Tube (container)

Materials

The earliest collapsible tubes were made of tin, zinc, or lead, sometimes coated with wax on the inside.

Aluminum tube caps and closures are generally threaded, as is the nozzle. Aluminium tubes generally have the far end folded several times after the contents have been added. The tube is typically hermetically sealed and nearly germ-free due to the high temperatures during the production process. The inside of the tube can be coated to prevent the material from reacting with the contents. Aluminum tubes are produced by impact extrusion from a small round blank. Designs can be printed onto the tube, using the wet-in-wet offset printing method. Six tones are often used. The filled content can be squeezed out by finger pressure. The main characteristic of aluminium tubes is the total separation of the contents from the surrounding atmosphere; therefore, such tubes are especially suitable for the packaging of highly perishable contents. Aluminium tubes are used for cosmetics, pharmaceuticals, food, paint, and technical products.

Tubes can also be produced in plastic, most commonly polyethylene. Plastic tubes are used for cosmetics such as hand creams, and also some foodstuffs. The plastic tube retains its shape after each squeeze unlike laminate tubes such as toothpaste tubes. Plastic tubes can be highly decorated or have a special additive such as soft touch to make the tube more appealing during use or at the point of sale. Plastic tubes are produced by extrusion. A sleeve is first produced on a specialised extrusion machine. It must be produced to a very high standard (for decoration purposes) and also to tight tolerances, compatible with automated processes after extrusion. Once the sleeve is produced, the tube head is fitted using an automated heading machine. Tube printing using specialised printing machines such as silk screen printing applies the desired decoration. The open tubes are typically filled and sealed at a separate facility. Multi-layer plastic tubes have become increasingly popular; they isolate the contents better from the air, allowing them to be used for a wider range of products, such as food.

Applications

Many commodities are commonly sold in collapsible tubes:

• Toothpaste, formerly metal, now of plastic
• Viscous artists' paint, including oil paint, acrylic paint, and concentrated watercolor paints (which must be diluted with water); typically metal
• Pastes used in food, such as anchovy paste, tomato paste, mustard, mayonnaise
• Pharmaceutical ointments
• Adhesives, caulk, glue, and sealants (larger quantities may use rigid caulk cartridges)
• Other cosmetics and gels