To prevent the ingress of gas. Well in dry conditions, but susceptible to moisture. When the humidity increases making the prevention of gas permeability decreases rapidly.
To prevent the penetration out of gas. Very well in dry conditions But sensitivity to moisture When humidity increases thus preventing the penetration of gas fell sharply.
Prevention of gas permeability in and out very well in dry conditions, but the sensitivity to moisture. When the humidity is increased rapidly, gas permeation prevention