Disclosed is a container sealing body applied to seal an inlet of a container, the container sealing body including: an upper layer; a lower layer provided below the upper layer; and a thermal bonding resin layer configured between the upper layer and the lower layer and thermally bonded by thermal bonding resin, in which the upper layer includes: a surface layer provided for printing and configured to prevent thermal bonding; and a synthetic resin layer having tensile strength and hardness and configured sequentially with the surface layer from above to below, an opening tab is configured by cutting and punching the upper layer, an opening initiation guide cutting line is formed at one side of the opening tab, the lower layer includes a blocking layer for preventing transmission of oxygen or moisture, and a thermal bonding sealing layer, and the synthetic resin layer of the upper layer and the blocking layer of the lower layer are bonded.

A fitment for a bag includes an integrally formed spike port, the spike port including an aperture, a puncture barrier film and an internal gasket. The fitment can be a fluoropolymer. The puncture barrier can be a fluoropolymer film. The internal gasket is positioned within the aperture and provides an additional puncture barrier to the spike port. The fitment can be incorporated into a bag by joining two sheets such as fluoropolymer sheets to one another and to the fitment around a perimeter of the sheets. The bag can be used in processes including exposure to or holding at cryogenic temperatures.