Inflation film and manufacturing method thereof

A method for manufacturing the inflation film for a tire inner liner, comprising a step of inflation a molten resin composition including:

• a polyamide-based resin;
• a copolymer containing a polyamide-based segment and a poly-ether-based segment;
• and an olefin-based polymer compound at a blow-up ratio (BUR) of 1.5 to 3,
• wherein the molten resin composition is inflated at a draw-down ratio (DDR) of 1 to 20,
• wherein the olefin-based polymer includes an olefin-based polymer or copolymer grafted with a dicarboxylic acid or an acid anhydride thereof,
• wherein the polyamide-based resin and copolymer containing polyamide-based segments and poly-ether-based segments are included in a base film formed from the molten resin composition at a weight ratio of 9:1 to 1:9, and
• the content of the polyether-based segments in the base film is 2% by weight to 40% by weight, and
• a ratio of a machine direction modulus of the base film to transverse direction modulus of the base film at 25% elongation after heat-treating the base film at 170° C. for 30 minutes, is from 0.8 to 1.2.