PREFORM FOR CONTAINER MADE OF PLASTIC MATERIAL

摘要

The part under the neck ring (9) of a preform for blowing a PET bottle of predetermined capacity not larger than 75 cl and with a max. material weight of 15 g, is inclined by an angle α less accentuated than normal, max. 17°, which allows to make a preform with a thickness t2 of the wall thinner than 1.9 mm and a thinner inner diameter of the preform body in order to allow a lower stretch ratio starting from a larger preform to obtain the final bottle of predetermined capacity.

主权项

1. A preform made of plastic material for producing a PET bottle having a volume smaller than 1 L and weighing less than 16 g by means of a stretching-blowing operation, said preform defining a longitudinal axis (X) and provided at a first end thereof with a cylindrical neck (3) and defining the following parts in sequence:
a threaded end portion (8) for screwing a cap, a neck ring (9), under said threaded end portion (8), a first cylindrical connection segment (10) having a first predetermined outer diameter and a wall having a first thickness (t1) substantially equal to the thickness of the bottle in the same zone, a preform body, intended to be heated before the blowing operation, defining in turn the following parts: a second connection segment (5) with outer wall (21) tapered by a first angle (α) with respect to the longitudinal axis (X) and with inner wall (22) tapered by a second angle (β) with respect to the longitudinal axis (X), and having a predetermined length (H3) on the longitudinal axis (X), a cylindrical segment (4) having a second outer diameter smaller than said first outer diameter and a second thickness (t2) greater than the first thickness (t1), a bottom (6) which closes a second end of the preform (2), wherein the first angle (α) is from 6° to 10°,characterized in that
the second thickness (t2) is from 1.4 to 1.7 mm, the second angle (β) is from 9 to 13°, the length (H3) is from 14 to 18.5 mm.