| 摘要 |
PURPOSE:To enhance bending pinhole resistance, waterproof properties and mildew properties without damaging bending holdability by using a polyethylene crosslinked stretched film whose crosslinking degree is lowered toward the inside of the film in the thickness direction thereof as a base material and bonding a plurality of the base materials. CONSTITUTION:High density polyethylene is used to be molded into a raw sheet by a T-die extrusion sheet molding machine. This raw sheet is irradiated with electron beam to obtain a crosslinked raw sheet wherein the crosslinking degrees on both sides of the irradiated surface are respectively 50% in a gel ratio and the lowest crosslinking degree in the thickness direction of the film is 0% in a gel ratio. This crosslinked raw sheet is successively stretched 4 times in its longitudinal direction and 6 times in its lateral direction to obtain a stretched film (BOHD film). This BOHD film is used as a base material and an adhesive LDPE film, a WLDPE (white low density polyethylene) film and an LDPE film as a heat seal base material are successively laminated to the single surfaces of the base material and an LDPE film, an ION film as an adhesive, an Al foil as a gas barrier base material, the ION film and the LDPE film are successively laminated to the other surface thereof. |
