Choosing Between Aluminium and Tinplate Depends on Your Formula
The container of a spray is called an aerosol can, and the law calls it an aerosol dispenser. It is almost always metal: aluminium, made in a single seamless piece, or tinplate, tin-coated steel assembled from several parts. You choose it according to the formula, the brand image and the format; the law caps a metal container at 1,000 ml.
How to Recognise a Compliant Aerosol Can
In everyday speech it is a spray can or aerosol can, and in the industry an aerosol container. Directive 75/324/EEC calls it an aerosol dispenser and requires it to carry the inverted epsilon symbol, by which whoever places it on the market certifies that it meets the Directive.
A metal can has a body, a concave base that resists the pressure, and a dome with the opening where the valve is crimped. An aluminium can forms all of that in one piece; a tinplate can usually joins a welded body, the base and the dome.
When you receive samples, look on each can for the inverted epsilon, the batch code and the net contents by weight and by volume: Directive 75/324/EEC requires all three on every aerosol dispenser, and if one is missing the can is not ready to be sold.
Aluminium or Tinplate: Which Is Better?
Neither is better across the board; each suits a type of product. The decision depends above all on compatibility with the formula, because the metal and its internal lacquer must live with the product for years without corroding or altering it.
| Criterion | Aluminium | Tinplate |
|---|---|---|
| Construction | One piece, extruded, seamless | Several parts, welded body |
| Weight | Lighter | Heavier |
| Corrosion | More resistant | Needs a suitable internal lacquer |
| Decoration | High-quality direct printing | Lithography on the sheet |
| Common uses | Cosmetics and personal care | Household, automotive, industry |
| Recycling | Metal packaging collection | Metal packaging collection |
Water-based or aggressive formulas need an internal lacquer tested with that specific product, in either metal. That is why each combination of formula and container is validated with storage tests before the batch is made.
💡 Technical tip: do not choose the metal for its looks and then the formula; ask for the compatibility test with the internal lacquer first and decide on the finish afterwards.
Which Can Size Should You Choose?
Aerosol dispenser law applies to containers of 50 ml and above and caps the maximum capacity by material. Within those limits, each manufacturer works with the formats its lines can fill.
- Metal container
- up to 1,000 ml
- Protected or non-splintering glass
- up to 220 ml
- Unprotected glass
- up to 150 ml
- Aerosols outside the Directive
- under 50 ml
- Formats at Ilerspray
- aluminium 50 to 600 ml, tinplate 100 to 750 ml (net)
The combination of material and capacity is chosen with the formula and set in the technical proposal. To choose, start from the format your channel asks for: up to 600 ml you can pick aluminium or tinplate by formula and look; if you need 750 ml, only tinplate reaches that size, and below 100 ml only aluminium.
How to Check Your Formula Fits the Can
The container sets the pressure ceiling for the product. The Directive sets a test pressure for the empty container: at least 10 bar if it will be filled at less than 6.7 bar at 50 °C, and 50 % above the internal pressure at 50 °C if it is filled higher. On top of that, the pressure of a filled aerosol at 50 °C may not exceed 12 bar with a flammable liquefied gas.
This shapes the propellant and the dose: a formula with LPG, DME or CO₂ is adjusted so that, at 50 °C, it stays within the margin of the chosen container. The final test on every filled unit confirms it.
Ask for your formula's pressure at 50 °C with the chosen propellant and compare it with two figures: the container's test pressure and the legal ceiling for its type of gas. If there is no margin, change the mix or the container before approving the sample, not after.
The Label, the Cap and Recycling the Can
A can is decorated in one of two ways: lithographed, with the design printed directly on the metal, or with a self-adhesive label. Lithography integrates the brand better; a label allows shorter runs or a design change with lower start-up cost. The cap protects the actuator and completes the look of the product.
At the end of its life, an empty can goes into the metal packaging collection your local scheme runs: the European Aerosol Federation notes that aerosol cans are generally steel or aluminium, recyclable materials with market demand, and argues for including empty aerosols in packaging collection schemes. Aluminium and tinplate are both recovered as metal.
When you define the container for your product, send us the formula with your aerosol contract manufacturing project and Ilerspray's technical proposal will set the metal, format and finish.
