초록 ▼

A container obtained by biaxially stretch-blow-molding a resin. Except the mouth-and-neck portion, vicinities thereof and the center of the bottom portion, the container as a whole is reduced in thickness under a highly drawing condition without accompanied by whitening, and a portion constituting t

A container obtained by biaxially stretch-blow-molding a resin. Except the mouth-and-neck portion, vicinities thereof and the center of the bottom portion, the container as a whole is reduced in thickness under a highly drawing condition without accompanied by whitening, and a portion constituting the bottom valley portions has an yielding load of not smaller than 25 kg/cm at 70.degree. C. The container exhibits excellent heat resistance, pressure resistance, shock resistance as well as self-standing ability.

대표청구항 ▼

[ What is claimed is:] [1.] A method of producing a heat resistant and pressure resistant self-standing container in which the bottom portion includes a plurality of foot portions and valley portions, said valley portions forming part of a substantially semispherical surface, by blow-molding a cylin

[ What is claimed is:] [1.] A method of producing a heat resistant and pressure resistant self-standing container in which the bottom portion includes a plurality of foot portions and valley portions, said valley portions forming part of a substantially semispherical surface, by blow-molding a cylindrical preform with bottom that is heated at a drawing temperature, said method comprising:a step for subjecting a preform to a biaxial stretch-blow-molding in a metal mold to obtain a secondary article in which a portion that should serve as the bottom portion of the final container has a surface area larger than the surface area of said semispherical surface, said secondary article further having a dome-shaped bottom portion of which thickness is reduced to not larger than 1 mm by the biaxial stretch-blow-molding except the center of the bottom portion and of which degree of crystallinity is not smaller than 20% except the center of the bottom portion;a step of exposing the bottom portion of said secondary article and part of the barrel portion continuous to the bottom portion to infrared-ray radiation and heat-shrinking the exposed portions in order to obtain a tertiary article in which the portion should serve as the bottom portion of the final container has a size that can be accommodated in said semispherical surface, and has a shape close to that of the semispherical surface; anda step for secondarily blow-molding said tertiary article in a heated state in a metal mold in order to obtain the final container.