| 摘要 |
PURPOSE:To obtain a shrinkable film, prominent in a resistance to heat, transparency and mechanical property upon bonding the film by employing specified copolymer of ethylene-propylene. CONSTITUTION:A sheet is formed by a composition consisting of 100 weight parts of the copolymer of polyprophlene, containing 2-10wt% of ethylene, and 0-50 weight parts of the monomer of polypropylene. The sheet is oriented into one direction after preheating the sheet to a temperature lower than the melting point of the copolymer of polypropylene. The shrinkage factor in the direction of the orientation of the film after dipping into an oil bath having the temperature of 150 deg.C for one minute is 40-85% while in the shrinkage factor in a direction, orthogonal to the direction of orientation, is 15% or less. In case the content of ethylene is up to 2wt%, the temper ature width of the shrinkage of the oriented film is narrow and it is hard to make the whole periphery of a coated bottle beautiful when hot air is blown against the film. In case it exceeds 10wt%, the rigidity of the film is deteriorated and loss is generated frequently when the film is bonded onto a glass bottle or the resistance to heat of the film is deteriorated. n case the content of polypropylene exceeds 50 weight parts, the temperature width of the shrinkage of the oriented film becomes narrow and product loss due to poor appearance upon bonding it onto the glass bottle is generated frequently. |
