The plastic tube - production and properties

Tubes are manufactured from a range of materials, each with specific properties, advantages and limitations. Choosing a suitable tube material depends primarily on the intended application, the characteristics of the filling product and the required barrier properties. The available material options allow tube constructions to be adapted to different product and packaging requirements.

Of the 15.5 billion tubes produced by European tube manufacturers in 2018, 38% were made of laminate, 35% of aluminum and 27% of plastic. Especially in the field of packaging for organic products and natural cosmetics, there are tubes made of alternative materials.

These are made of wood fibers, bamboo or cardboard. Their share of the total volume is far below one percent.

All important tube types at a glance:

• Plastic tubes
• Laminate tubes
• Aluminum tubes

THE PLASTIC TUBES

This type of tube includes monolayer tubes, seamless coextruded tubes and laminate tubes.

Markets: Plastics are increasingly replacing aluminum in tube production.The production of aluminium and plastic tube materials involves different manufacturing processes and energy requirements. The manufacturing costs of the finished tubes depend on factors such as material selection, production volume, tube dimensions and the chosen production process. The tube bodies of plastic tubes are mainly made of polyethylene (PE) and polypropylene (PP), and the closure is made of polypropylene.
All types of plastic tubes are ideal fillable tube packaging for fast moving consumer goods (FMCG). FMCGs are consumer goods that consumers buy frequently and usually need on a daily basis. FMCGs turn over quickly at retail.

These include food, cleaning products, detergents, hygiene and personal care products. Consumers buy these items spontaneously and routinely without a long decision-making phase.

Barrier: Tubes made of plastic have different barrier properties. The range extends from high-barrier properties to lower barrier behavior. Not all of them require high barrier properties, since the filling materials they contain are often subject to rapid consumption or there are few mass transfers.

Convenience: Plastic tubes allow simple, economical and hygienically clean dispensing. The fillable plastic tube springs back elastically after removal; there is a slight reabsorption of filling material or air during dispensing. Depending on the thickness of the material and the closure, this effect can be reduced. The plastic tube can have different closure variants.

Sustainability: Tube manufacturers see the issue of sustainability as an important driver and influencing factor for the development of packaging. The recyclability of plastic tubes depends on their complete material structure, including the tube body, shoulder, closure and any barrier layers. Certain mono-material tube constructions may be suitable for established plastic recycling processes, subject to the relevant sorting and recycling requirements. In Germany, empty plastic packaging, including suitable plastic tubes, is generally collected through the yellow bin or yellow bag system. The correct disposal route depends on the packaging composition and the applicable local collection rules. Waste management companies take the plastic waste to sorting plants. At sorting facilities, collected plastic packaging is separated into different material streams using suitable sorting technologies. Whether an empty PE or PP tube is subsequently recycled depends on its complete construction, sorting characteristics and the availability of an appropriate recycling process.
The discussion about the increasing pollution of the oceans by plastics and plastic waste has resulted in numerous brand manufacturers and retail chains entering into far-reaching voluntary commitments. According to these, only recyclable or reusable packaging is to be used from 2025. Labelprint24 offers different tube packaging options for a range of applications. When selecting a tube, customers should consider the material structure, required barrier properties and compatibility with the intended filling product. Any claim concerning the recyclability of a specific PP tube must be supported by an assessment of the complete tube construction and the relevant recycling system.

Attractiveness: Consumers buy an attractively packaged product that appeals to them both visually and haptically. The printed plastic tube is a real eye-catcher at the point of sale and offers high differentiation from competitor products. This is an important feature both for the brand owner, who wants his product to stand out from the competition, and for the consumer, who has to make a purchase decision at the supermarket shelf.

The most important advantages at a glance:

• favorable manufacturing costs
• graduated barrier properties
• wide range of materials
• ideal packaging for FMCGs
• simple, economical and hygienically clean dosing
• Recycling suitability depends on the specific tube construction and the available recycling system.
• good printability

PRODUCTION OF PLASTIC TUBES

Plastic tubes are produced by tube manufacturers using the extrusion process or the coextrusion process. During extrusion, plastic granulate (the extrudate) is melted and homogenized in an extruder by friction and heat input.

After the plastic exits the die on the extruder, it solidifies by means of water cooling. The application of a vacuum causes the profile to adhere to the outer wall of the calibration, and the molding process is complete.

If two or more materials of the same or different types are brought together before leaving the profile die, this is called coextrusion. In the course of extrusion or coextrusion, tubes can be produced in almost any length.

The "endless" plastic tube is then cut to tube length by rotary knives. The tube shoulder with the tube thread is formed, the resulting tube body is printed with the motif, possibly with additional finishing, and the tube cap is attached.