| 摘要 |
PURPOSE:To provide a polyester container which is excellent in mechanical strength, undergoes little thermal contraction, and is suitable for use as a container of food, cosmetics, or the like by a method wherein polyethylene terephthalate is formed by blow-in expansion using a pressurized condensible fluid. CONSTITUTION:When a container made of polyethylene terephthalate having a specific viscosity above 0.55 is formed by blow-in expansion, a pressurized condensible fluid is used. The thus-obtained container is excellent in mechanical strength, undergoes little thermal contraction, and has good heat resistance. Steam, alcohol vapor, or the like is used as a pressurized condensible fluid. It is preferable to use a fluid which has been heated to a temperature at least above the glass transition point of polyethylene terephthalate, has a pressure above the atmospheric pressure, and has a latent heat of condensation above 50Kcal/gmol. When steam is used, preferable conditions are 110-200 deg.C and 0.5-15kg/cm<2>G, particularly 130-180 deg.C and 2-9kg/cm<2>G. |
