation rate (%)=(1−(F60−W)/(F0−W))×100F0: weight at 0 second from the start of pressingF60: weight at 60 seconds from the start of pressingW: sample weight

主权项

1. A sealing sheet mainly composed of an adhesive sheet comprising a core film having a water vapor transmission rate of less than 7.5 g/100 sq. in 24 hr as measured by a method according to JIS Z 0208, and a Relaxation rate of not less than 10% as measured by the following bending-stress relaxation rate measurement test, and an adhesive layer formed on both surfaces of the core film:
[bending-stress relaxation rate measurement test] (1) a core film is cut into a tape (width 20 mm, length 100 mm), the tape is rolled to form a loop with one surface thereof being inside, one end (10 mm) of the rolled tape is laid on top of the other and fixed with an adhesive tape to give a loop sample, (2) the loop sample is put on a balance, and pressed with a flat plate surface of the jig such that the distance between the flat plate surface and the balance is 20 mm to deflect the loop sample, and (3) from the start of pressing, the weight of the loop sample is measured by the balance, a ratio of the weight of the loop sample at 60 seconds from the start of pressing to the weight of the loop sample at 0 second therefrom is calculated based on the following calculation formula, and the obtained rate is taken as the relaxation rate.
relaxation rate (%)=(1−(F60−W)/(F0−W))×100 F0: weight at 0 second from the start of pressing F50: weight at 60 seconds from the start of pressing W: sample weight