To prevent a packaging container from exploding and breaking even when a pressure which cannot be allowed is generated in the internal space of the packaging container, and prevent various kinds of bacteria and bugs or the like from entering the packaging container from the outside by a method wherein an adhesive layer is provided on the rear surface of an anti-stress relaxing sheet, and at the same time, a slit is provided on the anti-stress relaxing sheet.
For this pressure regulating body 1, on the rear surface of an anti-stress relaxing sheet 3 where a slit 2 is formed, an adhesive layer 4 is provided. The pressure regulating body 1 is used by affixing it on a ventilation port 11 which is formed on a packaging container 10 in a manner to cover the ventilation port 11 with the adhesive layer 4. The anti-stress relaxing sheet 3 which is used for the pressure regulating body 1 is constituted of a material equipped with an anti-stress relaxing property by which the slit 2 formed on the sheet 3 is normally closed, and the slit 2 is opened when a pressure exceeding an allowable value is applied from the inside of the packaging container 10, and the slit 2 returns to the original closed state when the pressure returns to the allowable value or less. The anti-stress relaxing property is preferable to be 40% of the tensile stress relaxing rate Rr (24 hours) to 100% of Rr (24 hours).
KATO KAZUYA
TAKANO AKIHIKO
