Manganese (3xxx, 8006)
Raises strength and stiffness without losing much ductility, so the tray holds its shape after filling and retorting.
Packaging material guide
Aluminium Foil for Pet Food Containers
Wet pet food trays are pressed from heavy-gauge container foil, usually 3003, 3004, 8011 or 8006, and sealed with a lacquered lidding foil. The foil must deep-draw without cracking, survive retort sterilisation at about 121 – 130 °C and keep a full barrier for a long shelf life. This guide covers alloy and temper choice, gauges, coatings and the food-contact standards tray makers should specify.
- Tray alloys
- 3003, 3004, 8011, 8006
- Lid alloys
- 8011, 8079, 5052, 3104
- Tray gauge
- About 0.045 – 0.12 mm
- Process
- Retort at about 121 – 130 °C
Why aluminium foil for pet food packaging?
Single-serve wet cat and dog food is commonly packed in small aluminium trays with a peelable foil lid. The tray maker presses container foil into shape, fills it, heat-seals the lid and sterilises the sealed pack in a retort. Aluminium is used because it is a complete barrier to light, oxygen, moisture and aroma, survives retorting, and is light and recyclable.
Compared with the alternatives, aluminium has clear advantages for this product. Plastic trays need multilayer barrier films to reach a similar shelf life, and they are harder to recycle. Glass and tinplate cans are heavier and need a can opener or ring-pull end. Paper-based packs need a barrier layer and are not usually suited to retorting. An aluminium tray opens easily, can be spooned from directly and goes into the aluminium recycling stream.
Metline supplies the aluminium container foil and lidding foil in coil and slit widths to tray and lid makers; the trays, lids and filled packs are produced by those manufacturers.
Typical foil specifications
| Use | Alloys | Tempers | Thickness | Width |
|---|---|---|---|---|
| Tray (container) foil | 3003, 3004, 8011, 8006 | O, H22, H24, H26 | About 0.045 – 0.12 mm | About 300 – 1600 mm |
| Lidding and sealing foil | 8011, 8079, 3104, 5052 | O, H24 (by lid design) | From about 0.035 mm | About 200 – 1960 mm |
Exact gauge depends on tray size and depth, whether the tray is wrinkle-wall or smooth-wall, and the stacking and retort loads. Smooth-wall trays with a flat flange, which give the best seal for retort packs, generally use the heavier end of the range and a ductile temper. Coil inner diameter, outer diameter and core material are agreed with the press line.
What to include in a foil specification
- Alloy and temper
- For example 8011-H24 or 3003-O
- Gauge and tolerance
- Nominal thickness with tolerance per EN 546-3 or the agreed limit
- Width and coil size
- Slit width, ID, maximum OD or coil weight
- Coating
- Inner food-contact lacquer, heat-seal layer, outer colour or print primer
- Surface
- Cleanliness (oil-free, wettability), no pinholes in critical gauges
- Certification
- EN 10204 3.1 certificate and food-contact declaration
Chemical composition of pet food container foil alloys (wt %)
Single values are maximums. Limits follow the Aluminum Association registrations used by EN 573-3 and ASTM B479.
| Element | 3003 | 3004 | 3104 | 5052 | 8011 | 8006 |
|---|---|---|---|---|---|---|
| Si | 0.60 | 0.30 | 0.60 | 0.25 | 0.50 – 0.90 | 0.40 |
| Fe | 0.70 | 0.70 | 0.80 | 0.40 | 0.60 – 1.0 | 1.2 – 2.0 |
| Cu | 0.05 – 0.20 | 0.25 | 0.05 – 0.25 | 0.10 | 0.10 | 0.30 |
| Mn | 1.0 – 1.5 | 1.0 – 1.5 | 0.8 – 1.4 | 0.10 | 0.20 | 0.30 – 1.0 |
| Mg | — | 0.8 – 1.3 | 0.8 – 1.3 | 2.2 – 2.8 | 0.05 | 0.10 |
| Cr | — | — | — | 0.15 – 0.35 | 0.05 | — |
| Zn | 0.10 | 0.25 | 0.25 | 0.10 | 0.10 | 0.10 |
| Ti | — | — | 0.10 | — | 0.08 | — |
| Others each / total | 0.05 / 0.15 | 0.05 / 0.15 | 0.05 / 0.15 | 0.05 / 0.15 | 0.05 / 0.15 | 0.05 / 0.15 |
| Al | Remainder | Remainder | Remainder | Remainder | Remainder | Remainder |
Iron and silicon (8xxx)
Form fine intermetallic particles that refine the grain, giving high elongation and good deep-drawing in thin gauges.
Magnesium (3004, 3104, 5052)
Adds strength for lids, stiff trays and easy-open features; 5052 also has excellent corrosion resistance.
Copper and chromium
Small additions increase strength after annealing and control recrystallisation and grain size.
Which alloy and temper to choose
| Alloy | Strengths | Typical use in pet food packs |
|---|---|---|
| 8011 | Fine grain, very good drawability, widely available | Standard tray foil and lidding foil |
| 8006 | Higher strength than 8011 with high elongation | Deeper or stiffer trays, thinner gauges for the same rigidity |
| 3003 | Good strength, formability and corrosion resistance | Rigid trays and smooth-wall containers |
| 3004 / 3104 | Higher strength from Mn and Mg | Stiff trays and lids that must resist deformation |
| 5052 | High strength, excellent corrosion resistance | Lids and easy-open components |
Soft O temper gives the deepest draw and the most uniform wall; it suits deep trays and complex shapes. H22 and H24 give a stiffer finished tray and better flange flatness, at the cost of some drawability. H26 is used where rigidity is the priority. The tray maker's tooling, draw depth and wall design decide the best combination, so trials on the actual tool are normal before a new gauge or temper is approved.
Lacquers, heat-seal layers and retort performance
Bare foil can be used for some dry products, but wet pet food trays are almost always lacquered. The internal lacquer protects the metal from salt, fats and acids in the food and provides the surface the lid seals to. Typical lacquer systems are epoxy-free or BPA-NI formulations, PP-compatible heat-seal lacquers for lids that seal to polypropylene-coated trays, and coloured or gold external lacquers for branding.
- Retort resistance: lacquers and seals must withstand sterilisation, commonly around 121 °C for 30 minutes and up to about 130 °C for some processes, without blushing, blistering or delamination
- Peel performance: the seal must stay intact through retorting, transport and storage yet open cleanly by hand
- Flexibility: lacquer must not crack during deep drawing of the tray wall and flange
- Food contact: coatings must comply with the migration limits of the market of sale
- Print: external lacquer must take multi-colour printing and resist scuffing on filling lines
Retort times and temperatures depend on the product and pack size and are set by the filler's thermal process validation, not by the foil supplier.
Standards and food-contact compliance
| Area | Reference |
|---|---|
| Foil properties and tolerances | EN 546-2 (mechanical properties), EN 546-3 (dimensional tolerances), ASTM B479 |
| Composition for food contact | EN 602 (aluminium for articles in contact with food), EN 573-3 |
| EU food-contact framework | Regulation (EC) No 1935/2004 and good manufacturing practice under (EC) No 2023/2006 |
| US food-contact coatings | FDA 21 CFR 175.300 (resinous and polymeric coatings) |
| Material certificate | EN 10204 3.1 with chemistry, gauge and mechanical results |
Pet food is regulated as food-contact packaging in most markets, so the same rules that apply to human food packaging normally apply. Ask for a declaration of compliance covering the lacquer system, and confirm migration testing with the coating supplier for your specific food simulants and retort conditions.
References and standards
- EN 546-2 – Aluminium and aluminium alloys: foil, mechanical properties
- EN 602 – Aluminium and aluminium alloys: wrought products, chemical composition of semi-products used for articles in contact with foodstuffs
- Regulation (EC) No 1935/2004 on materials and articles intended to come into contact with food
- ASTM B479 – Annealed Aluminum and Aluminum-Alloy Foil for Flexible Barrier, Food Contact, and Other Applications
- The Aluminum Association – International Alloy Designations and Chemical Composition Limits
Pet food container foil: frequently asked questions
Which aluminium alloy is used for pet food trays?
8011 and 3003 are the most common, with 8006 used where a stiffer tray or thinner gauge is wanted and 3004 for rigid trays. Lids are usually 8011 or 8079 foil, sometimes 3104 or 5052.
What thickness is pet food container foil?
Tray foil is typically about 0.045 – 0.12 mm, with deeper smooth-wall retort trays at the heavier end. Lidding foil starts from about 0.035 mm and is usually laminated or lacquered.
Can aluminium pet food trays be retorted?
Yes. Lacquered aluminium trays and lids are designed for retort sterilisation, typically around 121 °C and up to about 130 °C depending on the process and coating system.
Is aluminium foil safe for pet food contact?
Yes, when the alloy meets EN 602 or equivalent and the lacquer complies with food-contact rules such as EU Regulation 1935/2004 or FDA 21 CFR 175.300. Ask for a declaration of compliance.
What temper should I order for deep trays?
O temper gives the best drawability for deep trays. H22 or H24 gives a stiffer tray and flatter flange for shallower designs. Run trials on your tooling before approving a change.
Are aluminum pet food containers recyclable?
Yes. Aluminium can be recycled repeatedly without losing its properties, and empty, rinsed trays are accepted in many aluminium packaging collection schemes.
Need foil for pet food trays or lids?
Send the alloy, temper, gauge, width, coating and quantity. Our team will reply with a specification, certification and delivered price.
