About Us Sota Packaging Composite Cans Manufaturing

Let's start with the basics; what is a composite can?

We're all familiar with composite materials in our daily lives..........many examples of which are incredibly sophisticated materials in highly technical and innovative products. Motor vehicles (carbon fibre) houses (timber, steel reinforced concrete and synthetic laminates) and clothing (combinations of synthetic fibres and/or natural fibres) are all everyday examples of composites.

"In composites, materials are combined in such a way as to enable us to make better use of their virtues while minimising to some extent the effects of their deficiencies." – Bryan Harris, Institute of Materials, London, UK.

SOTA composite cans similarly combine different materials to produce a set of outcomes (environmental, functional and aesthetic) which couldn't be achieved by any single material.

Composite Can definition

A composite can has a convolute wound, spiral wound or linear draw formed rigid body, involving several layers of materials, including recycled and virgin paper, foil and plastics in various combinations, with one or both end closures permanently affixed.

Convolute wound cans consist of a series of layers of differing materials wrapped laterally around a mandrel (which establishes the size and shape of the can in cross section). Spiral winding involves wrapping on the diagonal, whilst the linear draw method of body making consists of pulling (drawing) the component materials in the machine direction, through a set of tools, to shape the can body.

Spiral Wound Cans

Spiral Wound Cans are produced by the diagonal winding (around a cylinder produces a spiral) and gluing (laminating) of typically 4 layers of material. The innermost layer will be a liner (PE/Paper or Surlyn® / Foil / Paper). The middle two layers provide the structure of the can and usually comprise recycled natural board. The label can be applied spirally (difficult to control and requiring some limitations in the graphics) or applied as a separate (convolute) process.

Modern spiral winding machines provide high speeds compared to the investment required, however the label may have to be applied as a separate process, adding to the overall cost.

Linear Draw Cans

Linear Draw Cans are produced by drawing the materials through the gluing section and then through the tooling (can body making) process before the tube is cut into individual cans using a photoelectric sensor to "read" the label. The complete can is made in a single process, length changes are controlled by artwork and most importantly, the shape of the can is infinitely variable.

Composite Can Attributes

A composite can is a cost effective, hermetic (if required), rigid, light weight, environmentally responsible alternative to folding cartons, metal cans, glass jars, plastic containers and "bag in a box" packaging ... using mostly recycled paper! They can be used as either primary or secondary packaging.

As we've seen, a composite can is mainly composed of: - a can body; - a top closure; and - a bottom closure.

The can body is made from a series of (typically 3-4) plies with the flexibility to choose a range of materials and combinations. The specification best suited to any individual application will be based on the required specific outcome for customers in terms of light, moisture and oxygen barriers, aesthetic appeal, weight, strength and cost.