Sidel Skyward and Curvy hot-fillable PET bottles

At less than 19 g for 0.5 L, Sidel’s hot-fillable PET bottles, the Skyward and Curvy, are claimed to beat the world record for lightweighting.

Skyward features a long silhouette with cylindrical and square shapes, an elegant belt and four panels. Curvy has curves, spirals and a twisted back that serves as a support beam, without panels. The two small 0.5 L bottles weigh only 18.9 g and their design is a breakthrough for the shape of hot-fill bottles, which traditionally have six or eight panels and often look exactly like each other.

Bottle lightweighting has been made possible by redesign of the neck, body and base. The 28 mm amorphous (non-crystallised) neck has been made lighter and accepts a standard cap for carbonated soft drinks. The base has also been revised, making it stiffer while also using fewer raw materials. The geometric structure of the bottle body compensates for deformations due to vacuum absorption after cooling.

The Skyward bottle has a square section over a cylindrical one, an antiovalisation waist and a rigid label area at the base. The rigidity of the Curvy bottle is obtained by an antiovalisation waist in the top third of the body, the heel and the base, the twisted shape that acts as support beams and the succession of curves that absorb the vacuum while also making the bottle easier to grasp.

Good material distribution is ensured by optimisation of the bi-orientation rates and preform thickness ratios, which are suited to the bottle shape.

In addition, the fast blow moulding speed of 1800 bottles/hour/mould with a standard HR process has been obtained due to heating optimisation with the SBO Universal range. Its benefits in terms of process include: improved blow-moulding rates, optimised cycle times, greater induced crystallinity due to the stretching rate, 100% heating regulation inside the inner walls ensuring perfect spherolitic crystallinity of the bottle, which at this speed remains in the oven for a shorter time.

Sidel’s bell nozzle also enables the blowing of lighter, amorphous necks without deforming them (isobaric pressure around the neck). Finally, the good heat conduction of F300 aluminium moulds helps produce bottles at this high output.