| 摘要 |
The Specification describes a process for producing transversely stretched hollow strips of thermoplastic synthetic resin having a noncircular cross-section which comprises passing a hollow strip of a thermoplastic synthetic resin in the thermoplastic state, said strip having a non-circular cross-section, through a stretching chamber, the transverse cross-sectional area of which increases, in the direction of travel of the said strip, to a size corresponding to the desired degree of transverse stretching of the strip, the hollow strip containing an inert gas under a pressure serving to press the strip against the walls of the said chamber whereby the strip is transversely stretched according to the cross-sectional area of the chamber; the stretched strip being subsequently cooled to a temperature below the softening temperature of the said resin. |
