Patent ID: 6702978
Filing Date: 2004-03-09
Classification: B29C,B29K,B29L,Y10T

Abstract:
A method for producing fillable plastic tube bodies, comprising the following steps:(a) producing a tube body preform which has a closure region, a lateral surface region and a closed end region; (b) heating the tube body preform; (c) biaxially expanding the tube body preform in order to bring the tube body preform to its final shape and size; and (d) cutting open the closed end region of the tube body to form an open end for filling of the tube body; wherein step (a) includes: (1) filling at least first and second feeding containers respectively with a first thermoplastic material and a second thermoplastic material; (2) plasticizing the first and second thermoplastic materials in the respective feeding containers; and (3) injecting the first and second thermoplastic materials through an annular nozzle and into a mold cavity of an injection mold at a portion of the mold that forms the closure region to form adjacent layers of a tube body preform, the mold cavity corresponding to the shape of the closure region, lateral surface region and closed end region of the tube preform, the nozzle having radially inner and outer concentrically arranged annular nozzle gaps which are arranged in a common plane for effecting simultaneously injection of the first and second materials, the nozzle at the annular gaps contacting the portion of the mold that forms the closure region, and the delivery rate being essentially the same in terms of direction and magnitude for the first and second materials, with the result that the homogeneity of the first and second materials is maintained after the first and second materials leave the annular nozzle and also within the mold cavity.